CN104638950A - AC to DC conversion device and method of operation thereof - Google Patents

Abstract

The invention provides an alternating current-direct current conversion device and an operation method thereof. The alternating current-direct current conversion device comprises a transformer, a first energy storage unit, a first output switch, a second energy storage unit, a second output switch and a secondary side control module. The transformer comprises a primary side winding and a secondary side winding. The first output switch is coupled between the secondary side winding and the first energy storage unit. The second output switch is coupled between the secondary side winding and the second energy storage unit. The secondary side control module monitors the first energy storage unit and the second energy storage unit and respectively determines the time length of the conduction period of the first output switch and the second output switch according to the monitoring result.

Description

AC to DC conversion device and method of operation thereof

technical field

The present invention relates to a power supply circuit, and in particular to an AC-DC conversion device and its operating method.

Background technique

Internal circuits of today's electronic devices often use a variety of DC voltages of different voltage levels, so an AC-DC converter is often provided in the electronic device to supply power to the internal circuits. The AC-DC converter can convert the mains power (alternating current) into direct current, so that the electronic device can obtain the required DC voltage for operation. FIG. 1 is a schematic circuit diagram of a known flyback converter (Flyback Converter). A known flyback converter includes a transformer 110 , a rectifier diode 131 and an output capacitor 132 . A first terminal and a second terminal of a secondary-side winding 112 of the transformer 110 are respectively coupled to the anode of the rectifier diode 131 and the reference voltage. Both ends of the output capacitor 132 are respectively coupled to the cathode of the rectifier diode 131 and the reference voltage.

The mains supply AC power to the rectifier 120 . The rectifier 120 converts the AC power into DC power and transmits it to the primary-side winding 111 of the transformer 110 . The control terminal of the transistor 140 is coupled to the control conduction circuit 150 . When the transistor 140 is turned on, the electric energy output by the rectifier 120 is stored in the primary winding 111 of the transformer 110 . When the transistor 140 is turned off, electric energy is transmitted from the primary winding 111 to the secondary winding 112 of the transformer 110 , so that the rectifier diode 131 conducts forward to charge the output capacitor 132 and generate a first output voltage at the first output terminal OUT_HV. The turn-on control circuit 150 can adjust the voltage level of the first output terminal OUT_HV by controlling the turn-on time of the transistor 140 , so as to optimize the voltage of the first output terminal OUT_HV.

However, if the same winding is to be used to generate multiple output voltages of different magnitudes, the known conversion circuit must be configured with a corresponding voltage converter to further convert the voltage of the first output terminal OUT_HV into other target voltages. For example, the flyback converter shown in FIG. 1 is configured to maintain the voltage of the first output terminal OUT_HV at A volts. The converter 160 (such as Boost converter) can boost the voltage of the first output terminal OUT_HV to B volts to supply power to the second output terminal OUT_LED. However, the extra converter 160 not only increases the cost, but also reduces the conversion efficiency. Furthermore, the known flyback converter shown in FIG. 1 can only optimize the voltage of the first output terminal OUT_HV, but cannot simultaneously optimize the first output voltage of the first output terminal OUT_HV and the voltage of the second output terminal OUT_LED. The second output voltage is optimized.

The above are all unsatisfactory parts of the existing technology, and it is necessary to further review and seek a feasible solution.

Contents of the invention

The present invention provides an AC-DC conversion device and an operation method thereof, which can generate multiple output voltages of different magnitudes by using the same winding.

An embodiment of the present invention provides an AC/DC conversion device, including a transformer, a first energy storage unit, a first output switch, a second energy storage unit, a second output switch, and a secondary side control module. The transformer includes at least one primary-side winding and at least one secondary-side winding. The first terminal and the second terminal of the first output switch are respectively coupled to the first energy storage unit and the first terminal of the secondary winding. A first end and a second end of the second output switch are respectively coupled to the second energy storage unit and the first end of the secondary winding. The secondary side control module is coupled to the first energy storage unit to monitor a first electrical characteristic of the first energy storage unit, and is coupled to the second energy storage unit to monitor a second electrical characteristic of the second energy storage unit. The secondary-side control module correspondingly determines the duration of the conduction period of the first output switch according to the monitoring result of the first electrical characteristic, and correspondingly determines according to the monitoring result of the second electrical characteristic The time of the conduction period of the second output switch is long.

An embodiment of the present invention provides an operation method of an AC-DC conversion device, including the following steps. A transformer is configured on the AC/DC conversion device, wherein the transformer includes at least one primary winding and at least one secondary winding. A first energy storage unit and a first output switch are configured in the AC-DC conversion device, wherein the first end and the second end of the first output switch are respectively coupled to the first end of the secondary winding and the first energy storage unit. A second energy storage unit and a second output switch are configured in the AC-DC conversion device, wherein the first end and the second end of the second output switch are respectively coupled to the second energy storage unit and the first end of the secondary winding. During the conduction period of the first output switch, the electric energy stored in the transformer is transmitted to the first energy storage unit, and the first electrical characteristic of the first energy storage unit is monitored, and a corresponding decision is made according to the monitoring result of the first electrical characteristic The length of time during which the first output switch is on. During the conduction period of the second output switch, the electric energy stored in the transformer is transmitted to the second energy storage unit, and the second electrical characteristic of the second energy storage unit is monitored, and a corresponding decision is made according to the monitoring result of the second electrical characteristic The length of time during which the second output switch is on.

Based on the above, the present invention provides an AC-DC conversion device and its operating method. The AC-DC conversion device uses a secondary-side control module to monitor the first energy storage unit and the second energy storage unit, and determines the first output switch according to the monitoring results. and the length of the conduction time of the second output switch, so only the same secondary side winding of the transformer can be used to generate multiple sets of output voltages that can be optimized and precisely adjusted without configuring additional voltage converters.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail together with the accompanying drawings.

Description of drawings

FIG. 1 is a schematic diagram of an existing AC-DC converter.

FIG. 2 is a schematic diagram of an AC-DC conversion device according to an exemplary embodiment of the present invention.

FIG. 3 is a flowchart illustrating an operation method of an AC/DC conversion device according to an exemplary embodiment of the present invention.

FIG. 4 is a schematic diagram of a first embodiment of the AC-DC conversion device shown in FIG. 2 .

FIG. 5 is a waveform diagram according to the first embodiment of the present invention.

FIG. 6 is a schematic diagram of a second embodiment of the AC-DC conversion device shown in FIG. 2 .

FIG. 7 is a schematic diagram of a third embodiment of the AC-DC converting device shown in FIG. 2 .

FIG. 8 is a schematic diagram of a fourth embodiment of the AC-DC converting device shown in FIG. 2 .

[Description of labels]

Detailed ways

Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The term "coupling" used throughout the specification of this case (including the scope of claims) may refer to any direct or indirect means of connection. For example, if it is described that a first device is coupled to a second device, it should be interpreted that the first device can be directly connected to the second device, or the first device can be connected through other devices or some kind of connection means. indirectly connected to the second device. In addition, wherever possible, elements/components/steps using the same reference numerals in the drawings and embodiments represent the same or similar parts. Elements/components/steps using the same symbols or using the same terms in different embodiments can refer to related descriptions.

FIG. 2 is a schematic diagram of an AC-DC conversion device 20 according to an exemplary embodiment of the present invention. The AC-DC conversion device 20 is coupled between the AC power source 30 and the loads 41 , 42 . The AC-DC conversion device 20 includes a transformer T1 , an energy storage unit 220 , an output switch 230 , an energy storage unit 240 and an output switch 250 . In this exemplary embodiment, the topology of the AC-DC conversion device 20 may be a flyback power conversion topology, but is not limited thereto.

The transformer T1 includes at least one primary winding 211 and at least one secondary winding 212 . In this exemplary embodiment, the power of the AC power source 30 is transmitted to the primary winding 211 of the transformer T1 through the primary circuit 270 . A first terminal of the output switch 230 is coupled to the energy storage unit 220 , and a second terminal of the output switch 230 is coupled to the first terminal of the secondary winding 212 . A first end of the output switch 250 is coupled to the energy storage unit 240 , and a second end of the output switch 250 is coupled to the first end of the secondary winding 212 . In this exemplary embodiment, the first end and the second end of the primary side winding 211 are respectively a common-polarity terminal (ie a dotted end) and an opposite-polarity terminal (ie an undotted end), The first end and the second end of the secondary side winding 212 are the opposite end and the same end respectively.

The secondary side control module 260 is coupled to the energy storage unit 220 to monitor an electrical characteristic of the energy storage unit 220 , and is coupled to the energy storage unit 240 to monitor an electrical characteristic of the energy storage unit 240 . In this exemplary embodiment, the electrical characteristic of the energy storage unit 220 may be the voltage difference between the energy storage unit 220 and the secondary side reference voltage (such as the secondary side ground voltage), and the electrical characteristic of the energy storage unit 240 may be The voltage difference between the energy storage unit 240 and the secondary side reference voltage is not limited thereto. The secondary-side control module 260 determines the duration of the conduction period of the output switch 230 according to the monitoring result of the electrical characteristics of the energy storage unit 220 , and according to the electrical characteristics of the energy storage unit 240 The time length of the conduction period of the output switch 250 is correspondingly determined according to the monitoring result of the output switch 250 .

FIG. 3 is a flowchart illustrating an operation method of the AC-DC conversion device 20 shown in FIG. 2 according to an exemplary embodiment of the present invention. Please refer to FIG. 2 and FIG. 3 at the same time. During the conduction period of the output switch 230, the electric energy stored in the transformer T1 is transmitted to the energy storage unit 220, and the secondary side control module 260 monitors the electrical characteristics of the energy storage unit 220 (step S310). The electrical characteristic of the energy storage unit 220 here may be the voltage, current or other electrical characteristics of the energy storage unit 220 , but is not limited thereto. Therefore, the energy storage unit 220 can supply power to the load 41 . In step S312 , the secondary-side control module 260 determines the duration of the conduction period of the output switch 230 according to the monitoring result of the electrical characteristics of the energy storage unit 220 . Therefore, the AC-DC conversion device 20 can generate an optimized and precise output voltage to the load 41 .

During the turn-on period of the output switch 250 , the electric energy stored in the transformer T1 is transmitted to the energy storage unit 240 , and the secondary side control module 260 monitors the electrical characteristics of the energy storage unit 240 of the energy storage unit 240 (step S314 ). The electrical characteristics of the energy storage unit 240 here may refer to voltage, current or other electrical characteristics on the energy storage unit 240 , but is not limited thereto. Therefore, the energy storage unit 240 can supply power to the load 42 . According to design requirements of actual products, the conduction period of the output switch 230 and the conduction period of the output switch 250 may partially overlap or may not overlap each other. In step S316 , the secondary-side control module 260 determines the duration of the conduction period of the output switch 250 according to the monitoring result of the electrical characteristics of the energy storage unit 240 . Therefore, the AC-DC conversion device 20 can generate an optimized and precise output voltage to the load 42 .

To sum up, the AC-DC conversion device 20 and its operation method described in this embodiment utilize the concept of energy distribution, first store electrical energy in the primary side winding 211 of the transformer T1, and then distribute the electrical energy stored in the transformer T1 sequentially Multiple outputs to the AC-DC conversion device 20 . For example, the output switch 230 is turned on so that the electric energy stored in the transformer T1 can be distributed to the energy storage unit 220 and the load 41 . In this embodiment, the secondary side control module 260 is used to monitor the electrical characteristics (such as voltage) of the energy storage unit 220 and the energy storage unit 240 , and correspondingly control the on-time length of the output switch 230 and the output switch 250 according to the monitoring result. For example, when the electric energy distributed to the energy storage unit 220 reaches a preset value, the secondary side control module 260 closes the output switch 230 and turns on the output switch 250 so that the electric energy stored in the transformer T1 can be used for the next The group power supply circuit (the energy storage unit 240 and the load 42 ) supplements electric energy. Therefore, the AC-DC conversion device 20 can generate multiple sets of individually optimized and precisely adjusted output voltages only by using the same secondary winding 212 of the transformer T1 , without additional voltage converters.

FIG. 4 is a schematic diagram illustrating a first embodiment of the AC-DC conversion device 20 shown in FIG. 2 according to an embodiment of the present invention. The AC-DC conversion device 20 is coupled between the AC power source 30 and the loads 41 , 42 , 43 . The load 42 is, for example, a string of light emitting diodes. In this embodiment, the secondary side control module 260 may include a sensor signal conditioner (Sensor Signal Conditioner) integrated circuit 261 and a comparator OP1, but is not limited thereto, and may also be an error amplifier (Error Amplifier) in other embodiments ) or other feedback adjustment forms that can judge the output voltage. The output terminal of the comparator OP1 is coupled to the signal sensing and adjusting integrated circuit 261 , and the signal sensing and adjusting integrated circuit 261 is coupled to the observation point Sync.

In this embodiment, the energy storage unit 220 is a capacitor C1 as an example, and the output switch 230 may be a transistor, a transmission gate or other types of switches, but is not limited thereto. The first end of the output switch 230 is coupled to the first end of the secondary winding 212 . The second terminal of the output switch 230 is coupled to the first terminal of the capacitor C1 , and the control terminal of the output switch 230 is coupled to the signal sensing and regulating integrated circuit 261 of the secondary side control module 260 . The second end of the capacitor C1 is coupled to a secondary reference voltage (such as a secondary ground voltage or other fixed voltage). The energy storage unit 240 in this embodiment takes the capacitor C2 as an example, and the output switch 250 may be a transistor, a pass gate or other types of switches, but is not limited thereto. The first terminal and the second terminal of the output switch 250 are respectively coupled to the first terminal of the secondary side winding 212 and the first terminal of the capacitor C2, and the control terminal of the output switch 250 is coupled to the signal sensor of the secondary side control module 260 regulation integrated circuit 261 . The second end of the capacitor C2 is coupled to the secondary side reference voltage. In this embodiment, the number of the secondary side winding 212 is one, but not limited thereto, and the number of the secondary side winding 212 may also be multiple.

The AC-DC conversion device 20 in this embodiment further includes a synchronous rectification unit 281 , an energy storage unit 282 and an output switch 283 . In this embodiment, the capacitor C3 is used as an example for the energy storage unit 282 , and the output switch 283 may be a transistor, a pass gate or other types of switches, but is not limited thereto. The first terminal of the output switch 283 is coupled to the first terminal of the secondary side winding 212, the second terminal of the output switch 283 is coupled to the first terminal of the capacitor C3, and the second terminal of the capacitor C3 is referenced to the secondary side. voltage coupling. The synchronous rectification unit 281 includes a synchronous rectification switch in this embodiment, and the synchronous rectification switch is a transistor Q1 in this embodiment, but is not limited thereto. The first terminal and the second terminal of the transistor Q1 are respectively coupled to the second terminal of the secondary side winding 212 and the secondary side reference voltage (such as the secondary side ground voltage or other fixed voltages), and the control terminal (gate pole) is coupled to the signal sensing and conditioning integrated circuit 261 of the secondary side control module 260 . In this embodiment, the signal sensing and regulating integrated circuit 261 of the secondary side control module 260 is coupled to the second end of the secondary side winding 212 (ie, the observation point Sync) to monitor a voltage characteristic, wherein the secondary side control module 260 The conducting state of the output switch 230 , the output switch 250 and/or the output switch 283 is correspondingly controlled according to the monitoring result of the voltage characteristic.

In this embodiment, the energy storage unit 240 supplies power to a current path of the load 42 , and the AC-DC conversion device 20 further includes a current detector 284 . The current detector 284 is disposed in the current path of the load 42 to detect the current of the load 42 and output a current detection result to the secondary side control module 260 . Current detector 284 is in series with load 42 in this embodiment. The first non-inverting input terminal of the comparator OP1 of the secondary side control module 260 is coupled to the current detector 284 to receive the current detection result. The inverting input terminal of the comparator OP1 receives the reference voltage Vref. The comparator OP1 can compare the current detection result output by the current detector 284 with the reference voltage Vref, and transmit the comparison result to the signal sensing and regulating integrated circuit 261 . The signal sensing and adjusting integrated circuit 261 can correspondingly adjust the duration of the conduction period of the output switch 250 according to the relationship between the current detection result output by the current detector 284 and the reference voltage Vref. Therefore, the secondary-side control module 260 can correspondingly control and determine the conduction time length of the output switch 250 according to the current detection result (ie, the monitoring result of the electrical characteristic of the energy storage unit 240 ). Accordingly, the AC-DC converting device 20 can optimize the output electric energy of the energy storage unit 240 .

The first terminal of the energy storage unit 220 is coupled to the second non-inverting input terminal of the comparator OP1 of the secondary side control module 260 . The comparator OP1 can compare the electrical characteristic of the first terminal of the energy storage unit 220 with the reference voltage Vref, and transmit the comparison result to the signal sensing and adjusting integrated circuit 261 . Although the embodiment shown in FIG. 4 directly couples the second non-inverting input end of the comparator OP1 to the first end of the energy storage unit 220 , the implementation of the present invention should not be limited thereto. For example, in other embodiments, a voltage divider circuit may be configured between the second non-inverting input terminal of the comparator OP1 and the first terminal of the energy storage unit 220, wherein the voltage divider circuit divides the first terminal of the energy storage unit 220 into The voltage is divided to generate a feedback voltage to the second non-inverting input terminal of the comparator OP1. Therefore, the signal sensing and adjusting integrated circuit 261 can correspondingly adjust the duration of the conduction period of the output switch 230 according to the relationship between the electrical characteristics of the first end of the energy storage unit 220 and the reference voltage Vref. Therefore, the secondary side control module 260 can correspondingly control and determine the conduction time length of the output switch 230 according to the monitoring result of the electrical characteristic of the energy storage unit 220 . Accordingly, the AC-DC conversion device 20 can optimize the output electric energy of the energy storage unit 220 .

In this embodiment, the primary side circuit 270 further includes a rectification circuit 271 , a primary side control switch 272 and a primary side control module 273 . The first DC end and the second DC end of the rectification circuit 271 are respectively coupled to the first end of the primary side winding 211 and the primary side reference voltage (such as the primary side ground voltage), and the first AC end of the rectification circuit 271 and the second AC end are respectively coupled to the AC power source 30 . The rectification circuit 271 can convert the AC power input from the AC power supply 30 into DC power. The embodiment of the primary side control switch 272 takes the transistor Q2 as an example, but it is not limited thereto. The first terminal and the second terminal of the transistor Q2 are respectively coupled to the second terminal of the primary winding 211 and the primary reference voltage. The primary-side control module 273 is coupled to the control terminal of the transistor Q2 of the primary-side control switch 272, and the primary-side control module 273 determines the time length of the conduction period of the transistor Q2 of the primary-side control switch 272 to determine the voltage stored in the transformer T1. electrical energy. The secondary side control module 260 determines the electric energy released from the transformer T1 by controlling the duration of the conduction period of the output switch 230 , the output switch 250 and the output switch 283 . The primary side control module 273 and the secondary side control module 260 can be configured in the same integrated circuit, or in different integrated circuits. For example, in some embodiments, the functions of the primary-side control module 273 can be integrated into the secondary-side control module 260 so as to omit the primary-side control module 273 shown in FIG. 4 . In other embodiments, the output switch 230 , the output switch 250 , the output switch 283 and the transistor Q1 as a synchronous rectification switch can also be integrated into the signal sensing and adjusting integrated circuit 261 according to the design requirements of actual products.

FIG. 5 is a waveform diagram of the first embodiment of the present invention. Please refer to FIG. 4 and FIG. 5 at the same time, and the operation process of the AC-DC conversion device 20 will be explained below. The signal VG represents the potential of the control terminal of the primary side control switch 272 . When the signal VG is at a high voltage level, it means that the primary side control switch 272 is turned on; when the signal VG is at a low voltage level, it means that the primary side control switch 272 is not turned on. During the period from time point t1 to t2 , the primary side control switch 272 is turned on, so that the current Ip on the primary side winding 211 increases at this time. That is to say, the primary side circuit 270 stores electric energy in the transformer T1 during the time point t1 to t2. During the period from time point t1 to t2, the control terminal potential VSW_SR of the transistor Q1, the control terminal potential VSW_1 of the output switch 230, the control terminal potential VSW_2 of the output switch 250, and the control terminal potential VSW_3 of the output switch 283 are all low voltage levels. , which means that the transistor Q1 serving as the synchronous rectification switch, the output switch 230 , the output switch 250 , and the output switch 283 are all off. During the charging period (ie, the period from time point t1 to t2 ), the electric energy output from the rectification circuit 271 is stored in the transformer T1 by turning on the primary side control switch 272 .

After the charging period ends, the discharging period (ie, the period from time point t2 to t5 ) enters. During the period from time point t2 to t5, the signal VG drops to a low voltage level, so that the primary side control switch 272 is not turned on. During the period from time point t2 to t5, the potential VSW_SR of the control terminal of the transistor Q1 of the synchronous rectification switch changes from low level to high level, so that the transistor Q1 is turned on, so that the electric energy stored in the transformer T1 can be distributed to the energy storage Units 220, 240 and 282. When the transistor Q1 is turned on at the time point t2, the voltage at the observation point Sync drops to a negative voltage due to the electromotive force of the secondary winding 212 and is lower than a preset reference value, such as -0.7V. The voltage level of the observation point Sync is responsive to (correlated with) the amount of electric energy stored in the transformer T1 , so the secondary side control module 260 can determine the amount of electric energy stored in the transformer T1 according to the voltage level of the observation point Sync . When the signal sensing and regulating integrated circuit 261 of the secondary side control module 260 receives the voltage of the observation point Sync lower than the preset reference value, it outputs a conduction signal to be the first to conduct during the period from time point t2 to t5 output switch. In this embodiment, the output switch 250 is the output switch that is turned on first, but it is not limited thereto. When the Sync voltage at the observation point is a negative voltage level, the secondary side control module 260 turns on the output switch 250, the output switch 230 and the output switch 283 in order to distribute the electric energy stored in the transformer T1 to the energy storage unit 240 (with load 42), the energy storage unit 220 (and the load 41), and the energy storage unit 282 (and the load 43). The manner of operation during the period from time point t2 to t5 is described in detail as follows.

During the period from time point t2 to t3 , the signal sensing and adjusting integrated circuit 261 pulls up the potential VSW_2 of the control terminal of the output switch 250 to a high level, so that the output switch 250 is turned on. Therefore, the electric energy stored in the transformer T1 can be distributed to the energy storage unit 240 and the load 42 during the time point t2 to t3, so that the current Is on the secondary winding 212 decreases (as shown in FIG. 5 ). When the output switch 250 is turned on, the secondary side control module 260 monitors the voltage of the energy storage unit 240 and/or the current flowing through the load 42 to optimize the output power of the energy storage unit 240 . When the electric energy distributed to the energy storage unit 240 reaches a preset value, for example, when the voltage of the energy storage unit 240 reaches the rated voltage level of the load 42 and/or when the current flowing through the load 42 reaches the rated current level of the load 42 , the secondary side control module 260 closes the output switch 250, and turns on the output switch 230 (from time point t3 to t4), so that the electric energy stored in the transformer T1 can be used for the next group of power supply circuits (energy storage unit 220 and the load 41) to supplement electric energy.

The signal sensing and adjusting integrated circuit 261 pulls up the control terminal potential VSW_1 of the output switch 230 to a high voltage level during the time point t3 to t4, so that the output switch 230 is turned on during the time point t3 to t4. Therefore, the electric energy stored in the transformer T1 can be distributed to the energy storage unit 220 and the load 41 during the time point t3 to t4, so that the current Is on the secondary winding 212 decreases. During the conduction period of the output switch 230 , the secondary side control module 260 monitors the voltage of the energy storage unit 220 to optimize the output power of the energy storage unit 220 . When the electric energy distributed to the energy storage unit 220 reaches a preset value, for example, when the voltage of the energy storage unit 220 reaches the rated voltage level of the load 41, the secondary side control module 260 closes the output switch 230 and makes the output switch 283 Turning on (entering the period from time point t4 to t5 ) allows the electric energy stored in the transformer T1 to supplement electric energy for the next group of power supply circuits (the energy storage unit 282 and the load 43 ).

The signal sensing and adjusting integrated circuit 261 pulls up the control terminal potential VSW_3 of the output switch 283 to a high voltage level during the time point t4 to t5, so that the output switch 283 is turned on during the time point t4 to t5. Therefore, the electric energy stored in the transformer T1 can be distributed to the energy storage unit 282 and the load 43 during the time point t4 to t5, so that the current Is on the secondary winding 212 decreases. During the conduction period of the output switch 283 , the secondary side control module 260 monitors the voltage of the energy storage unit 282 to optimize the output power of the energy storage unit 282 . When the electric energy distributed to the energy storage unit 282 reaches a preset value, for example, when the voltage of the energy storage unit 282 reaches the rated voltage level of the load 43 , the secondary side control module 260 closes the output switch 283 .

By observing the voltage of the common voltage observation point VCOM in the circuit shown in FIG. 4 (such as shown in FIG. 5 ), it can be known that the AC-DC conversion device 20 can control the voltage of the energy storage unit 220, the voltage of the energy storage unit 240, and the energy storage unit 282. The voltage can be individually adjusted without the need for an additional voltage converter. Therefore, the AC-DC conversion device 20 can generate multiple sets of optimized and precisely adjusted output voltages by using the same secondary winding of the transformer.

In this embodiment, the charging period (ie, the period from time point t1 to t2 ), the conduction period of the output switch 230 , the conduction period of the output switch 250 , and the conduction period of the output switch 283 do not overlap each other. The actions of the output switch 230 , the output switch 250 and the output switch 283 are independent of each other. However, the embodiments of the present invention should not be limited thereto. For example, in other embodiments, the conduction periods of the switches 230 , 250 and 283 may also be set to partially overlap each other according to actual design/application requirements. As another example, although the embodiment shown in FIG. 5 is sequentially turned on by the output switch 250, the output switch 230 and the output switch 283, in other embodiments, other order may be used depending on actual design/application requirements. Pass. For example, the output switch 230 , the output switch 250 and the output switch 283 are turned on in sequence.

Please refer to FIG. 5 , in this embodiment, when the period of supplementing electric energy to the first power output channel (that is, the period from time point t2 to t3) ends, the Sync voltage at the observation point rises to -310mV (for example only, but not limited thereto). When the period of supplementing electric energy to the second power output channel (ie, the period from time point t3 to t4) ends, the Sync voltage at the observation point rises to -12mV (just an example, but not limited thereto). And when the period of supplementing electric energy to the third power output channel (ie, the period from time point t4 to t5 ) ends, the voltage at the observation point Sync rises to 0V (just an example, but not limited thereto). Observing this phenomenon, it can be seen that the voltage level of the observation point Sync is responsive to (relative to) the remaining amount of electric energy stored in the transformer T1. Therefore, the secondary side control module 260 can determine the remaining amount of electric energy stored in the transformer T1 when the energy release period ends (such as time point t5 shown in FIG. 5 ) according to the voltage level of the observation point Sync, and transfer The remaining amount of electric energy is notified to the primary side control module 273 . The primary side control module 273 can adjust the conduction time length of the primary side control switch 272 according to the remaining amount of electric energy in the transformer T1 at the end of the discharge period, that is, adjust the charging period (for example, time points t1 to t2 shown in FIG. 5 period) the length of time.

FIG. 6 is a schematic diagram illustrating a second embodiment of the AC-DC conversion device 20 shown in FIG. 2 according to an embodiment of the present invention. The embodiment shown in FIG. 6 can be deduced by referring to the relevant descriptions in FIG. 4 to FIG. 5 . In the embodiment shown in FIG. 6 , the AC-DC conversion device 20 may further include a feedback module 285 . The sensing terminal of the feedback module 285 is coupled to the energy storage unit 240 to monitor the electrical characteristics of the energy storage unit 240 . In this embodiment, the third electrical characteristic is the voltage on the energy storage unit 240 . The output terminal of the feedback module 285 is coupled to the primary-side control module 273 to provide a corresponding information of the electrical characteristic of the energy storage unit 240 . The primary side control module 273 correspondingly controls and determines the conduction time length of the primary side control switch 272 according to the corresponding information.

In this embodiment, the feedback module 285 includes an optocoupler PC1, resistors R1-R3, capacitors C4 and C5, and a Zener diode ZD1. A first end of the resistor R1 is coupled to the energy storage unit 240 . The first terminal and the second terminal of the resistor R2 are respectively coupled to the second terminal of the resistor R1 and a secondary reference voltage (such as the secondary ground voltage or other fixed voltages). A first end of the resistor R3 is coupled to the energy storage unit 240 . The first end of the resistor R3 is the sensing end of the feedback module 285 . The first end of the capacitor C4 is coupled to the second end of the resistor R1. The cathode of the Zener diode ZD1 is coupled to the second terminal of the capacitor C4, and the anode of the Zener diode ZD1 is coupled to the secondary side reference voltage. The reference terminal of the Zener diode ZD1 is coupled to the second terminal of the resistor R1 and the first terminal of the resistor R2. In this embodiment, the Zener diode ZD1 can be a TL431 Zener diode from Texas Instruments or other brands, but is not limited thereto. The first terminal of the light emitting part of the optical coupler PC1 is coupled to the second terminal of the resistor R3, and the second terminal of the light emitting part of the optical coupler PC1 is coupled to the second terminal of the capacitor C4. The first end of the light-sensing portion of the optocoupler PC1 is coupled to the primary-side control module 273 to provide the corresponding information, and the first end of the light-emitting portion of the optocoupler PC1 is the output end of the feedback module 285 . The second terminal of the photosensitive part of the photocoupler PC1 is coupled to the primary side reference voltage. The first end of the capacitor C5 is coupled to the first end of the light-sensing portion of the photocoupler PC1 , and the second end of the capacitor C5 is coupled to the second end of the light-sensing portion of the photocoupler PC1 .

When the sensing terminal of the feedback module 285 senses the voltage on the energy storage unit 240 , the current will flow through the light emitting part of the optocoupler PC1 and the Zener diode ZD1 . When the voltage on the energy storage unit 240 changes, the current flowing through the light emitting part of the optocoupler PC1 changes, so that the luminous intensity of the light emitting part changes correspondingly. The output voltage output from the feedback module 285 to the primary side control module 273 will also change accordingly, thereby changing the conduction time of the primary side control switch 272 . For example, when the voltage on the energy storage unit 240 becomes larger, the voltage division between the resistor R1 and the resistor R2 becomes larger. The voltage at the reference end of the Zener diode ZD1 increases, so the current flowing through the Zener diode ZD1 and the light-emitting part of the photocoupler PC1 increases. Therefore, the luminous intensity of the light emitting part of the optical coupler PC1 increases, so that the output voltage of the output terminal of the feedback module 285 increases. The primary-side control module 273 reduces the conduction time of the primary-side control switch 272 after receiving an increase in the output voltage. A variable or self-optimizing voltage can be output using optocoupled feedback technology. To sum up, the AC-DC conversion device 20 described in the second embodiment can use the optical coupling feedback technology to feed back the voltage, so the conversion efficiency of the present invention can be further improved.

FIG. 7 is a schematic diagram illustrating a third embodiment of the AC-DC conversion device 20 shown in FIG. 2 according to an embodiment of the present invention. The embodiment shown in FIG. 7 can be deduced by referring to the related descriptions in FIG. 4 to FIG. 6 . In the embodiment shown in FIG. 7 , the primary side circuit 270 includes a rectifier circuit 271 , a primary side control switch 272 , a filter circuit 274 , a chip startup circuit 275 , an auxiliary voltage circuit 276 and a snubber circuit (snubber) 277 . And this embodiment further includes an energy storage unit 282 , an output switch 283 , a monitoring circuit 287 , a monitoring circuit 288 , a discharging circuit 289 and a buffer circuit 290 . In this embodiment, the primary winding of the transformer T1 further includes a first primary winding 211 and a second primary winding (herein referred to as the primary auxiliary winding 213 ). The primary-side auxiliary winding 213 is coupled to the chip start-up circuit 275 to form a primary-side regulator (PSR) feedback circuit.

The rectification circuit 271 in this embodiment includes diodes D3-D6. The anode of the diode D3 is coupled to the first AC end of the rectification circuit 271 and the cathode of the diode D4 , and the cathode of the diode D3 is coupled to the first DC end of the rectification circuit 271 and the cathode of the diode D5 . The anode of the diode D4 is coupled to the second DC terminal of the rectifier circuit 271 and the anode of the diode D6. The anode of the diode D5 is coupled to the second AC terminal of the rectifier circuit 271 and the cathode of the diode D6. The AC power provided by the AC power source 30 flows into the rectifier circuit 271 from the first AC end and the second AC end of the rectifier circuit 271 , and after being processed by the diodes D3 - D6 , the DC current flows out from the first DC end to be used by the AC-DC conversion device 20 .

In this embodiment, the first end and the second end of the primary side auxiliary winding 213 are the opposite end and the same end respectively. The primary-side auxiliary winding 213 has two purposes, one of which is for primary-side regulation (Primary-side Regulator, PSR) feedback, and the other is to generate an auxiliary voltage for the primary-side control module (not shown, refer to FIG. 4 The relevant description of the primary side control module 273 is used by analogy).

The primary side control switch 272 includes a transistor Q2, a resistor R12 and a resistor R13. A first terminal of the transistor Q2 is coupled to a second terminal of the first primary winding 211 . The control terminal of the transistor Q2 is coupled to the primary side control module to receive the control signal VSW. A first end of the resistor R12 is coupled to a second end of the transistor Q2. A second end of the resistor R12 is coupled to a primary reference voltage (such as a primary ground voltage or other fixed voltage). A first terminal of the resistor R13 is coupled to the control terminal of the transistor Q2. The second end of the resistor R13 is coupled to the primary side reference voltage. The resistor R13 is a pull-down (Pull-down) resistor, which can keep the control terminal of the transistor Q2 at a potential close to the reference voltage of the primary side at ordinary times. The current detection point VCS set at the first end of the resistor R12 is used to detect the magnitude of the current. If the current is too large, the overcurrent protection device will be activated. The primary-side reference voltage and the secondary-side reference voltage are at the same point in this embodiment, which means that the primary-side reference voltage is the secondary-side reference voltage, but they may not be at the same point in other embodiments.

The filter circuit 274 in this embodiment includes a capacitor C7. The first end of the capacitor C7 is coupled to the first DC end of the rectification circuit 271 and the first end of the primary winding 211 of the transformer T1 . The second end of the capacitor C7 is coupled to the second DC end of the rectification circuit 271 and the primary reference voltage. The capacitor of the filter circuit 274 is used to filter out the noise of the electric energy output from the first DC end and the second DC end of the rectification circuit 271 .

Two ends of the chip start-up circuit 275 are respectively coupled to the first DC terminal of the rectification circuit 271 and the primary-side control module (referring to the relevant description of the primary-side control module 273 in FIG. 4 and analogously). In this embodiment, the chip startup circuit 275 includes a resistor R14, a capacitor C8 and a diode D7. The first terminal of the resistor R14 is coupled to the first terminal of the primary winding 211 and the first DC terminal of the rectifier circuit 271 , and the second terminal of the resistor R14 is coupled to the power pin VDD of the primary control module. The power pin VDD can supply power to the primary-side control module (refer to the relevant description of the primary-side control module 273 in FIG. 4 ) and/or the secondary-side control module 260 (refer to FIG. 2 ). The cathode of the diode D7 is coupled to the second terminal of the resistor R14. The anode of the diode D7 is coupled to the first end of the primary side auxiliary winding 213 . The first terminal of the capacitor C8 is coupled to the second terminal of the resistor R14, and the second terminal of the capacitor C8 is coupled to the primary reference voltage. The second end of the primary side auxiliary winding 213 is coupled to the primary side reference voltage. In this embodiment, the resistor R14 can be a pull-up resistor, which can keep the power pin VDD of the primary side control module 273 at a high level at ordinary times. When the power supply is turned on, the input voltage will charge the capacitor C8 through the resistor R14. When the voltage at the first terminal of the capacitor C8 reaches the startup critical voltage, the primary side control module will start. The voltage rectified by the primary side auxiliary winding 213 through the diode D7 will also be transmitted to the primary side control module 273 to charge the capacitor C8.

The auxiliary voltage circuit 276 includes a resistor R15, a resistor R16 and a capacitor C9. The first end of the resistor R15 is coupled to the opposite end of the primary side auxiliary winding 213, and the second end of the resistor R15 is coupled to the primary side control module (referring to the related description of the primary side control module 273 in FIG. 4 and analogously) . A first end of the resistor R16 is coupled to a second end of the resistor R15. The second end of the resistor R16 is coupled to the same-named end of the primary side auxiliary winding 213 and the primary side reference voltage. The first terminal of the capacitor C9 is coupled to the first terminal of the resistor R16, and the second terminal of the capacitor C9 is coupled to the primary side reference voltage. The auxiliary voltage circuit 276 is configured to provide an auxiliary voltage VAUX (associated with the voltage across the primary side auxiliary winding 213 ) for use by the primary side control module.

A first end of the buffer circuit 277 is coupled to a first end of the primary winding 211 . The second end of the buffer circuit 277 is coupled to the second end of the primary winding 211 . The buffer circuit 277 of this embodiment is realized by using a circuit structure including a resistor R17, a capacitor C10 and a diode D8. A first end of the resistor R17 is coupled to the rectifier circuit 271 and the first end of the primary winding 211 of the transformer T1 . The first end of the capacitor C10 is coupled to the first end of the primary winding 211 . The second terminal of the capacitor C10 is coupled to the second terminal of the resistor R17. The cathode of the diode D8 is coupled to the second terminal of the resistor R17 and the second terminal of the capacitor C10 . The anode terminal of the diode D8 is coupled to the second terminal of the primary winding 211 of the transformer T1. Specifically, the snubber circuit 277 is used to absorb the energy generated by the leakage inductance of the transformer T1.

The output switch 230 is coupled to the first end of the secondary winding 212 . The output switch 230 can be a transistor Q3, but is not limited thereto. The capacitor C1 of the energy storage unit 220 is coupled to the output switch 230 . The monitoring circuit 287 is coupled to the capacitor C1 of the energy storage unit 220 . The monitoring circuit 287 includes resistors R4 and R5. The first end of the resistor R4 is coupled to the first end of the capacitor C1 in the energy storage unit 220 . The second end of the resistor R4 is coupled to the first end of the resistor R5. The second end of the resistor R5 is coupled to the secondary reference voltage (eg, the secondary ground voltage or other fixed voltages). The monitoring circuit 287 is used to divide the voltage of the capacitor C1 of the energy storage unit 220 and transmit the divided voltage VAUDIO to the secondary side control module 260 (refer to FIG. 2 ). The secondary side control module can obtain the electrical characteristics (such as voltage) of the energy storage unit 220 according to the divided voltage VAUDIO.

In this embodiment, the output switch 250 is a diode D2, but not limited thereto. The anode of the diode D2 is coupled to the first end of the secondary winding 212 , and the cathode of the diode D2 is coupled to the energy storage unit 240 . When the cathode voltage of the diode D2 is greater than the anode voltage, the diode D2 is in a cut-off state, so the diode D2 can also be regarded as an output switch. The monitoring circuit 288 is coupled to the capacitor C2 of the energy storage unit 240 . The monitoring circuit 288 includes resistors R8 and R9. The first terminal of the resistor R8 is coupled to the first terminal of the capacitor C2 in the energy storage unit 240 , and the second terminal of the resistor R8 is coupled to the first terminal of the resistor R9 . The second terminal of the resistor R9 is coupled to a secondary reference voltage (such as the secondary ground voltage or other fixed voltages). The monitoring circuit 288 is used to divide the voltage of the capacitor C2 in the energy storage unit 240, and transmit the divided voltage VLED to the secondary side control module (refer to the related description of the secondary side control module 260 in FIG. ).

Two ends of the buffer circuit 290 are respectively coupled to the anode end and the cathode end of the diode D2. The buffer circuit 290 includes a resistor R10 and a capacitor C6. A first terminal of the resistor R10 is coupled to an anode terminal of the diode D2. The second end of the resistor R10 is coupled to the first end of the capacitor C6. The second terminal of the capacitor C6 is coupled to the cathode terminal of the diode D2. The buffer circuit 290 can filter out the surge generated when the diode D2 is switched on and off.

The output switch 283 is coupled to the first end of the secondary winding 212 . The output switch 283 can be a transistor Q4, but is not limited thereto. The capacitor C3 of the energy storage unit 282 is coupled to the output switch 283 . In this embodiment, the primary side regulation (PSR) technology is used to control and adjust the output voltage of the energy storage unit 282 . This technology is realized by utilizing the circuit structure of the chip start-up circuit 275 and the auxiliary voltage circuit 276 including the diode D7, the resistors R15 and R16, and the capacitors C8 and C9. The principle of the primary side adjustment is to detect the change of the secondary side output voltage by detecting the voltage change of the primary side auxiliary winding 213 . During the discharge period, the output voltage and the forward conduction voltage drop of the synchronous rectification unit 281 are reflected to the primary side auxiliary winding 213 , and the voltage across the primary side auxiliary winding 213 responds to the output voltage. The remaining amount of electrical energy stored in the transformer T1 during the discharge period will be reflected in the output voltage of the output switch 283 that was turned on last. Therefore, in this embodiment, the voltage at both ends of the primary-side auxiliary winding 213 is related to the output voltage of the output switch 283 that is turned on last. The auxiliary voltage VAUX corresponding to the voltage across the primary-side auxiliary winding 213 is fed back to the primary-side control module (refer to the relevant description of the primary-side control module 273 in FIG. 4 and analogize it). Therefore, the primary-side control module can adjust the duration of the conduction period of the transistor Q2 in the primary-side control switch 272 according to the auxiliary voltage VAUX, and correspondingly adjust the duration of the conduction period of the output switch 283 . By using the primary-side regulation feedback technique, the output voltage of the output switch 283 that is turned on last can be maintained at a constant voltage.

In this embodiment, when the switches 230 and 283 are both turned off, the electric energy stored in the transformer T1 will be transferred to the energy storage unit 240, so that the output voltage VOUT can maintain the rated voltage of the load 42 (see FIG. 2 ). (eg 55V, but not limited thereto). The secondary side control module 260 (see FIG. 2 ) can monitor the voltage across the capacitor C2 of the energy storage unit 240 through the monitoring circuit 288 . When the voltage of the capacitor C2 in the energy storage unit 240 reaches the rated voltage level of the load 42 coupled to the capacitor C2, and/or when the current flowing through the load 42 coupled to the capacitor C2 reaches the rated current level of the load 42, The secondary side control module 260 can turn on the output switch 230 so that the electric energy stored in the transformer T1 can supplement electric energy for the next group of power supply circuits (the energy storage unit 220 and its load). Since the output switch 230 is turned on, the anode voltage of the diode D2 is pulled down. When the cathode voltage of the diode D2 is greater than the anode voltage, the diode D2 is in a cut-off state, so the diode D2 can maintain the voltage of the capacitor C2 in the energy storage unit 240 .

During the conduction period of the output switch 230 , the secondary side control module can monitor the voltage across the capacitor C1 of the energy storage unit 220 through the monitoring circuit 287 . When the output voltage VOUTA reaches the rated voltage level of the first load (not shown, refer to the relevant description of the load 41 in FIG. 4 and be analogized), the secondary-side control module closes the output switch 230 and notifies the primary-side control module (Refer to the relevant description of the primary side control module 273 in FIG. 4 and analogize it) Turn on the output switch 283 so that the electric energy stored in the transformer T1 can power the next group of power supply circuits (energy storage unit 282 and its load). Energy supplement. The primary side control module may use a primary side regulation (PSR) technique to control the output switch 283 to adjust the output voltage VOUTB of the energy storage unit 282 .

In this embodiment, the discharge circuit 289 is an example of the transistor Q5, but it is not limited thereto. And the first terminal and the second terminal of the transistor Q5 are respectively coupled to the cathode of the diode D2 and the energy storage unit 282 . The control terminal of the transistor Q5 is coupled to the secondary side control module 260 (refer to FIG. 2 ). In this embodiment, the output voltage VOUT is the largest voltage among the output voltage VOUT, the output voltage VOUTA and the output voltage VOUTB. When the electric energy of the capacitor C2 of the energy storage unit 240 needs to be released, the secondary side control module 260 controls the transistor Q5 to be turned on, and the electric energy can flow to VOUTB with a lower potential through the transistor Q5 to achieve the purpose of quick energy release.

In this embodiment, the synchronous rectification unit 281 includes a synchronous rectification diode D1, a resistor R6 and a resistor R7. The cathode and the anode of the synchronous rectification diode D1 are respectively coupled to the second terminal of the secondary winding 212 and a secondary reference voltage (such as the secondary ground voltage or other fixed voltages). When the cathode voltage of the diode D1 is greater than the anode voltage, the diode D1 is in a cut-off state, so the synchronous rectification diode D1 can also be regarded as a synchronous rectification switch. The first end of the resistor R6 is coupled to the cathode of the synchronous rectification diode D1. The first end and the second end of the resistor R7 are respectively coupled to the second end of the resistor R6 and the anode of the synchronous rectification diode D1. The resistor R6 is connected in series with the resistor R7 to divide the voltage. The secondary-side control module (referring to the related description of the secondary-side control module 260 in FIG. 4 and analogously) can capture the voltage signal on the monitoring point VSYNC at the coupling position between the second end of the resistor R6 and the first end of the resistor R7. . The secondary side control module 260 can judge the remaining amount of electric energy stored in the transformer T1 at the end of the energy release period according to the voltage level of the observation point Sync, and respond according to the remaining amount of electric energy in the transformer T1 at the end of the energy release period. Adjusting the conduction time length of the primary side control switch 272 is to adjust the time length of the charging period.

FIG. 8 is a schematic diagram illustrating a fourth embodiment of the AC-DC conversion device 20 shown in FIG. 2 according to an embodiment of the present invention. The embodiment shown in FIG. 8 can be deduced by referring to the relevant descriptions in FIG. 4 to FIG. 7 . The fourth embodiment is an embodiment applied in a monitor system. The fourth embodiment further includes an energy storage unit 292 , an output switch 293 , a monitoring circuit 291 , a monitoring circuit 294 , a low-dropout regulator (LDO) 295 and a low-dropout regulator 296 . The fourth embodiment can be used to provide power for a display driver board (Scalar Board) of a display system. In this embodiment, the monitoring circuit 291 includes resistors R18 and R19. The first terminal of the resistor R18 is coupled to the first terminal of the capacitor C3 of the energy storage unit 282 and the second terminal of the transistor Q4 of the output switch 283 . The second terminal of the resistor R18 is coupled to the first terminal of the resistor R19. The second end of the resistor R19 is coupled to a secondary reference voltage (such as the secondary ground voltage or other fixed voltages). The monitoring circuit 291 is used to divide the voltage of the capacitor C3 of the energy storage unit 282 and transmit the divided voltage to the secondary side control module 260 (as shown in FIG. 2 ). The secondary side control module 260 can obtain the electrical characteristics (such as voltage) of the energy storage unit 282 according to the divided voltage generated by the resistors R18 and R19 .

The energy storage unit 292 includes a capacitor C11. The output switch 293 includes a transistor Q6. The monitoring circuit 294 includes resistors R20 and R21. The first terminal of the resistor R20 is coupled to the first terminal of the capacitor C11 of the energy storage unit 292 and the second terminal of the transistor Q6 of the output switch 293 . A first end of the resistor R21 is coupled to a second end of the resistor R20. A second end of the resistor R21 is coupled to a secondary reference voltage (eg, a secondary ground voltage). In addition to providing the output voltage to the load 46 , the energy storage unit 292 can also provide power to the LDO regulators 295 , 296 . The LDO voltage regulators 295 and 296 can output different voltages to the loads 44 and 45 respectively after receiving electric energy.

During charging, the electric energy output by the rectifier circuit 271 is stored in the transformer T1 by turning on the primary side control switch 272 . After the charging period is over, it then enters the energy releasing period. During the discharge period, the electric energy stored in the transformer T1 can be distributed to the energy storage units 220 , 240 , 282 and 292 .

When the switches 230 , 283 and 293 are all turned off, the anode voltage of the diode D2 of the output switch 250 will be pulled up by the transformer T1 , so the electric energy stored in the transformer T1 can supplement the electric energy of the energy storage unit 240 and the load 42 . During the period when the switches 230, 283 and 293 are all off, the secondary side control module 260 (as shown in FIG. 2 ) monitors the voltage of the energy storage unit 240, and/or monitors the current flowing through the load 42, so as to control the energy storage unit 240 output power is optimized. For example, the secondary control module 260 can maintain the voltage of the energy storage unit 240 at the rated voltage level of the load 42 . For another example, the secondary side control module 260 may maintain the current flowing through the load 42 at the rated current level of the load 42 . The load 42 can be an LED backlight module of a display, the voltage output to the load 42 can be 30-60V, and the maximum current can be 0.3-0.4A, but it is not limited thereto. When the electric energy distributed to the energy storage unit 240 reaches a preset value, for example, when the voltage of the energy storage unit 240 reaches the rated voltage level of the load 42, and/or when the current flowing through the load 42 reaches the rated current level of the load 42 Normally, the secondary side control module 260 turns on the output switch 230 so that the electric energy stored in the transformer T1 can supplement electric energy for the next set of power supply circuits (the energy storage unit 220 and the load 41 ). Since the output switch 230 is turned on, the anode voltage of the diode D2 of the output switch 250 is pulled down. When the cathode voltage of the diode D2 is greater than the anode voltage, the diode D2 is in a cut-off state, so the diode D2 can maintain the voltage of the capacitor C2 in the energy storage unit 240 .

During the conduction period of the output switch 230 , the secondary side control module 260 (as shown in FIG. 2 ) monitors the voltage of the energy storage unit 220 to optimize the output electric energy of the energy storage unit 220 . For example, the secondary side control module 260 can maintain the voltage of the energy storage unit 220 at the rated voltage level of the load 41 . The load 41 can be an audio module of the display. The voltage output to the load 41 may be 5V, and the maximum current may be 1.2A, but not limited thereto. When the electric energy distributed to the energy storage unit 220 reaches a preset value, for example, when the voltage of the energy storage unit 220 reaches the rated voltage level of the load 41, the secondary side control module 260 closes the output switch 230 and makes the output switch 283 Turning on allows the electric energy stored in the transformer T1 to supplement electric energy for the next group of power supply circuits (the energy storage unit 282 and the load 43 ).

During the conduction period of the output switch 283 , the secondary side control module 260 (as shown in FIG. 2 ) monitors the voltage of the energy storage unit 282 to optimize the output power of the energy storage unit 282 . For example, the secondary side control module 260 can maintain the voltage of the energy storage unit 282 at the rated voltage level of the load 43 . The load 43 may be a video graphics array (Video Graphics Array, VGA) circuit in a display driver board (Scalar Board) of the display. The voltage output to the load 43 may be 5V, and the maximum current may be 1.5A, but not limited thereto. When the electric energy distributed to the energy storage unit 282 reaches a preset value, for example, when the voltage of the energy storage unit 282 reaches the rated voltage level of the load 43, the secondary side control module 260 closes the output switch 283 and makes the output switch 293 Turning on allows the electric energy stored in the transformer T1 to supplement electric energy for the next set of power supply circuits (the energy storage unit 292 , the load 46 , the LDO voltage regulator 295 and the LDO voltage regulator 296 ).

During the conduction period of the output switch 293 , the secondary side control module 260 (shown in FIG. 2 ) monitors the voltage of the energy storage unit 292 to optimize the output electric energy of the energy storage unit 292 . For example, the secondary control module 260 may maintain the voltage of the energy storage unit 292 at the rated voltage level of the load 46 . The load 46 may be an input/output (I/O) circuit in a display driver board of the display. The voltage output to the load 46 can be 3.3V, and the maximum current can be 0.8A, but not limited thereto. When the electric energy distributed to the energy storage unit 292 reaches a predetermined value, for example, when the voltage of the energy storage unit 292 reaches the rated voltage level of the load 46 , the secondary side control module 260 closes the output switch 293 .

The LDO 295 includes an amplifier OP2, a transistor Q7, and resistors R22 and R23. The non-inverting input terminal of the amplifier OP2 receives the reference voltage Vref1. The output terminal of the amplifier OP2 is coupled to the control terminal of the transistor Q7. The first end of the transistor Q7 (ie, the power input end of the LDO voltage regulator 295 ) is coupled to the capacitor C11 and the transistor Q6 . The second terminal of the transistor Q7 is coupled to the first terminal of the resistor R22. The second terminal of the resistor R22 is coupled to the inverting input terminal of the amplifier OP2 and the first terminal of the resistor R23. The second end of the resistor R23 is coupled to the secondary side reference voltage. The second terminal of the transistor Q7 is the output terminal of the LDO voltage regulator 295 to supply power to the load 44 . Therefore, the low dropout voltage regulator 295 can convert the voltage of the energy storage unit 292 into the rated voltage of the load 44 according to the reference voltage Vref1 . The load 44 can be a dynamic random access memory (Dynamic Random Access Memory, DRAM) in the display driver board of the display. The voltage output to the load 44 may be 2.5V, but not limited thereto.

The LDO 296 includes an amplifier OP3, a transistor Q8, and resistors R24 and R25. The non-inverting input of the amplifier OP3 receives the reference voltage Vref2. The output terminal of the amplifier OP3 is coupled to the control terminal of the transistor Q8. The first end of the transistor Q8 (ie, the power input end of the LDO voltage regulator 296 ) is coupled to the capacitor C11 and the transistor Q6 . The second terminal of the transistor Q8 is coupled to the first terminal of the resistor R24. The second terminal of the resistor R24 is coupled to the inverting input terminal of the amplifier OP3 and the first terminal of the resistor R25. The second end of the resistor R25 is coupled to the secondary side reference voltage. The second terminal of the transistor Q8 is the output terminal of the LDO voltage regulator 296 to supply power to the load 45 . Therefore, the low dropout voltage regulator 296 can convert the voltage of the energy storage unit 292 into the rated voltage of the load 45 according to the reference voltage Vref2. The load 45 can be a core (Core) module in the display driver board of the display. The voltage output to the load 45 may be 1.2V, but not limited thereto. In addition, in this embodiment, the voltage of the energy storage unit 292 can be the smallest among the voltages of the energy storage units 240, 220, 282, and 292, so that the voltage of the energy storage unit 292 can be closer to the voltage of the low dropout regulator 295 and The output voltage of the low dropout regulator 296. Since the voltage difference between the input voltage and the output voltage of the LDO can be further reduced, the voltage conversion efficiency can be improved.

In summary, various embodiments of the present invention provide an AC-DC conversion device 20 and an operation method thereof. The AC-DC conversion device 20 uses the secondary side control module 260 to monitor the energy storage unit 220 and the energy storage unit 240 , and determines or controls the on-time length of the output switch 230 and the output switch 250 according to the monitoring results. Therefore, only the same secondary side winding 212 of the transformer T1 can be used to generate multiple sets of output voltages that can be optimized and precisely adjusted without configuring additional voltage converters. Moreover, some embodiments of the present invention can use the optical coupling feedback technology or the primary-side adjustment feedback technology to feed back the voltage, which can further improve the conversion efficiency of the AC-DC conversion device 20 and its operation method.

Although the present invention has been disclosed as above with the embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims (24)

1. an AC/DC conversion equipment, comprising:

Transformer, comprises at least one first side winding and at least one secondary side winding;

First energy-storage units;

First output switch, the first end of described first output switch and the second end are coupled to the first end of described first energy-storage units and described secondary side winding respectively;

Second energy-storage units;

Second output switch, the first end of described second output switch and the second end are coupled to the described first end of described second energy-storage units and described secondary side winding respectively; And

Secondary side control module, be coupled to described first energy-storage units to monitor the first electrical property feature of described first energy-storage units, and be coupled to described second energy-storage units to monitor the second electrical property feature of described second energy-storage units, wherein said secondary side control module is the corresponding time span determining the conduction period of described first output switch according to the monitoring result to described first electrical property feature, and correspondence determines the time span of the conduction period of described second output switch according to the monitoring result to described second electrical property feature.

2. AC/DC conversion equipment according to claim 1, the conduction period of wherein said first output switch and the conduction period part of described second output switch overlap or do not overlap mutually.

3. AC/DC conversion equipment according to claim 1, also comprises:

Synchronous rectification unit, its first end and the second end are coupled to the second end and the reference voltage of described secondary side winding respectively.

4. AC/DC conversion equipment according to claim 3, described synchronous rectification unit comprises:

Synchronous rectification switch, its first end and the second end are coupled to described second end of described secondary side winding and described reference voltage respectively, and the control end of described synchronous rectification switch is coupled to described secondary side control module.

5. AC/DC conversion equipment according to claim 3, described synchronous rectification unit comprises:

Synchronous rectification diode, its negative electrode and positive electrode is coupled to described second end of described secondary side winding and described reference voltage respectively.

6. AC/DC conversion equipment according to claim 5, described synchronous rectification unit also comprises:

First resistance, its first end is coupled to the negative electrode of described synchronous rectification diode: and

Second resistance, its first end and the second end are coupled to the second end of described first resistance and the anode of described synchronous rectification diode respectively.

7. AC/DC conversion equipment according to claim 1, wherein said second energy-storage units is powered to the current path of load, and described AC/DC conversion equipment also comprises:

Current detector, is configured to detect the electric current of described load in described current path, and output electric current measure result is to described secondary side control module;

Wherein said secondary side control module receives the monitoring result of described current detecting result as described second electrical property feature.

8. AC/DC conversion equipment according to claim 1, also comprises:

3rd energy-storage units; And

Diode, the anode of described diode and negative electrode are coupled to the first end of described secondary side winding and described 3rd energy-storage units respectively.

9. AC/DC conversion equipment according to claim 1, at least one first side winding wherein said comprises the first first side winding, and described AC/DC conversion equipment also comprises:

Rectification circuit, its first DC terminal and the second DC terminal are coupled to first end and the primary side reference voltage of described first first side winding respectively;

Primary side control switch, the first end of described primary side control switch and the second end are coupled to the second end of described first first side winding and described primary side reference voltage respectively;

Primary side control module, the control end of itself and described primary side control switch couples;

Wherein said primary side control module decides by the time span of conduction period controlling described primary side control switch the electric flux being stored in described transformer, and described secondary side control module decides the electric flux that discharges from described transformer by the time span of the conduction period of described first output switch of control and described second output switch.

10. AC/DC conversion equipment according to claim 9, wherein said primary side control switch comprises:

Transistor, its first end is coupled to the second end of described first first side winding, and the control end of described transistor is coupled to described primary side control module;

First resistance, its first end and the second end are coupled to the second end of described transistor and described primary side reference voltage respectively; And

Second resistance, its first end and the second end are coupled to the described control end of described transistor and described primary side reference voltage respectively.

11. AC/DC conversion equipments according to claim 9, also comprise:

Bradyseism circuit, its first end and the second end couple with the first end of described first first side winding and the second end respectively.

12. AC/DC conversion equipments according to claim 11, wherein said bradyseism circuit comprises:

Resistance, its first end is coupled to the described first end of described first first side winding;

Electric capacity, its first end and the second end are coupled to the described first end of described first first side winding and the second end of described resistance respectively; And

Diode, its negative electrode and positive electrode is coupled to the second end of described resistance and the second end of described first first side winding respectively.

13. AC/DC conversion equipments according to claim 9, wherein said AC/DC conversion equipment also comprises:

Chip enable circuit, its two ends are coupled to described first DC terminal of described rectification circuit and described primary side control module respectively.

14. AC/DC conversion equipments according to claim 13, at least one first side winding wherein said also comprises the second first side winding, and described chip enable circuit comprises:

Resistance, its first end is coupled to described first DC terminal of described rectification circuit and the described first end of described first first side winding, and its second end is coupled to described primary side control module;

Diode, its negative electrode and positive electrode is coupled to the second end of described resistance and the first end of described second first side winding respectively; And

Electric capacity, its first end and the second end are coupled to the second end of described resistance and described primary side reference voltage respectively;

Second end of wherein said second first side winding is coupled to described primary side reference voltage.

15. AC/DC conversion equipments according to claim 9, also comprise:

Feedback module, its sense terminals is coupled to described second energy-storage units to monitor the 3rd electrical property feature of described second energy-storage units, the output of described feedback module is coupled to described primary side control module to provide the corresponding informance of described 3rd electrical property feature, and wherein said primary side control module is the corresponding ON time length determining described primary side control switch according to described corresponding informance.

16. AC/DC conversion equipments according to claim 15, wherein said feedback module comprises:

First resistance, its first end is coupled to described second energy-storage units;

Second resistance, its first end and the second end are coupled to the second end and the secondary side reference voltage of described first resistance respectively;

3rd resistance, its first end is coupled to described second energy-storage units;

First electric capacity, its first end is coupled to the second end of described first resistance;

Zener diode, its negative electrode and positive electrode is coupled to the second end of described first electric capacity and described secondary side reference voltage respectively;

Optical coupler, the first end of its illuminating part and the second end are coupled to the second end of described 3rd resistance and the second end of described first electric capacity respectively, and the first end of the photographic department of described optical coupler and the second end are coupled to described primary side control module respectively to provide described corresponding informance and described primary side reference voltage; And

Second electric capacity, its first end and the second end are coupled to first end and second end of the described photographic department of described optical coupler respectively.

17. AC/DC conversion equipments according to claim 9, wherein said primary side control module and described secondary side control module are all configured in same integrated circuit.

18. AC/DC conversion equipments according to claim 1, wherein said secondary side control module is coupled to the second end of described secondary side winding with monitoring voltage feature, and wherein said secondary side control module is the corresponding conducting sequential controlling described first output switch according to the monitoring result to described voltage characteristic.

19. AC/DC conversion equipments according to claim 1, also comprise low dropout voltage regulator, and its electrical energy inputs is coupled to described second energy-storage units.

20. AC/DC conversion equipments according to claim 19, the voltage of wherein said second energy-storage units is the minimum voltage among the voltage of multiple energy-storage units of described AC/DC conversion equipment.

The method of operation of 21. 1 kinds of AC/DC conversion equipments, comprising:

Configuration transformer is in described AC/DC conversion equipment, and wherein said transformer comprises at least one first side winding and at least one secondary side winding;

Configure the first energy-storage units and the first output switch in described AC/DC conversion equipment, the first end of wherein said first output switch and the second end are coupled to the first end of described secondary side winding and described first energy-storage units respectively;

Configure the second energy-storage units and the second output switch in described AC/DC conversion equipment, the first end of wherein said second output switch and the second end are coupled to the described first end of described second energy-storage units and described secondary side winding respectively;

In conduction period of described first output switch by delivery of electrical energy stored by described transformer to described first energy-storage units, and monitor the first electrical property feature of described first energy-storage units, and correspondence determines the time span of the conduction period of described first output switch according to the monitoring result to described first electrical property feature; And

In conduction period of described second output switch by delivery of electrical energy stored by described transformer to described second energy-storage units, and monitor the second electrical property feature of described second energy-storage units, and correspondence determines the time span of the conduction period of described second output switch according to the monitoring result to described second electrical property feature.

The method of operation of 22. AC/DC conversion equipments according to claim 21, also comprises:

Configuration rectification circuit is in described AC/DC conversion equipment, and the first DC terminal of wherein said rectification circuit and the second DC terminal are coupled to first end and the primary side reference voltage of described first side winding respectively;

Configuration primary side control switch is in described AC/DC conversion equipment, and the first end of wherein said primary side control switch and the second end are coupled to the second end of described first side winding and described primary side reference voltage respectively; And

The electrical power storage exported by described rectification circuit by primary side control switch described in conducting between charge period is at described transformer.

The method of operation of 23. AC/DC conversion equipments according to claim 22, between wherein said charge period, the conduction period of described first output switch and the conduction period of described second output switch do not overlap mutually.

The method of operation of 24. AC/DC conversion equipments according to claim 21, also comprises:

Detect the voltage of the second end of described secondary side winding, wherein when the second end of described secondary side winding is negative voltage level, the first output switch described in turn in order and described second output switch.