Lithium battery protection board detection protection circuit

Abstract

The utility model relates to a lithium battery protection board detection protection circuit, which comprises an MCU main control circuit, an AFE detection circuit, a charging MOS tube QC, a discharging MOS tube QD and a voltage detection circuit, the AFE detection circuit is used for detecting whether short circuit protection is triggered, and when the AFE detection circuit detects that the short circuit protection is triggered, the MCU main control circuit controls the voltage detection circuit to open; according to the utility model, the discharge MOS tube can be closed when the current does not reach the peak value under the condition of real short circuit, and the discharge MOS tube can be closed when the current value is small, so that the impact of the current on the MOS tube is effectively reduced, the damage and heat emission of the discharge MOS tube are reduced to the minimum, the discharge MOS tube is not easy to break down, and the service life of the discharge MOS tube is prolonged. And the service life of the discharge MOS tube is effectively prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium battery protection, in particular to a lithium battery protection board detection protection circuit. Background Art

[0002] With the extensive use of lithium batteries, the requirements for lithium battery protection boards are getting higher and higher, among which short-circuit protection for lithium batteries is particularly important. In the application process of lithium batteries, there is a situation where the short-circuit protection is easily triggered by mistake due to the excessive input capacitance of the inverter; the current common solution is to increase the short-circuit protection value or increase the delay to bypass the capacitor charging time, thereby avoiding the false triggering of the short-circuit protection. However, this solution is very dangerous for real short-circuit protection, and it is easy to break down the MOS and cause discharge without protection. Therefore, it is necessary to provide a technical solution that can solve the above problems. Utility Model Content

[0003] The utility model aims to provide a lithium battery protection board detection protection circuit to solve the problem in the prior art that the MOS tube is easily broken down when the short circuit protection is triggered.

[0004] The technical solution provided by the utility model is:

[0005] A lithium battery protection board detection protection circuit, the lithium battery protection board detection protection circuit has a positive output terminal and a negative output terminal, the lithium battery protection board detection protection circuit comprises an MCU main control circuit, an AFE detection circuit, a charging MOS tube QC, a discharging MOS tube QD and a voltage detection circuit, the AFE detection circuit is connected to the positive and negative electrodes of the lithium battery, the gates of the charging MOS tube QC and the discharging MOS tube QD are both connected to the AFE detection circuit, the drains of the charging MOS tube QC and the discharging MOS tube QD are connected to each other, the source of the discharging MOS tube QD is connected to the negative electrode of the lithium battery, the source of the charging MOS tube QC is connected to the negative output terminal, and the voltage detection circuit is connected to the negative electrode of the lithium battery, the MCU main control circuit and the negative output terminal;

[0006] The AFE detection circuit is used to detect whether the short-circuit protection is triggered. When the AFE detection circuit detects that the short-circuit protection is triggered, the MCU main control circuit controls the voltage detection circuit to turn on;

[0007] The voltage detection circuit is used to collect the voltage value U between the negative output terminal and the negative electrode of the lithium battery, and output a corresponding voltage signal to the MCU main control circuit;

[0008] The MCU main control circuit determines the size of the voltage value U according to the received voltage signal, and determines the short circuit type according to the size of the voltage value U. If it is determined to be a real short circuit, the short circuit protection is continued; if it is determined to be a false trigger short circuit, the short circuit protection is released.

[0009] In a preferred embodiment, when the MCU main control circuit determines that the voltage value U is greater than the preset voltage value U1, it is determined to be a falsely triggered short circuit; when the MCU main control circuit determines that the voltage value U is less than the preset voltage value U1, it is determined to be a real short circuit.

[0010] In a preferred embodiment, the voltage detection circuit includes an enable switch module, a voltage input switch module and an AD acquisition module connected in sequence, the enable switch module and the AD acquisition module are both connected to the MCU main control circuit, and the enable switch module is connected to the negative output terminal;

[0011] The voltage input switch module is used to control whether the voltage signal of the negative output terminal enters the AD acquisition module when the short circuit protection is triggered, and the enable switch module is used to control the working state of the voltage input switch module and the AD acquisition module.

[0012] In a preferred embodiment, the voltage input switch module is a first switch circuit; the first switch circuit includes a first transistor VQ1, the emitter of the first transistor VQ1 is connected to the negative output end, the base of the first transistor VQ1 is connected to the enable switch module, and the collector of the first transistor VQ1 is connected to the AD acquisition module.

[0013] In a preferred embodiment, a resistor is connected between the emitter and the base of the first transistor VQ1 , and the base of the first transistor VQ1 is connected to the enabling switch module via the resistor and the diode in sequence.

[0014] In a preferred embodiment, the enable switch module includes a second switch circuit and a third switch circuit connected to each other, the second switch circuit is used to receive the enable switch signal issued by the MCU main control circuit, and the third switch circuit is used to control the working state of the voltage input switch module and the AD acquisition module after the second switch circuit receives the enable switch signal issued by the MCU main control circuit.

[0015] In a preferred embodiment, the second switch circuit includes a second transistor VQ2; the base of the second transistor VQ2 is connected to the MCU main control circuit through a resistor, and the base of the second transistor VQ2 is grounded through a resistor, the collector of the second transistor VQ2 is connected to the voltage input switch module, and the emitter of the second transistor VQ2 is grounded;

[0016] The third switch circuit includes a first MOS transistor VM2, a gate of the first MOS transistor VM2 is connected to the collector of the second transistor VQ2 through a resistor, and the gate of the first MOS transistor VM2 is grounded through a resistor, and a source of the first MOS transistor VM2 is grounded.

[0017] In a preferred embodiment, the AD acquisition module includes a resistor voltage-dividing sampling circuit, which includes a first voltage-dividing resistor and a second voltage-dividing resistor connected in sequence, and a node J1 at which the first voltage-dividing resistor and the second voltage-dividing resistor are interconnected is connected to the MCU main control circuit, and the node J1 is connected to the voltage input switch module through a resistor.

[0018] In a preferred implementation, an RC filter circuit is connected between the node J1 and the MCU main control circuit; and the first voltage-dividing resistor and the second voltage-dividing resistor are respectively connected in parallel with diodes.

[0019] Compared with the prior art, the lithium battery protection board detection protection circuit provided by the utility model has the following advantages:

[0020] Beneficial effects:

[0021] When the lithium battery protection board triggers the short-circuit protection, it can be effectively judged whether the current short circuit is a real short circuit or a false trigger short circuit caused by the lithium battery charging the capacitor. When it is determined to be a real short circuit, the short-circuit protection state is maintained; when it is determined to be a false trigger short circuit, the short-circuit protection is released, and the capacitor continues to be charged until it is used normally. By using the utility model, in the case of a real short circuit, the discharge MOS tube can be turned off before the current reaches the peak value, and the discharge MOS tube can be turned off when the current value is small, thereby effectively reducing the impact of the current on the MOS tube, minimizing the damage and heat generation of the discharge MOS tube, and thus achieving the effect that the discharge MOS tube is not easy to be broken down, and the service life of the discharge MOS tube is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the circuit structure of the lithium battery protection board detection protection circuit described in the embodiment of the utility model;

[0023] Figure 2 A specific circuit diagram of the voltage detection circuit described in the embodiment of the utility model;

[0024] Figure 3 This is a specific circuit diagram of the enabling switch module described in the embodiment of the utility model.

[0025] The figures in the drawings are:

[0026] 10. MCU main control circuit; 20. AFE detection circuit; 30. Voltage detection circuit; 40. Lithium battery; 31. Enable switch module; 311. Second switch circuit; 312. Third switch circuit; 32. Voltage input switch module; 33. AD acquisition module. DETAILED DESCRIPTION

[0027] In order to better understand the purpose, technical solution and technical effect of the utility model, the utility model is further explained in conjunction with the accompanying drawings and embodiments. At the same time, it is stated that the embodiments described below are only used to explain the utility model and are not used to limit the utility model.

[0028] Example 1

[0029] like Figure 1-3 As shown, a lithium battery protection board detection protection circuit, the lithium battery protection board detection protection circuit has a positive output terminal and a negative output terminal, wherein the positive output terminal is attached Figure 1 The BATT+ in the negative output terminal is attached Figure 1 C- in the lithium battery protection board detection protection circuit includes an MCU main control circuit 10, an AFE detection circuit 20, a charging MOS tube QC, a discharging MOS tube QD and a voltage detection circuit 30, the AFE detection circuit is connected to the positive and negative electrodes of the lithium battery 40, the gates of the charging MOS tube QC and the discharging MOS tube QD are connected to the AFE detection circuit, the drains of the charging MOS tube QC and the discharging MOS tube QD are connected to each other, the source of the discharging MOS tube QD is connected to the negative electrode BATT- of the lithium battery, the source of the charging MOS tube QC is connected to the negative output terminal C-, the voltage detection circuit is connected to the negative electrode BATT- of the lithium battery, the MCU main control circuit and the negative output terminal C-; in this embodiment, a current detection resistor Rs is provided between the negative electrode BATT- of the lithium battery and the discharging MOS tube QD;

[0030] The AFE detection circuit is used to detect whether the short-circuit protection is triggered. When the AFE detection circuit detects that the short-circuit protection is triggered, the MCU main control circuit controls the voltage detection circuit to turn on;

[0031] The voltage detection circuit is used to collect the voltage value U between the negative output terminal and the negative electrode of the lithium battery, and output a corresponding voltage signal to the MCU main control circuit;

[0032] The MCU main control circuit determines the size of the voltage value U according to the received voltage signal, and determines the short circuit type according to the size of the voltage value U. If it is determined to be a real short circuit, the short circuit protection is continued; if it is determined to be a false trigger short circuit, the short circuit protection is released.

[0033] In the present patent application, the AFE detection circuit is used to detect whether the lithium battery protection board triggers the short circuit protection. When the AFE detection circuit detects that the short circuit protection is triggered, the MCU main control circuit controls the voltage detection circuit to turn on; the voltage detection circuit is used to detect and collect the voltage value U between the negative output terminal and the negative electrode of the lithium battery. By judging whether the voltage value U is greater than or less than the preset voltage value U1, it can be determined whether the triggered short circuit is a real short circuit or a false trigger short circuit. When the lithium battery protection board triggers the short circuit protection, the discharge MOS tube QD will be turned off. When it is determined to be a false trigger short circuit, the MCU main control circuit outputs a corresponding control signal (such as a switch signal) to control the discharge MOS tube QD to open; when it is determined to be a real short circuit, the MCU main control circuit continues to control the discharge MOS tube QD to remain closed; in addition, when it is determined to be a real short circuit, a real short circuit flag signal can also be reported, and the discharge MOS tube QD is allowed to open only after the real short circuit flag signal is released.

[0034] In a specific embodiment, when the MCU main control circuit determines that the voltage value U is greater than the preset voltage value U1, it is determined to be a false trigger short circuit, and when the MCU main control circuit determines that the voltage value U is less than the preset voltage value U1, it is determined to be a real short circuit. In a preferred embodiment, the preset voltage value U1 ranges from 1.8V to 2.2V, and preferably, the preset voltage value U1 is 2V.

[0035] Specifically, after the lithium battery protection board triggers the short-circuit protection, when the MCU main control circuit judges that the voltage value U is greater than 2V according to the received voltage signal, it is judged as a false triggering of the short circuit, and the MCU main control circuit outputs a corresponding control signal to control the discharge MOS tube QD to open; when the MCU main control circuit judges that the voltage value U is less than 2V according to the received voltage signal, it is judged as a real short circuit, and the MCU main control circuit continues to control the discharge MOS tube QD to remain closed, and reports a real short circuit flag signal.

[0036] It should be noted that in the scheme of this patent application, the MCU main control circuit determines the voltage value and outputs a corresponding control signal (such as a switch signal), and the AFE detection circuit detects whether the short-circuit protection is triggered and outputs a corresponding control signal (such as a switch signal), etc. are prior arts. The scheme in this patent application does not involve improvements to computer programs or algorithms.

[0037] In a specific implementation, the main control chip model of the MCU main control circuit is HC32L072KATA; the chip model of the AFE detection circuit is OZ3717. The MCU main control circuit and the AFE detection circuit are existing technologies or functional circuits that can be implemented by existing technologies, and their specific composition and working principle will not be described here.

[0038] The following is a detailed description of the specific composition and function of the improved voltage detection circuit involved in this patent solution:

[0039] As attached Figure 2-3 As shown, the voltage detection circuit includes an enabling switch module 31, a voltage input switch module 32 and an AD acquisition module 33 which are connected in sequence, the enabling switch module and the AD acquisition module are both connected to the MCU main control circuit, and the enabling switch module is connected to the negative output terminal;

[0040] The voltage input switch module 32 is used to control whether the voltage signal at the negative output end enters the AD acquisition module 33 when the short circuit protection is triggered, and the enable switch module 31 is used to control the working states of the voltage input switch module 31 and the AD acquisition module 33.

[0041] In a preferred embodiment, the voltage input switch module 32 is a first switch circuit; specifically, as shown in the attached Figure 2 As shown, the first switch circuit includes a first transistor VQ1, the emitter of the first transistor VQ1 is connected to the negative output terminal, that is, the emitter of the first transistor VQ1 is used to receive the voltage signal of the negative output terminal when the short-circuit protection is triggered, the base of the first transistor VQ1 is connected to the enabling switch module, and the collector of the first transistor VQ1 is connected to the AD acquisition module. In a preferred embodiment, a resistor is connected between the emitter and base of the first transistor VQ1, and the base of the first transistor VQ1 is connected to the enabling switch module via a resistor and a diode in sequence; a diode is connected between the emitter and collector of the first transistor VQ1. Figure 2 In the embodiment, the node C- in the voltage input switch module 32 is a node connected to the negative output terminal C-.

[0042] In a preferred embodiment, the enabling switch module 31 includes a second switch circuit 311 and a third switch circuit 312 connected to each other, wherein the second switch circuit 311 is used to receive the enabling switch signal sent by the MCU main control circuit, and the third switch circuit is used to control the working state of the voltage input switch module and the AD acquisition module after the second switch circuit receives the enabling switch signal sent by the MCU main control circuit. Specifically, when the third switch circuit is used to turn on the voltage input switch module 32 after the second switch circuit receives the enabling switch signal sent by the MCU main control circuit, the third switch circuit is turned on to start the voltage input switch module 32, and control the voltage signal at the negative output end to enter the AD acquisition module after the short circuit protection is triggered, and at the same time, the AD acquisition module 33 is turned on to start the voltage acquisition work.

[0043] In a preferred embodiment, as shown in the attached Figure 3 As shown, the second switch circuit 311 includes a second triode VQ2; the base of the second triode VQ2 is connected to the MCU main control circuit through a resistor, and the base of the second triode VQ2 is grounded through a resistor, the collector of the second triode VQ2 is connected to the voltage input switch module, and the emitter of the second triode VQ2 is grounded;

[0044] The third switch circuit 312 includes a first MOS transistor VM2, a gate of the first MOS transistor VM2 is connected to the collector of the second transistor VQ2 through a resistor, and the gate of the first MOS transistor VM2 is grounded through a resistor, and a source of the first MOS transistor VM2 is grounded.

[0045] Attached Figure 2-3 In the example, the node SC_EN of the second switch circuit 311 in the enable switch module 31 is a node connected to the MCU main control circuit. The node SC_EN of the second switch circuit 311 is used to receive the enable switch signal issued by the MCU main control circuit, and the third switch circuit 312 is used to convert the enable switch signal issued by the MCU main control circuit into a control signal for controlling the start-up of the voltage input switch module 32 and the AD acquisition module 33. At this time, the voltage input switch module 32 controls the voltage signal of the negative output end to enter the AD acquisition module 33 after the short-circuit protection is triggered, and the AD acquisition module 33 starts the voltage acquisition work. At this time, the first voltage divider resistor R44 in the resistor voltage divider sampling circuit in the AD acquisition module 33 is a pull-up circuit signal.

[0046] In a preferred embodiment, the AD acquisition module 33 is as shown in the attached Figure 2As shown, it includes a resistor voltage-dividing sampling circuit, and the resistor voltage-dividing sampling circuit includes a first voltage-dividing resistor R44 and a second voltage-dividing resistor R45 connected in sequence, and the node J1 where the first voltage-dividing resistor and the second voltage-dividing resistor are connected to each other is connected to the MCU main control circuit, and the node J1 is connected to the voltage input switch module through a resistor R47. In a preferred embodiment, an RC filter circuit is connected between the node J1 and the MCU main control circuit; the first voltage-dividing resistor and the second voltage-dividing resistor are respectively connected in parallel with a diode. Wherein, Figure 2 In the example, the node P-_AD in the AD acquisition module 33 is a node connected to the MCU main control circuit. The node P-_AD in the AD acquisition module 33 is a node for the MCU main control circuit to collect voltage information.

[0047] The working principle of the voltage detection circuit provided in this embodiment is briefly described below: When the voltage detection circuit detects a short circuit, there are the following situations:

[0048] (1) False trigger short circuit: During normal operation, the discharge MOS tube QD is in the on state. When the positive output terminal BATT+ and the negative output terminal C- are connected to a large capacitive load, the short circuit protection is triggered, and the discharge MOS tube QD is turned off. The MCU main control circuit outputs a corresponding control signal to turn on the voltage detection circuit. The voltage detection circuit collects the voltage value between the negative output terminal C- and the negative electrode BATT- of the lithium battery (i.e., the voltage value U). The voltage detection circuit converts the collected voltage signal into a low voltage signal and then transmits it to the MCU main control circuit to determine the size of the voltage value U, and compares it with the preset voltage value U1 (U1=2V in this embodiment, which can be appropriately adjusted as needed in actual application). If the voltage value U is greater than the preset voltage value U1, it is determined that the current state is a false trigger short circuit (false capacitor charging short circuit). The MCU main control circuit outputs a corresponding switch signal to turn on the discharge MOS tube QD to discharge the lithium battery again.

[0049] (2) Real short circuit situation: During normal operation, the discharge MOS tube QD is in the on state. When a real short circuit occurs, the discharge MOS tube QD is turned off, and the voltage of the negative output terminal C- is pulled up to the voltage of the positive output terminal BATT+ by the short-circuited device or cable. The MCU main control circuit outputs a corresponding control signal to start the voltage detection circuit. The voltage detection circuit collects the voltage value between the negative output terminal C- and the negative electrode BATT- of the lithium battery (i.e., the voltage value U). The voltage detection circuit converts the collected voltage signal into a low-voltage signal and then transmits it to the MCU main control circuit to determine the size of the voltage value U, and compares it with the preset voltage value U1. If the voltage value U is less than the preset voltage value U1 (in this embodiment, U1=2V, which can be adjusted appropriately as needed in actual application), the current state is determined to be a real short circuit. The MCU main control circuit continues to control the discharge MOS tube QD to remain closed and reports a real short circuit flag until the real short circuit flag is released, and then the discharge MOS tube QD is allowed to open.

[0050] Among them, the node SC_EN in the second switch circuit of the enable switch module 31 in the voltage detection circuit usually maintains a low level state. When the MCU main control circuit detects that the lithium battery protection board triggers the short circuit protection through the AFE detection circuit, the MCU main control circuit outputs a high level to turn on the first MOS tube VM2 and the first transistor VQ1, and transmits the voltage of the negative output terminal C- to the MCU main control circuit through the AD acquisition module 33. Through the first voltage-dividing resistor R44, the second voltage-dividing resistor R45 and the resistor R47, the MCU main control circuit can determine whether the voltage U at the output terminal C- is greater than or less than the preset voltage value U1, so as to determine whether the type of short circuit is a false trigger short circuit or a real short circuit.

[0051] The lithium battery protection board detection protection circuit provided in this embodiment has the following beneficial effects:

[0052] When the lithium battery protection board triggers the short-circuit protection, it can be effectively judged whether the current short circuit is a real short circuit or a false trigger short circuit caused by the lithium battery charging the capacitor. When it is determined to be a real short circuit, the short-circuit protection state is maintained; when it is determined to be a false trigger short circuit, the short-circuit protection is released, and the capacitor continues to be charged until it is used normally. By using the utility model, in the case of a real short circuit, the discharge MOS tube can be turned off before the current reaches the peak value, and the discharge MOS tube can be turned off when the current value is small, thereby effectively reducing the impact of the current on the MOS tube, minimizing the damage and heat generation of the discharge MOS tube, and thus achieving the effect that the discharge MOS tube is not easy to be broken down, and the service life of the discharge MOS tube is effectively improved.

[0053] In a preferred embodiment, the voltage detection circuit can also be used to detect negative voltage to effectively protect the lithium battery when charging, as follows: Under normal circumstances, the charging MOS tube QC is in a closed state. When the charger is connected to the positive output terminal BATT+ and the negative output terminal C-, the voltage of the negative output terminal C- is pulled down by the charger. At this time, the voltage of the charger is equal to the lithium battery voltage plus the voltage of the negative electrode BATT- of the lithium battery to the negative output terminal C-. The MCU main control circuit can detect and obtain the voltage information of the charger through the voltage detection circuit, and determine whether the voltage of the charger is within the voltage range that the current lithium battery can withstand. If so, the charging MOS tube QC is turned on to allow the charger to charge the lithium battery. If the voltage of the charger is not within the voltage range that the current lithium battery can withstand, the charging MOS tube QC continues to be kept closed to protect the lithium battery. (Take the 60V lithium battery pack on the market as an example, the maximum voltage that a ternary lithium 17-series battery can withstand cannot exceed 71.4V, and the maximum voltage that a lithium iron phosphate 20-series battery can withstand cannot exceed 75V.

[0054] It should be noted that in the present patent application, the MCU main control circuit is used to determine whether a voltage value is within a preset voltage value range (such as using the MCU main control circuit to determine whether the voltage value of the charger is within the voltage range that the current lithium battery can withstand), which belongs to the prior art. The solution in this patent application does not involve improvements to computer programs or algorithms.

[0055] In addition, the operating voltage and operating current required for the MCU main control circuit, AFE detection circuit and voltage detection circuit are powered by corresponding power supplies, which are common knowledge of those skilled in the art and will not be described in detail here.

[0056] The above embodiments only express several implementation methods of the utility model, and the descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the inventive concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A lithium battery protection board detection protection circuit, the lithium battery protection board detection protection circuit has a positive output terminal and a negative output terminal, characterized in that: It includes an MCU main control circuit, an AFE detection circuit, a charging MOS tube QC, a discharging MOS tube QD and a voltage detection circuit, wherein the AFE detection circuit is connected to the positive and negative electrodes of the lithium battery, the gates of the charging MOS tube QC and the discharging MOS tube QD are connected to the AFE detection circuit, the drains of the charging MOS tube QC and the discharging MOS tube QD are connected to each other, the source of the discharging MOS tube QD is connected to the negative electrode of the lithium battery, the source of the charging MOS tube QC is connected to the negative output terminal, and the voltage detection circuit is connected to the negative electrode of the lithium battery, the MCU main control circuit and the negative output terminal; The AFE detection circuit is used to detect whether the short-circuit protection is triggered. When the AFE detection circuit detects that the short-circuit protection is triggered, the MCU main control circuit controls the voltage detection circuit to turn on; The voltage detection circuit is used to collect the voltage value U between the negative output terminal and the negative electrode of the lithium battery, and output a corresponding voltage signal to the MCU main control circuit; The MCU main control circuit determines the size of the voltage value U according to the received voltage signal, and determines the short circuit type according to the size of the voltage value U. If it is determined to be a real short circuit, the short circuit protection is continued; if it is determined to be a false trigger short circuit, the short circuit protection is released.

2. The lithium battery protection board detection protection circuit according to claim 1, characterized in that: When the MCU main control circuit determines that the voltage value U is greater than the preset voltage value U1, it is determined to be a false trigger short circuit. When the MCU main control circuit determines that the voltage value U is less than the preset voltage value U1, it is determined to be a real short circuit.

3. The lithium battery protection board detection protection circuit according to claim 1, characterized in that: The voltage detection circuit comprises an enabling switch module, a voltage input switch module and an AD acquisition module which are connected in sequence, the enabling switch module and the AD acquisition module are both connected to the MCU main control circuit, and the enabling switch module is connected to the negative output terminal; The voltage input switch module is used to control whether the voltage signal of the negative output terminal enters the AD acquisition module when the short circuit protection is triggered, and the enable switch module is used to control the working state of the voltage input switch module and the AD acquisition module.

4. The lithium battery protection board detection protection circuit according to claim 3, characterized in that: The voltage input switch module is a first switch circuit.

5. The lithium battery protection board detection protection circuit according to claim 4, characterized in that: The first switch circuit includes a first transistor VQ1, the emitter of the first transistor VQ1 is connected to the negative output end, the base of the first transistor VQ1 is connected to the enabling switch module, and the collector of the first transistor VQ1 is connected to the AD acquisition module.

6. The lithium battery protection board detection protection circuit according to claim 5, characterized in that: A resistor is connected between the emitter and the base of the first transistor VQ1 , and the base of the first transistor VQ1 is connected to the enabling switch module via the resistor and the diode in sequence.

7. The lithium battery protection board detection protection circuit according to claim 3, characterized in that: The enabling switch module includes a second switching circuit and a third switching circuit connected to each other, wherein the second switching circuit is used to receive an enabling switch signal sent by the MCU main control circuit, and the third switching circuit is used to control the working state of the voltage input switch module and the AD acquisition module after the second switching circuit receives the enabling switch signal sent by the MCU main control circuit.

8. The lithium battery protection board detection protection circuit according to claim 7, characterized in that: The second switch circuit includes a second transistor VQ2; the base of the second transistor VQ2 is connected to the MCU main control circuit through a resistor, and the base of the second transistor VQ2 is grounded through a resistor, the collector of the second transistor VQ2 is connected to the voltage input switch module, and the emitter of the second transistor VQ2 is grounded; The third switch circuit includes a first MOS transistor VM2, a gate of the first MOS transistor VM2 is connected to the collector of the second transistor VQ2 through a resistor, and the gate of the first MOS transistor VM2 is grounded through a resistor, and a source of the first MOS transistor VM2 is grounded.

9. The lithium battery protection board detection protection circuit according to claim 3, characterized in that: The AD acquisition module includes a resistor voltage-dividing sampling circuit, which includes a first voltage-dividing resistor and a second voltage-dividing resistor connected in sequence, a node J1 at which the first voltage-dividing resistor and the second voltage-dividing resistor are interconnected is connected to the MCU main control circuit, and the node J1 is connected to the voltage input switch module through a resistor.

10. The lithium battery protection board detection protection circuit according to claim 9, characterized in that: An RC filter circuit is connected between the node J1 and the MCU main control circuit; and a diode is connected in parallel to the first voltage-dividing resistor and the second voltage-dividing resistor, respectively.

Images