Battery protection circuit and power supply equipment

Abstract

The utility model 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 utility model relates to battery management technical field, especially a kind of battery protection circuit and power supply equipment. BACKGROUND

[0002] Power supply product usually includes battery, battery management system and load circuit, battery management system controls and manages the charging and discharging of battery, and load circuit is connected with the two ends of battery.In the charge and discharge management of battery, battery has the minimum voltage requirement limit of working, and has discharge cutoff voltage to avoid overdischarge of battery.

[0003] The working of battery management system has running state, standby state and sleep state.When lower than the minimum working voltage of battery, system will enter sleep state, only a few components are working, at this time, the power consumption of battery is very small, about 10uA or so.However, although the discharge current of battery is very small in sleep state, continuous power consumption will lead to the power of battery being consumed completely, the capacity and life of battery will be greatly reduced, irreversible damage is generated, and there is safety hazard. SUMMARY

[0004] The technical problem to be solved by the embodiment of the utility model is to provide a battery protection circuit and power supply equipment to solve the problem that battery in sleep state still continuously consumes power in prior art, which leads to irreversible damage and safety hazard.

[0005] The utility model discloses a kind of battery protection circuits, for the protection of the charge and discharge of battery, the battery is connected with load circuit, the battery protection circuit includes charge and discharge switch unit, voltage stabilizing circuit unit, self-locking circuit unit, charge detection unit and battery management unit;

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

[0007] The self-locking circuit unit is arranged between the anode 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 charge detection unit is used to feed back first level signal to the battery management unit based on the potential of the cathode of the battery and the ground end of the load circuit, and drive the self-locking circuit unit to enter self-locking on state;

[0009] The battery management unit is used to output second level signal after comparing battery power with preset value, to drive the self-locking circuit unit to enter off state.

[0010] Optionally, the charging detection unit comprises a first transistor, a second transistor, a third transistor, 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 transistor and the negative electrode of the battery, the second resistor is connected in series between the base and the emitter of the first transistor, the emitter of the first transistor is connected to the ground terminal of the load circuit, the collector of the first transistor is connected to the base of the second transistor, the emitter of the second transistor is connected to the positive electrode of the battery, the collector is connected to the base of the third transistor, the third resistor is connected in series between the positive electrode of the battery and the collector of the third transistor, the fourth resistor is connected in series between the voltage output terminal of the voltage stabilization circuit unit and the collector of the third transistor, and the series connection node of the fourth resistor and the collector of the third transistor 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 transistor is connected to the ground terminal of the load circuit.

[0011] Optionally, the charging detection unit further comprises 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 further comprises 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 comprises an optocoupler, a fourth transistor, a self-locking MOS transistor and a shutdown driving module, the positive electrode of the emitter of the optocoupler is connected to the collector of the second transistor, the negative electrode is connected to the ground terminal of the load circuit, the collector of the receiving end of the optocoupler is connected to the gate of the self-locking MOS transistor, 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 transistor, the emitter is connected to the negative electrode of the battery, the base is connected to the drain of the self-locking MOS transistor and the shutdown driving module, and the driving end of the shutdown driving module is connected to the battery management unit to receive the second level signal.

[0014] Optionally, the shutdown driving module comprises 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.

[0015] Optionally, the self-locking circuit unit further 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 transistor, and the other end of the twelfth resistor is connected to the negative terminal of the battery.

[0016] Optionally, the self-locking circuit unit further 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 transistor. The other end of the thirteenth resistor is connected to the positive terminal 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 / discharge switch unit includes a first MOSFET and a second MOSFET. The source of the first MOSFET is connected to the negative terminal of the battery, the drain of the first MOSFET is connected to the drain of the second MOSFET, the source of the second MOSFET is connected to the ground terminal of the load circuit, and the gates of both the first MOSFET and the second MOSFET are connected to the battery management unit.

[0018] This utility model also discloses a power supply device, including a battery, a load circuit, and a battery protection circuit as described above. The charge / discharge switch unit of the battery protection circuit is disposed between the battery and the load circuit, and the self-locking circuit unit of the battery protection circuit is disposed between the positive terminal of the load circuit and the voltage input terminal of the voltage regulator circuit unit.

[0019] Compared with the prior art, the beneficial effects of the battery protection circuit provided by this utility model embodiment are as follows: By setting a self-locking circuit unit, which is located between the positive terminal of the load circuit and the voltage input terminal of the voltage regulator circuit unit, the battery management unit compares the battery charge with a preset value and outputs a second level signal to drive the self-locking circuit unit into the off state, cutting off the path between the positive terminal of the load circuit and the voltage input terminal of the voltage regulator circuit unit, thereby cutting off the power supply to the battery management unit and the power supply to the entire circuit, entering a "mechanical" shutdown state. This prevents circuit components from continuing to consume battery power when the battery charge is low, avoids irreversible damage to the battery, improves the service life of the battery and the power supply equipment used, and reduces safety hazards. Furthermore, the charging detection unit cleverly utilizes the potential difference between the negative terminal of the battery and the ground terminal of the load circuit to feed back a first level signal to the battery management unit and drive the self-locking circuit unit into the self-locking conduction state. This allows the charging detection unit to automatically activate and connect the path between the positive terminal of the load circuit and the voltage input terminal of the voltage regulator circuit unit when a charging device is connected, enabling the battery management unit to obtain power and enter the working state. Attached Figure Description

[0020] The technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0021] Figure 1 This is a structural block diagram of an embodiment of the battery protection circuit provided by this utility model;

[0022] Figure 2 This is a circuit diagram of an embodiment of the charging and discharging switch unit provided by this utility model, which is disposed between the battery and the load circuit.

[0023] Figure 3 This is a circuit diagram of an embodiment of the main control chip provided by this utility model;

[0024] Figure 4 This is a circuit diagram of an embodiment of the AEF module provided by this utility model;

[0025] Figure 5 This is a circuit diagram of an embodiment of the charging detection unit provided by this utility model;

[0026] Figure 6 This is a circuit diagram of an embodiment of the connection between the self-locking circuit unit and the voltage regulator circuit unit provided by this utility model.

[0027] The labels for the attached figures are as follows:

[0028] 110. Charge / discharge switch unit; 120. Voltage regulator circuit unit; 130. Self-locking circuit unit; 131. Shutdown drive module; 140. Charging detection unit; 150. Battery management unit;

[0029] Q1, Transistor 1; Q2, Transistor 2; Q3, Transistor 3; Q4, Transistor 4; Q5, Latch-off MOSFET; Q6, Transistor 5; Q7, MOSFET 1; Q8, MOSFET 2; R1, Resistor 1; R2, Resistor 2; R3, Resistor 3; R4, Resistor 4; R5, Resistor 5; R6, Resistor 6; R7, Resistor 7; R8, Resistor 8; R9, Resistor 9; R10, Resistor 10; R11, Resistor 11; R12, Resistor 12; R13, Resistor 13; R14, Resistor 14; C1, Capacitor 1; C2, Capacitor 2; C3, Capacitor 3; C4, Capacitor 4; C5, Capacitor 5; C6, Capacitor 6; U1, Main control chip; U2, Optocoupler; U3, Three-terminal regulator;

[0030] 160. Battery; 170. Load circuit. Detailed Implementation

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0032] This utility model embodiment provides a battery 160 protection circuit for protecting the charging and discharging of the battery 160, which is connected to the load circuit 170.

[0033] like Figure 1 and Figure 2 As shown, the battery 160 protection circuit provided in this application embodiment includes a charge / discharge switch unit 110, a voltage regulator 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 / discharge switch unit 110 is located between the battery 160 and the load circuit 170, and its drive end is connected to the battery management unit 150 to receive drive signals to turn on or off.

[0035] The self-locking circuit unit 130 is disposed between the positive terminal PACK+ of the load circuit 170 and the voltage input terminal of the voltage regulator circuit unit 120, and the voltage output terminal of the voltage regulator 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 terminal BAT- of the battery 160 and the ground terminal GND of the load circuit 170, and drive the self-locking circuit unit 130 into the self-locking conduction state.

[0037] The battery management unit 150 compares the battery charge of 160 with a preset value and outputs a second level signal to drive the self-locking circuit unit 130 into the off state.

[0038] This embodiment of the application incorporates a self-locking circuit unit 130, positioned between the positive terminal PACK+ of the load circuit 170 and the voltage input terminal of the voltage regulator circuit unit 120. The battery management unit 150 compares the battery 160's charge level with a preset value and outputs a second-level signal to drive the self-locking circuit unit 130 into a shutdown state. This disconnects the path between the positive terminal PACK+ of the load circuit 170 and the voltage input terminal of the voltage regulator circuit unit 120, thereby cutting off the power supply to the battery management unit 150 and the overall circuit, entering a "mechanical" shutdown state. This prevents circuit components from continuing to consume battery power when the battery 160's charge level is low. To prevent irreversible damage to the battery 160, extend the lifespan of the battery 160 and the power supply equipment used, and reduce safety hazards, the charging detection unit 140 cleverly utilizes the potential difference between the negative terminal BAT- of the battery 160 and the ground terminal GND of the load circuit 170 to feed back a first-level signal to the battery management unit 150, and drives the self-locking circuit unit 130 into a self-locking conduction state. This allows the charging detection unit 140 to automatically activate and connect the positive terminal PACK+ of the load circuit 170 and the voltage input terminal of the voltage regulator circuit unit 120 when a charging device is connected, so that the battery management unit 150 can obtain power and enter the working state.

[0039] The battery 160 protection circuit of this application embodiment ensures that the battery 160 will not drop to 0V even if it is left unattended for a long time, thus avoiding the problem of bulging when charging at 0V or charging at low power, protecting the battery 160 and improving 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 drive terminal of the charge / discharge switch unit 110 and the self-locking circuit unit 130, driving the charge / discharge switch unit 110 to turn on and off, and driving the self-locking circuit unit 130 to enter the off state. The main control chip U1 can use existing chips to output drive signals to drive the charge / discharge switch unit 110, and compare the battery charge level with a preset value to output a second-level signal to drive the self-locking circuit unit 130. Battery charge level acquisition can be achieved using conventional techniques, which will not be elaborated here.

[0041] The AFE module can monitor battery voltage, battery current, and battery temperature, and prevent battery overvoltage, undervoltage, overcurrent, short circuit, and equalization. It can be implemented using conventional technology, which will not be elaborated here. Figure 4 This is a circuit diagram of one embodiment of the AFE module.

[0042] refer to Figure 1 , Figure 3 and Figure 5 In an optional embodiment of this 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 terminal of the battery 160. The second resistor R2 is connected in series between the base and 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. The emitter of transistor Q2 is connected to the positive terminal of 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 terminal of battery 160 and the collector of the transistor. The fourth resistor R4 is connected in series between the voltage output terminal of the voltage regulator circuit unit 120 and the collector of the third transistor Q3. The series connection node of 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. The emitter of the third transistor Q3 is connected to the ground terminal GND of the load circuit 170.

[0043] In practice, both the first transistor Q1 and the third transistor Q3 are NPN transistors, while the second transistor Q2 is a PNP transistor. The PNP transistor is used to connect the positive terminal of the battery 160 to the third transistor Q3. The driving circuit is relatively simple; simply pulling the base of the second transistor Q2 low is sufficient to turn it on.

[0044] When the charging device is connected, the current flows through the positive terminal PACK+ of the load circuit 170, through the battery 160, and back to the negative terminal BAT- of the battery 160. At this time, the potential of the negative terminal 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 positive terminal of the battery 160 and the third transistor Q3. The self-locking circuit unit 130 receives a high-level signal and is driven to enter the self-locking conduction state, connecting the positive terminal PACK+ of the load circuit 170 and the voltage input terminal of the voltage regulator circuit unit 120. The battery management unit 150 is powered. 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 to work. The charging detection unit 140 of this application cleverly utilizes the potential difference between the negative terminal of the battery 160 and the ground terminal GND of the load circuit 170 when the charging device is connected. It uses a hardware circuit composed of multiple transistors to directly drive the self-locking circuit unit 130 and activate the power supply of the battery management unit 150. The control is simple and the cost is low.

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

[0046] Further reference 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 emitter of the second transistor Q2, and the sixth resistor R6 is connected in series between the base of the second transistor Q2 and the collector of the first transistor Q1. The first capacitor C1 and the sixth resistor R6 are connected in parallel.

[0047] The first capacitor C1 acts as a filter, helping to remove high-frequency noise or fluctuations in the signal. The fifth resistor R5 acts as a pull-up resistor; when the first transistor Q1 is in the off state, the fifth resistor R5 pulls the base of the second transistor Q2 high, keeping Q2 in the off state and preventing false turn-on. The sixth resistor R6 limits the current flowing to the base of the second transistor Q2, preventing excessive current from damaging Q2. Therefore, the first capacitor C1, the fifth resistor R5, and the sixth resistor R6 improve the stability and reliability 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 emitter of the third transistor Q3. The second capacitor C2 and the eighth resistor R8 are connected in parallel.

[0049] The second capacitor, C2, acts as a filter, helping to remove high-frequency noise or fluctuations in the signal. The seventh resistor, R7, limits the current flowing to the base of the third transistor, Q3, preventing excessive current from damaging it. The eighth resistor, R8, acts as a pull-down resistor; when the second transistor, Q2, is in the off state, R8 pulls the base of Q3 low, keeping Q3 in the off state and preventing false turn-on. Therefore, the second capacitor, C2, the seventh resistor, R7, and the eighth resistor, R8, improve the stability and reliability of the third transistor, Q3.

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

[0051] In practice, the fourth transistor Q4 is an NPN transistor.

[0052] The working principle of optocoupler U2 is to use the light signal emitted from its transmitter to illuminate the receiver, thereby controlling the electrical characteristics of the receiver. When the transmitter is turned on, it emits a light signal, which illuminates the receiver, causing the receiver to conduct or cut off, thus achieving electrical isolation between the input and output circuits.

[0053] When a 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 MOSFET Q5 is pulled low and begins to conduct, the fourth transistor Q4 turns on, and continues to pull down the gate voltage of the self-locking MOSFET Q5, so the self-locking MOSFET Q5 continues to conduct. The voltage input terminal of the voltage regulator circuit unit 120 is continuously powered, and the regulated output is 5V to power the battery management unit 150, thus forming a power self-locking to power the entire system. When the battery 160's charge is lower than a preset value, the battery management unit 150 outputs a second-level signal, which pulls down the voltage of the base of the fourth transistor Q4 through the shutdown drive module 131, making the fourth transistor Q4 in the off state, thereby turning off the self-locking MOSFET Q5, cutting off the voltage input of the voltage regulator circuit unit 120, cutting off the power supply to the subsequent circuits, and stopping the continued consumption of the battery 160's charge, 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, and the tenth resistor R10 is connected in series between the base and emitter of the fifth transistor Q6. The emitter of the fifth transistor Q6 is connected to the negative terminal BAT- of the battery 160.

[0055] In practice, 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 from the main control chip U1.

[0056] When the battery 160's charge level falls below a preset value, the battery management unit 150 outputs a second-level signal to drive the fifth transistor Q6 to conduct, pulling down the base voltage of the fourth transistor Q4 and putting Q4 in the off state, thereby turning off the self-locking MOSFET Q5. The ninth resistor R9 limits the current flowing to the base of the fifth transistor Q6, preventing excessive current from damaging it. The tenth resistor R10 pulls down the base of the fifth transistor Q6 when the battery management unit 150 has no signal output, keeping Q6 in the off state and preventing false turn-on.

[0057] Optionally, consider 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 MOSFET Q5. The other end of the twelfth resistor R12 is connected to the negative terminal BAT- of the battery 160.

[0058] When the self-locking MOSFET Q5 starts to conduct, the base of the fourth transistor Q4 is turned on by the voltage divider formed by the eleventh resistor R11 and the twelfth resistor R12, which continues to pull down the gate voltage of the self-locking MOSFET Q5, keeping the self-locking MOSFET Q5 continuously conducting.

[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 MOSFET Q5. The other end of the thirteenth resistor R13 is connected to the positive terminal 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, acts as a pull-up resistor. When the optocoupler U2 and the fourth transistor Q4 are in the off state, it pulls up the gate voltage of the self-locking MOSFET Q5, keeping Q5 in the off state and preventing it from being mistakenly turned on. The fourteenth resistor, R14, serves as a current limiter.

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

[0062] By configuring the first MOSFET Q7 and the second MOSFET Q8, their gates can receive drive signals to turn on or off, thereby connecting or disconnecting the path between the negative terminal BAT- of the battery 160 and the ground terminal GND of the load circuit 170, thus controlling charging and discharging. The main control chip U1 is connected to the gate of the first MOSFET Q7 and the gate of the second MOSFET Q8.

[0063] Optionally, the battery 160 protection circuit also includes a buck-boost circuit unit and a charge / discharge interface. The charge / discharge interface is connected to the buck-boost circuit unit, which is connected to the positive terminal of the battery 160 and the ground terminal GND of the load circuit 170. The buck-boost unit is a DC-DC converter circuit that simultaneously performs buck and boost functions. It can be implemented using conventional technology and will not be described in detail here. The charge / discharge interface can be a Type-C interface.

[0064] refer to Figure 1 , Figure 3 and Figure 6 In an optional embodiment of this application, the voltage regulator circuit unit 120 includes a three-terminal 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 regulator U3 and the self-locking circuit, and the second parallel node is connected to the ground terminal. 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 regulator U3 and the power supply terminal of the battery management unit 150, and the second parallel node is connected to the ground terminal. The ground pin of the three-terminal regulator U3 is connected to the ground terminal.

[0065] The three-terminal 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 subsequent circuits can operate under a stable voltage. The three-terminal regulator U3 is simple and efficient in design, making it easy to achieve stable voltage output in electronic designs. It is also very easy to use, requiring only a few external components to achieve the voltage regulation function, and its circuit structure is simple.

[0066] The third capacitor C3 and the fifth capacitor C5 are used to filter out low-frequency interference, while the fourth capacitor C4 and the sixth capacitor C6 are used to filter out high-frequency ripple. Together with the three-terminal voltage regulator U3, they step down and regulate the input voltage within a suitable range to power the battery management unit 150. Specifically, after the latch-up MOSFET Q5 is turned on, the input supply voltage is filtered by the third capacitor C3 and the fourth capacitor C4 before being input to the three-terminal voltage regulator U3. The voltage regulated by the three-terminal voltage regulator U3 is then filtered by the fifth capacitor C5 and the sixth capacitor C6, resulting in a stable 5V output to power the battery management unit 150.

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

[0068] The power supply device in this embodiment of the application incorporates a self-locking circuit unit 130, which is positioned between the positive terminal PACK+ of the load circuit 170 and the voltage input terminal of the voltage regulator circuit unit 120. The battery management unit 150 compares the battery charge of the battery 160 with a preset value and outputs a second-level signal to drive the self-locking circuit unit 130 into a shutdown state. This disconnects the path between the positive terminal PACK+ of the load circuit 170 and the voltage input terminal of the voltage regulator circuit unit 120, thereby cutting off the power supply to the battery management unit 150 and the overall circuit, entering a "mechanical" shutdown state to prevent further operation when the battery charge of the battery 160 is low. The battery management unit 150 is powered by the charging detection unit 140, which continuously consumes the power of the battery 160 to avoid irreversible damage, improves the service life of the battery 160 and the power supply equipment used, reduces safety hazards, and sets up a charging detection unit 140 to feed back a first level signal to the battery management unit 150 based on the potential of the negative terminal BAT- of the battery 160 and the ground terminal GND of the load circuit 170. This drives 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 terminal PACK+ of the load circuit 170 and the voltage input terminal of the voltage regulator circuit unit 120, and the battery management unit 150 obtains power and enters the working state.

[0069] Power supply equipment can be power products with batteries such as power banks and energy storage power supplies.

[0070] Battery 160 can be a lithium-ion battery, a nickel-metal hydride battery, etc. For example, battery 160 uses a lithium-ion battery, which may include multiple cells connected in series.

[0071] It should be understood that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of this utility model.

Claims

1. A battery protection circuit, characterized in that, The battery protection circuit is used to protect the charging and discharging of the battery. The battery is connected to the load circuit. The battery protection circuit includes a charging and discharging switch unit, a voltage regulator circuit unit, a self-locking circuit unit, a charging detection unit, and a battery management unit. The charge / discharge switch unit is disposed between the battery and the load circuit, and its drive terminal is connected to the battery management unit. The self-locking circuit unit is disposed between the positive terminal of the load circuit and the voltage input terminal of the voltage regulator circuit unit, and the voltage output terminal of the voltage regulator circuit unit is connected to the power supply terminal 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 of the negative terminal of the battery and the ground terminal of the load circuit, and drive the self-locking circuit unit to enter the self-locking conduction state. The battery management unit compares the battery charge with a preset value and outputs a second level signal to drive the self-locking circuit unit into a shutdown state.

2. The battery protection circuit according to claim 1, characterized in that, The charging detection unit includes a first transistor, a second transistor, a third transistor, 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 transistor and the negative terminal of the battery. The second resistor is connected in series between the base and emitter of the first transistor. The emitter of the first transistor is connected to the ground terminal of the load circuit. The collector of the first transistor is connected to the base of the second transistor. The emitter of the second transistor is connected to the positive terminal of the battery, and its collector is connected to the base of the third transistor. The third resistor is connected in series between the positive terminal of the battery and the collector of the transistor. The fourth resistor is connected in series between the voltage output terminal of the voltage regulator circuit unit and the collector of the third transistor. The series connection point of the fourth resistor and the collector of the third transistor is connected to the battery management unit to feed back a first level signal to the battery management unit. The emitter of the third transistor is connected to the ground terminal of the load circuit.

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

4. The battery protection circuit according to claim 3, characterized in that, The charging detection unit further 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 emitter of the third transistor. The second capacitor and the eighth resistor are connected in parallel.

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 MOSFET, and a shutdown drive module. The positive terminal of the emitter of the optocoupler is connected to the collector of the second transistor, and the negative terminal is connected to the ground terminal of the load circuit. The collector of the receiver of the optocoupler is connected to the gate of the self-locking MOSFET, and the emitter is connected to the negative terminal of the battery. The collector of the fourth transistor is connected to the gate of the self-locking MOSFET, the emitter is connected to the negative terminal of the battery, and the base is connected to the drain of the self-locking MOSFET and the shutdown drive module. The drive terminal 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 emitter of the fifth transistor. The emitter of the fifth transistor is connected to the negative terminal 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 transistor, and the other end of the twelfth resistor is connected to the negative terminal 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 transistor. The other end of the thirteenth resistor is connected to the positive terminal 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 1-8, characterized in that, The charge / discharge switch unit includes a first MOSFET and a second MOSFET. The source of the first MOSFET is connected to the negative terminal of the battery, the drain of the first MOSFET is connected to the drain of the second MOSFET, the source of the second MOSFET is connected to the ground terminal of the load circuit, and the gates of both the first MOSFET and the second MOSFET are connected to the battery management unit.

10. A power supply device, characterized in that, The device includes a battery, a load circuit, and a battery protection circuit as described in any one of claims 1-9, wherein a charge / discharge switch unit of the battery protection circuit is disposed between the battery and the load circuit, and a self-locking circuit unit of the battery protection circuit is disposed between the positive terminal of the load circuit and the voltage input terminal of the voltage regulator circuit unit.

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