Charging path switching circuit

Abstract

The utility model discloses a charging path switching circuit, which relates to the technical field of power management, aims to solve the problem of fast power consumption of a lithium battery product, and comprises a battery control module which is respectively connected with a battery power supply input end and a single chip microcomputer system, and the battery control module is respectively connected with a boosting module and a self-locking control module. The self-locking control module is further connected with a power supply control module, the power supply control module is connected with a power supply input end of a power supply, the self-locking control module, the power supply control module and the battery control module are all connected with the single-chip microcomputer system, and the boosting module and the power supply control module are connected with power supply output. The charging path switching circuit provided by the utility model can manage the charging path of the equipment, can automatically switch between the power supply of the power supply and the power supply of the battery, realizes the functions of standby zero power consumption and circuit self-locking, and effectively prolongs the working time of a lithium battery product.

Description

Technical Field

[0001] The utility model belongs to the technical field of power management, and particularly relates to a charging path switching circuit. Background Art

[0002] With the increasing number of lithium battery products, more lithium battery products have a demand for power supply path switching, and it is necessary to realize switching of different power supplies under different working conditions. Therefore, the device charging path switching circuit has emerged. However, the existing charging path switching circuits still have certain deficiencies.

[0003] For example, there is a Chinese patent with the publication number CN209419261U, which relates to a battery charging path switching circuit, including an IC control circuit, a charging circuit, and a path management circuit. The IC control circuit includes a charging management chip U1 with VCC pin, VIN pin, ACOK pin, CHGOK pin, SW pin, BST pin, CSP pin, BATT pin, and GND pin. The GND pin of the charging management chip U1 is grounded, the VCC pin of the charging management chip U1 is connected to the node Vin, the VIN pin of the charging management chip U1 is connected to the node Vout, the path management circuit is respectively connected to the VCC pin, the VIN pin, and the charging circuit, and the charging circuit is respectively connected to the SW pin, the BST pin, the CSP pin, and the BATT pin. This can greatly reduce the charge and discharge times of the battery, extend the service life of the battery, and at the same time maximize the preservation of battery energy and ensure a longer battery life. However, the Chinese patent with the publication number CN209419261U still powers the device by the battery during standby, resulting in a short standby time of the device and causing a certain amount of resource waste. Summary of the Utility Model

[0004] In order to solve the problem of fast power consumption of lithium battery products, the utility model proposes a charging path switching circuit, which can manage the charging path of the device, automatically switch between power supply and battery power supply, and can realize the functions of zero standby power consumption and circuit self-locking, effectively extending the working time of lithium battery products.

[0005] To achieve the above purpose, the utility model adopts the following technical solution: a charging path switching circuit,

[0006] including a battery control module, which is respectively connected to a battery power supply input terminal and a single-chip microcomputer system. The battery control module is respectively connected to a boost module and a self-locking control module. The self-locking control module is also connected to a power control module. The power control module is connected to the power supply input terminal. The self-locking control module, the power control module, and the battery control module are all connected to the single-chip microcomputer system. The boost module and the power control module are connected to the power supply output.

[0007] In this technical solution, the charging path switching circuit can realize the automatic switching of the device's charging path between the power supply and the battery through the single-chip microcomputer, saving battery power, reducing the number of battery charge and discharge cycles, and extending the battery life; it also realizes the functions of zero standby power consumption and circuit self-locking, effectively extending the working time of lithium battery products; the battery power supply can be controlled by a button, and the function of circuit self-locking when the button is released can be realized; moreover, the charging path switching circuit has a simple structure, which can effectively reduce costs.

[0008] The present utility model is further configured as: the power supply control module includes a first power supply control unit and a second power supply control unit connected to each other, and the second power supply control unit is further connected to a detection unit; the detection unit is connected to the power supply detection pin of the single-chip microcomputer system, and the first power supply control unit is connected to the power supply control pin of the single-chip microcomputer system.

[0009] In this technical solution, the power supply control module controls the power supply input to reach the single-chip microcomputer system to supply power to the single-chip microcomputer system, and transmits the detected power supply input signal to the single-chip microcomputer system to realize the control of the charging path switching by the single-chip microcomputer system.

[0010] The present utility model is further configured as: the battery control module includes a first battery control unit and a second battery control unit, and the second battery control module is connected to the battery power supply input terminal.

[0011] In this technical solution, the battery control module controls whether the battery power supply input can reach the boost module and whether the boost module can output the power supply to the single-chip microcomputer system to supply power to the single-chip microcomputer system to realize the control of the battery power supply by the single-chip microcomputer system.

[0012] The present utility model is further configured as: the boost module includes a boost control unit, the boost control unit is respectively connected to the power supply input terminal and the boost unit, the boost unit is respectively connected to the RC absorption unit and the feedback unit, and the feedback unit is connected to the power supply control module through a capacitor unit.

[0013] In this technical solution, the boost module realizes the boosting of the battery power supply, and the on-off of the boost module can be automatically controlled by the single-chip microcomputer system.

[0014] The present utility model is further configured as: the first power supply control unit includes a triode TR1, the emitter of TR1 is grounded, the collector of TR1 is connected to the second power supply control unit, and the base of TR1 is connected to the single-chip microcomputer system through a resistor R11.

[0015] In this technical solution, the on-off of the first power supply control unit is controlled by the single-chip microcomputer system, and the on-off of the first power supply control unit affects the on-off of the second power supply control unit, thereby controlling whether the power supply input can reach the power supply input terminal of the single-chip microcomputer system.

[0016] The present utility model is further configured as follows: The second power control unit includes a PMOS transistor Q2. The drain of Q2 is respectively connected to the power supply input terminal and the detection unit. The gate of Q2 is connected to the first power control unit through a resistor R6. The source of Q2 is connected to the boost module.

[0017] In this technical solution, the on / off of the second power control unit determines whether the power supply input can reach the power supply input terminal of the single-chip microcomputer system. The on / off of the second power control unit is affected by the on / off of the first power control unit.

[0018] The present utility model is further configured as follows: The first battery control unit includes a triode TR2. The emitter of TR2 is grounded. The collector of TR2 is respectively connected to the second battery control unit and the self-locking control module. The base of TR2 is connected to the single-chip microcomputer system through a resistor R13.

[0019] In this technical solution, the on / off of the first battery control unit is controlled by the single-chip microcomputer system. The on / off of the first battery control unit affects the on / off of the second battery control unit.

[0020] The present utility model is further configured as follows: The second battery control unit includes a PMOS transistor Q1. The source of Q1 is connected to the battery power supply input terminal. The gate of Q1 is connected to the first battery control unit and the self-locking control module through a resistor R4. The drain of Q1 is connected to the boost module.

[0021] In this technical solution, the on / off of the second battery control unit affects whether the battery power supply input can reach the boost module, and further affects whether the battery power supply input can reach the single-chip microcomputer system, so as to control whether the device is powered by the battery.

[0022] The present utility model is further configured as follows: The boost voltage unit includes an integrated chip U1. The enable pin of U1 is connected to the boost control unit. The switch pin of U1 is connected to the RC absorption unit. An inductor L1 is connected between the voltage input pin and the switch pin of U1. The feedback unit is connected to the output pin and the voltage feedback pin of U1.

[0023] In this technical solution, the boost unit is controlled by the single-chip microcomputer system through the boost control unit, boosts the lithium battery power supply input voltage transmitted by the battery control module, and then outputs it to the single-chip microcomputer system via the capacitor unit, thereby powering the device.

[0024] The present utility model is further configured as follows: The boost control unit includes a triode TR3. The emitter of TR3 is grounded. The collector of TR3 is connected to the enable pin of the boost unit. The base of TR3 is connected to one end of a resistor R15. The other end of the resistor R15 is respectively connected to the power supply input terminal and the boost control pin of the single-chip microcomputer system through diodes.

[0025] In this technical solution, the boost control unit realizes whether the boost circuit works under the control of the single-chip microcomputer system, and further controls whether the power supply at the input end of the lithium battery can be output to the single-chip microcomputer system.

[0026] The beneficial effects of the present utility model are as follows:

[0027] 1. Automatically switch between power supply and battery power supply, save battery power, reduce the number of battery charging and discharging times, and extend the battery life;

[0028] 2. When the system is in standby, automatically cut off the output of the battery power supply, achieve zero power consumption in the standby state, and meet the ultra-long standby function of lithium battery products;

[0029] 3. The battery power supply can be controlled by a button, and the function of circuit self-locking when the button is released is realized;

[0030] 4. The circuit is simple, which can effectively reduce costs. Description of the Drawings

[0031] Figure 1 is the schematic diagram of a charging path switching circuit of the present utility model. Detailed Embodiments

[0032] To make the purpose, technical solution and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only the best embodiments of the present utility model, which are only used to explain the present utility model and do not limit the protection scope of the present utility model. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present utility model.

[0033] The charging path switching circuit of the present utility model realizes the seamless switching between device charging through the power supply and charging through the battery.

[0034] When the power supply is on, the battery is automatically powered off. When the power supply is removed, the battery automatically starts to supply power, and the zero power consumption in the system standby state and the function of button release self-locking are also realized.

[0035] Embodiment 1

[0036] This embodiment provides a charging path switching circuit. Refer to Figure 1 , which includes a power control module, a battery control module, a boost module and a self-locking control module.

[0037] The power control module includes a detection unit, a first power control unit and a second power control unit.

[0038] The power control module includes a first battery control unit and a second battery control unit.

[0039] The boost module includes a boost control unit, a boost unit, an RC absorption unit, a feedback unit, and a capacitor unit.

[0040] The battery control module is respectively connected to a battery power supply input terminal and a microcontroller system. The battery control module is respectively connected to a boost module and a self-locking control module. The self-locking control module is also connected to a power supply control module. The power supply control module is connected to a power supply input terminal. The self-locking control module, the power supply control module, and the battery control module are all connected to the microcontroller system.

[0041] The power supply control module includes a first power supply control unit. The first power supply control unit is connected to a second power supply control unit. The second power supply control unit is also connected to a detection unit. The detection unit is connected to the power supply detection pin of the microcontroller system. The first power supply control unit is connected to the power supply control pin of the microcontroller system. The power supply control pin is an output pin.

[0042] In this embodiment, the battery power supply is a lithium battery power supply, and the power supply is input by TYPEC.

[0043] In some other embodiments, the power supply can also be input by a DC plug.

[0044] The power supply control module controls the power supply input to reach the microcontroller system to supply power to the microcontroller system, and transmits the detected power supply input signal to the microcontroller system to realize the control of the charging path switching by the microcontroller system.

[0045] The first power supply control unit includes a triode TR1. The emitter of the triode TR1 is grounded. The collector of the triode TR1 is connected to the second power supply control unit. The base of the triode TR1 is respectively connected to one end of a resistor R11 and one end of a resistor R12. The other end of the resistor R11 is connected to the power supply control pin of the microcontroller system. The other end of the resistor R12 is connected to the emitter of the triode TR1.

[0046] The on / off of the first power supply control unit is controlled by the microcontroller system. The on / off of the first power supply control unit affects the on / off of the second power supply control unit, thereby controlling whether the power supply input can reach the power supply input terminal of the microcontroller system.

[0047] The second power supply control unit includes a PMOS transistor Q2. The drain of the PMOS transistor Q2 is respectively connected to the power supply input terminal and the detection unit. The gate of the PMOS transistor Q2 is respectively connected to one end of a resistor R5 and one end of a resistor R6. The other end of the resistor R5 is connected to the source of the PMOS transistor Q2. The other end of the resistor R6 is connected to the first power supply control unit. The source of the PMOS transistor Q2 is also connected to the capacitor unit of the boost module.

[0048] The on / off state of the second power control unit determines whether the power supply input can reach the power supply input terminal of the single-chip microcomputer system. The on / off state of the second power control unit is affected by the on / off state of the first power control unit.

[0049] The detection unit includes a resistor R17. One end of the resistor R17 is connected to the power supply input terminal, and the other end is respectively connected to one end of a resistor R18 and one end of a resistor R19. The other end of the resistor R18 is respectively connected to the power supply detection pin of the single-chip microcomputer system and one end of a capacitor C8. The other end of the resistor R19 is grounded, and the other end of the capacitor C8 is grounded.

[0050] The detection module detects whether there is a power supply input at the power supply input terminal and transmits the signal to the single-chip microcomputer system through the power supply detection pin, so that the single-chip microcomputer system can control the on / off state of the boost module.

[0051] The battery control module includes a first battery control unit and a second battery control unit. The second battery control module is connected to the battery power supply input terminal.

[0052] The battery control module controls whether the battery power supply input can reach the boost module and whether the boost module can output the power supply to the single-chip microcomputer system to supply power to the single-chip microcomputer system, so as to realize the control of the single-chip microcomputer system over the battery power supply.

[0053] The first battery control unit includes a triode TR2. The emitter of the triode TR2 is grounded. The collector of the triode TR2 is respectively connected to the second control unit and the self-locking control module. The base of the triode TR2 is respectively connected to one end of a resistor R13 and one end of an R14. The other end of the resistor R13 is connected to the battery control pin of the single-chip microcomputer system, and the other end of the resistor R14 is connected to the emitter of the triode TR2.

[0054] The on / off state of the first battery control unit is controlled by the single-chip microcomputer system. The on / off state of the first battery control unit affects the on / off state of the second battery control unit.

[0055] The second battery control unit includes a PMOS transistor Q1. The source of the PMOS transistor Q1 is connected to the battery power supply input terminal. The gate of the PMOS transistor Q1 is respectively connected to one end of a resistor R2 and one end of a resistor R4. The other end of the resistor R2 is connected to the source of the PMOS transistor Q1. The other end of the resistor R4 is respectively connected to the collector of the triode TR2 of the first battery control unit and the self-locking control module. The drain of the PMOS transistor Q1 is connected to the voltage input pin of the boost module.

[0056] The on / off state of the second battery control unit affects whether the battery power supply input can reach the boost module, and further affects whether the battery power supply input can reach the single-chip microcomputer system, so as to realize the control of whether the device is powered by the battery.

[0057] The boost module includes a boost control unit. The boost control unit is respectively connected to the power input terminal and the boost unit. The boost unit is respectively connected to the RC absorption unit and the feedback unit. The feedback unit is connected to the power control module through a capacitor unit.

[0058] The boost module realizes the boost of battery power supply, and the on / off of the boost module can be automatically controlled by the single-chip microcomputer system.

[0059] The boost unit includes an integrated chip U1. The integrated chip U1 has 6 pins, namely a voltage input pin, an enable pin, a ground pin, a switch pin, an output pin, and a voltage feedback pin.

[0060] The enable pin of the integrated chip U1 is connected to the collector of the triode TR3 of the boost control unit. The switch pin of the integrated chip U1 is connected to the RC absorption unit. An inductor L1 is connected between the voltage input pin and the switch pin of the integrated chip U1. The feedback unit of the boost module is connected to the output pin and the voltage feedback pin of the integrated chip U1.

[0061] The boost unit is controlled by the single-chip microcomputer system through the boost control unit, boosts the lithium battery power supply input voltage transmitted by the battery control module, and then outputs it to the single-chip microcomputer system through the capacitor unit, and then supplies power to the device.

[0062] The boost control unit includes a triode TR3. The emitter of the triode TR3 is grounded. The collector of the triode TR3 is connected to the enable pin of the boost unit. The base of the triode TR3 is connected to one end of a resistor R15. The other end of the resistor R15 is respectively connected to the negative electrodes of a diode D3 and a diode D4. The positive electrode of the diode D3 is connected to the power input terminal. The positive electrode of the diode D4 is connected to the boost control pin of the single-chip microcomputer system.

[0063] When D3 is damaged, the single-chip microcomputer system detects the power supply. The software can turn on TR3 through the boost control pin of the single-chip microcomputer system, pull down the enable pin of the boost unit U1, and the boost unit is disabled, stopping the battery from supplying power to the system.

[0064] The boost control unit realizes the control of whether the boost circuit works by the single-chip microcomputer system, and then controls whether the power supply at the lithium battery input end can be output to the single-chip microcomputer system.

[0065] The RC absorption unit includes a resistor R1 and a capacitor C1, which are connected in series. The resistor R1 is connected to the switch pin of the integrated chip U1, and the capacitor C1 is grounded.

[0066] The main function of the RC absorption unit is to reduce the switching speed of the switch pin of the integrated chip U1 to achieve the effect of suppressing EMI.

[0067] The feedback unit includes a resistor R7 and a parallel resonant circuit. The resistor R7 is connected between the output pin and the voltage feedback pin of the integrated chip U1. The parallel resonant circuit is formed by the parallel connection of a capacitor C7 and R10. One end of the parallel resonant circuit is grounded, and the other end is connected to the voltage feedback pin of the integrated chip U1.

[0068] The feedback unit realizes the closed-loop of the boost output voltage. The feedback unit continuously detects the output voltage and adjusts the switching frequency of the boost chip through the change of the output voltage to achieve the effect of stable output voltage.

[0069] The capacitor unit is formed by the parallel connection of a capacitor C4, a capacitor C5, a capacitor C6 and a transient voltage suppressor diode TVS1. The negative terminal of TVS1 is connected to the output pin of the boost circuit and the power supply output. The power supply output is connected to the power supply input terminal of the single-chip microcomputer system. The positive terminal of TVS1 is grounded.

[0070] The capacitor unit functions as energy storage and filtering. The capacitance values of the three capacitors in the capacitor unit are different.

[0071] Among them, the capacitor C4 and the capacitor C5 are two capacitors with large capacitance values, and the capacitor C6 is a capacitor with a small capacitance value.

[0072] Since a single chip capacitor cannot reach the required high capacitance value, the method of parallel connection of two capacitors C4 and C5 is used to increase the capacitance value.

[0073] Filtering of interference signals in each frequency band is achieved through the combination of large and small capacitance values. The large-capacitance capacitor filters the low-frequency interference signals, and the small-capacitance capacitor filters the high-frequency interference signals.

[0074] TVS1, as an ESD protection device, plays an ESD protection role for the subsequent circuit.

[0075] The self-locking control module includes a switch SW1. A transient voltage suppressor diode TVS2 is connected in parallel across the two ends of the switch SW1. One end of the switch SW1 is grounded, and the other end is connected to the negative electrode of the diode D1. The positive electrode of the diode D1 is respectively connected to one end of a resistor R8 and one end of a resistor R9. The other end of the resistor R8 is connected to the power supply input terminal, and the other end of the resistor R9 is connected to the self-locking detection pin of the single-chip microcomputer system.

[0076] The self-locking control module can enable the user to control the lithium battery power supply through a button and realize the function of circuit self-locking when the button is released.

[0077] In the system standby state, since the external power supply is cut off, TR3 is disconnected and the boost unit is in the enabled state.

[0078] When the user presses the button switch SW1, a loop is formed from the battery power supply terminal through R2, R4, D2, SW1 to GND, enabling the PMOS transistor Q1 to conduct and realizing the power supply of the system by the lithium battery.

[0079] After the user presses the button, the button needs to be released. Without a self-locking module, releasing the button will cause the circuit to break, then Q1 will turn off and the power supply will be interrupted. The self-locking control module realizes circuit self-locking, so that the battery power supply will not be interrupted due to button release.

[0080] The single-chip microcomputer system detects that the button is pressed through the self-locking detection pin, controls TR2 to conduct through the battery control pin, and then controls Q1 to conduct. At this time, even if the user releases the button, the PMOS transistor Q1 still conducts, avoiding the risk of system power-off caused by Q1 not conducting due to button release.

[0081] The working principle of the charging path switching circuit of this embodiment will be described in detail below.

[0082] 1. When externally powered, the battery does not supply power, and the function of the battery not supplying power when externally powered can be realized.

[0083] When externally powered, that is, when there is a voltage input at the power input terminal, at this time, the PMOS transistor Q2 of the second control unit is in a weakly conducting state with a very large internal resistance. The external power supply supplies power to the single-chip microcomputer system through the PMOS body diode of the PMOS transistor Q2 of the second control unit, and then the device is externally powered.

[0084] The single-chip microcomputer system detects the input voltage through the power detection pin of the detection unit.

[0085] The single-chip microcomputer system power control pin outputs a high level to turn on the triode TR1 of the first power control unit.

[0086] At this time, the voltage at the GS terminal of the PMOS transistor Q2 of the second control unit exceeds the VGS(th) voltage, and the PMOS transistor Q2 is fully turned on with a smaller internal resistance.

[0087] The external power supply input flows through the base of the triode TR3 through the diode D3 of the boost control unit. At this time, TR3 is saturated and conducting.

[0088] The enable pin of the integrated chip U1 of the boost unit is pulled low, and the U1 chip is disabled, and the battery does not supply power to the system through boosting.

[0089] 2. When externally powered off, the battery supplies power, and it can be realized that after the external power supply is removed, the battery automatically starts to supply power.

[0090] When externally powered off, that is, when there is no voltage input at the power input terminal, the single-chip microcomputer system power control pin outputs a high level to turn on the triode TR2 of the first battery control unit.

[0091] At this time, the voltage at the GS terminal of the PMOS transistor Q1 of the second battery control unit exceeds the VGS(th) voltage, the PMOS transistor Q1 is fully turned on, the internal resistance becomes smaller, and the power supply input from the battery supply input terminal is input to the voltage input pin of the integrated chip U1 through the PMOS transistor Q1.

[0092] At this time, the triode TR3 of the boost control unit is in the off state, the enable pin of the integrated chip U1 of the boost unit is pulled up to a high level by the pull-up resistor R3, U1 is enabled, and the single-chip microcomputer system is powered by the battery.

[0093] 3. The battery does not supply power in the standby state, which realizes zero power consumption in the system standby state.

[0094] When the system is in the standby state, the single-chip microcomputer system outputs a low level at the power supply control pin to turn off the triode TR2 of the first battery control unit.

[0095] At this time, the PMOS transistor Q1 of the second battery control unit is in the off state, and the battery does not supply power to the outside.

[0096] 4. The button controls the lithium battery power supply in the standby state, which can realize the circuit self-locking function after the button is released.

[0097] When the button SW1 is pressed, a loop is formed from R2, R4, D2, SW1 of the self-locking detection unit to GND.

[0098] The voltage at the GS terminal of the PMOS transistor Q1 of the second battery control unit exceeds the VGS(th) voltage, the PMOS transistor Q1 is turned on, and the power supply input from the battery supply input terminal is input to the voltage input pin of the boost chip U1 through the PMOS transistor Q1.

[0099] At this time, the triode TR3 of the boost control unit is in the off state, the enable pin of U1 is pulled up to a high level by the pull-up resistor R3, U1 is enabled, and the single-chip microcomputer system is powered by the battery.

[0100] The single-chip microcomputer system detects that the button SW1 is pressed through the self-locking detection unit, and outputs a high level at the power supply control pin to turn on the triode TR2 of the first battery control unit, and Q1 is turned on.

Claims

1. A charging path switching circuit, characterized in that: It includes a battery control module, which is respectively connected to the battery power supply input terminal and the single-chip computer system. The battery control module is respectively connected to the boost module and the self-locking control module. The self-locking control module is also connected to the power supply control module. The power supply control module is connected to the power supply input terminal. The self-locking control module, the power supply control module and the battery control module are all connected to the single-chip computer system. The boost module and the power supply control module are connected to the power supply output.

2. A charging path switching circuit according to claim 1, characterized in that: The power control module includes a first power control unit and a second power control unit connected to each other, and the second power control unit is also connected to a detection unit; the detection unit is connected to the power detection pin of the single-chip system, and the first power control unit is connected to the power control pin of the single-chip system.

3. A charging path switching circuit according to claim 1 or 2, characterized in that: The battery control module includes a first battery control unit and a second battery control unit, and the second battery control module is connected to the battery power supply input terminal.

4. A charging path switching circuit according to claim 1, characterized in that: The boost module comprises a boost control unit, which is respectively connected to the power input terminal and the boost unit, the boost unit is respectively connected to the RC absorption unit and the feedback unit, and the feedback unit is connected to the power control module via the capacitor unit.

5. A charging path switching circuit according to claim 2, characterized in that: The first power control unit comprises a transistor TR1, an emitter of TR1 is grounded, a collector of TR1 is connected to the second power control unit, and a base of TR1 is connected to the single chip computer system via a resistor R11.

6. A charging path switching circuit according to claim 2 or 5, characterized in that: The second power control unit includes a PMOS tube Q2, the drain of Q2 is respectively connected to the power supply input terminal and the detection unit, the gate of Q2 is connected to the first power control unit through a resistor R6, and the source of Q2 is connected to the boost module.

7. A charging path switching circuit according to claim 3, characterized in that: The first battery control unit includes a transistor TR2, the emitter of TR2 is grounded, the collector of TR2 is respectively connected to the second battery control unit and the self-locking control module, and the base of TR2 is connected to the single-chip computer system through a resistor R13.

8. A charging path switching circuit according to claim 3, characterized in that: The second battery control unit includes a PMOS tube Q1, the source of Q1 is connected to the battery power input terminal, the gate of Q1 is connected to the first battery control unit and the self-locking control module through a resistor R4, and the drain of Q1 is connected to the boost module.

9. A charging path switching circuit according to claim 4, characterized in that: The boost unit includes an integrated chip U1, an enable pin of U1 is connected to a boost control unit, a switch pin of U1 is connected to an RC absorption unit, an inductor L1 is connected between a voltage input pin and a switch pin of U1, and a feedback unit is connected to an output pin and a voltage feedback pin of U1.

10. A charging path switching circuit according to claim 4 or 9, characterized in that: The boost control unit includes a transistor TR3, the emitter of TR3 is grounded, the collector of TR3 is connected to the boost unit enable pin, the base of TR3 is connected to one end of a resistor R15, and the other end of the resistor R15 is connected to the power input end and the boost control pin of the microcontroller system through a diode.

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