TWI420777B - Charging indication circuit and the protable electronic device employing the same - Google Patents

Description

Charging indicating circuit and portable electronic device using the same

The present invention relates to a charging state indicating circuit and a portable electronic device using the same, and more particularly to a cost saving charging indicating circuit and a portable electronic device using the same.

At present, portable electronic products such as mobile phones and PDAs (Personal Digital Assistants) are popular among modern people because of their small size and easy portability, and have significantly improved people's work efficiency and quality of life. . The portable electronic product widely uses a rechargeable battery. In the application, when the battery is insufficient in power, it can be re-used by being connected to another power source by a charging device for charging.

Generally, the portable electronic device is provided with an indicator light indicating the working state of the charging device. When the rechargeable battery installed on the portable electronic device is charged, the indicator light can display different colors or brightness. And indicating the state of charge of the rechargeable battery. The existing electronic devices generally control the conduction state of the indicator light by using a logic circuit, a dedicated integrated chip, etc., and such a control circuit may be disadvantageous to the portable electronic device due to the large number of circuit components and complicated structure. And will increase the overall manufacturing cost. In addition, when the portable electronic device has not been used for a long time If the battery is used for a long period of time, the rechargeable battery of the electronic device may be over-discharged, so that the battery voltage is lower than the starting voltage of the electronic device circuit system, so that the battery cannot be started due to the battery voltage being too low at the initial stage of charging. When the indicator light on the portable electronic device is turned off, people may mistake the portable electronic device for damage or the battery cannot be charged, thereby causing unnecessary trouble.

In view of this, it is necessary to provide a charging indicating circuit which is simple in structure, low in cost, and convenient in application.

In addition, it is necessary to provide a portable electronic device to which the charging indicating circuit is applied.

A charging indicating circuit includes a charging control unit electrically connected in sequence, a charging indicating unit, and a battery unit electrically connected to the charging control unit, and a microprocessor unit. The charging indicating unit is configured to indicate a charging state of the battery unit, and the charging control unit comprises a transistor Q2 electrically connected to the charging indicating unit, when the voltage of the battery unit is greater than or equal to the activation of a portable electronic device At the time of voltage, the microprocessor unit controls the transistor Q2 to be turned on or off, thereby controlling the charging indicating unit to be in a different state to indicate the charging state of the charging unit.

A portable electronic device includes a housing and a charging indicating circuit disposed in the housing, the charging indicating circuit includes a power input unit and a charging control unit, a charging indicating unit and a charging indicating unit The charging control unit is electrically connected to one of the battery unit and the microprocessor unit. The power input unit is disposed in the housing, the housing is connected to a charging power source for providing electrical energy, the charging indicating unit is configured to indicate a charging state of the battery unit, and the charging control unit includes a charging indicator unit Sexually connected transistor Q2, when the voltage of the battery unit is greater than or equal to the above When the voltage of the portable electronic device is turned on, the microprocessor unit controls the transistor Q2 to be turned on or off, thereby controlling the charging indicating unit to be in a different state to indicate the charging state of the charging unit.

Compared with the prior art, the charging indicating circuit of the preferred embodiment of the present invention controls the charging indicating unit by the charging control unit and the microprocessor unit to cause the charging indicating unit to display the charging state of the battery unit. In addition, when the battery unit is in the over-discharge state, the charging indicating unit can still determine whether the charging unit is in the charging state. The charging indicating circuit has fewer circuit components and a simple circuit structure. The charging indicating unit can be controlled by controlling the turning on or off of the transistor Q2, and the cost is lower and the use is more convenient.

100‧‧‧Charging indicating circuit

20‧‧‧Filter unit

40‧‧‧Charging control unit

52‧‧‧First signal output pin

60‧‧‧Charging indicator unit

80‧‧‧shell

C‧‧‧ capacitor

D5‧‧‧Light Emitting Diode

R1-R4‧‧‧ resistance

10‧‧‧Power input unit

30‧‧‧Protection unit

50‧‧‧Microprocessor unit

54‧‧‧Second signal output pin

70‧‧‧ battery unit

200‧‧‧Portable electronic devices

D1-D4‧‧‧ diode

F‧‧‧Fuse

O1, Q2‧‧‧O crystal

FIG. 1 is a schematic diagram showing the position of a power input unit and a light emitting diode mounted in a portable electronic device according to a preferred embodiment of the present invention.

2 is a block diagram of a functional unit of a charging indicating circuit in accordance with a preferred embodiment of the present invention.

3 is a circuit schematic diagram of a charging indicating circuit in accordance with a preferred embodiment of the present invention.

Referring to FIG. 1 and FIG. 3, a preferred embodiment of the present invention provides a charging indicating circuit 100, which is applicable to a portable electronic device 200. The portable electronic device 200 can be a mobile phone, a PDA, or an MP3. Wait. The charging indicating circuit 100 includes a power input unit 10, a filtering unit 20, a protection unit 30, a charging control unit 40, a microprocessor unit 50, a charging indicating unit 60, and a battery unit 70. The power input unit 10, the filtering unit 20, the protection unit 30, the charging control unit 40, and the charging indicating unit 60 are electrically connected in sequence, and the protection unit 30 simultaneously performs micro processing. The unit, the charging unit 60 and the battery unit 70 are electrically connected, and the microprocessor unit 50 is electrically connected to the charging control unit 40 at the same time. The portable electronic device 200 has a housing 80. The power input unit 10, the filtering unit 20, the protection unit 30, the charging control unit 40, the microprocessor unit 50, and the battery unit 70 can be mounted on the housing. Within body 80.

Referring to FIG. 2 , the power input unit 10 can be an existing charging port electrically connected to an existing charging device for accessing a charging power source to provide a charging voltage Vc. The power input unit 10 can be configured. The housing 80 is adapted to be connected to any location of the charging power source. The filtering unit 20 includes a capacitor C and a fuse F electrically connected to the power input unit 10. The current of the power input unit 10 is output through a fuse F, which is a filter capacitor and is directly grounded for filtering. The noise in the current output from the power input unit 10 is removed.

The protection unit 30 includes diodes D1, D2, D3, and D4, which may be existing Schottky Barrier Diodes, which constitute a protection circuit. The battery unit 70 and the pins of the damaged microprocessor unit 50 are affected by the current that prevents the current output from the current input unit 10 from being reversed.

The charging control unit 40 includes resistors R1, R2, and R3 and transistors Q1 and Q2. The resistor R1 is a voltage dividing resistor, and one end thereof is connected between the fuse F and the positive (N) pole of the diode D2, and the other is One end is connected between the anode of the diode D3 and the drain D (Drain) of the transistor Q1. The resistor R2 is a pull-down resistor connected between the gate G (Gate) and the source S (Source) of the transistor Q1. The resistor R3 is a voltage dividing resistor connected between the gate G and the source S of the transistor Q2. The drain D of the transistor Q2 is electrically connected to the charging indicating unit 60, and the gate of the transistor Q2 is connected. The pole G is electrically connected to the diode D3 at the same time. Negative (P) pole of D4. The transistors Q1 and Q2 may be existing NMOS (N-Metal-Oxide-Semiconductor, N-metal oxide semiconductor) tubes. When the power input unit 10 is connected to a charging voltage Vc, the gate of the transistor Q2 is The voltage between G and source S is Vgs2 = Vc * R3 / (R1 + R3).

The microprocessor unit 50 can be integrated with a device such as a Micro Controller Unit (MCU) of the portable electronic device 200, and has a programmable logic function and a corresponding control program therein. The microprocessor unit 50 has a first signal output pin (GPIO1) 52 and a second signal output pin (GPIO2) 54. The first signal output pin 52 is connected to the anode of the diode D4, and the second The signal output pin 54 is connected between the gate G of the transistor Q1 and the resistor R2. The first signal output pin 52 and the second signal output pin 54 are two general-purpose output ports, which can be controlled by the internal program of the microprocessor unit 50 to be high/low level to control the external device.

The charging indicating unit 60 includes a light emitting diode (LED) D5 and a resistor R4 connected to the negative electrode of the light emitting diode D5. The other end of the resistor R4 is electrically connected to the drain of the transistor Q2. The pole D, the resistor R4 can be a conventional variable resistor for adjusting the current of the LED D5. The positive electrode of the light-emitting diode D5 is electrically connected to the negative electrode of the diodes D1 and D2, and the forward current flowing through the diodes D1 and D2 can flow to the light-emitting diode D5. It can be understood that the LED D5 can be disposed on the housing 80 at any position for observing the state of charge of the battery unit 70.

The battery unit 70 can be a rechargeable battery such as an existing lithium battery, and is electrically connected to the anode of the diode D1. When the voltage of the battery unit 70 is greater than one of the circuit systems of the portable electronic device 200 When the voltage is activated, it activates the electronic device 200 and provides electrical energy support.

Referring to FIG. 2 and FIG. 3, when the charging indicating circuit 100 is used to indicate the charging state of the battery unit 70 of the portable electronic device 200, the specific operation of the charging indicating circuit 100 under different working states will be described below. Happening.

When the power input unit 10 described above is not connected to the charging power source. At this time, the charging voltage Vc is 0, and the battery unit 70 is in an over-discharged state or a depleted state, the circuit system of the portable electronic device 200 cannot be activated, and there is no current in the light-emitting diode D5. Therefore, it appears to be extinguished.

When the power input unit 10 is connected to the charging power source, and the voltage of the battery unit 70 is still less than the starting voltage of the circuit system of the portable electronic device 200. At this time, the voltage Vgs1 between the gate G and the source S of the transistor Q1 is 0, and the transistor Q1 cannot be turned on, so that the transistor Q1 is turned off. The voltage Vgs2=Vc*R3/(R1+R3) between the gate G and the source S of the transistor Q2, due to the voltage division of the voltage dividing resistor R3, the Vgs2 can reach the turn-on voltage of the transistor Q2. VT2 causes the transistor Q2 to be in a conducting state, at which time the current forms a path through the fuse F, the diode D2, the light-emitting diode D5, the resistors R4 and Q2, D and S, thereby illuminating the light-emitting diode D5, and Keep it in a light state. During the charging process, the light-emitting diode D5 is controlled by the charging voltage Vc, and the light-emitting diode D5 is always in a light-emitting state.

When the power input unit 10 is connected to the charging power source, and the voltage of the battery unit 70 is greater than or equal to the starting voltage of the circuit system of the portable electronic device 200. At this time, the circuit system of the portable electronic device 200 is activated, and the transistor Q2 and the light-emitting diode D5 are controlled by the microprocessor unit 50. The second signal output pin 54 of the microprocessor unit 50 outputs a high level to the gate G of the transistor Q1 to turn on the transistor Q1. Since the source S of the transistor Q1 is grounded, the transistor Q1 is Drain D voltage Vd and electro-crystal The source S voltage Vs of the body Q1 is 0, and the voltage of the gate G of both ends of the diode D3 and the transistor Q2 is also 0. Since the transistor Q2 has no external bias voltage, the transistor Q2 is in an off state. . At the same time, the first signal output pin 52 of the microprocessor unit 50 outputs a high level to the gate G of the transistor Q2 via the diode D4, and the voltage between the gate G and the source S of the transistor Q2. Vgs2 is greater than the turn-on voltage VT2 of the transistor Q2, so the transistor Q2 is controlled by the microprocessor unit 50 to be in an on state. Then, the current supplied from the battery unit 70 forms a path via the diode D1, the light-emitting diode D5, and the resistor R4, thereby illuminating the light-emitting diode D5 and causing it to be in a light-emitting state. During the charging process, the LED D5 is controlled by the microprocessor unit 50, and the LED 2 is kept in a light-emitting state by holding the conductive crystal Q2.

When the power input unit 10 is connected to the charging power source, and the battery unit 70 is fully charged, the microprocessor unit 50 detects that one of the output of the battery unit 70 indicates that the power signal has been fully charged, and the microprocessor unit The first signal output pin 52 is controlled by the logic signal to output a low level to the gate G of the transistor Q2 via the diode D4. The transistor Q2 is turned off by the microprocessor unit 50. status. The above-mentioned light-emitting diode D5 has no current passing therethrough and is in an extinguished state.

The charging indicating circuit 100 of the preferred embodiment of the present invention controls the charging instructing unit 60 by the charging control unit 40 and the microprocessor unit 50 to cause the charging instructing unit 60 to display the state of charge of the battery unit 70. In addition, when the battery unit 70 is in the over-discharge state, the charging indicating unit 60 can still determine whether the charging unit 70 is in the charging state. The charging indicating circuit 100 has a simple structure, and the charging indicating unit 60 can be controlled by controlling the turning on or off of the transistor Q2, and the cost is low, which satisfies people's consumption needs.

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. However, the above-mentioned embodiments are only the embodiments of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and those skilled in the art will be equivalently modified or changed in the spirit of the invention. It is included in the scope of the following patent application.

100‧‧‧Charging indicating circuit

20‧‧‧Filter unit

40‧‧‧Charging control unit

52‧‧‧First signal output pin

60‧‧‧Charging indicator unit

C‧‧‧ capacitor

D5‧‧‧Light Emitting Diode

R1-R4‧‧‧ resistance

10‧‧‧Power input unit

30‧‧‧Protection unit

50‧‧‧Microprocessor unit

54‧‧‧Second signal output pin

70‧‧‧ battery unit

D1-D4‧‧‧ diode

F‧‧‧Fuse

Q1, Q2‧‧‧O crystal

Claims (10)

A charging indicating circuit includes a charging indicating unit and a battery unit, wherein the charging indicating unit is configured to indicate a charging state of the battery unit, and the improvement is that the charging indicating circuit further comprises an electrical connection with the charging indicating unit a charging control unit and a microprocessor unit electrically connected to the charging control unit, the charging control unit includes a transistor Q2 electrically connected to the charging indicating unit, when the voltage of the battery unit is greater than or equal to one When the voltage of the portable electronic device is turned on, the microprocessor unit controls the transistor Q2 to be turned on or off, thereby controlling the charging indicating unit to be in a different state to indicate the charging state of the charging unit; when the battery unit When the voltage is less than the starting voltage of the portable electronic device, the charging control unit controls the charging indicating unit to be in a different state to indicate the charging state of the charging unit. The charging indicating circuit of claim 1, wherein the charging indicating circuit further comprises a power input unit, wherein the power input unit is configured to access a charging power source to provide power, and when the voltage of the battery unit is less than The power input unit controls the on or off of the transistor Q2 when the startup voltage of the portable electronic device is turned on, thereby controlling the charging indication unit to be in a different state to indicate the charging state of the charging unit. The charging indicating circuit according to claim 1, wherein the charging control unit further comprises resistors R1, R2, R3 and a transistor Q1, and a drain D of the transistor Q1 is connected to the resistor R1, and a gate thereof G and source S are respectively connected to both ends of the resistor R2, and the gate G and the source S of the transistor Q2 are respectively connected to the ends of the resistor R3, and the drain thereof D is electrically connected to the charging indicating unit, the resistor R1 is a voltage dividing resistor of the transistor Q2, the resistor R2 is a pull-down resistor of the transistor Q1, and the resistor R3 is a bias resistor of the transistor Q2. The charging indicating circuit according to claim 3, wherein the transistor Q1 and the transistor Q2 are N-type MOS transistors. The charging indicating circuit of claim 3, wherein the charging indicating circuit further comprises a protection unit electrically connected to the charging control unit, the microprocessor unit, the charging indicating unit and the battery unit, The protection unit comprises diodes D1, D2, D3 and D4, the anode of the diode D1 is connected to the battery unit, the cathodes of the diodes D1 and D2 are connected to the charging indicating unit, and the diode D2 and the diode D3 are connected. The positive electrode is connected to both ends of the resistor R1, the negative electrodes of the diodes D3 and D4 are connected to the gate G of the transistor Q2, and the anode of the diode D4 is connected to the microprocessor unit. The charging indicating circuit of claim 5, wherein the microprocessor unit has a first signal output pin and a second signal output pin, the first signal output pin and the second signal output. The pin is used to output a control signal, and the first signal output pin is connected to the anode of the diode D4, and the second signal output pin is connected between the gate G of the transistor Q1 and the resistor R2. The charging indicating circuit of claim 5, wherein the charging indicating unit comprises a light emitting diode D5 and a resistor R4 connected to the negative electrode of the light emitting diode D5, and the positive electrode of the light emitting diode D5 Electrically connected to the negative poles of the diodes D1 and D2, the other end of the resistor R4 is electrically connected to the drain D of the transistor Q2. When the transistor Q2 is turned on, the light emitting diode D5 emits light when the transistor Q2 is turned off. At the time, the light-emitting diode D5 is extinguished. The charging indicating circuit of claim 5, wherein the charging indicating circuit further comprises a filter electrically connected to the protection unit and the power input unit. a wave unit, the filter unit includes a capacitor C and a fuse F. The power input unit is electrically connected to the capacitor C and the fuse F, and is used for accessing a charging power source, and the current of the power input unit is output through the fuse F. The capacitor C is a filter capacitor and is directly grounded to filter out the clutter in the current output from the power input unit 10. The fuse F is electrically connected to the resistor R1 and the cathode of the diode D2. A portable electronic device includes a housing and a charging indicating circuit disposed in the housing, the charging indicating circuit includes a power input unit, a charging indicating unit and a battery unit, and the power input unit is disposed in the shell The charging indicating unit is configured to indicate the charging state of the battery unit by using a charging power supply, and the charging indicating circuit comprises: electrically connecting with the charging indicating unit a charging control unit and a microprocessor unit electrically connected to the charging control unit, the charging control unit includes a transistor Q2 electrically connected to the charging indicating unit, when the voltage of the battery unit is greater than or equal to a portable When the voltage of the electronic device is turned on, the microprocessor unit controls the transistor Q2 to be turned on or off, thereby controlling the charging indicating unit to be in a different state to indicate the charging state of the charging unit. The portable electronic device of claim 9, wherein the charging indicating circuit further comprises a filtering unit electrically connected to the power input unit and a protection unit, wherein the filtering unit is configured to eliminate the power input unit The clutter of the current is input, and the protection unit is electrically connected to the filtering unit, the charging control unit, the microprocessor unit, the charging indicating unit and the battery unit, and is used for preventing reverse current circulation.