Lithium battery charger zero standby power consumption zero voltage output circuit

Abstract

This utility model discloses a zero-standby power consumption and zero-voltage output circuit for a lithium battery charger, including an RC charging and discharging circuit, a first switching circuit, a second switching circuit, and an NFC induction coil circuit. The RC charging and discharging circuit includes a resistor and a capacitor connected in series between the power bus and ground. The first switching circuit is connected to the control terminal of the MCU system, the NFC induction coil circuit, and the RC charging and discharging circuit. The control signal from the MCU system or the NFC induction coil circuit controls the opening and closing of the first switching circuit to charge and discharge the capacitor in the RC charging and discharging circuit. The second switching circuit is connected to the RC charging and discharging circuit and an auxiliary power supply. The charging and discharging of the capacitor in the RC charging and discharging circuit controls the opening and closing of the second switching circuit to turn the auxiliary power supply off or on. This utility model's zero-standby power consumption and zero-voltage output circuit for a lithium battery charger achieves zero standby power consumption and zero-voltage output, effectively solving problems such as high standby power consumption and safety hazards.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery charging technology, and in particular to a zero standby power consumption and zero voltage output circuit for a lithium battery charger. Background Technology

[0002] Most lithium battery chargers on the market remain powered on in standby mode, even when no device is connected, and continuously output open-circuit voltage. This results in significant standby power consumption. For example, a 48V lithium battery charger typically outputs around 55V in standby mode. Assuming a common standby power consumption of 10W, if left plugged in unused for 24 hours a day, the annual power consumption could reach 87.6 kWh.

[0003] Standby mode not only consumes a lot of power, but more seriously, the voltage output during standby poses numerous safety hazards: prolonged power-on can cause internal components to overheat, accelerating the aging of insulation materials and increasing the risk of short circuits and leakage. In hot and humid environments, these hazards are more likely to cause serious accidents such as fires and electric shocks. In addition, some substandard chargers may also generate electromagnetic radiation in standby mode, and long-term exposure may pose a potential threat to human health.

[0004] Therefore, how to solve the problems of high power consumption and safety hazards caused by the standby state of lithium battery chargers is an important technical issue that urgently needs to be addressed. Utility Model Content

[0005] In view of the shortcomings of the existing technology, the technical problem to be solved by this utility model is to provide a zero standby power consumption and zero voltage output circuit for lithium battery chargers, which effectively solves the problems of high power consumption and safety hazards in standby mode.

[0006] To achieve the above objectives, this utility model provides a zero standby power consumption and zero voltage output circuit for a lithium battery charger, including an RC charging and discharging circuit, a first switching circuit, a second switching circuit, and an NFC induction coil circuit; wherein, The RC charging and discharging circuit includes a first resistor and a capacitor, wherein the first resistor and the capacitor are connected in series between the power bus and ground. The first switching circuit is connected to the control terminal of the MCU system, the NFC induction coil circuit, and the RC charging and discharging circuit. The control signal from the control terminal of the MCU system or the control signal from the NFC induction coil circuit controls the opening and closing of the first switching circuit to charge and discharge the capacitor of the RC charging and discharging circuit. The second switching circuit is connected to the RC charging and discharging circuit and the auxiliary power supply. The charging and discharging of the capacitor in the RC charging and discharging circuit controls the opening and closing of the second switching circuit to turn the auxiliary power supply off or on.

[0007] Furthermore, the first switching circuit includes a second resistor, a third resistor, and a first field-effect transistor; wherein, one end of the second resistor is connected to the control terminal of the MCU system and the NFC induction coil circuit, and the other end is connected to the third resistor and the gate of the first field-effect transistor respectively; the third resistor is connected between the gate and drain of the first field-effect transistor; the source and drain of the first field-effect transistor are connected in parallel across the capacitor of the RC charging and discharging circuit, and the drain is grounded.

[0008] Furthermore, the second switching circuit includes a fourth resistor and a second field-effect transistor; wherein the fourth resistor, the gate and drain of the second field-effect transistor are connected in parallel across the capacitor of the RC charging and discharging circuit; the source of the second field-effect transistor is connected to the auxiliary power supply, and the drain is grounded.

[0009] Furthermore, the second switching circuit also includes a clamping diode connected between the drain and gate of the second field-effect transistor.

[0010] Furthermore, the NFC induction coil circuit includes an NFC induction coil and a capacitor; wherein one end of the NFC induction coil and the capacitor are both connected to the first switching circuit; and the other end of the NFC induction coil and the capacitor are both grounded.

[0011] Furthermore, the NFC induction coil circuit also includes a diode, which is connected between one end of the NFC induction coil and the first switching circuit.

[0012] Furthermore, a diode is connected between the MCU system and the first switching circuit.

[0013] The zero standby power consumption and zero voltage output circuit for lithium battery charger provided by this utility model adopts a MOSFET switching circuit, an RC charging and discharging circuit, and an NFC induction coil circuit. In the charging state, it can be connected to an auxiliary power supply to ensure normal charging of the lithium battery. When entering the standby state, the connection path with the auxiliary power supply is disconnected, so that the auxiliary power supply cannot supply power to the AC-DC system and the MCU system, thereby achieving zero standby power consumption and zero voltage output. This effectively avoids the safety hazards caused by standby and achieves the purpose of energy saving and emission reduction. Attached Figure Description

[0014] Figure 1 The circuit diagram of the zero standby power consumption and zero voltage output circuit for the lithium battery charger provided by this utility model. Detailed Implementation

[0015] The following, in conjunction with the accompanying drawings and preferred embodiments of the present invention, further illustrates the technical means adopted by the present invention to achieve its intended purpose.

[0016] like Figure 1 As shown, an embodiment of this utility model provides a zero standby power consumption and zero voltage output circuit for a lithium battery charger, including an RC charging and discharging circuit 11, a first switching circuit 12, a second switching circuit 13, and an NFC induction coil circuit 14. The RC charging and discharging circuit 11 includes a resistor and a capacitor, connected in series between the power bus VBUS and ground. The first switching circuit 12 is connected to the control terminal of the MCU system 21, the NFC induction coil circuit 14, and the RC charging and discharging circuit 11. The control signal from the MCU control circuit or the NFC induction coil circuit 14 controls the opening and closing of the first switching circuit 12 to charge and discharge the capacitor of the RC charging and discharging circuit 11. The second switching circuit 13 is connected to the RC charging and discharging circuit 11 and an auxiliary power supply 22. The charging and discharging of the capacitor in the RC charging and discharging circuit 11 controls the opening and closing of the second switching circuit 13 to turn the auxiliary power supply 22 on or off. The auxiliary power supply provides energy to the AC-DC system and the MCU system 21. The auxiliary power supply includes a control chip U1, which controls the opening or closing of the auxiliary power supply 22 by enabling the control chip U1.

[0017] Specifically, the RC charging and discharging circuit 11 includes a resistor R1 and a capacitor C1. One end of the resistor R1 is connected to VBUS, and the other end is grounded through the capacitor C1. The voltage across the capacitor C1 is configured by the RC parameters.

[0018] The first switching circuit 12 includes resistors R2 and R3, and a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) Q1. One end of resistor R2 is the drive terminal Drive_Power, which is connected to the control terminal of the MCU system 21 and the NFC induction coil circuit 14. The other end is connected to one end of resistor R3 and the gate of MOSFET Q1. The other end of resistor R3 and the drain of MOSFET Q1 are both grounded. The source and drain of MOSFET Q1 are connected in parallel across capacitor C1 of RC charging and discharging circuit 11.

[0019] The second switching circuit 13 includes a resistor R4 and a MOSFET Q2; where resistor R4 is a voltage divider resistor, and resistor R4 is connected in parallel across capacitor C1. The gate and drain of MOSFET Q2 are connected in parallel across capacitor C1 in the RC charging / discharging circuit 11, the source is connected to the auxiliary power supply 22, and the drain is grounded. The gate voltage of MOSFET Q2 is generated by the voltage divider of VBUS by resistors R1 and R4. A clamping diode D1 is also connected between the drain and gate of MOSFET Q2, which protects MOSFET Q2 when there is an abnormality or voltage spike in VBUS. The turn-on time of MOSFET Q2 is determined by the RC time constant of the RC charging / discharging circuit 11. When MOSFET Q2 is off, the main control chip U1 used for the disabled auxiliary power supply 22 ensures that the auxiliary power supply 22 has no output in standby mode, the AC-DC system and MCU system 21 have no power supply, and the entire charger generates no losses.

[0020] The NFC induction coil circuit 14 includes an NFC induction coil and a capacitor C2; one end of both the NFC induction coil and the capacitor C2 is connected to the first switching circuit 12; the other end of both the NFC induction coil and the capacitor C2 is grounded. To suppress reverse current, a diode D3 is also provided between one end of the NFC induction coil and the first switching circuit 12 in the NFC induction coil circuit 14. The anode of the diode D3 is connected to the NFC induction coil, and the cathode is connected to the Drive_Power of the first switching circuit 12.

[0021] Preferably, a diode D2 is connected between the control terminal of the MCU system 21 and the first switching circuit 12. The anode of the diode D2 is connected to the control terminal of the MCU system 21, and the cathode is connected to the Drive_Power of the first switching circuit 12.

[0022] The working principle of the zero standby power consumption and zero voltage output circuit of the lithium battery charger provided by this utility model will be described in detail below with reference to the accompanying drawings:

[0023] 1) When the lithium battery charger is connected to AC power, VBUS charges capacitor C1 through resistor R1. The values ​​of resistor R1 and capacitor C1 are relatively large, resulting in a large time constant. This ensures that the time it takes for the voltage on capacitor C1 to reach the threshold voltage of MOSFET Q2 is greater than the startup time of MCU system 21. MCU system 21 outputs a high level to Drive_Power, turning on MOSFET Q1 and making the gate of MOSFET Q2 low. MOSFET Q2 is in the off state, and the entire system can perform normal logic judgment and charging process.

[0024] 2) When the system determines that it is fully charged, or when no battery has been connected for charging for an extended period, the system will perform zero standby and zero voltage output processing. The MCU control system outputs a low level to Drive_Power, MOSFET Q1 is off, and VBUS charges capacitor C1 through resistor R1. When the voltage on capacitor C1 exceeds the threshold voltage of MOSFET Q2, MOSFET Q2 closes, pulling the enable pin of the auxiliary power supply 22 main control chip U1 to a low level, thereby shutting down auxiliary power supply 22 and thus shutting down the output of the entire system, achieving zero standby power consumption and zero voltage output.

[0025] 3) When the system is in a state of zero standby power consumption and zero voltage, and the lithium battery needs to be charged, this utility model provides two startup methods:

[0026] One method is NFC induction start-up: using a terminal with NFC function, the NFC function is used to sense the NFC induction coil, which charges the capacitor C2. When the voltage on the capacitor C2 exceeds the threshold voltage of MOSFET Q1, MOSFET Q1 closes, capacitor C1 discharges rapidly, MOSFET Q2 opens, the auxiliary power supply 22 main control chip U1 is enabled, and the system starts up and works normally.

[0027] One method is to use a hard-plug method to start the device when there is no NFC function: unplug the AC plug, let the resistor R1 discharge the capacitor C1, and wait for the voltage of the capacitor C1 to drop to 0V (wait a few seconds), then plug the AC plug back in to enter the startup process mentioned in 1) above.

[0028] As can be seen from the above, the lithium battery charger zero standby power consumption and zero voltage output circuit provided by this utility model, by adopting a MOSFET switching circuit, an RC charging and discharging circuit 11 and an NFC induction coil circuit 14, connects to the auxiliary power supply 22 in the charging state to ensure normal charging of the lithium battery; when entering the standby state, the connection path between the auxiliary power supply 22 is disconnected, so that the AC-DC system and the MCU system 21 have no power supply, realizing zero standby power consumption and zero voltage output, effectively avoiding the safety hazards caused by standby power consumption.

[0029] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to preferred embodiments, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model's technical solution. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the content of the present utility model's technical solution shall still fall within the scope of the present utility model's technical solution.

Claims

1. A zero-standby power consumption and zero-voltage output circuit for a lithium battery charger, characterized in that, It includes an RC charging and discharging circuit, a first switching circuit, a second switching circuit, and an NFC induction coil circuit; among which, The RC charging and discharging circuit includes a first resistor and a capacitor, wherein the first resistor and the capacitor are connected in series between the power bus and ground. The first switching circuit is connected to the control terminal of the MCU system, the NFC induction coil circuit and the RC charging and discharging circuit. The control terminal of the MCU system or the control signal of the NFC induction coil circuit controls the opening and closing of the first switching circuit to charge and discharge the capacitor of the RC charging and discharging circuit. The second switching circuit is connected to the RC charging and discharging circuit and the auxiliary power supply. The charging and discharging of the capacitor in the RC charging and discharging circuit controls the opening and closing of the second switching circuit to turn the auxiliary power supply off or on.

2. The zero standby power consumption and zero voltage output circuit for a lithium battery charger according to claim 1, characterized in that, The first switching circuit includes a second resistor, a third resistor, and a first field-effect transistor; wherein, one end of the second resistor is connected to the control terminal of the MCU system and the NFC induction coil circuit, and the other end is connected to the third resistor and the gate of the first field-effect transistor respectively; the third resistor is connected between the gate and the drain of the first field-effect transistor; the source and drain of the first field-effect transistor are connected in parallel across the capacitor of the RC charging and discharging circuit, and the drain is grounded.

3. The zero standby power consumption and zero voltage output circuit for a lithium battery charger according to claim 1 or 2, characterized in that, The second switching circuit includes a fourth resistor and a second field-effect transistor; wherein the fourth resistor, the gate and drain of the second field-effect transistor are connected in parallel across the capacitor of the RC charging and discharging circuit; the source of the second field-effect transistor is connected to the auxiliary power supply, and the drain is grounded.

4. The zero standby power consumption and zero voltage output circuit for a lithium battery charger according to claim 3, characterized in that, The second switching circuit also includes a clamping diode connected between the drain and gate of the second field-effect transistor.

5. The zero standby power consumption and zero voltage output circuit for a lithium battery charger according to claim 1 or 2, characterized in that, The NFC induction coil circuit includes an NFC induction coil and a capacitor; wherein one end of the NFC induction coil and one end of the capacitor are both connected to the first switching circuit; and the other end of the NFC induction coil and the capacitor are both grounded.

6. The zero standby power consumption and zero voltage output circuit for a lithium battery charger according to claim 5, characterized in that, The NFC induction coil circuit also includes a diode, which is connected between one end of the NFC induction coil and the first switching circuit.

7. The zero standby power consumption and zero voltage output circuit for a lithium battery charger according to claim 1 or 2, characterized in that, A diode is connected between the MCU system and the first switching circuit.

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