KR20200077082A - Wireless power transmitter, wireless power receiver, method for modulating a backscatter signal of wireless power receiver and mhod for demodulating a backscatter signal of wireless power transmitter - Google Patents

Abstract

A backscatter signal modulation method according to an embodiment includes generating a symbol including a first bit and a second bit based on a data signal; And modulating the data signal by switching a rectifier based on the symbol, wherein modulating the data signal changes the load during a first half cycle by switching the rectifier based on the first bit, The rectifier is switched based on the second bit to change the load during the second half cycle.

Description

Wireless Power Receiver, Wireless Power Transmitter, Backscatter Signal Modulation Method of Wireless Power Transmitter and Backscatter Signal Demodulation Method of Wireless Power Transmitter A BACKSCATTER SIGNAL OF WIRELESS POWER TRANSMITTER}

Embodiments relate to a wireless power receiver, a wireless power transmitter, a method for modulating backscatter signals in a wireless power receiver, and a method for demodulating a backscatter signal in a wireless power transmitter.

With the recent rapid development of information and communication technology, a ubiquitous society based on information and communication technology has been formed.

In order for information communication devices to be accessed anytime, anywhere, sensors in a computer chip with a communication function must be installed in all social facilities.

Therefore, the problem of supplying power to these devices and sensors has become a new task. In addition, as the number of mobile devices, such as Bluetooth handsets and iPods, as well as mobile phones, has rapidly increased, charging the battery has required time and effort from users.

Current electromagnetic induction type wireless charging systems use in-band communication.

In particular, the wireless power transmission device periodically receives a feedback signal from the wireless power receiving device during charging, and performs power control based on the received feedback signal.

In the electromagnetic induction method, the wireless charging area of the wireless power transmission device may be defined as an area in which communication between wireless power transmission and reception devices is possible rather than intensity of power received by the wireless power reception device.

Therefore, demodulation performance of the wireless power transmission device is an essential element in maximizing the chargeable area.

In general, the wireless charging interruption occurs when the feedback signal generated by the wireless power receiving device is not normally demodulated in the wireless power transmitting device than when the intensity of the power received by the wireless power receiving device is less than the reference value. .

Therefore, the conventional wireless power transmission apparatus has a problem in that the demodulation performance is deteriorated and the wireless charging is stopped even though the strength of the power received by the wireless power reception apparatus is sufficient.

Embodiments provide a wireless power receiver, a wireless power transmitter, a method for modulating the backscatter signal of the wireless power receiver, and a method for demodulating the backscatter signal of the wireless power transmitter that can improve the data transmission speed.

In addition, in the embodiment, to provide a wireless power receiver, a wireless power transmitter, a backscatter signal modulation method of a wireless power receiver, and a backscatter signal demodulation method of a wireless power transmitter that can increase the amount of data that can be transmitted for a certain period of time. do.

The technical problems to be achieved in the embodiment are not limited to the technical problems mentioned above, and other technical problems that are not mentioned will be clearly understood by those skilled in the art from the following description. Will be able to.

A backscatter signal modulation method according to an embodiment includes generating a symbol including a first bit and a second bit based on a data signal; And modulating the data signal by switching a rectifier based on the symbol, wherein modulating the data signal changes the load during a first half cycle by switching the rectifier based on the first bit, The rectifier is switched based on the second bit to change the load during the second half cycle.

Further, the symbol is plural, and the switching of the rectifier during the first half cycle and the switching of the rectifier during the second half cycle are controlled by the first bit and the second bit included in one symbol.

Further, the rectifier is a half bridge rectifier or a full bridge rectifier.

In addition, the first half period is a section in which AC power having a positive polarity is input, and the second half period is a section in which AC power having a negative polarity is input.

Further, modulating the data signal includes modulating the data signal such that the amplitude of the AC power having the positive polarity and the amplitude of the AC power having the negative polarity are asymmetric.

In addition, a plurality of the first half period and the second half period alternately exist in one symbol period.

Meanwhile, a method for demodulating a backscatter signal according to an embodiment includes detecting a first modulation of a first voltage or a first current of a first switch group shorted during a first half cycle of a power signal; Detecting a second modulation of a second voltage or a second current of the second switch group shorted during the second half period of the power signal; Demodulating a first bit using the first modulation; And demodulating the second bit using the second modulation.

Further, the first modulation corresponds to the amplitude of the power signal changed during the first half period, and the second modulation corresponds to the amplitude of the power signal changed during the second half period.

Further, the first switch group is connected to one end of the wireless power transmission coil, and the second switch group is connected to the other end of the wireless power transmission coil.

In addition, in the first modulation, a difference in amplitude due to load switching during the first half cycle of the rectifier of the wireless power receiver is reflected, and in the second modulation, the amplitude due to load switching during the second half cycle of the rectifier The difference is reflected.

Meanwhile, the wireless power receiver according to the embodiment may include a receiving coil; A rectifier connected to the receiving coil; A switch coupled to the rectifier; And a control unit controlling the switch, wherein the rectifier comprises a first diode group rectifying AC power having positive polarity; And a second diode group rectifying AC power having negative polarity, the switch comprising: a first switch coupled with the first diode group; And a second switch coupled with the second diode group.

In addition, the control unit controls the first switch and the second switch so that the amplitude of the AC power having the positive polarity and the amplitude of the AC power having the negative polarity are asymmetric.

Further, the first switch and the second switch are composed of a MOSFET.

In addition, the first diode group may include: a first diode having an anode connected to one end of the receiving coil and a cathode connected to one end of the load; And a second diode having an anode connected to the other end of the load and a cathode connected to the other end of the receiving coil, wherein the first switch is connected in parallel with the first diode or the second diode.

In addition, a first capacitor is disposed between the first switch and the first diode or the second diode.

In addition, the second diode group may include a third diode having an anode connected to the other end of the receiving coil and a cathode connected to the other end of the load; And a fourth diode connected to one end of the load and a cathode connected to one end of the receiving coil, and the second switch is connected in parallel to the third diode or the fourth diode.

In addition, a second capacitor disposed between the second switch and the third diode or the fourth diode is further included.

Meanwhile, the wireless power receiver according to the embodiment may include a receiving coil; A rectifier connected to the receiving coil; A switch coupled to the rectifier; And a control unit controlling the switch, wherein the control unit generates a symbol including the first bit and the second bit based on the data signal, modulates the data signal by controlling the switch based on the symbol, and , The switch includes a first switch for changing the load during the first half cycle based on the first bit, and a second switch for changing the load during the second half cycle based on the second bit.

In addition, the rectifier is a bridge rectifier, the bridge rectifier includes first to fourth diodes, the first switch is connected to both ends of the second diode, and the second switch is connected to both ends of the first diode.

In addition, the control unit, the first half cycle, a section of AC power of a positive polarity is input, the second half cycle is a section of AC power of a negative polarity, the first switch is connected to the first The two diodes are disposed on a path in which AC power of negative polarity is rectified, and the first diode to which the second switch is connected is disposed on a path in which AC power of positive polarity is rectified.

On the other hand, the wireless power transmitter according to the embodiment includes a transmitting coil for transmitting an AC power signal; An inverter connected to the transmitting coil and including a first switch group and a second switch group; A sensor connected to the inverter; And a controller that controls the inverter, wherein the sensor detects a first modulation of a first voltage or a first current during a first half cycle of the AC power signal when the first switch group is in a short state, and the When the second switch group is in a short state, the second modulation of the second voltage or the second current during the second half cycle of the AC power signal is detected, and the controller controls the first switch group and the second switch group. Control the on/off, demodulate the first bit using the first modulation, and demodulate the second bit using the second modulation.

In addition, the first switch group and the second switch group are alternately short/open based on a half cycle.

In addition, the sensor includes a first sensor connected to the first switch group and a second sensor connected to the second switch group.

In addition, the first switch group switches the AC power signal so that the voltage of the transmitting coil is applied in the first direction, and the second switch group is the AC power signal so that the voltage of the transmitting coil is applied in the second direction. Switches.

In addition, the first modulation includes a bit signal of 0 or 1 according to an amplitude difference corresponding to the first direction of the voltage or current of the transmission coil, and the second modulation is the voltage or current of the voltage or current of the transmission coil. A bit signal of 0 or 1 is included according to the amplitude difference corresponding to the second direction.

In addition, the AC power signal is asymmetrically amplitude modulated in the first direction and the second direction by the wireless power receiver.

In addition, the first direction and the second direction are different polar directions.

In addition, the first switch group includes a first switch disposed between one end of the power supply line and the transmitting coil, and a second switch connected between one end of the transmitting coil and a ground line, and the second switch group includes the And a third switch disposed between the power supply line and the other end of the transmitting coil, and a fourth switch connected between the other end of the transmitting coil and the ground line, wherein the first sensor includes the DC power supply line and the first. It is disposed between the switches and the second sensor is disposed between the DC power supply line and the third switch.

The wireless power receiver in the embodiment transmits a first bit during a first half cycle in which AC power of positive polarity is received, and a second during a second half cycle in which AC power of negative polarity is received. Bit. The wireless power receiver in the embodiment modulates the data signal based on one symbol including the first bit and the second bit.

According to this, the wireless power receiver can transmit 2 bits of data in one symbol, so that the data transmission speed can be doubled compared to the prior art.

In addition, the wireless power receiver according to the embodiment may increase the amount of data transmitted over a period of time to twice that of the prior art.

In addition, the wireless power receiver in the embodiment maintains the symbol period (or data modulation rate) as it is even when the data transmission rate or the data transmission amount increases. Accordingly, in an embodiment, data accuracy may be improved by reducing a bit error rate (BER).

In addition, the wireless power receiver in the embodiment can prevent a situation in which power is continuously received in an abnormal state as the control error packet is transmitted to the wireless power transmitter at a faster time.

The wireless power transmitter in the embodiment may receive a feedback signal transmitted from the wireless power receiver in a faster time. According to this, the wireless power transmitter can transmit stable power to the wireless power receiver, thereby improving operational reliability.

In addition, the wireless power transmitter in the embodiment may improve demodulation performance for the feedback signal of in-band communication, thereby maximizing the chargeable area. In addition, the wireless power transmitter in the embodiment may minimize charging interruption due to deterioration of demodulation performance.

1 is a block diagram illustrating a wireless charging system according to an embodiment.
2 is a view for explaining a method for controlling power transmission on a wireless charging system according to an embodiment.
3 is a view for explaining the structure of a wireless power receiver according to an embodiment.
4 is a diagram more specifically illustrating the wireless power receiver illustrated in FIG. 3.
5 is a diagram illustrating a data format structure of a wireless power receiver according to an embodiment.
6 is a view for explaining the structure of a wireless power transmitter according to an embodiment.
7 is a view more specifically showing some configurations of a wireless power transmitter according to an embodiment.
8 is a diagram illustrating a modulation operation of a wireless power receiver according to a first symbol according to an embodiment.
9 is a diagram illustrating a modulation operation of a wireless power receiver according to a second symbol according to an embodiment.
10 is a diagram illustrating a modulation operation of a wireless power receiver according to a third symbol according to an embodiment.
11 is a diagram illustrating a modulation operation of a wireless power receiver according to a fourth symbol according to an embodiment.
12 is a view showing an equivalent circuit of a wireless power receiver according to a switching state of a rectifier according to an embodiment.
13 is a diagram showing demodulation data according to an embodiment.
14 is a diagram illustrating a wireless power receiver according to another embodiment.
15 is a diagram illustrating a wireless power receiver according to another embodiment.
16 is a diagram illustrating a wireless power receiver according to another embodiment.
17 is a diagram illustrating a wireless power receiver according to another embodiment.
18 is a flowchart illustrating step-by-step a method for modulating a backscatter signal of a wireless power receiver according to an embodiment.
19 is a flowchart illustrating step-by-step a method for demodulating a backscatter signal of a wireless power receiver according to an embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical spirit of the present invention is not limited to some embodiments described, but may be implemented in various different forms, and within the technical spirit scope of the present invention, one or more of its components between embodiments may be selectively selected. It can be used by bonding and substitution.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention, unless explicitly defined and described, can be generally understood by those skilled in the art to which the present invention pertains. It can be interpreted as a meaning, and terms that are commonly used, such as a dictionary-defined term, may interpret the meaning in consideration of the contextual meaning of the related technology. In addition, the terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention.

In the present specification, a singular form may also include a plural form unless specifically stated in the phrase, and is combined as A, B, C when described as "at least one (or more than one) of A and B, C". It can contain one or more of all possible combinations. In addition, in describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used.

These terms are only for distinguishing the component from other components, and the term is not limited to the nature, order, or order of the component. In addition, when a component is described as being'connected','coupled' or'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also to the component It may also include a case of'connected','coupled' or'connected' due to another component between the other components.

In addition, when described as being formed or disposed in the "top (top) or bottom (bottom)" of each component, the top (top) or bottom (bottom) is one as well as when the two components are in direct contact with each other. It also includes a case in which another component described above is formed or disposed between two components. In addition, when expressed as "up (up) or down (down)", it may include the meaning of the downward direction as well as the upward direction based on one component.

In the description of the embodiment, a device equipped with a function for transmitting wireless power on a wireless charging system includes a wireless power transmitter, a wireless power transmitter, a wireless power transmitter, a wireless power transmitter, a transmitter, a transmitter, and a transmitter for convenience of description. , The transmitting side, a wireless power transmission device, a wireless power transmitter, etc. will be used interchangeably.

In addition, a wireless power receiving device, a wireless power receiver, a wireless power receiving device, a wireless power receiver, a receiving terminal, a receiving side, for convenience of description as an expression of a device equipped with a function for receiving wireless power from a wireless power transmitting device A receiving device, a receiver, and the like can be used interchangeably.

The transmitter according to the present invention may be configured in a pad form, a cradle form, an AP (Access Point) form, a small base station form, a stand form, a ceiling buried form, a wall-mounted form, etc., and one transmitter may be connected to a plurality of wireless power receiving devices. You can also transmit power.

To this end, the transmitter may be provided with at least one wireless power transmission means. Here, as the wireless power transmission means, various radio power transmission standards based on an electromagnetic induction method that generates a magnetic field in the coil of the power transmitting end and charges it using the electromagnetic induction principle in which electricity is induced in the coil of the receiving end under the influence of the magnetic field may be used.

In addition, the receiver according to an embodiment of the present invention may be provided with at least one wireless power receiving means, and may simultaneously receive wireless power from two or more transmitters.

The receiver according to the embodiment is a mobile phone, a smart phone, a laptop computer, a terminal for digital broadcasting, PDA (Personal Digital Assistants), PMP (Portable Multimedia Player), navigation, MP3 player, electric It may be used in small electronic devices such as toothbrushes, electronic tags, lighting devices, remote controllers, fishing floats, wearable devices such as smart watches, but is not limited thereto, and if the device is equipped with a wireless power receiving means according to the present invention and is capable of battery charging Is enough.

1 is a block diagram illustrating a wireless charging system according to an embodiment.

Referring to FIG. 1, the wireless charging system includes a wireless power transmitter 10 that wirelessly transmits power, a wireless power receiver 20 that receives the transmitted power, and an electronic device 30 that receives the received power. Can be configured.

For example, the wireless power transmitting end 10 and the wireless power receiving end 20 may perform in-band communication for exchanging information using the same frequency band as the operating frequency used for wireless power transmission. As another example, the wireless power transmitting end 10 and the wireless power receiving end 20 perform out-of-band communication for exchanging information using a separate frequency band different from the operating frequency used for wireless power transmission. You can also do

For example, information exchanged between the wireless power transmission end 10 and the wireless power reception end 20 may include control information as well as status information of each other. Here, the state information and control information exchanged between the transmitting and receiving terminals will become clearer through the description of embodiments to be described later.

The in-band communication and the out-of-band communication may provide two-way communication, but are not limited thereto, and in other embodiments, one-way communication or half-duplex communication may be provided.

For example, the unidirectional communication may be that the wireless power receiving end 20 transmits information only to the wireless power transmitting end 10, but is not limited thereto, and the wireless power transmitting end 10 sends information to the wireless power receiving end 20. It may be to transmit.

In the half-duplex communication method, two-way communication between the wireless power receiving end 20 and the wireless power transmitting end 10 is possible, but there is a feature in that information can be transmitted by only one device at any one time.

The wireless power receiver 20 according to an embodiment may acquire various state information of the electronic device 30. For example, the status information of the electronic device 30 may include current power usage information, information for identifying a running application, CPU usage information, battery charge status information, battery output voltage/current information, etc., but is not limited thereto. If not, it is sufficient if the information can be obtained from the electronic device 30 and can be used for wireless power control.

Hereinafter, a power control loop on a wireless charging system will be described. 2 is a view for explaining a method for controlling power transmission on a wireless charging system according to an embodiment.

Referring to FIG. 2, the wireless power transmitter 300 may receive a feedback signal transmitted from the wireless power receiver 200 using in-band communication, and perform power control based on the received feedback signal. Here, the feedback signal may be a control error packet.

Referring to FIG. 2, the wireless power receiver 200 may receive AC power transmitted through the wireless power transmitter 300 (S201).

The wireless power receiver 200 may determine an actual control point based on the received power strength (S202 ).

Also, the wireless power receiver 200 may select a desired control point (S203).

Here, the request control point may be selected based on the type and power reception class of the corresponding wireless power receiver 200, but is not limited thereto, and the request control point is dynamic through a predetermined negotiation procedure with the wireless power transmitter 300. It may be selected as.

However, it should be noted that this is only an example, and the method of selecting the required control point may be different according to the design of a person skilled in the art.

The wireless power receiver 200 may calculate a control error value based on the determined actual control point and the selected request control point (S204).

The wireless power receiver 200 may generate a control error packet including a control error value and transmit it to the wireless power transmitter 300 (S205). To this end, the wireless power receiver 200 may change the load based on a control error packet including a control error value.

The wireless power transmitter 300 may receive an error packet transmitted through the wireless power receiver 200. For example, the wireless power transmitter 300 may demodulate a backcast signal transmitted through in-band communication to identify a control error value included in the control error packet.

The wireless power transmitter 300 may determine the actual transmit coil current by measuring the intensity of the current flowing through the transmit coil (S301).

The wireless power transmitter 300 may determine a new transmission coil current based on the control error value included in the control error packet and the determined actual transmission coil current (S302).

The wireless power transmitter 300 may control the actual transmit coil current to converge to the determined new transmit coil current (S303).

At this time, the wireless power transmitter 300 may determine a control method for adjusting the current flowing through the current transmission coil to the determined new transmission coil current. Here, the wireless power transmitter 300 may calculate a new operation point according to the determined control method.

The wireless power transmitter 300 may set the calculated new operation point (S2304).

The wireless power transmitter 300 may convert power according to the set new operation point and transmit it to the wireless power receiver 200 (S305).

In the above-described embodiment of FIG. 2, the control method for adjusting the current flowing through the current transmission coil to the determined new transmission coil current may be determined by at least one of the following four control methods.

1) A voltage control method that controls the DC voltage input to the inverter, that is, the inverter operating voltage.

2) Phase control method to control the phase of the pulse width modulated signal applied to the inverter

3) Duty control method for controlling the duty rate of the pulse width modulated signal applied to the inverter

4) Frequency control method to control the frequency of the reference signal input to the inverter, that is, the operating frequency.

The wireless power transmitter 300 according to the present embodiment can adjust the current flowing in the transmission coil by using any one of the four methods described above.

3 is a view for explaining the structure of a wireless power receiver according to an embodiment.

Referring to FIG. 3, the wireless power receiver 500 includes a receiving antenna 510, a rectifier 520, a DC/DC converter 530, a load 540, a sensing unit 550, and a communication unit 560, and a control unit 570. Here, the communication unit 560 may include at least one of a demodulation unit 562 and a modulation unit 561.

The wireless power receiver 500 illustrated in the example of FIG. 3 described above transmits a data signal to the wireless power transmitter through in-band communication.

Preferably, the wireless power receiver 500 transmits a data signal to the wireless power transmitter using orthogonal two channel inband communication. This may mean that a plurality of bits are included in one symbol and transmitted to the wireless power transmitter through two channels configured independently of each other. This will be described in more detail below.

In addition, the wireless power receiver supporting short-range communication may further include a wireless communication coil (not shown) and a short-range communication unit (not shown) for short-range communication (NFC communication).

The AC power received through the receiving antenna 510 may be transmitted to the rectifier 520. The rectifier 520 may convert AC power into DC power and transmit it to the DC/DC converter 530.

To this end, the receiving antenna 510 may include a receiving coil L2 and a receiving capacitor C2 receiving AC power through resonance with a transmitting antenna provided in the wireless power transmitter.

The DC/DC converter 530 may convert the intensity of DC power output from the rectifier 520 to a specific intensity required by the load 540. To this end, the DC/DC converter 530 may include a converter that receives DC power of the first intensity and converts it into DC power of the second intensity. For example, the DC/DC converter 530 may be configured as a buck converter, alternatively may be configured as a boost converter, or alternatively may be configured as a buck-boost converter. The DC power of the second intensity converted through the DC/DC converter 530 may be transmitted to the load 540.

The sensing unit 550 may measure the intensity of DC power output from the rectifier 520 and provide it to the control unit 570. In addition, the sensing unit 550 may measure the strength of the current applied to the receiving antenna 510 (more specifically, the receiving coil) as AC power is received, and transmit the measurement result to the control unit 570. In addition, the sensing unit 550 may measure the internal temperature of the wireless power receiver 500 and provide the measured temperature value to the control unit 570.

The control unit 570 controls the overall operation of the wireless power receiver 500.

That is, the control unit 570 may perform operations such as determining an actual control point, selecting a request control point, and calculating a control error value, as described in FIG. 2. Then, when the error control value is calculated, the control unit 570 may generate a control error packet based on the calculated error control value and transmit it to the wireless power transmitter.

To this end, the controller 570 may generate a symbol including the first bit and the second bit based on the data signal. Here, the data signal may include a control error packet corresponding to the calculated control error value. In addition, the symbol may be provided to the modulator 561 to transmit the data signal to the wireless power transmitter using load variation. Here, the symbol in the embodiment may include first to fourth symbols. The first symbol SB1 may be a case where both the first bit and the second bit are '0'. The second symbol SB2 may be a case where the first bit is '1' and the second bit is '0'. The third symbol SB3 may be a case where the first bit is '0' and the second bit is '1'. The fourth symbol SB4 may be a case where both the first bit and the second bit are '1'. Accordingly, the controller 570 generates any one of the first to fourth symbols SB1, SB2, SB3, and SB4 based on the data signal, and controls the modulator 561 based on this to control the rectifier 520 ).

For example, the control unit 570 may receive the intensity of the DC power output through the rectifier 520 from the sensing unit 550 and compare the intensity of the DC power with a predetermined reference value to determine whether an overvoltage occurs. have. In addition, when it is determined that an overvoltage has occurred, the control unit 570 may generate a symbol of a predetermined packet indicating that the overvoltage has occurred and transmit it to the modulator 561.

The modulator 561 may modulate a data signal to be transmitted to the wireless power transmitter by switching the rectifier 520 based on the symbol provided from the controller 570. At this time, a single symbol provided from the control unit 570 includes a plurality of bits. That is, in the embodiment, one symbol may be composed of 2 bits. Accordingly, the modulator 561 may modulate the data signal by changing the load based on the first bit and the second bit during one symbol period. The one symbol period may be a time taken to modulate a data signal corresponding to one symbol. That is, the one symbol period may be a switching period corresponding to the data modulation rate of the modulator 561.

In this case, one symbol period may include a first half period and a second half period. The first half cycle may be a section in which AC power having a positive polarity is received from the wireless power transmitter, and the second half cycle may be a section in which AC power having a negative polarity is received from the wireless power transmitter. This will be described in more detail below.

Meanwhile, the signal modulated by the modulator 561 may be transmitted to the wireless power transmitter through the receiving antenna 510 or a separate coil (not shown). In addition, the control unit 570 may determine that the detection signal has been received when the intensity of the DC power of the rectifier 520 is greater than or equal to a predetermined reference value, and when the detection signal is received, the signal strength indicator corresponding to the detection signal is the modulator 561 It can be controlled to be transmitted to the wireless power transmitter through. That is, the controller 570 may generate symbols including the first bit and the second bit corresponding to the signal strength indicator, and control the modulator 561 using the generated symbols.

As another example, the demodulator 562 demodulates an AC power signal between the receiving antenna 510 and the rectifier 520 or a DC power signal of the rectifier 520 to identify whether a detection signal is received, and then controls the identification result. 570. In this case, the controller 570 may control the signal strength indicator corresponding to the detection signal to be transmitted through the modulator 561.

4 is a diagram more specifically illustrating the wireless power receiver illustrated in FIG. 3. In FIG. 4, some of the components included in FIG. 3 are omitted to describe the configuration and operation of the modulator 561. That is, FIG. 4 is a view showing the receiving antenna 510, the rectifier 520, the load 540 and the modulator 561 in more detail.

Referring to FIG. 4, the wireless power receiver 500 includes a receiving coil L2 and a receiving capacitor C2 constituting the receiving antenna 510.

In addition, the wireless power receiver 500 includes first diode groups D1 and D4 and second diode groups D2 and D3 constituting the rectifier 520.

The first diode groups D1 and D4 are formed on the first path. The first path may be a rectification path of AC power of positive polarity for supplying power to the load 540.

That is, the first diode groups D1 and D4 may be located on a path through which AC power of positive polarity passes through when rectifying AC power having positive polarity. For example, AC power of positive polarity is rectified through the first diode D1 and the fourth diode D4 disposed on the first path.

The second diode groups D2 and D3 are formed on the second path. The second path may be a rectification path of AC power of negative polarity for supplying power to the load 540.

That is, the second diode groups D2 and D3 may be located on a path through AC power of negative (-) polarity when rectifying AC power having negative (-) polarity. For example, AC power of negative polarity is rectified through the second diode D2 and the third diode D3 disposed on the second path.

The modulator 561 includes a first switch S1. The first switch S1 may change the load by switching the rectifier 520 based on the first bit during a first half cycle in which AC power of positive polarity is input. At this time, the first switch S1 may change the load by changing the path of the AC power of positive polarity. That is, the first switch S1 may amplitude-modulate the AC power of the positive polarity by changing the path of the AC power of the positive polarity.

The first switch S1 may be connected to the second diode groups D2 and D3 in parallel. As illustrated in FIG. 3, the first switch S1 may be connected in parallel with the second diode D2 constituting the second diode groups D2 and D3. One end of the first switch S1 may be connected to the anode of the second diode D2. In addition, the other end of the first switch S1 may be connected to the cathode of the second diode D2 by switching based on the first bit provided from the control unit 570. That is, when the first switch S1 operates in the open (OPEN) state, the other end of the first switch S1 is not connected to the cathode of the second diode D2. In addition, when the first switch S1 operates in a short (SHORT) state, the other end of the first switch S1 may be connected to the cathode of the second diode D2. Accordingly, the first switch S1 allows the AC power of the positive polarity to flow in a path not including the load 540 in a section in which the AC power of the positive polarity is input. That is, the first switch S1 may change the impedance of the wireless power receiver seen by the wireless power transmitter during the first half cycle in which AC power of positive polarity is input.

When the first switch S1 is in the open (OPEN) state, AC power of positive polarity is rectified through the normal first path. At this time, the impedance of the wireless power receiver viewed from the wireless power transmitter may be the first impedance. The first impedance may be the impedance of the wireless power receiver viewed from the wireless power transmitter when the first switch S1 is in an open (OPEN) state.

When the first switch S1 is in the SHORT state, AC power of positive polarity is transmitted to a path that does not include the load 540. At this time, the impedance of the wireless power receiver viewed from the wireless power transmitter may be the second impedance. The second impedance may be the impedance of the wireless power receiver viewed from the wireless power transmitter when the first switch S1 is in the SHORT state. At this time, the absolute value of the first impedance is smaller than the absolute value of the second impedance. This is because the first impedance includes the load 540 in the equivalent circuit of the wireless power receiver seen in the wireless power transmitter, and the second impedance does not include the load 540 in the equivalent circuit of the wireless power receiver seen in the wireless power transmitter. to be. The first impedance and the second impedance will be described in more detail below.

Also, the modulator 561 includes a second switch S2. The second switch S2 may change the load by switching the rectifier 520 based on the second bit during the second half cycle in which AC power of negative polarity is input. At this time, the second switch S2 may change the load by changing the path of AC power of negative polarity. That is, the second switch S2 may amplitude-modulate AC power of negative polarity.

That is, the AC power is composed of AC power of positive (+) polarity and AC power of negative (-) polarity. Here, the positive (+) polarity and the negative (-) polarity may be phases of AC power. At this time, in the related art, AC power of positive (+) polarity and negative (-) polarity was not distinguished, and the amplitude was modulated in the same manner. In contrast, in the embodiment, the AC power of the positive polarity is amplitude-modulated based on the first bit during the first half cycle, and the AC power of the negative (-) polarity is based on the second bit during the second half cycle. Amplitude modulate. Accordingly, conventionally, the amplitudes of alternating current powers of positive (+) polarity and negative (-) polarity are mutually symmetric. On the other hand, in the embodiment, the amplitudes of the AC power having a positive (+) polarity and the amplitudes of the AC power having a negative (-) polarity may be asymmetric based on the first bit and the second bit.

The second switch S2 may be connected to the first diode groups D1 and D4 in parallel. As illustrated in FIG. 3, the second switch S2 may be connected in parallel to the first diode D1 constituting the first diode groups D1 and D4. One end of the second switch S2 may be connected to the cathode of the first diode D1. In addition, the other end of the second switch S2 may be connected to the anode of the first diode D1 by switching based on the second bit provided from the control unit 570. That is, when the second switch S2 operates in the open (OPEN) state, the other end of the second switch S2 is not connected to the anode of the first diode D1. In addition, when the second switch S2 operates in a short (SHORT) state, the other end of the second switch S2 may be connected to the anode of the first diode D1. Accordingly, in the section in which the AC power of the polarity of the negative (-) polarity is input, the second switch S2 flows so that the AC power of the negative (-) polarity flows in a path not including the load 540. do. That is, the second switch S2 changes the impedance of the wireless power receiver seen by the wireless power transmitter during the second half cycle in which AC power of negative polarity is input.

When the second switch S2 is in the open (OPEN) state, the alternating current of negative (-) polarity is rectified through a normal second path (path including the second diode group). At this time, the impedance of the wireless power receiver viewed from the wireless power transmitter may be the third impedance. The third impedance may be the impedance of the wireless power receiver viewed from the wireless power transmitter when the second switch S2 is in an open (OPEN) state.

When the second switch S2 is in a short (SHORT) state, AC power having a negative polarity is transmitted to a path not including the load 540. At this time, the impedance of the wireless power receiver viewed from the wireless power transmitter may be the fourth impedance. The fourth impedance may be the impedance of the wireless power receiver viewed by the wireless power transmitter when the second switch S2 is in the SHORT state. At this time, the absolute value of the third impedance is smaller than the absolute value of the fourth impedance. The third impedance and the fourth impedance will be described in more detail below.

The controller 570 generates any one of the first to fourth symbols based on the first bit and the second bit as shown in Table 1 below, and based on this, the first switch S1 and the second switch ( S2) can be controlled.

symbol Transmission data First switch state Second switch state First symbol (SB1) 0 OPEN (first half cycle) OPEN (first half cycle) 0 OPEN (2nd half cycle) OPEN (2nd half cycle) Second symbol (SB2) One SHORT (first half cycle) OPEN (first half cycle) 0 SHORT (2nd half cycle) OPEN (2nd half cycle) 3rd symbol (SB3) 0 OPEN (first half cycle) SHORT (first half cycle) One OPEN (2nd half cycle) SHORT (2nd half cycle) 4th symbol (SB4) One SHORT (first half cycle) SHORT (first half cycle) One SHORT (2nd half cycle) SHORT (2nd half cycle)

The control unit 590 may modulate the data signal by controlling the first switch S1 during the first half cycle in which AC power of positive polarity is input based on the first bit. For example, when the first bit is '0', the controller 590 opens (OPEN) the first switch S1, and when the first bit is '1', shorts the first switch S1. (SHORT). Then, on the wireless power transmitter side, the current or voltage applied to the inverter varies based on the switching state of the first switch S1. This is because, as described above, the impedance of the wireless power receiver seen in the wireless power transmitter varies according to the switching state of the first switch S1. This will be described in more detail below.

Also, the control unit 570 may modulate the data signal by controlling the second switch S2 during the second half period in which the negative polarity is input based on the second bit. For example, the control unit 570 opens the second switch S2 when the second bit is '0' (OPEN), and shorts the second switch S2 when the second bit is '1'. (SHORT). Then, on the wireless power transmitter side, the current or voltage applied to the inverter varies depending on the switching state of the second switch S2. This is because, as described above, the impedance of the wireless power receiver seen by the wireless power transmitter varies according to the state of the second switch S2. This will be described in more detail below.

The wireless power receiver in the embodiment transmits a first bit during a first half cycle in which AC power of positive polarity is received, and a second during a second half cycle in which AC power of negative polarity is received. Bit. The wireless power receiver in the embodiment modulates the data signal based on one symbol including the first bit and the second bit.

According to this, the wireless power receiver can transmit 2 bits of data in one symbol, so that the data transmission speed can be doubled compared to the prior art.

In addition, the wireless power receiver according to the embodiment may increase the amount of data transmitted over a period of time to twice that of the prior art.

In addition, the wireless power receiver in the embodiment maintains the symbol period (or data modulation rate) as it is even when the data transmission rate or the data transmission amount increases. Accordingly, in an embodiment, data accuracy may be improved by reducing a bit error rate (BER).

In addition, the wireless power receiver in the embodiment can prevent a situation in which power is continuously received in an abnormal state as the control error packet is transmitted to the wireless power transmitter at a faster time.

Meanwhile, the symbol period or data modulation rate may be a time taken to modulate a data signal corresponding to one symbol. For example, the data modulation rate may be 1KHz. The symbol period at this time may be a 1 ms time interval. Accordingly, the first switch S1 and the second switch S2 have a period of 1 ms time and can modulate a data signal corresponding to one symbol. That is, each of the first switch S1 and the second switch S2 maintains an open (OPEN) state or a short (SHORT) state for 1 ms time corresponding to a symbol period. In this case, while transmitting one symbol, the first half cycle and the second half cycle may be alternately repeated multiple times. This can be determined based on the operating frequency of the inverter constituting the wireless power transmitter.

For example, if the operating frequency of the inverter is 100KHz, the first switch group and the second switch group alternately operate at a period of 10 Hz. In addition, the first switch S1 and the second switch S2 may operate with a period of 1 ms time. That is, the switching cycle of the inverter may be 100 times faster than the switching cycle of the rectifier. Accordingly, in order to modulate the first bit and the second bit for one symbol, when the first switch S1 and the second switch S2 maintain a constant switching state, the inverter performs 100 switching alternating operations. Is done. Accordingly, 50 first half periods and 50 second half periods may be included in one symbol period for one symbol.

Meanwhile, the wireless power receiver according to the embodiment may transmit bit data to the wireless power transmitter using a 7 symbol serial format.

5 is a diagram illustrating a data format structure of a wireless power receiver according to an embodiment.

5, the data format transmitted from the wireless power receiver includes a start symbol, 4 data bits (So, S1, S2, and S3), a parity symbol, and a stop symbol can do.

As described above, in the embodiment, bit data may be transmitted during the first half period and the second half period of AC power, respectively, and thus data may be transmitted through two channels. In this case, the first channel may use a first half cycle of AC power, and the second channel may use a second half cycle of AC power.

In the data format structure, the start symbol is located at the front and may have a bit signal such as '00'. That is, the bit signal of the first channel corresponding to the start symbol may be '0', and the bit signal of the second channel may also be '0'.

And, in 4 data bits (So, S1, S2, S3), the first bit transmitted through the first channel-during the first half cycle-may be bo, b2, b4 and b6 in FIG. 5. That is, in 4 data bits, bo, b2, b4, and b6 may be transmitted through a load change during a first half period within one symbol period (t _CLK ). Also, in 4 data bits, b1, b3, b5, and b7 may be transmitted through the second channel-during the second half period.

The parity symbol may be composed of 2 bits. At this time, if there is an even number of '1' bit signals in the first bits transmitted through the first channel-during the first half cycle-the first bit signal of the parity symbol transmitted through the first channel is '1' In some embodiments, when an odd number of '1' bit signals exist, the first bit signal of the parity symbol transmitted through the first channel may be '0'.

In addition, when there is an even number of '1' bit signals in the first bits transmitted through the second channel-during the second half period-the 12th bit signal of the parity symbol transmitted through the second channel is '1'. When there is an odd number of '1' bit signals, the second bit signal of the parity symbol transmitted through the twelfth channel may be '0'.

Hereinafter, a wireless power transmitter will be described. In addition, the interaction relationship between the wireless power receiver and the wireless power transmitter will be described in detail.

6 is a view for explaining the structure of a wireless power transmitter according to an embodiment.

Referring to FIG. 6, the wireless power transmitter 700 includes a power conversion unit 710, a power transmission unit 720, a wireless charging communication unit 730, a control unit 740, a current sensor 750, and a temperature sensor 760. , It may be configured to include a storage unit 770, a fan 780, a timer 790, a short-range communication unit 701, a wireless communication coil 702. The configuration of the wireless power transmitter 700 is not necessarily an essential configuration, and may be configured to include more or less components.

As illustrated in FIG. 6, the power supply unit 600 may provide power. The power supply unit 600 may correspond to a battery built into the wireless power transmitter 700 or may be an external power supply. The embodiment is not limited to the form of the power supply unit 600.

The power converter 710 may perform a function of converting power to power of a predetermined intensity when power is supplied from the power unit 600.

To this end, the power conversion unit 710 may include a DC/DC conversion unit 711 and an amplifier 712.

The DC/DC conversion unit 711 may convert a DC power supplied from the power supply unit 600 into DC power of a specific intensity according to a control signal of the controller 740.

The amplifier 712 may adjust the intensity of the DC/DC converted power according to the control signal of the controller 740. For example, the control unit 740 may receive the power reception state information or the power control signal of the wireless power receiver through the wireless charging communication unit 730, and the amplifier 712 based on the received power reception state information or the power control signal. The amplification factor of can be dynamically adjusted. For example, the power reception state information may include intensity information of a rectifier output voltage, information of intensity of a current applied to the receiving coil, and the like, but is not limited thereto. The power control signal may include a signal for requesting power increase, a signal for requesting power reduction, and the like.

The current sensor 750 may measure an input current input to the driver 710. The current sensor 750 may provide the measured input current value to the controller 740. For example, the control unit 740 may adaptively cut off the supply of power from the power supply unit 600 or block power from being supplied to the amplifier 712 based on the input current value measured by the current sensor 750.

The temperature sensor 760 may measure the internal temperature of the wireless power transmitter 700 and provide the measurement result to the control unit 740. Specifically, the temperature sensor 760 may include one or more temperature sensors. One or more temperature sensors may be disposed to correspond to the transmission coil 732 of the power transmission unit 720 to measure the temperature of the transmission coil 732. For example, the controller 740 may adaptively cut off power supply from the power supply unit 600 or block power from being supplied to the amplifier 712 based on the temperature value measured by the temperature sensor 760. To this end, a predetermined power blocking circuit may be further provided on one side of the power conversion unit 710 to cut off power supplied from the power supply unit 600 or to cut off power supplied to the amplifier 712. As another example, the control unit 740 may adjust the intensity of power provided to the power transmission unit 720 based on the temperature value measured by the temperature sensor 760. Accordingly, the wireless power transmitter according to the embodiment can prevent the internal circuit from being damaged due to overheating.

The power transmission unit 720 transmits a signal output from the power conversion unit 710 to a wireless power receiver. To this end, the power transmission unit 720 may include a driving unit 721, a selection unit 722, and one or more transmission coils 732.

The driver 721 may generate an AC power signal in which an AC component having a specific frequency is inserted into the AC power signal output from the power converter 710 and transmit the AC power signal to the transmitting coil 732. At this time, the frequencies of the AC power signals transmitted to the plurality of transmission coils included in the transmission coil 732 may be the same or different from each other. Here, the driving unit 721 may also be referred to as an inverter. To this end, the driving unit 721 may include a first switch group and a second switch group. For example, the driving unit may include four switch elements.

Specifically, the driving unit 721 includes a first switch group that switches the AC power signal so that the voltage of the transmission coil is applied in the first direction, and a second switch that switches the AC power signal so that the voltage of the transmission coil is applied in the second direction. Switch groups.

The first switch group is shorted for a first half period to switch the AC signal so that the voltage of the transmitting coil is applied in the first direction. In addition, the second switch group may be shorted for a second half period to switch the AC signal so that the voltage of the transmitting coil is applied in the second direction. For example, the first switch group may be shorted for a first half cycle to generate an AC power signal having positive polarity. For example, the second switch group may be shorted for a second half cycle to generate an AC power signal having a negative polarity. At this time, the second switch group may be opened (OPEN) for the first half cycle, and the first switch group may be opened (OPEN) for the second half cycle.

That is, the first switch group and the second switch group are alternately shorted (SHORT) to change the direction of the voltage applied to the transmission coil. For example, the first switch group and the second switch group may generate an AC power signal having a positive polarity and an AC power signal having a negative polarity.

The selector 722 may receive an AC power signal having a specific frequency from the driver 721 and transfer the AC power signal to a selected transmission coil among a plurality of transmission coils. Here, the coil selector 722 may transmit the power signal to the transmission coil selected by the controller 740 according to a predetermined control signal of the controller 740. Here, the selector 722 may control the AC power signal to be transmitted to the coil selected by the controller 740 according to a predetermined control signal of the controller 740. More specifically, the selector 722 may include a switch (not shown) that connects the LC resonance circuit corresponding to the plurality of transmission coils 732. The selection unit 722 is not limited thereto, and may be excluded from the power transmission unit 720 when the transmission coil 732 is configured as one transmission coil.

The transmission coil 732 may include at least one transmission coil and may transmit an AC power signal received from the selector 722 to the receiver through the transmission coil. When there are a plurality of transmission coils, the plurality of transmission coils 732 may include first to nth transmission coils. The selector 722 may be implemented as a switch or a multiplexer in order to select “corresponding transmission coil” among a plurality of transmission coils. In addition, the transmitting coil 732 may include one capacitor (not shown) connected in series with a plurality of transmitting coils to implement the LC resonance circuit. The capacitor has one end connected to the transmitting coil 732 and the other end driving unit. It can be connected to (721). Here, the “corresponding transmission coil” may mean a transmission coil having a state that can be coupled by an electromagnetic field and a reception coil of a wireless power receiver that is qualified to receive power wirelessly. According to an embodiment of the present disclosure, the controller 740 dynamically uses a transmission coil to be used for wireless power transmission among a plurality of transmission coils provided based on a received signal strength indicator corresponding to a digital ping signal transmitted for each transmission coil. You can choose.

The control unit 740 may control the selector 722 or the multiplexer so that the detection signals may be sequentially transmitted through the first to nth transmission coils 732 during the first detection signal transmission procedure. At this time, the control unit 740 may identify when the detection signal is transmitted using the timer 790. When the detection signal transmission time arrives, the control unit 722 or a multiplexer is controlled to sense through a corresponding transmission coil. It can be controlled so that the signal can be transmitted. For example, the timer 790 may transmit a specific event signal to the controller 740 at a predetermined period during the ping transmission step, and when the event signal is detected, the controller 740 controls the selector 722 or multiplexer It is possible to control the digital ping to be transmitted through the transmission coil.

In particular, in the present embodiment, the control unit 740 includes a wireless power transmission control unit for controlling wireless power transmission, a wireless communication control unit for performing wireless communication, and a main control unit for controlling the wireless power transmission control unit and the wireless communication control unit. Can be. Specifically, the wireless communication controller according to the present embodiment may control a short-range communication module for performing short-range communication with the receiving device according to a receiving device that is tagged with the wireless power transmission device. Specifically, the wireless communication control unit may control to perform a user authentication and short-range communication application based on the identifier information received from the detected receiving device. In addition, the wireless power transmission control unit may perform overall control of the wireless charging mode operation. Specifically, the wireless power transmission control unit may execute a wireless power transmission operation according to the detected receiving device. In addition, an operation control signal of the wireless communication control unit or an operation control signal of the wireless power transmission control unit may be generated according to a sensing device sensed by controlling the operation of the wireless communication control unit and the wireless power transmission control unit. However, the present invention is not limited thereto, and the wireless power transmission control unit, the wireless communication control unit, and the main control unit may be configured as one control unit.

The modulator 731 modulates the control signal generated by the controller 740 and transmits the modulated signal to the driver 710. Here, the modulation method for modulating the control signal is FSK (Frequency Shift Keying) modulation method, Manchester Coding (Manchester Coding) modulation method, PSK (Phase Shift Keying) modulation method, Pulse Width Modulation (Pulse Width Modulation) method, differential 2 steps (Differential bi-phase) may include a modulation method, but is not limited thereto.

The demodulator 732 senses a current or voltage applied to the driver 721 and demodulates a data signal using the sensed current or voltage. The demodulated signal through the demodulator 732 may be transmitted to the controller 740. Here, the demodulated signal may include a signal strength indicator, an error correction (EC) indicator for power control during wireless power transmission, an end of charge (EOC) indicator, and an overvoltage/overcurrent/overheat indicator, It is not limited thereto, and various state information for identifying the state of the wireless power receiver may be included.

Also, the demodulator 732 may identify which transmit coil the demodulated signal is from, and may provide a predetermined transmit coil identifier corresponding to the identified transmit coil to the controller 740.

In particular, the demodulation unit 732 may include a sensor connected to the driving unit 721. At this time, the sensor may be a current sensor or, alternatively, a voltage sensor.

The demodulator 732 may include a first sensor connected to the first switch group of the driving unit 721 and a second sensor connected to the second switch group. At this time, the current or voltage detected by the first sensor and the second sensor changes according to the states of the first switch S1 and the second switch S2 of the wireless power receiver 500.

Accordingly, the first sensor of the demodulator 732 detects the first modulation of the first voltage or the first current during the first half cycle of the AC power signal when the first switch group is in the SHORT state. Can. The first modulation may correspond to a first bit included in one symbol transmitted by the wireless power receiver 500.

Also, the second sensor of the demodulator 732 may detect the second modulation of the second voltage or the second current during the second half cycle of the AC power signal when the second switch group is short (SHORT). . The second modulation may correspond to a second bit included in one symbol transmitted by the wireless power receiver 500.

Also, the demodulator 732 may transmit the detected first and second modulations to the controller 740. The control unit 740 may demodulate the first bit and the second bit using the first modulation and the second modulation, respectively. This will be described in more detail below.

Through this, the wireless power transmitter 700 may obtain the signal strength indicator through orthogonal 2-channel in-band communication according to an embodiment.

In addition, the wireless power transmitter 700 may not only transmit wireless power using the transmission coil 732, but also exchange various information with the wireless power receiver through the transmission coil 732. As another example, the wireless power transmitter 700 further includes a separate coil corresponding to each of the transmission coils, that is, the first to nth transmission coils, and the in-band wireless power receiver and the in-band by using the provided separate coils. Communication can also be performed.

The storage unit 770 includes the input current value of the wireless power transmitter according to the charging state of the wireless power receiver, the charging power strength, whether charging is stopped, the temperature of the wireless power transmitter to restart charging, the time after charging is stopped to restart charging, the fan Whether it works or not, fan RPM, etc. can be saved In particular, the storage unit 770 according to the present exemplary embodiment may store information on impedance change according to a receiving device sensed by the wireless power transmitter 700. For example, when a receiving device is detected in a wireless power transmitter, a reference value for a variable impedance may be stored. Also, the storage unit 770 may store information for detecting whether or not the receiver is detected by the wireless power transmitter. For example, the above-described impedance change amount, transmission speed information, and the like may be stored.

The fan 780 may be rotated by a motor to cool the overheated wireless power transmitter 700. The fan 780 may be disposed in correspondence with a configuration having severe overheating. For example, the fan 780 may be disposed corresponding to the power transmission unit 720. More specifically, the fan 780 may be disposed corresponding to the transmission coil 732 of the power transmission unit 720. The control unit 740 may operate the fan 780 according to the charging state of the wireless power receiver.

The short-range communication unit 701 may perform short-range two-way communication through a frequency band different from a frequency band used for wireless power signal transmission. For example, short-range two-way communication may be NFC (Near Field Communication). NFC is one of radio frequency identification (RFID) technologies, and is a wireless communication technology that exchanges various wireless data within a short distance of 10 cm using a frequency of 13.56 MGz.

The wireless communication coil 702 may transmit and receive signals used in short-distance bidirectional communication with the wireless power receiver.

Meanwhile, in the present embodiment, a configuration of a wireless power receiver including a short-range communication unit 701 and a wireless communication coil 702 has been described as an example, but is not limited thereto, and the wireless power receiver does not support short-range communication. The short-range communication unit and the wireless communication coil may be omitted.

7 is a view more specifically showing some configurations of a wireless power transmitter according to an embodiment.

Referring to FIG. 7, the wireless power transmitter 800 includes a full bridge inverter 810, an LC resonance circuit 820, a first sensor 830, a second sensor 840, a first comparator 850, and a second Comparator 860 may be included. Here, the full bridge inverter 810 may correspond to the driving unit 721 in FIG. 6. In addition, the first sensor 830, the second sensor 830, the first comparator 850, and the second comparator 850 may correspond to the demodulator 732 in FIG. Hereinafter, a bit data demodulation method according to an embodiment will be described in detail.

The full bridge inverter 810 may include first to fourth switching elements 811, 812, 813, and 814. The first to fourth switching elements 811, 812, 813, and 814 may be divided into a first switch group and a second switch group to generate an AC power signal, and operate alternately. That is, the first switch group includes the first switching elements 811 and Q1 and the fourth switching elements 814 and Q4. The second switch group includes second switching elements 812 and Q2 and third switching elements 813 and Q3.

The LC resonant circuit 820 may include transmission coils L1 and 821 connected in series and transmission capacitors C1 and 822.

Each of the first to fourth switching elements 811, 812, 813, and 814 may be applied with first switch control signals to fourth switch control signals SC_1 to SC_4, which are pulse width modulation signals for controlling the inverter switch. .

Here, the first switch control signal to the fourth switch control signal SC_1 to SC_4 may be pulse width modulation signals generated by the controller 740.

As shown in FIG. 7, one end of the LC resonant circuit 820 is connected between the first switching element 811 and the second switching element 812, and the other end is the second switching element 813 and the third switching It may be connected between the elements 814.

In this case, the amplitude modulated signal input to the demodulator 732 in FIG. 6 may include a signal flowing in the first switch group and a signal flowing in the second switch group. That is, the signal flowing in the first switch group may be a first current or a first voltage. In addition, the signal flowing in the second switch group may be a second current or a second voltage.

To this end, a first sensor 830 is connected to one end of the first switch group. Specifically, the first sensor 830 is connected to one end of the first switching element Q1.

In addition, a second sensor 840 is connected to one end of the second switch group. Specifically, the second sensor 840 is connected to one end of the third switching element Q3.

That is, the full bridge inverter 810 includes a first switching element Q1 disposed between the power supply line and one end of the transmission coils L1 and 821, and between one end of the transmission coils L1 and 821 and a ground line. A second switching element Q2 connected to the third switching element Q4 disposed between the power supply line and the other end of the transmitting coils L1 and 821, and the other end of the transmitting coils L1 and 821. And a fourth switching element Q4 connected between the ground lines,

The first sensor 830 is disposed between the DC power supply line and the first switching element Q1, and the second sensor 840 is the DC power supply line and the third switching element Q3. ).

The first sensor 830 detects the first voltage or the first current during the first half cycle when the first switch group is in the SHORT state.

Further, the second sensor 840 detects the second voltage or the second current during the second half cycle when the second switch group is in the SHORT state.

The first voltage or the first current may correspond to the amplitude of the power signal in the first direction changed during the first half cycle. Further, the second voltage or the second current may correspond to the amplitude of the power signal in the second direction changed during the second half period. The first direction and the second direction may be different polarity directions.

That is, the first voltage or the first current reflects a difference in amplitude due to load switching during the first half cycle of the rectifier 520 of the wireless power receiver 500, and the second voltage or the second current is the rectifier ( The difference in amplitude due to load switching during the second half cycle of 520) may be reflected.

In other words, the first voltage or the first current corresponds to the first modulation during the first half cycle of the rectifier 520 of the wireless power receiver 500, and the second voltage or the second current is the wireless power receiver 500 ) May correspond to the second modulation during the second half cycle of the rectifier 520.

In addition, the first modulation includes a first bit signal of '0' or '1' according to an amplitude difference corresponding to the first direction of the voltage or current of the transmission coil, and the second modulation is the transmission coil A second bit signal of '0' or '1' may be included according to an amplitude difference corresponding to the second direction of the voltage or current of.

The first comparator 850 is connected to the first sensor 830.

The first comparator 850 is provided with a first detection value V1 corresponding to the first voltage or first current detected through the first sensor 830 and can compare it with a preset reference value Vref. have. The first comparator 850 compares the reference value Vref and the first detection value V1. That is, the first comparator 850 may receive a reference value Vref through a positive terminal and a first detection value V1 through a negative terminal. Accordingly, the first comparator 850 may output a low level signal when the first detection value V1 is greater than the reference value Vref. Also, the first comparator 850 may output a high level signal when the first detection value V1 is smaller than the reference value Vref. In this case, the high level signal and the low level signal output through the first comparator 850 may be demodulated first bits. For example, the low level signal may be a bit signal of '0', and the high level signal may be a bit signal of '1'.

The second comparator 860 is connected to the second sensor 840.

The second comparator 860 is provided with a second detection value V2 corresponding to the second voltage or second current detected through the second sensor 840 and can compare it with a preset reference value Vref. have. The second comparator 860 compares the reference value Vref and the second detection value V2. That is, the second comparator 860 may receive a reference value Vref through a positive terminal and a second detection value V2 through a negative terminal. Accordingly, the second comparator 860 may output a low level signal when the second detection value V2 is greater than the reference value Vref. Also, the second comparator 860 may output a high level signal when the second detection value V2 is smaller than the reference value Vref. In this case, the high level signal and the low level signal output through the second comparator 860 may be demodulated second bits. For example, the low level signal may be a bit signal of '0', and the high level signal may be a bit signal of '1'.

As another example, in the above description, the first sensor and the second sensor are distinguished, and the first comparator and the second comparator are distinguished and connected to each switching group. However, it is composed of one sensor and one comparator, The timing may be divided to operate to sense each of the switching phases of each switching group.

Hereinafter, the modulation operation of the wireless power receiver 500 and the demodulation operation of the wireless power transmitter 800 will be described in more detail.

8 is a diagram illustrating a modulation operation of a wireless power receiver according to a first symbol according to an embodiment, FIG. 9 is a diagram illustrating a modulation operation of a wireless power receiver according to a second symbol according to an embodiment, FIG. 10 Is a diagram illustrating a modulation operation of a wireless power receiver according to a third symbol according to an embodiment, and FIG. 11 is a diagram illustrating a modulation operation of a wireless power receiver according to a fourth symbol according to an embodiment.

The full bridge inverter 810 of the wireless power transmitter 800 is switched to generate the AC power signal in the first direction during the first half cycle, and is switched to generate the AC power signal in the second direction during the second half cycle. That is, the first switching element Q1 and the fourth switching element Q4 are shorted during the first half period, and open during the second half period. Conversely, the second switching element Q2 and the third switching element Q3 are opened during the first half period, and shorted during the second half period. Accordingly, a voltage in a first direction may be applied to the transmission coils L1 and 821 during a first half period, and a voltage in a second direction opposite to the first direction may be applied during the second half period. Accordingly, the AC power signal of positive (+) polarity may be transmitted to the wireless power receiver 500 during the first half cycle, and the AC power signal of negative (−) polarity may be transmitted during the second half cycle.

Referring to FIG. 8, in the first symbol, both the first bit and the second bit may be '0'. Then, the wireless power receiver 500 may modulate the data signal corresponding to the first symbol by switching the rectifier 520 based on the first symbol. That is, both the first switch S1 and the second switch S2 may operate in an open state.

At this time, as shown in (a) of FIG. 8, during the first half cycle in which the AC power of positive polarity is received, the first switch S1 is opened, and thus the amount (+) through the first path ) Polarity of alternating current power can be transmitted. That is, during the first half period, rectification of AC power of positive polarity is performed through the first diode D1 and the fourth diode D4. Then, the rectified power is converted through a DC/DC converter 530 and supplied to the load 540. At this time, in the drawing, for convenience of explanation, the power that has passed through the first diode D1 is shown to be directly supplied to the load 540, but is substantially alternating through the first diode D1 and the fourth diode D4. The power is rectified to DC power, and thus DC power is supplied to the load.

Also, as shown in FIG. 8(b), since the second switch S2 is opened during the second half cycle in which AC power of negative polarity is received, the negative (- ) Polarity of alternating current power can be transmitted. That is, during the second half period, rectification of AC power of negative polarity is performed through the second diode D2 and the third diode D3. Then, the rectified power is converted through a DC/DC converter 530 and supplied to the load 540. At this time, in the drawing, for convenience of explanation, the power passed through the third diode D3 is shown to be directly supplied to the load 540, but is substantially alternating through the third diode D3 and the second diode D2. The power is rectified to DC power, and thus DC power is supplied to the load.

In conclusion, when both the first switch S1 and the second switch S1 operate in an open state based on the first symbol, power is supplied to the load 540, and accordingly, constant power is consumed from the load. Can. Accordingly, the load can be expressed as a resistance (R).

Referring to FIG. 9, in the second symbol, the first bit may be '1' and the second bit may be '0'. Then, the wireless power receiver 500 may modulate a data signal corresponding to the second symbol by switching the rectifier 520 based on the second symbol. That is, the first switch S1 may operate in a short (SHORT) state, and the second switch S2 may operate in an open (OPEN) state.

At this time, as shown in (a) of FIG. 9, during the first half cycle in which the AC power of positive (+) polarity is received, since the first switch S1 is in a short state, the third path AC power of positive polarity may be transmitted. That is, the AC power of the positive polarity may be transferred to the path including the first switch S1 and the fourth diode D4 during the first half cycle. That is, when the first switch S1 is in the open state, the current of the AC power received through the receiving antennas L2 and C2 flows toward the first diode D1.

At this time, when the first switch S1 is in a short state, the current of the AC power is a node to which the first switch S1 is connected (hereinafter referred to as'node 1') and a node to which a load is connected (hereinafter referred to as a'node'). 2'). At this time, the node 2 has a constant impedance greater than 0 due to the load, and the impedance of the node 1 becomes 0 due to the short state of the first switch S1. In addition, since the impedance in the node 1 direction becomes 0, the current of the received AC power flows only through the path including the first switch S1. Accordingly, when the first switch S1 is short-circuited, AC power of positive (+) polarity flows through a third path including the first switch S1 and the fourth diode D4, and the load 540 No power is supplied to the furnace.

In addition, as shown in FIG. 9(b), since the second switch S2 is opened during the second half-cycle in which AC power of negative polarity is received, the negative (- ) Polarity of alternating current power can be transmitted. That is, during the second half period, rectification of AC power of negative polarity is performed through the second diode D2 and the third diode D3. Then, the rectified power is converted through a DC/DC converter 530 and supplied to the load 540. At this time, in the drawing, for convenience of explanation, the power passed through the third diode D3 is shown to be directly supplied to the load 540, but is substantially alternating through the third diode D3 and the second diode D2. The power is rectified to DC power, and thus DC power is supplied to the load.

In conclusion, when the first switch S1 operates in a short state based on the second symbol and the second switch S1 operates in an open state, power is not supplied to the load 540 during the first half cycle. Power consumption does not occur, and power is supplied to the load 540 only during the second half cycle to generate power.

Referring to FIG. 10, in the third symbol, the first bit may be '0' and the second bit may be '1'. Then, the wireless power receiver 500 may modulate the data signal corresponding to the third symbol by switching the rectifier 520 based on the third symbol. That is, the first switch S1 may operate in an open (OPEN) state, and the second switch S2 may operate in a short state (SHORT).

At this time, as shown in (a) of FIG. 10, during the first half cycle in which the AC power of positive (+) polarity is received, the first switch (S1) is in an open state, and thus the amount (+) through the first path ) Polarity of alternating current power can be transmitted. That is, during the first half period, rectification of AC power of positive polarity is performed through the first diode D1 and the fourth diode D4. Then, the rectified power is converted through a DC/DC converter 530 and supplied to the load 540. At this time, in the drawing, for convenience of explanation, the power that has passed through the first diode D1 is shown to be directly supplied to the load 540, but is substantially alternating through the first diode D1 and the fourth diode D4. The power is rectified to DC power, and thus DC power is supplied to the load.

As shown in (b) of FIG. 10, during the second half cycle in which AC power of negative (-) polarity is received, the second switch S2 is in a short (SHORT) state. AC power of polarity of -) can be transmitted. That is, during the second half cycle, the AC power having the negative polarity may be transmitted to a path including the third diode D3 and the second switch S2. That is, when the second switch S2 is open, the current passing through the third diode D3 flows toward the load 540. At this time, when the second switch S2 is in a short state, since the impedance of the node connected to the second switch S2 becomes 0 as described above, the current passing through the third diode D3 is the second switch ( The current flows only through the path including 2). Accordingly, when the second switch S2 is shorted, AC power having a negative polarity flows in a fourth path including the third diode D3 and the second switch S2, and the load 540 No power is supplied to the furnace.

In conclusion, based on the third symbol, when the first switch S1 operates in an open state and the second switch S2 operates in a short state, power is supplied to the load 540 during the first half cycle to power Consumption occurs, and power is not generated because power is not supplied to the load 540 during the second half cycle.

Referring to FIG. 11, in the fourth symbol, the first bit may be '1' and the second bit may be '0'. Then, the wireless power receiver 500 may modulate a data signal corresponding to the fourth symbol by switching the rectifier 520 based on the fourth symbol. That is, both the first switch S1 and the second switch S2 may operate in a short (SHORT) state.

At this time, as shown in (a) of FIG. 11, during the first half cycle in which the AC power of positive (+) polarity is received, the first switch S1 is in a short (SHORT) state. AC power of positive polarity may be transmitted. That is, the AC power of the positive polarity may be transferred to the path including the first switch S1 and the fourth diode D4 during the first half cycle. That is, when the first switch S1 is in the open state, the current of the AC power received through the receiving antennas L2 and C2 flows toward the first diode D1. At this time, when the first switch S1 is in a short state, since the impedance of the node connected to the first switch S1 becomes 0 as described above, current flows only through the path including the first switch S1. . Accordingly, when the first switch S1 is short-circuited, AC power of positive (+) polarity flows through a third path including the first switch S1 and the fourth diode D4, and the load 540 No power is supplied to the furnace.

Also, as shown in FIG. 11B, during the second half-cycle in which AC power of negative polarity is received, the second switch S2 is in a short state, and thus, through the fourth path, AC power of negative polarity may be transmitted. That is, during the second half cycle, the AC power having the negative polarity may be transmitted to a path including the third diode D3 and the second switch S2. That is, when the second switch S2 is open, the current passing through the third diode D3 flows toward the load 540. At this time, when the second switch S2 is in a short state, since the impedance of the node connected to the second switch S2 becomes 0 as described above, the current passing through the third diode D3 is the second switch 2 ), only the current flows through the path. Accordingly, when the second switch S2 is short-circuited, AC power of negative polarity flows in a fourth path including the third diode D3 and the second switch S2, and the load 540 The furnace is not powered.

In conclusion, when both the first switch S1 and the second switch S2 operate in a short state based on the fourth symbol, power is not supplied to the load 540 during the first half cycle and the second half cycle, thereby powering No consumption occurs.

12 is a view showing an equivalent circuit of a wireless power receiver according to a switching state of a rectifier according to an embodiment.

12A illustrates an equivalent circuit of the wireless power receiver 500 seen from the first sensor 830 and the second sensor 840 in the open state of the first switch S1 or the second switch S2. It is shown.

When the first switch S1 is in the open state, the equivalent circuit seen when the first sensor 830 looks at the wireless power receiver during the first half cycle includes a load.

Similarly, when the second switch S2 is in an open state, a load is included in the equivalent circuit that is seen when the second sensor 840 looks at the wireless power receiver for the second half cycle.

12(b) illustrates an equivalent circuit of the wireless power receiver 500 seen from the first sensor 830 and the second sensor 840 in the short state of the first switch S1 or the second switch S2. It is shown.

When the first switch S1 is in a short state, the equivalent circuit seen when the first sensor 830 looks at the wireless power receiver during the first half cycle does not include a load.

Similarly, when the second switch S2 is in a short state, the equivalent circuit shown when the second sensor 840 looks at the wireless power receiver during the second half cycle does not include a load.

In addition, the impedance measured at the wireless power transmitter side according to the switching states of the first switch S1 and the second switch S2 may be as follows.

First, the impedance when the first switch S1 and the second switch are both open based on the first symbol is as follows.

)는 다음의 수학식 1과 같다.Impedance of the first sensor 830 when both the first switch S1 and the second switch are open (

) Is as shown in Equation 1 below.

Here, L1 is the inductance of the transmitting coil, L2 is the inductance of the receiving coil, C1 is the capacitance expressed when converting the transmitting capacitor into an equivalent circuit, C2 is the capacitance expressed when converting the receiving capacitor into an equivalent circuit, ω is the transmitting coil and the receiving coil When the resonance is resonant, K may be a coupling coefficient between a transmitting coil and a receiving coil, and R may mean a load impedance of the load wireless power receiver. For example, when the wireless power receiver is a mobile phone, the load may be a battery. And, when the battery is charged with a voltage of 5V and a current of 1A, the load impedance may be 5 Ω.

)는 다음의 수학식 1과 같다.In addition, the impedance of the second sensor 840 in the case where both the first switch S1 and the second switch are open (

) Is as shown in Equation 1 below.

In addition, the impedance when the first switch S1 is in a short state and the second switch is in an open state based on the second symbol is as follows.

)는 다음의 수학식 3과 같다.The impedance of the first sensor 830 when the first switch S1 is in a short state and the second switch S2 is in an open state (

) Is as in Equation 3 below.

)는 다음의 수학식 4과 같다.In addition, the impedance of the second sensor 840 when the first switch S1 is in a short state and the second switch S2 is in an open state (

) Is as shown in Equation 4 below.

In addition, the impedance when the first switch S1 is in the open state and the second switch is in the short state based on the third symbol is as follows.

)는 다음의 수학식 5와 같다.The impedance of the first sensor 830 when the first switch S1 is open and the second switch S2 is short (

) Is as in Equation 5 below.

)는 다음의 수학식 6과 같다.In addition, the impedance of the second sensor 840 when the first switch S1 is open and the second switch S2 is short (

) Is as in Equation 6 below.

In addition, the impedance when the first switch S1 and the second switch are both shorted based on the fourth symbol is as follows.

)는 다음의 수학식 7와 같다.The impedance of the first sensor 830 in the case where both the first switch S1 and the second switch S2 are in a short state (

) Is as in Equation 7 below.

)는 다음의 수학식 8과 같다.In addition, the impedance of the second sensor 840 when both the first switch S1 and the second switch S2 are in a short state (

) Is as in Equation 8 below.

In conclusion, the impedance of the wireless power receiver 500 seen from the first sensor 830 is determined by the state of the first switch S1, and the impedance of the wireless power receiver 500 seen from the second sensor 840 is It is determined by the state of the second switch S2.

Therefore, the impedance seen by the first sensor 830 during the first half cycle when the first switch S1 is open and the second sensor 840 during the second half cycle when the second switch is open The impedance may be as shown in Equation 9 below.

In addition, the impedance seen by the first sensor 830 during the first half cycle when the first switch S1 is in the short state and the second sensor 840 during the second half cycle when the second switch is in the short state The impedance may be equal to Equation 10 below.

That is, as shown in equations (9) and (10), the absolute value of Zopen appears smaller than the absolute value of Zshort. At this time, currents flowing through the first sensor 830 and the second sensor 830 are changed according to the impedance. In addition, since the absolute value of Zopen is smaller than the absolute value of Zshort, more current flows through the first sensor 830 and the second sensor 830 when it is Zopen than when it is Zshort.

That is, the current flowing through the first sensor 830 during the first half cycle when the first switch is open and the current flowing through the second sensor 840 during the second half cycle when the second switch is open are Iopen Can be In addition, the current flowing through the first sensor 830 during the first half cycle when the first switch is in the short state and the current flowing through the second sensor 840 during the second half cycle when the second switch is in the short state are Ishort. Can be

At this time, the relationship between Iopen and Ishort is as follows.

Iopen> Ishort

Accordingly, in an embodiment, the reference value Vref of the first comparator 850 and the second comparator 860 may be set as the reference value Vref using the intermediate value between Iopen and Ishort.

In conclusion, demodulation data according to the switching states of the first switch and the second switch of the wireless power receiver may be as shown in Table 2.

Wireless power receiver Wireless power transmitter symbol Switch status impedance electric current Comparator output Demodulation data First symbol (SB1) OPEN
(First switch) Zopen Iopen
(First sensor) Low
(1st comparator) 0 OPEN
(Second switch) Zopen Iopen
(Second sensor) Low
(2nd comparator) 0 Second symbol (SB2) OPEN
(First switch) Zshort Ishort
(First sensor) High
(1st comparator) One OPEN
(Second switch) Zopen Iopen
(Second sensor) Low
(2nd comparator) 0 3rd symbol (SB3) SHORT
(First switch) Zopen Iopen
(First sensor) Low
(1st comparator) 0 SHORT
(Second switch) Zshort Ishort
(Second sensor) High
(2nd comparator) One 4th symbol (SB4) SHORT
(First switch) Zshort Ishort
(First sensor) High
(1st comparator) One SHORT
(Second switch) Zshort Ishort
(Second sensor) High
(2nd comparator) One

13 is a diagram showing demodulation data according to an embodiment.

Referring to FIG. 13, one symbol 900 includes a first bit 910 and a second bit 920. Then, the wireless power transmitter may demodulate the first bit and the second bit included in each symbol according to the symbol period (T1 to T11).

At this time, as described above, the reference values Vref of the first comparator 850 and the second comparator 860 may be set with intermediate values of Iopen and Ishort.

In addition, each of the first comparator 850 and the second comparator 860 is high when a first detection value V1 or a second detection value V2 corresponding to an Ishort having a small reference value Vref is received. The level signal is output to demodulate the bit data of '1'. In addition, each of the first comparator 850 and the second comparator 860 is low when the first detection value V1 or the second detection value V2 corresponding to the Iopen having a large reference value Vref is received. Level signal is output so that '0 bit data is demodulated

The wireless power receiver in the embodiment transmits a first bit during a first half cycle in which AC power of positive polarity is received, and a second during a second half cycle in which AC power of negative polarity is received. Bit. The wireless power receiver in the embodiment modulates the data signal based on one symbol including the first bit and the second bit.

According to this, the wireless power receiver can transmit 2 bits of data in one symbol, so that the data transmission speed can be doubled compared to the prior art.

In addition, the wireless power receiver according to the embodiment may increase the amount of data transmitted over a period of time to twice that of the prior art.

In addition, the wireless power receiver in the embodiment maintains the symbol period (or data modulation rate) as it is even when the data transmission rate or the data transmission amount increases. Accordingly, in an embodiment, data accuracy may be improved by reducing a bit error rate (BER).

In addition, the wireless power receiver in the embodiment can prevent a situation in which power is continuously received in an abnormal state as the control error packet is transmitted to the wireless power transmitter at a faster time.

The wireless power transmitter in the embodiment may receive a feedback signal transmitted from the wireless power receiver in a faster time. According to this, the wireless power transmitter can transmit stable power to the wireless power receiver, thereby improving operational reliability.

In addition, the wireless power transmitter in the embodiment may improve demodulation performance for the feedback signal of in-band communication, thereby maximizing the chargeable area. In addition, the wireless power transmitter in the embodiment may minimize charging interruption due to deterioration of demodulation performance.

14 is a diagram illustrating a wireless power receiver according to another embodiment.

Referring to FIG. 14, the wireless power receiver 1100 may include a receiving antenna 1110, a rectifier 1120, a demodulator 1161, and a load 1140.

The rectifier 1120 may include first diode groups D1 and D4 and second diode groups D2 and D3. Since this has already been described in FIG. 6, detailed description is omitted.

The demodulator 1161 includes a first switch S1 connected in parallel with the second diode groups D2 and D3, and a second switch S2 connected in parallel with the first diode groups D1 and D4. do.

In this case, in FIG. 4, the first switch S1 is connected in parallel with the second diode D2, and the second switch S2 is connected in parallel with the first diode D1.

Alternatively, in another embodiment, in the wireless power receiver, the first switch S1 is connected in parallel with the third diode D3 among the second diode groups D2 and D3, and the second switch S2 is the first diode Among the groups D1 and D4, the fourth diode D4 may be connected in parallel.

15 is a diagram illustrating a wireless power receiver according to another embodiment.

Referring to FIG. 15, the wireless power receiver 1100A may include a receiving antenna 1110, a rectifier 1120, a demodulator 1161 and a load 1140.

The rectifier 1120 may include first diode groups D1 and D4 and second diode groups D2 and D3. Since this has already been described in FIG. 4, detailed description is omitted.

The demodulator 1161 includes a first switch S1 connected in parallel with the second diode groups D2 and D3, and a second switch S2 connected in parallel with the first diode groups D1 and D4. do.

At this time, in FIG. 14, the first switch S1 is connected in parallel with the third diode D3, and the second switch S2 is connected in parallel with the fourth diode D4.

Alternatively, in another embodiment, in the wireless power receiver, the first switch S1 is connected in parallel with the second diode D2 among the second diode groups D2 and D3, and the first switch S2 is the first. Among the diode groups D1 and D4, the fourth diode D4 may be connected in parallel.

In addition, differently, the first switch S1 may be connected in parallel with the third diode D3, and the second switch S2 may be connected in parallel with the second diode D2.

16 is a diagram illustrating a wireless power receiver according to another embodiment.

Referring to FIG. 16, the wireless power receiver 1200 may include a receiving antenna 1210, a rectifier 1220, a demodulator 1261, and a load 1240.

The rectifier 1220 may include first diode groups D1 and D4 and second diode groups D2 and D3.

At this time, in the previous embodiment, only the first switch S1 and the second switch S2 are included to switch the rectifier 1220. At this time, when the first switch S1 operates in a short state, power is not supplied to the load during the first half cycle. In addition, when the second switch S2 operates in a short state, power is not supplied to the load during the second half cycle.

Accordingly, in the embodiment of FIG. 16, while supplying power to the load, the first switch S1 and the second switch S2 can be shorted.

To this end, the wireless power receiver further includes a fourth capacitor C4 connected to the first switch S1 and a fifth capacitor C5 connected to the second switch S2.

One end of the fourth capacitor C4 is connected to one end of the first switch S1, and the other end of the fourth capacitor C4 is connected to the anode of the second diode D2.

One end of the fifth capacitor C5 is connected to one end of the second switch S2, and the other end of the fifth capacitor C5 is connected to the cathode of the first diode D1.

The fourth capacitor C4 causes a constant impedance to be generated in the direction of the first switch S1 while the first switch S1 is short-circuited. That is, according to the previous embodiment, when the first switch S1 is in a short operation, the impedance in the direction of the first switch S1 becomes 0, so that no power is supplied to the load. Accordingly, in the case where the first switch S1 is short-circuited, the fourth capacitor C4 has the impedance at the side of the first switch S1 having a constant value greater than zero.

At this time, if the fourth capacitor (C4) is included, even if the first switch (S1) is short, the impedance of the first switch (S1) side has a value greater than 0, which is the fourth capacitor (C4) It can be determined by the capacitance of. Accordingly, power may be distributed as much as the impedance formed by the fourth capacitor C4. Specifically, since a constant impedance is formed by the fourth capacitor C4, current distribution may be performed even when the first switch S1 is shorted based on the formed impedance. Will flow toward you. Accordingly, constant power may be supplied to the load even when the load is changed through the short of the first switch S1.

That is, in the drawing (a) of FIG. 9, when the fourth capacitor C4 is present, some current corresponding to the impedance formed by the fourth capacitor C4 flows in the direction of the first diode D1. Based on this, constant power can be supplied to the load.

The fifth capacitor C5 causes the constant impedance to be generated in the direction of the second switch S2 while the second switch S2 is short-circuited. That is, according to the previous embodiment, when the second switch S2 is short-circuited, power is not supplied to the load at all as the impedance in the direction of the second switch S2 becomes zero. Accordingly, in the case where the second switch S2 is short-circuited, the fifth capacitor C5 has the impedance at the side of the second switch S2 having a constant value greater than zero.

At this time, if the fifth capacitor (C5) is included, even if the second switch (S2) is short, the impedance of the second switch (S2) side has a value greater than 0, which is the fifth capacitor (C5) It can be determined by the capacitance of. Accordingly, power may be distributed as much as the impedance formed by the fifth capacitor C5. Specifically, since a constant impedance is formed by the fifth capacitor C5, current distribution may be performed even when the second switch S2 is shorted based on the formed impedance. Will flow toward you. Accordingly, even if the load is changed through the short of the second switch S2, constant power may be supplied to the load.

That is, in the drawing (b) of FIG. 10, when the fifth capacitor C5 is present, some current corresponding to the impedance formed by the fifth capacitor C5 flows in the direction of the second diode D2. Based on this, constant power can be supplied to the load.

In addition, when the fourth capacitor C4 and the fifth capacitor C5 are included, the reference of the first comparator and the second comparator is equal to the current distributed by the fourth capacitor C4 and the fifth capacitor C5. The value can be adjusted.

17 is a diagram illustrating a wireless power receiver according to another embodiment.

Referring to FIG. 17, the wireless power receiver 1300 may include a receiving antenna 1310, a rectifier 1320, a demodulator 1321 and a load 1340.

The rectifier 1320 may include first diode groups D1 and D4 and second diode groups D2 and D3. Since this has already been described in FIG. 6, detailed description is omitted.

In addition, the demodulator 1361 includes a first switch S1 connected in parallel with the second diode groups D2 and D3, and a second switch S2 connected in parallel with the first diode groups D1 and D4. do.

In this case, the first switch S1 may be connected in parallel with the second diode D2, and the second switch S2 may be connected in parallel with the first diode D1.

In addition, each of the first switch S1 and the second switch S2 may be formed of a MOSFET (Metal Oxide Semiconductor Field Effect transistor).

Meanwhile, the rectifier of the wireless power receiver is illustrated as being a full bridge rectifier, but is not limited thereto. That is, the rectifier of the wireless power receiver may be a half bridge rectifier. Accordingly, the first switch and the second switch may be connected to the two diodes constituting the half bridge rectifier in parallel.

18 is a flowchart illustrating step-by-step a method for modulating a backscatter signal of a wireless power receiver according to an embodiment.

Referring to FIG. 18, the wireless power receiver generates a symbol including the first bit and the second bit based on the data signal (S1410). That is, the symbol may include first to fourth symbols. The first symbol SB1 may be a case where both the first bit and the second bit are '0'. The second symbol SB2 may be a case where the first bit is '1' and the second bit is '0'. The third symbol SB3 may be a case where the first bit is '0' and the second bit is '1'. The fourth symbol SB4 may be a case where both the first bit and the second bit are '1'. Accordingly, the wireless power receiver may generate any one of the first to fourth symbols SB1, SB2, SB3, and SB4 based on the data signal.

Then, when the symbol is generated, the wireless power receiver changes the load during the first half cycle by switching the rectifier based on the first bit of the generated symbol (S1420). That is, the wireless power receiver switches the first switch S1 to a short state or an open state based on the first bit. When the first switch S1 is in the open state, the impedance of the wireless power receiver viewed from the first sensor of the wireless power transmitter has a first impedance, and in the short state, the second impedance is smaller than the first impedance.

The wireless power receiver changes the load during the second half cycle by switching the rectifier based on the second bit of the generated symbol (S1430). That is, the wireless power receiver switches the second switch S2 to a short state or an open state based on the second bit. When the second switch S2 is in the open state, the impedance of the wireless power receiver viewed from the second sensor of the wireless power transmitter has a first impedance, and in the short state, the second impedance is smaller than the first impedance.

That is, the rectifier switching during the first half cycle and the rectifier switching during the second half cycle may be controlled by the first bit and the second bit included in one symbol.

The wireless power receiver in the embodiment transmits a first bit during a first half cycle in which AC power of positive polarity is received, and a second during a second half cycle in which AC power of negative polarity is received. Bit. The wireless power receiver in the embodiment modulates the data signal based on one symbol including the first bit and the second bit.

According to this, the wireless power receiver can transmit 2 bits of data in one symbol, so that the data transmission speed can be doubled compared to the prior art.

In addition, the wireless power receiver according to the embodiment may increase the amount of data transmitted over a period of time to twice that of the prior art.

In addition, the wireless power receiver in the embodiment maintains the symbol period (or data modulation rate) as it is even when the data transmission rate or the data transmission amount increases. Accordingly, in an embodiment, data accuracy may be improved by reducing a bit error rate (BER).

In addition, the wireless power receiver in the embodiment can prevent a situation in which power is continuously received in an abnormal state as the control error packet is transmitted to the wireless power transmitter at a faster time.

19 is a flowchart illustrating step-by-step a method for demodulating a backscatter signal of a wireless power receiver according to an embodiment.

Referring to FIG. 19, the wireless power transmitter acquires a first detection value for a first voltage or a first current of a first switch group that is short-operated for a first half cycle of a power signal (S1510).

In addition, the wireless power transmitter may acquire a second detection value for the second voltage or the second current of the second switch group operating in a short period during the second half cycle (S1520).

Then, the wireless power transmitter compares the first detection value with the reference value, and demodulates the first bit according to the comparison result (S1530).

In addition, the wireless power transmitter compares the second detection value with the reference value, and demodulates the second bit according to the comparison result (S1540).

At this time, since the detailed contents of the demodulation method of the wireless power transmitter have already been described in FIGS. 8 to 14, detailed description thereof will be omitted.

The wireless power receiver in the embodiment transmits a first bit during a first half cycle in which AC power of positive polarity is received, and a second during a second half cycle in which AC power of negative polarity is received. Bit. The wireless power receiver in the embodiment modulates the data signal based on one symbol including the first bit and the second bit.

According to this, the wireless power receiver can transmit 2 bits of data in one symbol, so that the data transmission speed can be doubled compared to the prior art.

In addition, the wireless power receiver according to the embodiment may increase the amount of data transmitted over a period of time to twice that of the prior art.

In addition, the wireless power receiver in the embodiment maintains the symbol period (or data modulation rate) as it is even when the data transmission rate or the data transmission amount increases. Accordingly, in an embodiment, data accuracy may be improved by reducing a bit error rate (BER).

In addition, the wireless power receiver in the embodiment can prevent a situation in which power is continuously received in an abnormal state as the control error packet is transmitted to the wireless power transmitter at a faster time.

The wireless power transmitter in the embodiment may receive a feedback signal transmitted from the wireless power receiver in a faster time. According to this, the wireless power transmitter can transmit stable power to the wireless power receiver, thereby improving operational reliability.

In addition, the wireless power transmitter in the embodiment may improve demodulation performance for the feedback signal of in-band communication, thereby maximizing the chargeable area. In addition, the wireless power transmitter in the embodiment may minimize charging interruption due to deterioration of demodulation performance.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit and essential features of the present invention.

Accordingly, the above detailed description should not be construed as limiting in all respects, but should be considered illustrative. The scope of the invention should be determined by rational interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

Features, structures, effects, and the like described in the above-described embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, features, structures, effects, and the like exemplified in each embodiment may be combined or modified for other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Therefore, it should be interpreted that contents related to such combinations and modifications are included in the scope of the present invention.

In addition, although the embodiments have been mainly described above, these are merely examples and do not limit the present invention, and those skilled in the art to which the present invention pertains are exemplified above without departing from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be implemented by modification. And differences related to these modifications and applications should be construed as being included in the scope of the invention defined in the appended claims.

Claims (28)

Generating a symbol including the first bit and the second bit based on the data signal;
And modulating the data signal by switching a rectifier based on the symbol,
The step of modulating the data signal is
Switching the rectifier based on the first bit to change the load during the first half cycle,
Switching the rectifier based on the second bit to change the load during the second half cycle
Backscatter signal modulation method. According to claim 1,
A plurality of the symbols,
The rectifier switching during the first half cycle and the switching of the rectifier during the second half cycle are controlled by the first bit and the second bit included in one symbol.
Backscatter signal modulation method. According to claim 1,
The rectifier,
Half bridge rectifier or full bridge rectifier
Backscatter signal modulation method. According to claim 1,
The first half cycle,
It is a section where AC power having positive polarity is input,
The second half cycle,
This is the section where AC power with negative polarity is input.
Backscatter signal modulation method. According to claim 4,
The step of modulating the data signal is
And a step of modulating the data signal such that the amplitude of the AC power having the positive polarity and the amplitude of the AC power having the negative polarity are asymmetric.
Backscatter signal modulation method. According to claim 1,
The first half cycle and the second half cycle,
Multiples alternately within one symbol period
Backscatter signal modulation method. Detecting a first modulation of a first voltage or a first current of the first switch group shorted during the first half cycle of the power signal;
Detecting a second modulation of a second voltage or a second current of the second switch group shorted during the second half period of the power signal;
Demodulating a first bit using the first modulation; And
And demodulating the second bit using the second modulation.
Method for demodulating backscatter signal. The method of claim 7,
The first modulation,
Corresponds to the amplitude of the power signal changed during the first half cycle,
The second modulation,
Corresponding to the amplitude of the power signal changed during the second half cycle
Method for demodulating backscatter signal. The method of claim 7,
The first switch group is connected to one end of the wireless power transmission coil,
The second switch group is connected to the other end of the wireless power transmission coil
Method for demodulating backscatter signal. The method of claim 7,
The first modulation,
The difference in amplitude due to load switching during the first half cycle of the rectifier of the wireless power receiver is reflected,
The second modulation,
The difference in amplitude due to load switching during the second half cycle of the rectifier is reflected.
Method for demodulating backscatter signal. Receiving coil;
A rectifier connected to the receiving coil;
A switch coupled to the rectifier; And
It includes a control unit for controlling the switch,
The rectifier,
A first diode group for rectifying AC power having positive polarity; And
And a second diode group rectifying AC power having negative polarity,
The switch,
A first switch connected to the first diode group; And
And a second switch connected to the second diode group.
Wireless power receiver. The method of claim 11,
The control unit,
Controlling the first switch and the second switch so that the amplitude of the AC power having the positive polarity and the amplitude of the AC power having the negative polarity are asymmetrical
Wireless power receiver. The method of claim 11,
The first switch and the second switch,
Consisting of MOSFET
Wireless power receiver. The method of claim 11,
The first diode group,
A first diode having an anode connected to one end of the receiving coil and a cathode connected to one end of the load; And
An anode is connected to the other end of the load, and a second diode to which a cathode is connected to the other end of the receiving coil,
The first switch,
It is connected in parallel with the first diode or the second diode
Wireless power receiver. The method of claim 14,
And a first capacitor disposed between the first switch and the first diode or the second diode.
Wireless power receiver. The method of claim 11,
The second diode group,
A third diode having an anode connected to the other end of the receiving coil and a cathode connected to the other end of the load; And
And a fourth diode connected to one end of the load and a cathode connected to one end of the receiving coil,
The second switch,
It is connected in parallel with the third diode or the fourth diode
Wireless power receiver. The method of claim 16,
Further comprising a second capacitor disposed between the second switch and the third diode or the fourth diode
Wireless power receiver. Receiving coil;
A rectifier connected to the receiving coil;
A switch coupled to the rectifier; And
It includes a control unit for controlling the switch,
The control unit
Generate a symbol including the first bit and the second bit based on the data signal,
Modulating the data signal by controlling the switch based on the symbol,
The switch
A first switch for changing the load during the first half cycle based on the first bit, and
And a second switch for changing the load during the second half cycle based on the second bit.
Wireless power receiver. The method of claim 18,
The rectifier is a bridge rectifier,
The bridge rectifier includes first to fourth diodes,
The first switch is connected to both ends of the second diode,
The second switch is connected to both ends of the first diode
Wireless power receiver. The method of claim 19,
The control unit,
The first half cycle,
It is a section where AC power of positive polarity is input,
The second half cycle,
This is the section where AC power of negative polarity is input,
The second diode to which the first switch is connected,
It is arranged on a path in which AC power of negative polarity is rectified,
The first diode to which the second switch is connected,
A positive polarity alternating current is placed on the rectifying path.
Wireless power receiver. A transmitting coil that transmits an AC power signal;
An inverter connected to the transmitting coil and including a first switch group and a second switch group;
A sensor connected to the inverter; And
It includes a controller for controlling the inverter,
The sensor detects a first modulation of a first voltage or a first current during the first half cycle of the AC power signal when the first switch group is in a short state,
Detecting a second modulation of a second voltage or a second current during the second half cycle of the AC power signal when the second switch group is in a short state,
The control unit,
Control the on/off of the first switch group and the second switch group,
Demodulate the first bit using the first modulation,
Demodulating the second bit using the second modulation
Wireless power transmitter. The method of claim 21,
The first switch group and the second switch group are alternately short/open based on a half cycle
Wireless power transmitter. The method of claim 21,
The sensor,
And a first sensor connected to the first switch group and a second sensor connected to the second switch group.
Wireless power transmitter. The method of claim 21,
The first switch group
Switching the AC power signal so that a voltage of the transmitting coil is applied in a first direction,
The second switch group
Switching the AC power signal so that the voltage of the transmitting coil is applied in the second direction
Wireless power transmitter. The method of claim 21,
The first modulation
A bit signal of 0 or 1 is included according to an amplitude difference corresponding to the first direction of the voltage or current of the transmitting coil,
The second modulation
A bit signal of 0 or 1 is included according to an amplitude difference corresponding to the second direction of the voltage or current of the transmitting coil.
Wireless power transmitter. The method of claim 21,
The AC power signal is asymmetric amplitude modulated in the first direction and the second direction by the wireless power receiver
Wireless power transmitter. The method of claim 21,
The first direction and the second direction are different polar directions
Wireless power transmitter. The method of claim 23,
The first switch group
A first switch disposed between the power supply line and one end of the transmitting coil, and
A second switch connected between one end of the transmitting coil and a ground line,
The second switch group includes a third switch disposed between the power supply line and the other end of the transmission coil, and
And a fourth switch connected between the other end of the transmitting coil and the ground line,
The first sensor
Disposed between the DC power supply line and the first switch,
The second sensor
Disposed between the DC power supply line and the third switch
Wireless power transmitter.

Images