Battery protection circuit and power supply equipment

Abstract

The invention relates to the technical field of battery management, and relates to a battery protection circuit and power supply equipment. The circuit comprises a charging and discharging switch unit, a voltage stabilizing circuit unit, a self-locking circuit unit, a charging detection unit and a battery management unit, the charge-discharge switch unit is arranged between the battery and the load circuit, and the driving end of the charge-discharge switch unit is connected with the battery management unit; the self-locking circuit unit is arranged between the positive electrode of the load circuit and the voltage input end of the voltage stabilizing circuit unit, and the voltage output end of the voltage stabilizing circuit unit is connected with the power supply end of the battery management unit; the charging detection unit is used for feeding back a first level signal to the battery management unit based on the potentials of the negative electrode of the battery and the grounding end of the load circuit, and driving the self-locking circuit unit to enter a self-locking conduction state; the battery management unit is used for comparing the battery electric quantity with a preset value and then outputting a second level signal so as to drive the self-locking circuit unit to enter a turn-off state. The service lives of the battery and the applied power supply equipment can be prolonged, and potential safety hazards are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management, and in particular to a battery protection circuit and a power supply device. Background Art

[0002] Power products usually include batteries, battery management systems, and load circuits. The battery management system controls and manages the charging and discharging of the battery, and the load circuit is connected to both ends of the battery. In the battery charging and discharging management, the battery will have a minimum operating voltage requirement and a discharge cut-off voltage to prevent the battery from being over-discharged.

[0003] The battery management system has three working states: running state, standby state, and sleep state. When the voltage is lower than the minimum working voltage of the battery, the system will enter the sleep state, and only a few components will be working. At this time, the power consumption of the battery is very small, about 10uA. However, although the discharge current of the battery is very small in the sleep state, the continuous power consumption will cause the battery power to be exhausted, and the battery capacity and life will be greatly reduced, resulting in irreversible damage and potential safety hazards. Summary of the invention

[0004] The technical problem to be solved by the embodiments of the present invention is to provide a battery protection circuit and a power supply device to solve the problem in the prior art that the battery continues to consume power in a dormant state, causing irreversible damage and posing a potential safety hazard.

[0005] The present invention discloses a battery protection circuit for protecting the charging and discharging of a battery. The battery is connected to a load circuit. The battery protection circuit comprises a charging and discharging switch unit, a voltage stabilizing circuit unit, a self-locking circuit unit, a charging detection unit and a battery management unit.

[0006] The charge and discharge switch unit is arranged between the battery and the load circuit, and a driving end thereof is connected to the battery management unit;

[0007] The self-locking circuit unit is arranged between the positive electrode of the load circuit and the voltage input end of the voltage stabilizing circuit unit, and the voltage output end of the voltage stabilizing circuit unit is connected to the power supply end of the battery management unit;

[0008] The charging detection unit is used to feed back a first level signal to the battery management unit based on the potential between the negative electrode of the battery and the ground terminal of the load circuit, and drive the self-locking circuit unit to enter a self-locking conduction state;

[0009] The battery management unit is used to compare the battery power with a preset value and then output a second level signal to drive the self-locking circuit unit to enter a shutdown state.

[0010] Optionally, the charging detection unit includes a first triode, a second triode, a third triode, a first resistor, a second resistor, a third resistor and a fourth resistor, the first resistor is connected in series between the base of the first triode and the negative electrode of the battery, the second resistor is connected in series between the base and the emitter of the first triode, the emitter of the first triode is connected to the ground end of the load circuit, the collector of the first triode is connected to the base of the second triode, the emitter of the second triode is connected to the positive electrode of the battery, and the collector is connected to the base of the third triode, the third resistor is connected in series between the positive electrode of the battery and the collector of the triode, the fourth resistor is connected in series between the voltage output end of the voltage stabilizing circuit unit and the collector of the third triode, and the series node of the fourth resistor and the collector of the third triode is connected to the battery management unit to feed back a first level signal to the battery management unit, and the emitter of the third triode is connected to the ground end of the load circuit.

[0011] Optionally, the charging detection unit also includes a first capacitor, a fifth resistor and a sixth resistor, the fifth resistor is connected in series between the base and the emitter of the second transistor, the sixth resistor is connected in series between the base of the second transistor and the collector of the first transistor, and the first capacitor is connected in parallel with the sixth resistor.

[0012] Optionally, the charging detection unit also includes a second capacitor, a seventh resistor and an eighth resistor, the seventh resistor is connected in series between the collector of the second transistor and the base of the third transistor, the eighth resistor is connected in series between the base and the emitter of the third transistor, and the second capacitor is connected in parallel with the eighth resistor.

[0013] Optionally, the self-locking circuit unit includes an optocoupler, a fourth transistor, a self-locking MOS tube and a shutdown drive module, the positive electrode of the transmitting end of the optocoupler is connected to the collector of the second transistor, and the negative electrode is connected to the ground end of the load circuit, the collector of the receiving end of the optocoupler is connected to the gate of the self-locking MOS tube, and the emitter is connected to the negative electrode of the battery, the collector of the fourth transistor is connected to the gate of the self-locking MOS tube, the emitter is connected to the negative electrode of the battery, the base is connected to the drain of the self-locking MOS tube and the shutdown drive module, and the driving end of the shutdown drive module is connected to the battery management unit to receive the second level signal.

[0014] Optionally, the shutdown drive module includes a fifth transistor, a ninth resistor and a tenth resistor, the ninth resistor is connected in series between the base of the fifth transistor and the battery management unit, the tenth resistor is connected in series between the base and the emitter of the fifth transistor, and the emitter of the fifth transistor is connected to the negative pole of the battery.

[0015] Optionally, the self-locking circuit unit also includes an eleventh resistor and a twelfth resistor connected in series, the series node of the eleventh resistor and the twelfth resistor is connected to the base of the fourth transistor, the other end of the eleventh resistor is connected to the drain of the self-locking MOS tube, and the other end of the twelfth resistor is connected to the negative electrode of the battery.

[0016] Optionally, the self-locking circuit unit also includes a thirteenth resistor and a fourteenth resistor connected in series, the series node of the thirteenth resistor and the fourteenth resistor is connected to the gate of the self-locking MOS tube, the other end of the thirteenth resistor is connected to the positive electrode of the load circuit, and the other end of the fourteenth resistor is connected to the collector of the fourth transistor.

[0017] Optionally, the charge and discharge switch unit includes a first MOS tube and a second MOS tube, the source of the first MOS tube is connected to the negative electrode of the battery, the drain of the first MOS tube is connected to the drain of the second MOS tube, the source of the second switch is connected to the ground terminal of the load circuit, and the gate of the first MOS tube and the gate of the second MOS tube are both connected to the battery management unit.

[0018] The present invention also discloses a power supply device, comprising a battery, a load circuit and a battery protection circuit as described in any one of claims 1 to 9, wherein a charge and discharge switch unit of the battery protection circuit is arranged between the battery and the load circuit, and a self-locking circuit unit of the battery protection circuit is arranged between the positive pole of the load circuit and the voltage input end of the voltage stabilizing circuit unit.

[0019] Compared with the prior art, the battery protection circuit provided by the embodiment of the present invention has the beneficial effect that: by setting a self-locking circuit unit, the self-locking circuit unit is set between the positive electrode of the load circuit and the voltage input end of the voltage stabilizing circuit unit, the battery management unit compares the battery power with the preset value and outputs a second level signal to drive the self-locking circuit unit into the off state, cut off the path between the positive electrode of the load circuit and the voltage input end of the voltage stabilizing circuit unit, thereby cutting off the power supply of the battery management unit, cutting off the power supply of the overall circuit, and entering a "mechanical" shutdown state, avoiding the circuit elements from continuing to consume the battery power when the battery power is low, avoiding irreversible damage to the battery, and improving the service life of the battery and the power supply equipment used, reducing safety hazards, and setting a charging detection unit to cleverly use the potential difference between the negative electrode of the battery and the ground end of the load circuit to feedback the first level signal to the battery management unit, and drive the self-locking circuit unit into the self-locking conduction state, so that when a charging device is connected, the charging detection unit can automatically activate the path between the positive electrode of the load circuit and the voltage input end of the voltage stabilizing circuit unit, so that the battery management unit obtains power and enters the working state. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, in which:

[0021] Figure 1 is a structural block diagram of an embodiment of a battery protection circuit provided by the present invention;

[0022] Figure 2 It is a circuit diagram of an embodiment of the present invention in which the charge and discharge switch unit is arranged between the battery and the load circuit;

[0023] Figure 3 It is a circuit diagram of an embodiment of a main control chip provided by the present invention;

[0024] Figure 4 is a circuit diagram of an embodiment of an AEF module provided by the present invention;

[0025] Figure 5 is a circuit diagram of an embodiment of a charging detection unit provided by the present invention;

[0026] Figure 6 The present invention is a circuit diagram of an embodiment of the present invention in which a self-locking circuit unit is connected to a voltage stabilizing circuit unit.

[0027] The reference numerals in the figures are:

[0028] 110, charge and discharge switch unit; 120, voltage stabilizing circuit unit; 130, self-locking circuit unit; 131, shutoff drive module; 140, charge detection unit; 150, battery management unit;

[0029] Q1, the first transistor; Q2, the second transistor; Q3, the third transistor; Q4, the fourth transistor; Q5, the self-locking MOS transistor; Q6, the fifth transistor; Q7, the first MOS transistor; Q8, the second MOS transistor; R1, the first resistor; R2, the second resistor; R3, the third resistor; R4, the fourth resistor; R5, the fifth resistor; R6, the sixth resistor; R7, the seventh resistor; R8, the eighth resistor; R9, the ninth resistor; R10, the tenth resistor; R11, the eleventh resistor; R12, the twelfth resistor; R13, the thirteenth resistor; R14, the fourteenth resistor; C1, the first capacitor; C2, the second capacitor; C3, the third capacitor; C4, the fourth capacitor; C5, the fifth capacitor; C6, the sixth capacitor; U1, the main control chip; U2, the optical coupler; U3, the three-terminal regulator;

[0030] 160. Battery; 170. Load circuit. DETAILED DESCRIPTION

[0031] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the accompanying drawings, the preferred embodiments of the present invention are described in detail.

[0032] The embodiment of the present invention provides a battery 160 protection circuit for protecting the battery 160 from charging and discharging. The battery 160 is connected to a load circuit 170 .

[0033] like Figure 1 and Figure 2 As shown, the battery 160 protection circuit provided in the embodiment of the present application includes a charge and discharge switch unit 110, a voltage stabilizing circuit unit 120, a self-locking circuit unit 130, a charging detection unit 140 and a battery management unit 150. Figure 2 The medium load circuit 170170 is only a simplified equivalent circuit.

[0034] The charge and discharge switch unit 110 is disposed between the battery 160 and the load circuit 170 , and a driving end thereof is connected to the battery management unit 150 , and receives a driving signal to be turned on or off.

[0035] The self-locking circuit unit 130 is disposed between the positive electrode PACK+ of the load circuit 170 and the voltage input terminal of the voltage stabilizing circuit unit 120 , and the voltage output terminal of the voltage stabilizing circuit unit 120 is connected to the power supply terminal of the battery management unit 150 .

[0036] The charging detection unit 140 is used to feed back a first level signal to the battery management unit 150 based on the potential of the negative electrode BAT- of the battery 160 and the ground terminal GND of the load circuit 170, and drive the self-locking circuit unit 130 to enter a self-locking conduction state.

[0037] The battery management unit 150 is used to compare the power level of the battery 160 with a preset value and then output a second level signal to drive the self-locking circuit unit 130 to enter a shutdown state.

[0038] In the embodiment of the present application, a self-locking circuit unit 130 is provided, and the self-locking circuit unit 130 is provided between the positive electrode PACK+ of the load circuit 170 and the voltage input terminal of the voltage stabilizing circuit unit 120. The battery management unit 150 compares the power of the battery 160 with the preset value and outputs a second level signal to drive the self-locking circuit unit 130 to enter the shutdown state, cut off the path between the positive electrode PACK+ of the load circuit 170 and the voltage input terminal of the voltage stabilizing circuit unit 120, thereby cutting off the power supply of the battery management unit 150, cutting off the power supply of the entire circuit, and entering a "mechanical" shutdown state, so as to prevent the circuit elements from continuing to consume the power of the battery 160 when the power of the battery 160 is low. The amount of charge detection is reduced, thereby avoiding irreversible damage to the battery 160, increasing the service life of the battery 160 and the power supply equipment used, and reducing safety hazards. In addition, the charging detection unit 140 is set to cleverly use the potential difference between the negative electrode BAT- of the battery 160 and the ground terminal GND of the load circuit 170 to feedback the first level signal to the battery management unit 150, and drive the self-locking circuit unit 130 to enter the self-locking conduction state, so that when a charging device is connected, the charging detection unit 140 can automatically activate the path between the positive electrode PACK+ of the load circuit 170 and the voltage input terminal of the voltage stabilizing circuit unit 120, so that the battery management unit 150 obtains power supply and enters the working state.

[0039] By adopting the battery 160 protection circuit of the embodiment of the present application, the battery 160 will not drop to 0V even if the battery 160 is left for a long time, thereby avoiding the problem of 0V charging or low-power charging bulging, protecting the battery 160, and increasing the service life of the battery 160 and the power supply equipment used.

[0040] refer to Figures 2 to 4 The battery management unit 150 includes a main control chip U1 and an AFE (Analog Front End) module connected to the main control chip U1. The main control chip U1 is connected to the driving end of the charge and discharge switch unit 110 and the self-locking circuit unit 130, driving the charge and discharge switch unit 110 to be turned on and off, and driving the self-locking circuit unit 130 to enter the off state. The acquisition of battery power can be achieved by conventional technology, which will not be described in detail here.

[0041] The AFE module can monitor the battery 160 voltage, battery 160 current, battery 160 temperature, and prevent the battery 160 from overvoltage, battery 160 undervoltage, overcurrent, short circuit, and balancing functions, which can be implemented using conventional technology and will not be described in detail here. Figure 4 FIG. 4 is a circuit diagram of an embodiment of an AFE module.

[0042] refer to Figure 1 , Figure 3 and Figure 5In an optional embodiment of the present application, the charging detection unit 140 includes a first transistor Q1, a second transistor Q2, a third transistor Q3, a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4, the first resistor R1 is connected in series between the base of the first transistor Q1 and the positive electrode of the battery 160, the second resistor R2 is connected in series between the base and the emitter of the first transistor Q1, the emitter of the first transistor Q1 is connected to the ground terminal GND of the load circuit 170, the collector of the first transistor Q1 is connected to the base of the second transistor Q2, and the second transistor Q 2 is connected to the positive electrode of the battery 160, the collector of the second transistor Q2 is connected to the base of the third transistor Q3, the third resistor R3 is connected in series between the positive electrode of the battery 160 and the collector of the transistor, the fourth resistor R4 is connected in series between the voltage output end of the voltage stabilizing circuit unit 120 and the collector of the third transistor Q3, and the series node between the fourth resistor R4 and the collector of the third transistor Q3 is connected to the battery management unit 150 to feed back the first level signal to the battery management unit 150, and the emitter of the third transistor Q3 is connected to the ground terminal GND of the load circuit 170.

[0043] In specific implementation, the first transistor Q1 and the third transistor Q3 are both NPN transistors, and the second transistor Q2 is a PNP transistor. The PNP transistor is used to connect the path between the positive electrode of the battery 160 and the third transistor Q3. Its driving circuit is relatively simple, and the second transistor Q2 can be turned on by pulling down the base.

[0044] When the charging device is connected, the current passes through the positive electrode PACK+ of the load circuit 170 and the battery 160 and returns to the negative electrode BAT- of the battery 160. At this time, the potential of the negative electrode BAT- of the battery 160 is higher than the potential of the ground terminal GND of the load circuit 170, the first transistor Q1 is turned on, and the base of the second transistor Q2 is pulled low and turned on, thereby connecting the path between the positive electrode of the battery 160 and the third transistor Q3, and the self-locking circuit unit 130 receives a high-level signal and is driven into a self-locking conduction state, connecting the path between the positive electrode PACK+ of the load circuit 170 and the voltage input terminal of the voltage stabilizing circuit unit 120, and the battery management unit 150 obtains power supply. At the same time, the third transistor Q3 is turned on, and the connection node between the fourth resistor R4 and the collector of the third transistor Q3 feeds back a high-level signal to the battery management unit 150, and the battery management unit 150 starts working. The charging detection unit 140 of the present application cleverly utilizes the potential difference between the negative electrode of the battery 160 and the ground terminal GND of the load circuit 170 when the charging device is connected, and adopts a hardware circuit composed of multiple transistors to directly turn on and drive the self-locking circuit unit 130, thereby activating the power supply of the battery management unit 150. The control is simple and the cost is low.

[0045] Specifically, the series node connecting the collector of the third transistor Q3 and the fourth resistor R4 is connected to the main control chip U1.

[0046] Further, continue to refer to Figure 1 , Figure 3 and Figure 5 The charging detection unit 140 also includes a first capacitor C1, a fifth resistor R5 and a sixth resistor R6. The fifth resistor R5 is connected in series between the base and the emitter of the second transistor Q2, the sixth resistor R6 is connected in series between the base of the second transistor Q2 and the collector of the first transistor Q1, and the first capacitor C1 is connected in parallel with the sixth resistor R6.

[0047] The first capacitor C1 is used for filtering to help remove high-frequency noise or fluctuations in the signal. The fifth resistor R5 is used as a pull-up resistor. When the first transistor Q1 is in the cut-off state, the fifth resistor R5 can pull up the base of the second transistor Q2 to keep the second transistor Q2 in the cut-off state to avoid misconnection. The sixth resistor R6 can limit the current flowing to the base of the second transistor Q2 to avoid excessive current damaging the second transistor Q2. Therefore, the first capacitor C1, the fifth resistor R5 and the sixth resistor R6 can improve the stability and reliability of the operation of the second transistor Q2.

[0048] Optionally, continue to refer to Figure 1 , Figure 3 and Figure 5 The charging detection unit 140 also includes a second capacitor C2, a seventh resistor R7 and an eighth resistor R8. The seventh resistor R7 is connected in series between the collector of the second transistor Q2 and the base of the third transistor Q3. The eighth resistor R8 is connected in series between the base and the emitter of the third transistor Q3. The second capacitor C2 is connected in parallel with the eighth resistor R8.

[0049] The second capacitor C2 is used as a filter to help remove high-frequency noise or fluctuations in the signal. The seventh resistor R7 can limit the current flowing to the base of the third triode Q3 to prevent the third triode Q3 from being damaged by excessive current. The eighth resistor R8 is used as a pull-down resistor. When the second triode Q2 is in the cut-off state, the eighth resistor R8 can pull down the base of the third triode Q3 to keep the third triode Q3 in the cut-off state to avoid misconnection. Therefore, the second capacitor C2, the seventh resistor R7 and the eighth resistor R8 can improve the stability and reliability of the operation of the third triode Q3.

[0050] refer to Figure 1 , Figure 3 , Figure 5 and Figure 6In an optional embodiment of the present application, the self-locking circuit unit 130 includes an optocoupler U2, a fourth transistor Q4, a self-locking MOS tube Q5 and a shutdown drive module 131, the positive electrode of the transmitter end of the optocoupler U2 is connected to the collector of the second transistor Q2, the negative electrode is connected to the ground terminal GND of the load circuit 170, the collector of the receiving end of the optocoupler U2 is connected to the gate of the self-locking MOS tube Q5, the emitter is connected to the negative electrode BAT- of the battery 160, the collector of the fourth transistor Q4 is connected to the gate of the self-locking MOS tube Q5, the emitter is connected to the negative electrode BAT- of the battery 160, the base is connected to the drain of the self-locking MOS tube Q5 and the shutdown drive module 131, and the driving end of the shutdown drive module 131 is connected to the battery management unit 150 to receive the second level signal.

[0051] During specific implementation, the fourth transistor Q4 is an NPN transistor.

[0052] The working principle of the optocoupler U2 is to use the light signal emitted by its transmitting end to irradiate the receiving end, thereby controlling the electrical characteristics of the receiving end. When the transmitting end is turned on, a light signal is emitted, and the light signal is irradiated to the receiving end, turning the receiving end on or off, thereby achieving electrical isolation between the input circuit and the output circuit.

[0053] When the charging device is connected, the second transistor Q2 is turned on, the optocoupler U2 receives a high-level signal and turns on, the gate of the self-locking MOS tube Q5 is pulled down, and it starts to turn on. The fourth transistor Q4 is turned on, and the gate voltage of the self-locking MOS tube Q5 is continuously pulled down, and the self-locking MOS tube Q5 is continuously turned on. The voltage input end of the voltage stabilizing circuit unit 120 is continuously powered, and the voltage stabilizing output is 5V, which supplies power to the battery management unit 150, so that the power supply is self-locking and supplies power to the entire system. When the battery 160 power is lower than the preset value, the battery management unit 150 outputs a second level signal, and the voltage of the base of the fourth transistor Q4 is pulled down by turning off the driving module 131, so that the fourth transistor Q4 is in a cut-off state, thereby turning off the self-locking MOS tube Q5, cutting off the voltage input of the voltage stabilizing circuit unit 120, cutting off the power supply of the subsequent circuit, and stopping the continued consumption of the battery 160 power, which is equivalent to the battery 160 being in a disconnected and idle state.

[0054] Optionally, the shutdown drive module 131 includes a fifth transistor Q6, a ninth resistor R9 and a tenth resistor R10, the ninth resistor R9 is connected in series between the base of the fifth transistor Q6 and the battery management unit 150, the tenth resistor R10 is connected in series between the base and the emitter of the fifth transistor Q6, and the emitter of the fifth transistor Q6 is connected to the negative electrode BAT- of the battery 160.

[0055] In specific implementation, the fifth transistor Q6 is an NPN transistor. The ninth resistor R9 is connected in series between the base of the fifth transistor Q6 and the main control chip U1 to receive the second level signal of the main control chip U1.

[0056] When the power of the battery 160 is lower than the preset value, the battery management unit 150 outputs a second level signal to drive the fifth transistor Q6 to turn on, pull down the base voltage of the fourth transistor Q4, so that the fourth transistor Q4 is in a cut-off state, and then turn off the self-locking MOS tube Q5. Among them, the ninth resistor R9 can limit the current flowing to the base of the fifth transistor Q6 to prevent excessive current from damaging the fifth transistor Q6. The tenth resistor R10 can pull down the base of the fifth transistor Q6 when there is no signal output from the battery management unit 150, so that the fifth transistor Q6 is in a cut-off state to prevent mis-conduction.

[0057] Optionally, Figure 1 , Figure 3 , Figure 5 and Figure 6 The self-locking circuit unit 130 also includes an eleventh resistor R11 and a twelfth resistor R12 connected in series, the series node of the eleventh resistor R11 and the twelfth resistor R12 is connected to the base of the fourth transistor Q4, the other end of the eleventh resistor R11 is connected to the drain of the self-locking MOS tube Q5, and the other end of the twelfth resistor R12 is connected to the negative electrode BAT- of the battery 160.

[0058] When the self-locking MOS tube Q5 starts to conduct, the base of the fourth transistor Q4 is conducted after being divided by the eleventh resistor R11 and the twelfth resistor R12, and continues to lower the voltage of the gate of the self-locking MOS tube Q5, so that the self-locking MOS tube Q5 is continuously conducted.

[0059] Optionally, continue to refer to Figure 1 , Figure 3 , Figure 5 and Figure 6 The self-locking circuit unit 130 also includes a thirteenth resistor R13 and a fourteenth resistor R14 connected in series, the series node of the thirteenth resistor R13 and the fourteenth resistor R14 is connected to the gate of the self-locking MOS tube Q5, the other end of the thirteenth resistor R13 is connected to the positive electrode PACK+ of the load circuit 170, and the other end of the fourteenth resistor R14 is connected to the collector of the fourth transistor Q4.

[0060] The thirteenth resistor R13 is used as a pull-up resistor. When the optical coupler U2 and the fourth transistor Q4 are in the cut-off state, the gate voltage of the self-locking MOS transistor Q5 is pulled up to keep the self-locking MOS transistor Q5 in the cut-off state to prevent the self-locking MOS transistor Q5 from being mistakenly turned on. The fourteenth resistor R14 has a current limiting function.

[0061] refer to Figures 1 to 3In an optional embodiment of the present application, the charge and discharge switch unit 110 includes a first MOS tube Q7 and a second MOS tube Q8, the source of the first MOS tube Q7 is connected to the negative electrode BAT- of the battery 160, the drain of the first MOS tube Q7 is connected to the drain of the second MOS tube Q8, the source of the second switch is connected to the ground terminal GND of the load circuit 170, and the gate of the first MOS tube Q7 and the gate of the second MOS tube Q8 are both connected to the battery management unit 150.

[0062] By providing the first MOS transistor Q7 and the second MOS transistor Q8, the gates of the first MOS transistor Q7 and the second MOS transistor Q8 can receive a driving signal to be turned on or off, thereby turning on or off the path between the negative electrode BAT- of the battery 160 and the ground terminal GND of the load circuit 170 to control charging and discharging. The main control chip U1 is connected to the gate of the first MOS transistor Q7 and the gate of the second MOS transistor Q8.

[0063] Optionally, the battery 160 protection circuit further includes a buck-boost circuit unit and a charge-discharge interface, the charge-discharge interface is connected to the buck-boost circuit unit, and the buck-boost circuit unit is connected to the positive electrode of the battery 160 and the ground terminal GND of the load circuit 170. The buck-boost unit is a DC-DC conversion circuit that realizes both buck and boost functions, which can be implemented using conventional technology and will not be described in detail here. The charge-discharge interface can use a TYPE-C interface.

[0064] refer to Figure 1 , Figure 3 and Figure 6 In an optional embodiment of the present application, the voltage stabilizing circuit unit 120 includes a three-terminal voltage regulator U3, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6, the third capacitor C3 and the fourth capacitor C4 are connected in parallel, and the first parallel node is connected to the voltage input pin of the three-terminal voltage regulator U3 and the self-locking circuit, the second parallel node is connected to the ground, the fifth capacitor C5 and the sixth capacitor C6 are connected in parallel, and the first parallel node is connected to the voltage output pin of the three-terminal voltage regulator U3 and the power supply terminal of the battery management unit 150, the second parallel node is connected to the ground, and the ground pin of the three-terminal voltage regulator U3 is connected to the ground.

[0065] The three-terminal voltage regulator U3 is a commonly used electronic component used to provide a stable output voltage. It is widely used in various electronic circuits to ensure that the subsequent circuit can operate at a stable voltage. The design of the three-terminal voltage regulator U3 is simple and efficient, which is convenient for achieving stable voltage output in electronic design. It is also very simple to use, requiring only a small number of external components to achieve the voltage regulation function, and the circuit structure is simple.

[0066] The third capacitor C3 and the fifth capacitor C5 are used to filter out low-frequency interference, and the fourth capacitor C4 and the sixth capacitor C6 are used to filter out high-frequency ripples, and cooperate with the three-terminal voltage regulator U3 to step down and stabilize the input voltage within a suitable range to supply power to the battery management unit 150. Specifically, after the self-locking MOS tube Q5 is turned on, the input power supply voltage is filtered by the third capacitor C3 and the fourth capacitor C4 and then input to the three-terminal voltage regulator U3. The voltage stabilized by the three-terminal voltage regulator U3 is then filtered by the fifth capacitor C5 and the sixth capacitor C6 to output a stable 5V to supply power to the battery management unit 150.

[0067] The present application also provides a preferred embodiment of a power supply device. The power supply device includes a battery 160, a load circuit 170, and the battery 160 protection circuit as described above, wherein the charge and discharge switch unit 110 of the battery 160 protection circuit is arranged between the battery 160 and the load circuit 170, and the self-locking circuit unit 130 of the battery 160 protection circuit is arranged between the positive electrode PACK+ of the load circuit 170 and the voltage input terminal of the voltage stabilizing circuit unit 120.

[0068] The power supply device of the embodiment of the present application is provided with a self-locking circuit unit 130, and the self-locking circuit unit 130 is provided between the positive electrode PACK+ of the load circuit 170 and the voltage input terminal of the voltage stabilizing circuit unit 120. The battery management unit 150 compares the power of the battery 160 with the preset value and outputs a second level signal to drive the self-locking circuit unit 130 to enter the shutdown state, cut off the path between the positive electrode PACK+ of the load circuit 170 and the voltage input terminal of the voltage stabilizing circuit unit 120, thereby cutting off the power supply of the battery management unit 150, cutting off the power supply of the entire circuit, and entering a "mechanical" shutdown state, so as to avoid the battery 160 continuing to be powered on when the power is low. The battery 160 power is continuously consumed to avoid irreversible damage, the service life of the battery 160 and the power supply equipment used is increased, and potential safety hazards are reduced. The charging detection unit 140 is set to feedback the first level signal to the battery management unit 150 based on the potential of the negative electrode BAT- of the battery 160 and the ground terminal GND of the load circuit 170, and drive the self-locking circuit unit 130 to enter the self-locking conduction state, so that when a charging device is connected, the charging detection unit 140 can activate the path between the positive electrode PACK+ of the load circuit 170 and the voltage input terminal of the voltage stabilizing circuit unit 120, and the battery management unit 150 obtains power supply and enters the working state.

[0069] The power supply device may be a power supply product with a battery 160, such as a mobile power supply, an energy storage power supply, etc.

[0070] The battery 160 may be a lithium-ion battery, a nickel-metal hydride battery, etc. Exemplarily, the battery 160 is a lithium-ion battery, which may include a plurality of cells connected in series.

[0071] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A battery protection circuit, characterized in that: Used to protect the charging and discharging of the battery, the battery is connected to the load circuit, and the battery protection circuit includes a charging and discharging switch unit, a voltage stabilizing circuit unit, a self-locking circuit unit, a charging detection unit and a battery management unit; The charge and discharge switch unit is arranged between the battery and the load circuit, and a driving end thereof is connected to the battery management unit; The self-locking circuit unit is arranged between the positive electrode of the load circuit and the voltage input end of the voltage stabilizing circuit unit, and the voltage output end of the voltage stabilizing circuit unit is connected to the power supply end of the battery management unit; The charging detection unit is used to feed back a first level signal to the battery management unit based on the potential between the negative electrode of the battery and the ground terminal of the load circuit, and drive the self-locking circuit unit to enter a self-locking conduction state; The battery management unit is used to compare the battery power with a preset value and then output a second level signal to drive the self-locking circuit unit to enter a shutdown state.

2. The battery protection circuit according to claim 1, characterized in that: The charging detection unit includes a first triode, a second triode, a third triode, a first resistor, a second resistor, a third resistor and a fourth resistor, the first resistor is connected in series between the base of the first triode and the negative electrode of the battery, the second resistor is connected in series between the base and the emitter of the first triode, the emitter of the first triode is connected to the ground end of the load circuit, the collector of the first triode is connected to the base of the second triode, the emitter of the second triode is connected to the positive electrode of the battery, and the collector is connected to the base of the third triode, the third resistor is connected in series between the positive electrode of the battery and the collector of the triode, the fourth resistor is connected in series between the voltage output end of the voltage stabilizing circuit unit and the collector of the third triode, and the series node of the fourth resistor and the collector of the third triode is connected to the battery management unit to feed back a first level signal to the battery management unit, and the emitter of the third triode is connected to the ground end of the load circuit.

3. The battery protection circuit according to claim 2, characterized in that: The charging detection unit also includes a first capacitor, a fifth resistor and a sixth resistor, the fifth resistor is connected in series between the base and the emitter of the second transistor, the sixth resistor is connected in series between the base of the second transistor and the collector of the first transistor, and the first capacitor is connected in parallel with the sixth resistor.

4. The battery protection circuit according to claim 3, characterized in that: The charging detection unit also includes a second capacitor, a seventh resistor and an eighth resistor, the seventh resistor is connected in series between the collector of the second transistor and the base of the third transistor, the eighth resistor is connected in series between the base and the emitter of the third transistor, and the second capacitor is connected in parallel with the eighth resistor.

5. The battery protection circuit according to claim 2, characterized in that: The self-locking circuit unit includes an optocoupler, a fourth transistor, a self-locking MOS tube and a shutdown drive module, the positive electrode of the transmitting end of the optocoupler is connected to the collector of the second transistor, and the negative electrode is connected to the ground end of the load circuit, the collector of the receiving end of the optocoupler is connected to the gate of the self-locking MOS tube, and the emitter is connected to the negative electrode of the battery, the collector of the fourth transistor is connected to the gate of the self-locking MOS tube, the emitter is connected to the negative electrode of the battery, the base is connected to the drain of the self-locking MOS tube and the shutdown drive module, and the driving end of the shutdown drive module is connected to the battery management unit to receive the second level signal.

6. The battery protection circuit according to claim 5, characterized in that: The shutdown drive module includes a fifth transistor, a ninth resistor and a tenth resistor, the ninth resistor is connected in series between the base of the fifth transistor and the battery management unit, the tenth resistor is connected in series between the base and the emitter of the fifth transistor, and the emitter of the fifth transistor is connected to the negative electrode of the battery.

7. The battery protection circuit according to claim 5, characterized in that: The self-locking circuit unit also includes an eleventh resistor and a twelfth resistor connected in series, the series node of the eleventh resistor and the twelfth resistor is connected to the base of the fourth transistor, the other end of the eleventh resistor is connected to the drain of the self-locking MOS tube, and the other end of the twelfth resistor is connected to the negative electrode of the battery.

8. The battery protection circuit according to claim 7, characterized in that: The self-locking circuit unit also includes a thirteenth resistor and a fourteenth resistor connected in series, the series node of the thirteenth resistor and the fourteenth resistor is connected to the gate of the self-locking MOS tube, the other end of the thirteenth resistor is connected to the positive electrode of the load circuit, and the other end of the fourteenth resistor is connected to the collector of the fourth transistor.

9. The battery protection circuit according to any one of claims 1 to 8, characterized in that: The charge and discharge switch unit includes a first MOS tube and a second MOS tube, the source of the first MOS tube is connected to the negative electrode of the battery, the drain of the first MOS tube is connected to the drain of the second MOS tube, the source of the second switch is connected to the ground end of the load circuit, and the gate of the first MOS tube and the gate of the second MOS tube are both connected to the battery management unit.

10. A power supply device, characterized in that: The invention comprises a battery, a load circuit and a battery protection circuit as claimed in any one of claims 1 to 9, wherein a charge and discharge switch unit of the battery protection circuit is arranged between the battery and the load circuit, and a self-locking circuit unit of the battery protection circuit is arranged between the positive electrode of the load circuit and the voltage input terminal of the voltage stabilizing circuit unit.

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