Charging temperature protection circuit and charging equipment

Abstract

The utility model relates to the technical field of charging detection, in particular to a charging temperature protection circuit and charging equipment. The charging temperature protection circuit comprises a first temperature detection unit, a second temperature detection unit, a switch selection unit and a temperature sampling unit, the control end of the switch selection unit is connected with a charging interface of charging equipment, the first input end of the switch selection unit is connected with the first end of the first temperature detection unit, the second input end of the switch selection unit is connected with the first end of the second temperature detection unit, and the output end of the switch selection unit is connected with the temperature sampling unit. The second end of the first temperature detection unit and the second end of the second temperature detection unit are connected with the temperature sampling unit. Compatible control of the two temperature detection units is selected by controlling the switch selection unit to be conducted, additional two-path temperature sampling design does not need to be designed, the area and the material cost of a charging equipment protection plate are reduced, and meanwhile the stability of temperature detection is enhanced.

Description

Technical Field

[0001] The utility model relates to the technical field of charging detection, in particular to a charging temperature protection circuit and a charging device. Background Art

[0002] With the rapid development of electronic products, the proportion of battery-powered products in startups has also increased dramatically, making the safety design of corresponding battery products extremely important. This is especially true for temperature detection during charging. Batteries typically have only one thermistor temperature coefficient (NTC) detection element. If only connected to a microcontroller unit (MCU) for detection and controlled by system software, if the MCU system crashes, the NTC protection function will be lost, posing a safety risk. If only analog circuit control using the comparator within the power chip is used, current control under various temperature conditions during battery charging cannot be achieved, nor can battery temperature protection be provided during discharge, thus posing a battery temperature safety risk. If two NTC leads are connected to the battery, the battery cost and size will increase. Furthermore, the different positions of the two NTC leads will lead to large temperature detection errors.

[0003] The above content is only used to assist in understanding the technical solution of the present invention and does not constitute an admission that the above content is prior art. Utility Model Content

[0004] The main purpose of the utility model is to provide a charging temperature protection circuit and a charging device, aiming to solve the technical problems in the prior art of battery-powered products having poor stability and inaccurate results during the temperature detection process.

[0005] To achieve the above objectives, the present invention proposes a charging temperature protection circuit and a charging device. The charging temperature protection circuit includes: a first temperature detection unit, a second temperature detection unit, a switch selection unit, and a temperature sampling unit. The control end of the switch selection unit is connected to the charging interface of the charging device, the first input end of the switch selection unit is connected to the first end of the first temperature detection unit, the second input end of the switch selection unit is connected to the first end of the second temperature detection unit, the output end of the switch selection unit is connected to the temperature sampling unit, and the second end of the first temperature detection unit and the second end of the second temperature detection unit are both connected to the temperature sampling unit. The temperature sampling unit is configured to collect the battery temperature of the charging device and convert the battery temperature into a voltage sampling signal. The switch selection unit is configured to connect the first temperature detection unit to the temperature sampling unit when an external power source is not connected to the charging interface, and the first temperature detection unit receives the voltage sampling signal from the temperature sampling unit for temperature detection. The switch selection unit is further configured to connect the second temperature detection unit to the temperature sampling unit when an external power source is connected to the charging interface, and the first temperature detection unit receives the voltage sampling signal from the temperature sampling unit for temperature detection. By controlling the conduction of the switch selection unit, the compatible control of the two temperature detection units is selected, eliminating the need to design two additional temperature sampling designs, reducing the area and material cost of the charging device protection board, and enhancing the stability of temperature detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0007] Figure 1 This is a schematic structural diagram of the first embodiment of the charging temperature protection circuit of the present utility model;

[0008] Figure 2 This is a structural diagram of the logic switch chip in the first embodiment of the charging temperature protection circuit of the present utility model;

[0009] Figure 3 This is a schematic structural diagram of a second embodiment of a charging temperature protection circuit according to the present invention;

[0010] Figure 4 This is a schematic structural diagram of the third embodiment of the charging temperature protection circuit of the present invention.

[0011] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0012] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0013] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0014] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0015] In addition, the descriptions of "first," "second," etc. in this utility model are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this utility model.

[0016] Reference Figure 1 , Figure 1 This is a structural diagram of the first embodiment of the charging temperature protection circuit of the present utility model.

[0017] The utility model provides a first embodiment of a charging temperature protection circuit.

[0018] In this embodiment, the charging temperature protection circuit includes: a first temperature detection unit 10, a second temperature detection unit 20, a switch selection unit 30 and a temperature sampling unit 40; the control end of the switch selection unit 30 is connected to the charging interface 50 of the charging device, the first input end of the switch selection unit 30 is connected to the first end of the first temperature detection unit 10, the second input end of the switch selection unit 30 is connected to the first end of the second temperature detection unit 20, the output end of the switch selection unit 30 is connected to the temperature sampling unit 40, and the second end of the first temperature detection unit 10 and the second end of the second temperature detection unit 20 are both connected to the temperature sampling unit 40.

[0019] It should be noted that the temperature sampling unit 40 can be used to collect the battery temperature of the charging device and convert the battery temperature into a voltage sampling signal; the switch selection unit 30 can be used to connect the first temperature detection unit 10 with the temperature sampling unit 40 when the external power supply is not connected to the charging interface, and the first temperature detection unit 10 receives the voltage sampling signal of the temperature sampling unit 40 for temperature detection; the switch selection unit 30 can also be used to connect the second temperature detection unit 20 with the temperature sampling unit 40 when the external power supply is connected to the charging interface, and the first temperature detection unit 10 receives the voltage sampling signal of the temperature sampling unit 40 for temperature detection.

[0020] It should be understood that the switch selection unit 30 can be an electronic device with signal recognition and loop control functions, such as a logic switch chip, a transistor or a field effect tube. Figure 2 , Figure 2 This is a structural diagram of the logic switch chip in the first embodiment of the charging temperature protection circuit of the present utility model.

[0021] Among them, the logic switch chip includes four pins (A pin, B1 pin, B2 pin and Select pin), which can switch the input signal of B1 pin or B2 pin to be output by A pin according to the high or low level state received by Select pin. The above-mentioned first temperature detection unit 10 can be connected to B1 pin, and the second temperature detection unit 20 can be connected to B2 pin, so as to realize that when the external power supply is not connected, the Select pin receives a low level external power supply voltage to turn on the first temperature detection unit 10 and disconnect the second temperature detection unit 20. When the external power supply is connected through the charging port, the Select pin receives a high level external power supply voltage to turn on the second temperature detection unit 20 and disconnect the first temperature detection unit 10.

[0022] Furthermore, the temperature sampling unit 40 can be an electronic device with the ability to proportionally change the temperature coefficient, such as a thermistor, whose resistance decreases as the temperature increases, and the temperature change condition is reflected by measuring the voltage amplitude on the thermistor. The first temperature detection unit 10 and the second temperature detection unit 20 can both be component structures that can determine the temperature condition of the battery of the charging device based on the voltage sampling signal. For example, an MCU chip can be used. The MCU chip can include a processor and memory. By executing pre-set programming software, it receives a signal from the input end and generates a signal corresponding to the software detection result at the output end. A power supply chip can also be used. The power supply chip can be an electronic component for managing and controlling the charging current and voltage. It can detect and control the current and voltage of the device during the charging process, and achieve over-temperature detection and protection through built-in components such as comparators and pre-set temperature protection thresholds.

[0023] It should be understood that in the non-charging state, the pull-up voltage level of the temperature sampling unit is provided by the power supply terminal of the MCU chip. At the same time, the MCU chip receives the voltage sampling signal from the temperature sampling unit and detects the temperature condition according to the preset programming software. In the charging state, the pull-up voltage level of the temperature sampling unit is provided by the power supply terminal of the power chip. At the same time, the power chip receives the voltage sampling signal from the temperature sampling unit and determines whether an overtemperature condition has occurred based on the comparison result of the comparator.

[0024] This embodiment provides a charging temperature protection circuit, which includes: a first temperature detection unit, a second temperature detection unit, a switch selection unit, and a temperature sampling unit. The control end of the switch selection unit is connected to the charging interface of the charging device, the first input end of the switch selection unit is connected to the first end of the first temperature detection unit, the second input end of the switch selection unit is connected to the first end of the second temperature detection unit, and the output end of the switch selection unit is connected to the temperature sampling unit. The second end of the first temperature detection unit and the second end of the second temperature detection unit are also connected to the temperature sampling unit. The temperature sampling unit is configured to collect the battery temperature of the charging device and convert the battery temperature into a voltage sampling signal. The switch selection unit is configured to, when an external power source is not connected to the charging interface, connect the first temperature detection unit to the temperature sampling unit, and the first temperature detection unit receives the voltage sampling signal from the temperature sampling unit for temperature detection. The switch selection unit is further configured to, when an external power source is connected to the charging interface, connect the second temperature detection unit to the temperature sampling unit, and the first temperature detection unit receives the voltage sampling signal from the temperature sampling unit for temperature detection. By controlling the conduction of the switch selection unit, the compatible control of the two temperature detection units is selected, eliminating the need to design two additional temperature sampling designs, reducing the area and material cost of the charging device protection board, and enhancing the stability of temperature detection.

[0025] Reference Figure 3 , Figure 3 The second embodiment of the charging temperature protection circuit of the present invention is a schematic structural diagram of the second embodiment of the charging temperature protection circuit of the present invention. The second embodiment of the charging temperature protection circuit of the present invention is proposed based on the first embodiment of the charging temperature protection circuit.

[0026] The first temperature detection unit 10 includes: a first resistor R1 and an MCU chip U1; the first end of the first resistor R1 is connected to the first end of the MCU chip U1, the second end of the first resistor R1 is connected to the first input end of the switch selection unit 30, and the second end of the MCU chip U1 is connected to the output end of the switch selection unit 30. The second temperature detection unit 20 includes: a second resistor R2 and a power chip U2; the first end of the second resistor R2 is connected to the first end of the power chip U2, the second end of the second resistor R2 is connected to the first input end of the switch selection unit 30, and the second end of the power chip U2 is connected to the output end of the switch selection unit 30.

[0027] Furthermore, the temperature sampling unit includes: a third resistor R3 and a first capacitor C1; the first end of the third resistor R3 is connected to the output end of the switch selection unit 30, the second end of the MCU chip U1 and the second end of the power supply chip U2, the second end of the third resistor R3 is grounded, and the first capacitor C1 is arranged in parallel with the third resistor R3.

[0028] It should be noted that when the device is in a non-charging working mode, the external power supply voltage is at a low level. At this time, the power supply end of the MCU chip generates a pull-up level, and the voltage sampling signal is generated after the voltage is divided by the third resistor (which is set as a thermistor). Then, it is connected to the sampling interface of the MCU chip to realize the temperature detection function of the device. When the device is in a charging working mode, the external power supply voltage is at a high level. At this time, the power supply end of the power supply chip generates a pull-up level, and the voltage sampling signal is generated after the voltage is divided by the third resistor. Then, it is connected to the sampling interface of the power supply chip to realize the temperature detection function of the device. At the same time, the voltage sampling signal can also be connected to the MCU chip to realize the two-level protection function in the charging mode. For example: the battery in the device requires a maximum charging temperature of 55°C, the first charging protection temperature threshold set in the MCU chip is 52±1°C, and the second charging protection temperature threshold set in the power chip is 54±1°C. When the MCU chip determines that the battery temperature reaches the first charging protection temperature threshold based on the voltage sampling signal, the charging function is stopped. If the MCU chip fails and cannot stop charging at the first charging protection temperature threshold, the power chip will stop charging at the second charging protection temperature threshold to realize two-level protection of software and hardware.

[0029] Furthermore, the charging temperature protection circuit may further include: a first voltage dividing unit 60 ; an input end of the first voltage dividing unit 60 is connected to the temperature sampling unit 40 , and an output end of the first voltage dividing unit 60 is connected to the first temperature detection unit 10 .

[0030] It should be noted that the first voltage divider unit 60 can be used to divide the voltage sampling signal of the temperature sampling unit 40 and transmit the divided voltage sampling signal to the first temperature detection unit 10 for temperature detection. This controls the voltage input to the sampling terminal of the MCU chip to not exceed the rated operating voltage.

[0031] In one possible implementation, the first voltage divider unit 60 includes: a fourth resistor R4, a fifth resistor R5, and a second capacitor C2; the first end of the fourth resistor R4 is connected to the first end of the third resistor R3, the second end of the fourth resistor R4 is simultaneously connected to the first end of the fifth resistor R5 and the second end of the MCU chip, the second end of the fifth resistor R5 is grounded, and the second capacitor C2 is arranged in parallel with the fifth resistor R5.

[0032] Furthermore, the charging temperature protection circuit further includes: a second voltage dividing unit 70 ; an input end of the second voltage dividing unit 70 is connected to the charging interface 50 , and an output end of the second voltage dividing unit 70 is connected to the control end of the switch selection unit 30 .

[0033] It should be noted that the second voltage divider unit can be used to transmit the external power supply voltage to the switch selection unit after voltage division when the external power supply is connected to the charging interface; the switch selection unit can also be used to determine that the external power supply is connected to the charging interface when the amplitude of the received external power supply voltage exceeds a preset voltage threshold, and to determine that the external power supply is not connected to the charging interface when the amplitude of the received external power supply voltage is lower than the preset voltage threshold.

[0034] In one possible implementation, the second voltage divider unit 70 includes: a sixth resistor R6 and a seventh resistor R7; a first end of the sixth resistor R6 is connected to the charging interface 50, a second end of the sixth resistor R6 is connected to the first end of the seventh resistor R7 and the control end of the switch selection unit 30, and a second end of the seventh resistor R7 is grounded.

[0035] In this embodiment, the first temperature detection unit includes a first resistor and an MCU chip; the first end of the first resistor is connected to the first end of the MCU chip, the second end of the first resistor is connected to the first input end of the switch selection unit, and the second end of the MCU chip is connected to the output end of the switch selection unit. The second temperature detection unit includes a second resistor and a power supply chip; the first end of the second resistor is connected to the first end of the power supply chip, the second end of the second resistor is connected to the first input end of the switch selection unit, and the second end of the power supply chip is connected to the output end of the switch selection unit. The voltage sampling signal is collected by the resistor voltage division sampling method and it is determined whether an overtemperature fault occurs to achieve two-level protection. The control is precise, the adjustment is convenient, the application range is wide, the area and material cost of the protection board of the charging device are reduced, and the stability of the temperature detection is enhanced.

[0036] Reference Figure 4 , Figure 4 The third embodiment of the charging temperature protection circuit of the present invention is proposed based on the above embodiments of the charging temperature protection circuit.

[0037] The switch selection unit includes: first to fourth field effect transistors; the gate (G) of the first field effect transistor Q1 is connected to the gate of the second field effect transistor Q2 and the charging interface, the source (S) of the first field effect transistor Q1 is connected to the source of the second field effect transistor Q2, the drain (D) of the first field effect transistor Q1 is connected to the first end of the second temperature detection unit 20, the drain of the second field effect transistor Q2 is connected to the temperature sampling unit 40, the gate of the third field effect transistor Q3 is connected to the gate of the fourth field effect transistor Q4 and the charging interface, the drain of the third field effect transistor Q3 is connected to the drain of the fourth field effect transistor Q4, the source of the third field effect transistor Q3 is connected to the first end of the first temperature detection unit 10, and the source of the fourth field effect transistor Q4 is connected to the temperature sampling unit 40.

[0038] It should be noted that two sets of linked MOS tubes (Q1 and Q2) are used as the power supply port of the MCU chip and (Q3 and Q4) as the power supply port switching switch of the power chip to realize the pull-up power switching function of the temperature sampling unit.

[0039] It should be understood that the power supply port voltage of the power chip is approximately equal to the input voltage of the charging interface. At the same time, the power supply interface voltage of the MCU chip will be lower than the power supply port voltage of the above-mentioned power chip after the voltage of the charging interface is stepped down. Since there is a parasitic diode between the DS pins inside the MOS tube, only one-way cutoff can be achieved, and a complete shutdown effect cannot be achieved. If a shared output terminal is used, when the power chip is turned on, if the output terminal voltage is higher than the power supply port voltage of the other MCU chip, the current will flow back from the output terminal to the power supply port of the MCU chip, which may cause the voltage to be pulled down or cause damage to the MCU chip. Therefore, two sets of MOS pairs are used to prevent the level from flowing back, that is, Q1 and Q2 use PMOS tubes, and Q3 and Q4 use NMOS tubes.

[0040] When the device is not charging and no external power is input, the G pins of both MOS transistors are at a low level. The NMOS transistor GS voltage (VGS) is less than VGS(th), causing the NMOS transistor to be cut off, the D and S pins to be open, and the power supply chip to be disconnected. The PMOS transistor GS voltage (VGS) is less than VGS(th), causing the PMOS transistor to be on, the D and S pins to be connected, and the MCU chip circuit to be connected. The pull-up voltage for the temperature sampling unit is provided by the MCU chip's power supply. The MCU chip receives the voltage sampling signal from the temperature sampling unit and detects the temperature according to the pre-programmed software.

[0041] When the device is charging and receiving voltage from an external power source, the G pins of both MOS transistors are high. The GS voltage of the NMOS transistor, VGS, exceeds VGS(th), turning the NMOS transistor on. The D and S pins are connected, and the power chip circuit is connected. The GS voltage of the PMOS transistor, VGS, exceeds VGS(th), turning the PMOS transistor off. The D and S pins are disconnected, disconnecting the MCU chip circuit. The pull-up voltage for the temperature sampling unit is provided by the power supply terminal of the power chip. The power chip receives the voltage sampling signal from the temperature sampling unit and uses the comparison result of the comparator to determine whether an overtemperature condition has occurred.

[0042] In this embodiment, the switch selection unit includes: first to fourth field-effect transistors; the gate of the first field-effect transistor is connected to the gate of the second field-effect transistor and the charging interface, the source of the first field-effect transistor is connected to the source of the second field-effect transistor, the drain of the first field-effect transistor is connected to the first end of the second temperature detection unit, the drain of the second field-effect transistor is connected to the temperature sampling unit, the gate of the third field-effect transistor is connected to the gate of the fourth field-effect transistor and the charging interface, the drain of the third field-effect transistor is connected to the drain of the fourth field-effect transistor, the source of the third field-effect transistor is connected to the first end of the first temperature detection unit, and the source of the fourth field-effect transistor is connected to the temperature sampling unit. By using two MOS pairs to construct the switch selection unit, two-stage protection for overtemperature fault detection is achieved, which is low-cost, easy to adjust, and has a wide range of applications. It reduces the area and material cost of the protection board of the charging device, while enhancing the stability of temperature detection.

[0043] Furthermore, an embodiment of the present invention also provides a charging device, which includes the charging temperature protection circuit as described above.

[0044] Since the charging device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0045] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the utility model concept, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A charging temperature protection circuit, characterized in that: The charging temperature protection circuit is applied to the charging device and includes: a first temperature detection unit, a second temperature detection unit, a switch selection unit and a temperature sampling unit; The control end of the switch selection unit is connected to the charging interface of the charging device, the first input end of the switch selection unit is connected to the first end of the first temperature detection unit, the second input end of the switch selection unit is connected to the first end of the second temperature detection unit, the output end of the switch selection unit is connected to the temperature sampling unit, and the second end of the first temperature detection unit and the second end of the second temperature detection unit are both connected to the temperature sampling unit; The temperature sampling unit is used to collect the battery temperature of the charging device and convert the battery temperature into a voltage sampling signal; The switch selection unit is configured to connect the first temperature detection unit to the temperature sampling unit when an external power source is not connected to the charging interface, so that the first temperature detection unit receives the voltage sampling signal from the temperature sampling unit to perform temperature detection; The switch selection unit is further used to connect the second temperature detection unit to the temperature sampling unit when an external power supply is connected to the charging interface, and the first temperature detection unit receives the voltage sampling signal of the temperature sampling unit to perform temperature detection.

2. The charging temperature protection circuit according to claim 1, wherein: The first temperature detection unit includes: a first resistor and an MCU chip; The first end of the first resistor is connected to the first end of the MCU chip, the second end of the first resistor is connected to the first input end of the switch selection unit, and the second end of the MCU chip is connected to the output end of the switch selection unit.

3. The charging temperature protection circuit according to claim 2, wherein: The second temperature detection unit includes: a second resistor and a power supply chip; The first end of the second resistor is connected to the first end of the power chip, the second end of the second resistor is connected to the first input end of the switch selection unit, and the second end of the power chip is connected to the output end of the switch selection unit.

4. The charging temperature protection circuit according to claim 3, wherein: The temperature sampling unit includes: a third resistor and a first capacitor; The first end of the third resistor is connected to the output end of the switch selection unit, the second end of the MCU chip and the second end of the power supply chip, the second end of the third resistor is grounded, and the first capacitor is arranged in parallel with the third resistor.

5. The charging temperature protection circuit according to claim 4, characterized in that: The charging temperature protection circuit further includes: a first voltage dividing unit; The input end of the first voltage dividing unit is connected to the temperature sampling unit, and the output end of the first voltage dividing unit is connected to the first temperature detecting unit; The first voltage dividing unit is used to perform voltage dividing processing on the voltage sampling signal of the temperature sampling unit, and transmit the voltage sampling signal after voltage dividing processing to the first temperature detection unit for temperature detection.

6. The charging temperature protection circuit according to claim 5, characterized in that: The first voltage dividing unit includes: a fourth resistor, a fifth resistor and a second capacitor; The first end of the fourth resistor is connected to the first end of the third resistor, the second end of the fourth resistor is connected to the first end of the fifth resistor and the second end of the MCU chip at the same time, the second end of the fifth resistor is grounded, and the second capacitor is arranged in parallel with the fifth resistor.

7. The charging temperature protection circuit according to claim 1, wherein: The charging temperature protection circuit further includes: a second voltage dividing unit; The input end of the second voltage dividing unit is connected to the charging interface, and the output end of the second voltage dividing unit is connected to the control end of the switch selection unit; The second voltage dividing unit is configured to divide the external power supply voltage and transmit it to the switch selection unit after voltage division when the external power supply is connected to the charging interface; The switch selection unit is further used to determine that the external power supply is connected to the charging interface when the amplitude of the received external power supply voltage exceeds a preset voltage threshold, and to determine that the external power supply is not connected to the charging interface when the amplitude of the received external power supply voltage is lower than the preset voltage threshold.

8. The charging temperature protection circuit according to claim 7, wherein: The second voltage dividing unit includes: a sixth resistor and a seventh resistor; A first end of the sixth resistor is connected to the charging interface, a second end of the sixth resistor is connected to the first end of the seventh resistor and the control end of the switch selection unit, and a second end of the seventh resistor is grounded.

9. The charging temperature protection circuit according to claim 1, wherein: The switch selection unit includes: first to fourth field effect transistors; The gate of the first field effect transistor is connected to the gate of the second field effect transistor and the charging interface, the source of the first field effect transistor is connected to the source of the second field effect transistor, the drain of the first field effect transistor is connected to the first end of the second temperature detection unit, the drain of the second field effect transistor is connected to the temperature sampling unit, the gate of the third field effect transistor is connected to the gate of the fourth field effect transistor and the charging interface, the drain of the third field effect transistor is connected to the drain of the fourth field effect transistor, the source of the third field effect transistor is connected to the first end of the first temperature detection unit, and the source of the fourth field effect transistor is connected to the temperature sampling unit.

10. A charging device, characterized in that: The charging device includes: a charging temperature protection circuit according to any one of claims 1 to 9.

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