A charging circuit with adaptive charging current to temperature

Abstract

The utility model discloses a charging circuit of charging current self -adaptation temperature, including charging chip module, reference voltage output module, voltage comparison module and ground resistance module, the thermistor detection input pin of charging chip module is equipped with first voltage division module, still including the output of reference voltage output module with voltage comparison module's first input electric connection, voltage comparison module's second input with first voltage division module's output electric connection, voltage comparison module's output with the resistance value control end electric connection of ground resistance module, one end of ground resistance module with the charging current configuration pin electric connection of charging chip module, the other end of ground resistance module is grounded. The utility model does not need MCU to intervene, reduces the software development workload, realizes different charging current under different temperature simultaneously, guarantees the healthy charging of battery.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to a charging circuit with temperature-adaptive charging current. Background Technology

[0002] For general-purpose batteries, considering the balance between charging efficiency, safety and lifespan, current practices recommend charging the cells with normal current when the ambient temperature range is 10℃-45℃, charging with a small current when the temperature is below 10℃, and prohibiting charging when the temperature is below 0℃.

[0003] Therefore, it is necessary to control the charging current of the battery. Currently, there are two main approaches: one is to use a charging IC (integrated circuit) that configures the charging current via an MCU (microcontroller unit), which limits the selection of the charging IC and requires additional software development on the MCU; the other is to charge at a fixed value regardless of temperatures below 10°C, but this can damage the battery to some extent and reduce its lifespan. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a charging circuit with temperature-adaptive charging current, which does not require MCU intervention, reduces software development workload, and achieves different charging currents at different temperatures to ensure healthy battery charging.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: A charging circuit with adaptive charging current and temperature includes a charging chip module. The thermistor detection input pin of the charging chip module is provided with a first voltage divider module for connecting the thermistor of the charging battery. It also includes a reference voltage output module, a voltage comparison module, and a grounding resistor module. The output terminal of the reference voltage output module is electrically connected to the first input terminal of the voltage comparison module, and the second input terminal of the voltage comparison module is electrically connected to the output terminal of the first voltage divider module. The output terminal of the voltage comparison module is electrically connected to the resistance adjustment terminal of the grounding resistor module. One end of the grounding resistor module is electrically connected to the charging current configuration pin of the charging chip module, and the other end of the grounding resistor module is grounded. Furthermore, the grounding resistor module includes a first resistor, a first switch, and a second resistor; One end of the first resistor and one end of the second resistor are simultaneously electrically connected to the charging current configuration pin of the charging chip module, and the other end of the first resistor is grounded with the other end of the second resistor through the first switch; The output terminal of the voltage comparison module is electrically connected to the control terminal of the first switch.

[0006] Furthermore, the first switch is a field-effect transistor; The drain of the first switch is electrically connected to the end of the first resistor furthest from the charging current configuration pin, and the source of the first switch is grounded. The gate of the first switch is electrically connected to the output terminal of the voltage comparison module.

[0007] Furthermore, the reference voltage output module includes a second voltage divider module; The output terminal of the second voltage divider module is electrically connected to the first input terminal of the voltage comparison module, and the input terminal of the second voltage divider module is used to connect to an external power supply.

[0008] Furthermore, the second voltage divider module includes a third resistor and a fourth resistor; One end of the third resistor and one end of the fourth resistor are simultaneously electrically connected to the first input terminal of the voltage comparison module. The other end of the third resistor is used to connect to the external power supply, and the other end of the fourth resistor is grounded.

[0009] Furthermore, the voltage comparison module includes a comparator and a fifth resistor; The first input terminal of the comparator is electrically connected to the output terminal of the reference voltage output module, and the second input terminal of the comparator is electrically connected to the output terminal of the first voltage divider module. The output terminal of the comparator is electrically connected to one end of the fifth resistor and the resistance adjustment terminal of the grounding resistor module, while the other end of the fifth resistor and the power supply terminal of the comparator are used to connect to an external power source.

[0010] Furthermore, it also includes a terminal block; The terminal block is provided with a first interface and a second interface; The first interface is electrically connected to the battery connection pin of the charging chip module, and the second input terminal of the voltage comparison module is electrically connected to the output terminal of the first voltage divider module through the second interface.

[0011] Furthermore, the first voltage divider module has a thermistor on its input pin for connecting to a rechargeable battery.

[0012] Furthermore, the first voltage divider module includes a sixth resistor and a seventh resistor; One end of the sixth resistor, one end of the seventh resistor, the thermistor detection input pin of the charging chip module, and the second input terminal of the voltage comparison module are all used to connect to the thermistor of the rechargeable battery. The other end of the sixth resistor is used to connect to an external power source, and the other end of the seventh resistor is grounded.

[0013] The beneficial effects of this utility model are as follows: It provides a charging circuit with temperature-adaptive charging current, which converts the change in the resistance of the thermistor caused by temperature changes during the charging process into a change in the output voltage of the first voltage divider module, and then compares it with the reference voltage provided by the reference voltage output module. The resistance of the grounding resistor module is adjusted according to the charging current configuration pin of the charging chip module, which has the function of changing the charging current due to the change in resistance. The charging current adjustment is realized without the need for MCU intervention, reducing the workload of software development. At the same time, different charging currents are achieved at different temperatures to ensure healthy charging of the battery. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the connection of a charging circuit with adaptive charging current and temperature according to this utility model. Figure 2 This is a wiring diagram of the terminal block for a charging circuit with temperature-adaptive charging current according to this utility model.

[0015] Label Explanation: 1. Charging chip module; 2. First voltage divider module; 3. Reference voltage output module; 4. Voltage comparator module; 5. Grounding resistor module; J1, Terminal block; Q1, First switch; 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; U1, charging chip; U2, comparator; VCC, external power supply. Detailed Implementation

[0016] To explain in detail the technical content, objectives, and effects of this utility model, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0017] Please refer to Figure 1 and Figure 2 A charging circuit with temperature-adaptive charging current includes a charging chip module 1, a first voltage divider module 2 on the thermistor detection input pin of the charging chip module 1, and also includes a reference voltage output module 3, a voltage comparison module 4 and a grounding resistor module 5. The output terminal of the reference voltage output module 3 is electrically connected to the first input terminal of the voltage comparison module 4, and the second input terminal of the voltage comparison module 4 is electrically connected to the output terminal of the first voltage divider module 2. The output terminal of the voltage comparison module 4 is electrically connected to the resistance adjustment terminal of the grounding resistor module 5. One end of the grounding resistor module 5 is electrically connected to the charging current configuration pin of the charging chip module 1, and the other end of the grounding resistor module 5 is grounded. As can be seen from the above description, the beneficial effects of this utility model are as follows: the change in the resistance of the thermistor caused by temperature changes during the charging process of the rechargeable battery is converted into a change in the output voltage of the first voltage divider module 2, which is then compared with the reference voltage provided by the reference voltage output module 3. The resistance of the grounding resistor module 5 is adjusted based on the comparison result. According to the function of the charging current configuration pin of the charging chip module 1 itself, which is caused by the change in resistance, the charging current is adjusted without the need for MCU intervention, reducing the workload of software development. At the same time, different charging currents are achieved at different temperatures to ensure healthy charging of the battery.

[0018] Furthermore, the grounding resistor module 5 includes a first resistor R1, a first switch Q1, and a second resistor R2; One end of the first resistor R1 and one end of the second resistor R2 are simultaneously electrically connected to the charging current configuration pin of the charging chip module 1, and the other end of the first resistor R1 is grounded with the other end of the second resistor R2 through the first switch Q1; The output terminal of the voltage comparison module 4 is electrically connected to the control terminal of the first switch Q1.

[0019] As can be seen from the above description, the output terminal of the voltage comparison module 4 is used to control the conduction state of the first switch Q1; when the first switch Q1 is closed, the first resistor R1 and the second resistor R2 are connected in parallel to the charging current configuration pin of the charging chip module 1; when the first switch Q1 is open, only the second resistor R2 is connected to the charging current configuration pin of the charging chip module 1; in this way, the overall resistance value of the circuit is controlled, and the two-stage adjustment of the current is realized.

[0020] Furthermore, the first switch Q1 is a field-effect transistor; The drain of the first switch Q1 is electrically connected to the end of the first resistor R1 away from the charging current configuration pin, and the source of the first switch Q1 is grounded. The gate of the first switch Q1 is electrically connected to the output terminal of the voltage comparison module 4.

[0021] As can be seen from the above description, the field-effect transistor is selected as the first switch Q1, which has the characteristics of fast switching speed, low on-resistance and low control power consumption. It can efficiently respond to the control signal of the voltage comparison module 4, ensure that the resistance value switching of the grounding resistor module 5 is completed instantly, reduce the transition time in the current adjustment process, and reduce the battery loss caused by current fluctuations.

[0022] Furthermore, the reference voltage output module 3 includes a second voltage divider module; The output terminal of the second voltage divider module is electrically connected to the first input terminal of the voltage comparison module 4, and the input terminal of the second voltage divider module is used to connect to the external power supply VCC.

[0023] As described above, the reference voltage output module 3 adopts the structure of a second voltage divider module, utilizing the principle of resistor voltage division to provide a stable reference voltage. This eliminates the need for a dedicated reference voltage chip, reducing circuit costs. By appropriately selecting the parameters of the voltage divider resistors, the magnitude of the reference voltage can be flexibly adjusted to adapt to the temperature protection thresholds of different batteries, meeting diverse charging needs.

[0024] Furthermore, the second voltage divider module includes a third resistor R3 and a fourth resistor R4; One end of the third resistor R3 and one end of the fourth resistor R4 are simultaneously electrically connected to the first input terminal of the voltage comparison module 4. The other end of the third resistor R3 is used to connect to the external power supply VCC, and the other end of the fourth resistor R4 is grounded.

[0025] As can be seen from the above description, the second voltage divider module uses a combination of the third resistor R3 and the fourth resistor R4. The structure is simple and easy to implement. By adjusting the resistance ratio of the two resistors, the reference voltage value can be accurately set to meet charging scenarios with different accuracy requirements.

[0026] Furthermore, the voltage comparison module 4 includes a comparator U2 and a fifth resistor R5; The first input terminal of the comparator U2 is electrically connected to the output terminal of the reference voltage output module 3, and the second input terminal of the comparator U2 is electrically connected to the output terminal of the first voltage divider module 2. The output terminal of the comparator U2 is electrically connected to one end of the fifth resistor R5 and the resistance adjustment terminal of the grounding resistor module 5. The other end of the fifth resistor R5 and the power supply terminal of the comparator U2 are used to connect to the external power supply VCC.

[0027] As can be seen from the above description, the voltage comparison module 4 adopts a combination of comparator U2 and fifth resistor R5. Comparator U2 can quickly compare the output voltage of the first voltage divider module 2 with the reference voltage, and output high and low level signals to control the grounding resistor module 5. It has a fast response speed and high comparison accuracy, ensuring that the voltage difference caused by temperature changes is captured in time.

[0028] Furthermore, it also includes terminal block J1; The terminal block J1 is provided with a first interface and a second interface; The first interface is electrically connected to the battery connection pin of the charging chip module 1, and the second input terminal of the voltage comparison module 4 is electrically connected to the output terminal of the first voltage divider module 2 through the second interface.

[0029] As can be seen from the above description, the terminal block J1 provides a convenient interface for circuit connection. The first interface connects the charging chip module 1 to the battery, and the second interface connects the voltage comparison module 4 to the first voltage divider module 2, making the assembly and disassembly of the circuit more convenient and facilitating later maintenance and repair.

[0030] Furthermore, the first voltage divider module has a thermistor on its input pin for connecting to a rechargeable battery.

[0031] Furthermore, the first voltage divider module 2 includes a sixth resistor R6 and a seventh resistor R7; One end of the sixth resistor R6, one end of the seventh resistor R7, the thermistor detection input pin of the charging chip module 1, and the second input terminal of the voltage comparison module 4 are all used to connect to the thermistor. The other end of the sixth resistor R6 is used to connect to the external power supply VCC, and the other end of the seventh resistor R7 is grounded.

[0032] As can be seen from the above description, the first voltage divider module 2 adopts a combination structure of the sixth resistor R6 and the seventh resistor R7, which can more accurately convert the resistance change of the thermistor of the charging battery into a recognizable voltage signal, thereby improving the sensitivity and accuracy of temperature detection.

[0033] Please refer to Figure 1 and Figure 2 Embodiment 1 of this utility model is as follows: A charging circuit with temperature-adaptive charging current includes a charging chip module 1. The thermistor detection input pin of the charging chip module 1 is provided with a first voltage divider module 2 for connecting a thermistor to a rechargeable battery. The circuit also includes a reference voltage output module 3, a voltage comparison module 4, and a grounding resistor module 5. The output terminal of the reference voltage output module 3 is electrically connected to the first input terminal of the voltage comparison module 4, and the second input terminal of the voltage comparison module 4 is electrically connected to the output terminal of the first voltage divider module 2. The output terminal of the voltage comparison module 4 is electrically connected to the resistance value adjustment terminal of the grounding resistor module 5. One end of the grounding resistor module 5 is electrically connected to the charging current configuration pin of the charging chip module 1, and the other end of the grounding resistor module 5 is grounded. It is worth noting that charging chip module 1 is built using existing charging chip U1 and its peripheral circuits, such as the charging chip U1MP2625 shown in the figure, while the first voltage divider module 2 is included in the peripheral circuits. Specifically, the thermistor detection input pin (NTC pin) of charging chip module 1, according to the existing chip internal design, allows normal charging only when the NTC (thermistor) resistance is within a certain range; charging is prohibited when the NTC resistance is outside this range. The charging current configuration pin (INSET pin) of charging chip module 1, according to the existing chip internal design, has a resistance value inversely proportional to the charging current; that is, a change in the resistance value of the grounding resistor module 5 will cause a corresponding change in the charging current.

[0034] Therefore, the operation process of a charging current adaptive temperature charging circuit in this embodiment is as follows: When the rechargeable battery is charging, the resistance of the thermistor changes accordingly due to temperature changes, which in turn causes the voltage divider output of the first voltage divider module 2 to change. The thermistor detection input pin of the charging chip module 1 determines whether charging can continue based on the voltage divider output of the first voltage divider module 2. Meanwhile, the voltage divider output of the first voltage divider module 2 and the reference voltage provided by the reference voltage output module 3 are compared by the voltage comparison module 4. The output terminal of the voltage comparison module 4 outputs an electrical signal representing the comparison result to the resistance adjustment terminal of the grounding resistor module 5, thereby changing the resistance value of the grounding resistor module 5 and changing the charging current.

[0035] In this embodiment, as Figure 1 As shown, the grounding resistor module 5 includes a first resistor R1, a first switch Q1, and a second resistor R2. One end of the first resistor R1 and one end of the second resistor R2 are simultaneously electrically connected to the charging current configuration pin of the charging chip module 1. The other end of the first resistor R1 is grounded with the other end of the second resistor R2 through the first switch Q1. The output terminal of the voltage comparison module 4 is electrically connected to the control terminal of the first switch Q1. Preferably, the first switch Q1 is a field-effect transistor, and the closed state of the first switch Q1 corresponds to the two states of whether the first resistor R1 and the second resistor R2 are connected in parallel.

[0036] In this embodiment, as Figure 1 As shown, the first voltage divider module 2 includes a sixth resistor R6 and a seventh resistor R7; one end of the sixth resistor R6, one end of the seventh resistor R7, the thermistor detection input pin of the charging chip module 1, and the second input terminal of the voltage comparison module 4 are all used to connect to the thermistor; the other end of the sixth resistor R6 is used to connect to the external power supply VCC, and the other end of the seventh resistor R7 is grounded.

[0037] Among them, the sixth resistor R6 and the seventh resistor R7 are not single nominal resistors, but are formed by connecting other resistors in series and parallel; taking the sixth resistor R6 as 7.7kΩ, the seventh resistor R7 as 29.1kΩ, the first resistor R1 as 1.3kΩ, and the second resistor R2 as 5.1kΩ as an example, the following explanation is given: When the temperature is below 0 degrees Celsius, the charging chip module 1 will not charge based on the detection result of the thermistor detection input pin.

[0038] When the temperature is between 0 and 10 degrees Celsius, according to the circuit configuration described above, charging chip module 1 charges. At this time, the NTC resistance inside the battery pack is greater than approximately 18KΩ. The voltage V at the second input terminal of voltage comparator module 4 is greater than 1.83V, which is equal to the external power supply VCC × [sixth resistor R6 / (sixth resistor R6 + seventh resistor R7‖NTC)]. The external power supply VCC can be selected as the output voltage of pin 20 of charging chip module 1. Therefore, the voltage at the second input terminal of voltage comparator module 4 is higher than the voltage at the first input terminal of voltage comparator module 4. The output terminal of voltage comparator module 4 outputs a low level, causing the first switch Q1 to turn off. The first resistor R1 is left floating and is not connected in parallel with the second resistor R2. Therefore, the charging current configuration pin of charging chip module 1 is connected to the second resistor R2 to ground, and the configured charging current is approximately 0.4A, which meets the requirements for low-current charging at 0-10°C.

[0039] When the temperature is between 10°C and 45°C, according to the circuit configuration described above, the charging chip module 1 charges. At this time, the NTC resistance inside the battery pack is less than approximately 18KΩ, and the voltage at the second input terminal of the voltage comparison module 4 is less than 1.83V. Therefore, the voltage at the second input terminal of the voltage comparison module 4 is lower than the voltage at the first input terminal of the voltage comparison module 4. The output terminal of the voltage comparison module 4 outputs a high level, which turns on the first switch Q1, realizing the parallel connection of the first resistor R1 and the second resistor R2. Therefore, the charging current configuration pin of the charging chip module 1 is the first resistor R1 connected in parallel with the second resistor R2 to ground, that is, connected to a 1.04KΩ resistor to ground. The configured charging current is approximately 2A, which meets the requirements for normal high-current charging at 10-45°C.

[0040] When the temperature is above 45 degrees Celsius, the charging chip module 1 will not charge based on the detection result of the thermistor detection input pin.

[0041] In this embodiment, as Figure 2 As shown, it also includes a terminal block J1; the terminal block J1 is provided with a first interface and a second interface; the first interface is electrically connected to the battery connection pin, i.e., the VBAT pin, of the charging chip module 1, and the second input terminal of the voltage comparison module 4 is electrically connected to the output terminal of the first voltage divider module 2 through the second interface.

[0042] Please refer to Figure 1Embodiment two of this utility model is as follows: A charging circuit with temperature-adaptive charging current, based on the above embodiment one, includes a reference voltage output module 3 comprising a second voltage divider module. The output terminal of the second voltage divider module is electrically connected to the first input terminal of the voltage comparison module 4, and the input terminal of the second voltage divider module is used to connect to an external power supply VCC. The second voltage divider module includes a third resistor R3 and a fourth resistor R4. One end of the third resistor R3 and one end of the fourth resistor R4 are simultaneously electrically connected to the first input terminal of the voltage comparison module 4, the other end of the third resistor R3 is used to connect to the external power supply VCC, and the other end of the fourth resistor R4 is grounded.

[0043] Please refer to Figure 1 Embodiment three of this utility model is as follows: A charging circuit with temperature-adaptive charging current, based on the above embodiment one or two, includes a voltage comparison module 4 comprising a comparator U2 and a fifth resistor R5; the first input terminal of the comparator U2 is electrically connected to the output terminal of the reference voltage output module 3, and the second input terminal of the comparator U2 is electrically connected to the output terminal of the first voltage divider module 2; the output terminal of the comparator U2 is simultaneously electrically connected to one end of the fifth resistor R5 and the resistance value adjustment terminal of the grounding resistor module 5, and the other end of the fifth resistor R5 and the power supply terminal of the comparator U2 are simultaneously used to connect to the external power supply VCC.

[0044] In addition to using the LMV331 comparator U2, other general-purpose comparators such as the LM393 comparator U2 can also be used for comparator U2.

[0045] In summary, this utility model provides a temperature-adaptive charging current circuit. It converts the resistance change of the thermistor caused by temperature variations during charging into a change in the output voltage of the first voltage divider module. This voltage is then compared with a reference voltage provided by a reference voltage output module. The comparison result is used to adjust the resistance of the grounding resistor module. Based on the charging current configuration pin of the charging chip module, which inherently allows for charging current adjustment due to resistance changes, the charging current is adjusted without MCU intervention, reducing software development workload. Furthermore, it achieves different charging currents at different temperatures, ensuring healthy battery charging. The grounding resistor module uses the output of the voltage comparison module to control the conduction state of the first switch. When the first switch is closed, the first and second resistors are connected in parallel to the charging current configuration pin of the charging chip module. When the first switch is open, only the second resistor is connected to the charging current configuration pin. This controls the overall resistance of the circuit, achieving two-stage adjustment of the charging current. The voltage comparison module uses a combination of a comparator and a fifth resistor. The comparator can quickly compare the output voltage of the first voltage divider module with the reference voltage and output high and low level signals to control the grounding resistor module. It has a fast response speed and high comparison accuracy, ensuring that voltage differences caused by temperature changes are captured in time.

[0046] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent modifications made based on the content of this utility model specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A charging circuit which is adaptive to temperature of a charging current, characterized by, The system includes a charging chip module, wherein the thermistor detection input pin of the charging chip module is provided with a first voltage divider module, and also includes a reference voltage output module, a voltage comparison module and a grounding resistor module; The output terminal of the reference voltage output module is electrically connected to the first input terminal of the voltage comparison module, and the second input terminal of the voltage comparison module is electrically connected to the output terminal of the first voltage divider module. The output terminal of the voltage comparison module is electrically connected to the resistance adjustment terminal of the grounding resistor module. One end of the grounding resistor module is electrically connected to the charging current configuration pin of the charging chip module, and the other end of the grounding resistor module is grounded.

2. A charging current adaptive temperature charging circuit according to claim 1, wherein, The grounding resistor module includes a first resistor, a first switch, and a second resistor; One end of the first resistor and one end of the second resistor are simultaneously electrically connected to the charging current configuration pin of the charging chip module, and the other end of the first resistor is grounded with the other end of the second resistor through the first switch; The output terminal of the voltage comparison module is electrically connected to the control terminal of the first switch.

3. The charging circuit with temperature-adaptive charging current according to claim 2, characterized in that, The first switch is a field-effect transistor; The drain of the first switch is electrically connected to the end of the first resistor furthest from the charging current configuration pin, and the source of the first switch is grounded. The gate of the first switch is electrically connected to the output terminal of the voltage comparison module.

4. The charging current adaptive temperature charging circuit according to claim 2, wherein, The reference voltage output module includes a second voltage divider module; The output terminal of the second voltage divider module is electrically connected to the first input terminal of the voltage comparison module, and the input terminal of the second voltage divider module is used to connect to an external power supply.

5. A charging current adaptive temperature charging circuit according to claim 4, wherein, The second voltage divider module includes a third resistor and a fourth resistor; One end of the third resistor and one end of the fourth resistor are simultaneously electrically connected to the first input terminal of the voltage comparison module. The other end of the third resistor is used to connect to the external power supply, and the other end of the fourth resistor is grounded.

6. A charging current adaptive temperature charging circuit according to claim 1, wherein, The voltage comparison module includes a comparator and a fifth resistor; The first input terminal of the comparator is electrically connected to the output terminal of the reference voltage output module, and the second input terminal of the comparator is electrically connected to the output terminal of the first voltage divider module. The output terminal of the comparator is electrically connected to one end of the fifth resistor and the resistance adjustment terminal of the grounding resistor module, while the other end of the fifth resistor and the power supply terminal of the comparator are used to connect to an external power source.

7. The temperature adaptive charging current circuit of claim 1, wherein, It also includes a terminal block; The terminal block is provided with a first interface and a second interface; The first interface is electrically connected to the battery connection pin of the charging chip module, and the second input terminal of the voltage comparison module is electrically connected to the output terminal of the first voltage divider module through the second interface.

8. The temperature adaptive charging current circuit of claim 1, wherein, The first voltage divider module has a thermistor on its input pin for connecting to a rechargeable battery.

9. A charging current adaptive temperature charging circuit according to claim 8, wherein, The first voltage divider module includes a sixth resistor and a seventh resistor; One end of the sixth resistor, one end of the seventh resistor, the thermistor detection input pin of the charging chip module, and the second input terminal of the voltage comparison module are all used to connect to the thermistor. The other end of the sixth resistor is used to connect to an external power source, and the other end of the seventh resistor is grounded.

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