Protection circuit, power supply circuit and vehicle

Abstract

The utility model provides a protection circuit, a power supply circuit and a vehicle. When a load is in a normal working state, a switch control module responds to an external control signal and outputs a switch control signal to a control end of a first switch circuit, so that a power supply end provides working voltage for the load through the first switch circuit; meanwhile, in the working process of the load, if the load is short-circuited, the short-circuit protection module can enable the switch control module to output a switch control signal for disconnecting the first switch circuit, so that a power supply loop between the power supply end and the load is disconnected, the voltage of the power supply end is prevented from being pulled down by the short circuit of the load, and the safety of the circuit is ensured; after the short-circuit fault is eliminated, power supply to the load is automatically recovered. The circuit is simple in structure, is low in power consumption, is long in service life, and is high in response speed.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a protection circuit, a power supply circuit and a vehicle. Background Art

[0002] In the application scenario of low-voltage power supply, it is usually required that the circuit has a short-circuit protection function when a short-circuit fault occurs in the load, that is, power supply can be restored automatically after the short-circuit fault is eliminated.

[0003] In conventional self-restoring protection measures, a self-restoring fuse or a dedicated protection chip is usually adopted. However, the self-restoring fuse has obvious heat generation during use and attenuation problems after multiple protections; while using a dedicated protection chip faces the problem of high cost. Summary of the Utility Model

[0004] The present application provides a protection circuit, a power supply circuit and a vehicle to solve the problems in the prior art.

[0005] In a first aspect, the present application provides a protection circuit, including: a first switch circuit, a switch control module and a short-circuit protection module;

[0006] The input end of the first switch circuit is connected to the power supply end, and the output end is used for connecting a load;

[0007] The input end of the switch control module is used for receiving an external control signal, and the output end of the switch control module is connected to the control end of the first switch circuit;

[0008] The short-circuit protection module is connected between the output end of the first switch circuit and the input end of the switch control module. After the load is short-circuited, the short-circuit protection module enables the switch control module to output a switch control signal for disconnecting the first switch circuit.

[0009] In one embodiment, the short-circuit protection module includes a diode and a pull-up circuit;

[0010] The cathode of the diode is connected to the output end of the first switch circuit, and the anode of the diode is connected to the input end of the switch control module; the first end of the pull-up circuit is connected to the power supply end, and the second end is connected to the input end of the switch control module;

[0011] After the load is short-circuited, the voltage of the input end of the switch control module is pulled down through the diode, and after the load short-circuit fault is removed, the pull-up circuit raises the voltage of the output end of the switch control module.

[0012] In one embodiment, the pull-up circuit includes a first resistor. The first end of the first resistor is connected to the power supply terminal, and the second end of the first resistor is connected to the input terminal of the switch control module.

[0013] In one embodiment, the first switch circuit includes: a first switching device;

[0014] The first end of the first switching device is connected to the power supply terminal, the second end of the first switching device is used to connect to the load, and the control terminal of the switching device is connected to the output terminal of the switch control module.

[0015] In one embodiment, the switch control module includes a first voltage dividing circuit and a main control circuit;

[0016] The input terminal of the first voltage dividing circuit receives the external control signal, the output terminal is connected to the input terminal of the main control circuit, and the output terminal of the main control circuit is connected to the control terminal of the first switch circuit.

[0017] In one embodiment, the main control circuit includes a second voltage dividing circuit and a second switch circuit;

[0018] The first end of the second voltage dividing circuit is connected to the power supply terminal, the second end of the second voltage dividing circuit is connected to the first end of the second switch circuit, the output terminal of the second voltage dividing circuit is connected to the control terminal of the first switch circuit, the second end of the second switch circuit is grounded, and the control terminal of the second switch circuit is connected to the output terminal of the first voltage dividing circuit.

[0019] In one embodiment, the first voltage dividing circuit includes a second resistor and a third resistor. The first end of the second resistor is the input terminal of the first voltage dividing circuit, the second end of the second resistor is connected to the first end of the third resistor, the node between the second resistor and the third resistor is the output terminal of the first voltage dividing circuit, and the second end of the third resistor is grounded.

[0020] In one embodiment, the second voltage dividing circuit includes a fourth resistor and a fifth resistor. The first end of the fourth resistor is the first end of the second voltage dividing circuit, the second end of the fourth resistor is connected to the first end of the fifth resistor, the connection node of the fourth resistor and the fifth resistor is the output terminal of the second voltage dividing circuit, and the second end of the fifth resistor is the second end of the second voltage dividing circuit.

[0021] In one embodiment, the second switch circuit includes a second switching device. The first end of the second switching device is connected to the second end of the second voltage dividing circuit, the second end of the second switching device is grounded, and the control terminal of the second switching device is connected to the output terminal of the first voltage dividing circuit.

[0022] In a second aspect, the present application further provides a power supply circuit, including the protection circuit, the power supply module, and the power-on control module as described in any one of the above first aspects. The output end of the power supply module is connected to the input end of the first switching circuit, and the power-on control module is connected to the input end of the switching control module. The power-on control module is used to output the external control signal.

[0023] In a third aspect, the present application further provides a vehicle, including a vehicle body and the power supply circuit as described in the second aspect located inside the vehicle body.

[0024] The above protection circuit, power supply circuit, and vehicle have at least the following advantages:

[0025] When the load is in a normal working state in the present application, the switching control module responds to an external control signal and outputs a switching control signal to the control end of the first switching circuit, so that the power supply terminal provides a working voltage for the load through the first switching circuit. At the same time, during the operation of the load, if a load short circuit occurs, the short-circuit protection module can cause the switching control module to output a switching control signal for disconnecting the first switching circuit, thereby disconnecting the power supply loop between the power supply terminal and the load, preventing the voltage of the power supply terminal from being pulled down by the load short circuit, and ensuring the safety of the circuit; after the short-circuit fault is eliminated, the power supply to the load is automatically restored. The present application has a simple structure, low power consumption, and advantages of long life and fast response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0027] Figure 1 It is a structural block diagram of the protection circuit in an embodiment;

[0028] Figure 2 It is a structural block diagram of the short-circuit protection module in an embodiment;

[0029] Figure 3 It is a structural block diagram of the switching control module in an embodiment;

[0030] Figure 4 It is a schematic diagram of the result of the protection circuit in an embodiment;

[0031] Figure 5 It is a structural block diagram of the power supply circuit in an embodiment;

[0032] Figure 6 It is a structural block diagram of the vehicle in an embodiment.

[0033] Through the above-mentioned accompanying drawings, specific embodiments of the present application have been shown, and more detailed descriptions will be provided hereinafter. These drawings and written descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Detailed Embodiments

[0034] The following uses specific specific examples to illustrate the implementation manners of the present utility model. Those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification. The present utility model can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present utility model. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0035] It should be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concept of the present utility model. Therefore, only the components related to the present utility model are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0036] For the purpose of illustration, some exemplary embodiments of the present utility model have been described. It should be understood that the present utility model can be implemented in other ways not specifically shown in the drawings.

[0037] Please refer to Figure 1 , in one embodiment, the present application provides a protection circuit 100, including: a first switch circuit 102, a switch control module 104, and a short-circuit protection module 106.

[0038] The first switch circuit 102 has its input end connected to the power supply end 108, its control end connected to the output end of the switch control module 104, and its output end connected to the external load 110. The first switch circuit 102 is used to connect or disconnect the power supply circuit between the power supply end 108 and the external load 110 according to the switch control signal of the switch control module 104. When the first switch circuit 102 is turned on under the action of the switch control signal, the positive power supply of the power supply end 108 provides working power for the external load 110 through the first switch circuit 102, so that the external load can work normally; when the first switch circuit 102 is turned off under the action of the switch control signal of the first switch circuit 102, the external load 110 will stop working due to power loss.

[0039] A switch control module 104, whose input end is connected to an external control signal 112, is configured to receive the external control signal 112 and output a switch control signal to the control end of the first switch circuit 102 according to the external control signal 112. It should be noted that the external control signal 112 is a high-level signal or a low-level signal. When the external load 110 is in a normal working state, if the received external control signal 112 is a high-level signal, the switch control signal output by the switch control module 104 can turn on the first switch circuit 102, thereby enabling the external load 110 to work normally; if the received external control signal is a low-level signal, the switch control signal output by the switch control module 104 can turn off the first switch circuit 102, thereby causing the external load 110 to stop working. It should be understood that in practical applications, the technologies for outputting high and low level signals are relatively mature. For example, a single-chip microcomputer or a signal generator can both achieve good signal output functions. Therefore, the specific models thereof are not limited in this application.

[0040] A short-circuit protection module 106 is connected between the output end of the first switch circuit 102 and the input end of the switch control module 104. After the load 110 is short-circuited, the short-circuit protection module 106 causes the switch control module 104 to output a switch control signal for turning off the first switch circuit 102, thereby disconnecting the power supply loop between the power supply terminal 108 and the load 110 and preventing the voltage of the power supply terminal 108 from being pulled down by the short circuit of the load 110.

[0041] In the above protection circuit, when the load is in a normal working state, the switch control module responds to the external control signal and outputs a switch control signal to the control end of the first switch circuit, so that the power supply terminal provides a working voltage for the load through the first switch circuit; at the same time, during the operation of the load, if a load short-circuit occurs, the short-circuit protection module can cause the switch control module to output a switch control signal for turning off the first switch circuit, thereby disconnecting the power supply loop between the power supply terminal and the load and preventing the voltage of the power supply terminal from being pulled down by the load short circuit, ensuring the safety of the circuit; after the short-circuit fault is eliminated, the power supply to the load is automatically restored. This application has a simple structure, low power consumption, and advantages such as a long service life and a fast response speed.

[0042] Please refer to Figure 2 , optionally, the short-circuit protection module 106 includes a diode 1062 and a pull-up circuit 1064.

[0043] The diode 1062 is reversely connected between the output end of the first switch circuit 102 and the input end of the switch control module 104. Its cathode is connected to the output end of the first switch circuit 102, and its anode is connected to the input end of the switch control module 104, and is configured to conduct or cut off according to the voltage across the diode 1062.

[0044] The first end of the pull-up circuit 1064 is connected to the power supply terminal 108, and the second end is connected to the input terminal of the switch control module 104. With this solution, in addition to the functions of current limiting and voltage division, by setting the pull-up circuit 1064 between the power supply terminal 108 and the diode, it is also possible to reduce the high-frequency oscillation caused by the switching of the diode 1062 and ensure the safe and stable operation of the circuit. After the load 110 is short-circuited, the voltage at the load 110 terminal is directly connected to the ground wire. At this time, the power supply terminal 108 provides a high-level signal for the anode of the diode 1062 through the pull-up circuit 1064, causing the diode 1062 to conduct, thereby pulling down the voltage at the input terminal of the switch control module 104. The switch control module 104 outputs a switch control signal 112 for disconnecting the first switch circuit 102, thus disconnecting the power supply loop between the power supply terminal 108 and the load 110. After the short-circuit fault of the load 110 is removed, the pull-up circuit 1064 raises the voltage at the output terminal of the switch control module 104. The switch control module 104 outputs a switch control signal 112 for connecting the first switch circuit 102, and the power supply terminal 108 resumes power supply to the load 110 through the first switch circuit 102.

[0045] In the above protection circuit, when the load 110 is operating normally, the diode 1062 is cut off, and the power supply terminal 108 provides the operating voltage for the load 110 through the first switch circuit 102; when the load 110 is short-circuited, the power supply terminal 108 provides the conduction voltage for the diode 1062 through the pull-up circuit 1064, pulling down the voltage at the input terminal of the switch control module 104, thereby automatically disconnecting the power supply loop of the load 110; after the short-circuit fault of the load 110 is removed, the diode 1062 resumes the cut-off state, and the pull-up circuit 1064 raises the voltage at the output terminal of the switch control module 104, automatically resuming the power supply to the load 110.

[0046] Optionally, the pull-up circuit 1064 includes a first resistor. The first end of the first resistor is connected to the power supply terminal 108, and the second end of the first resistor is connected to the input terminal of the switch control module 104. It should be understood that the above first resistor is only an example of this embodiment. In actual applications, multiple resistors, or a combination of resistors and capacitors, can be set as needed to achieve the above functions.

[0047] Optionally, the first switch circuit 102 includes: a first switching device.

[0048] The first end of the first switching device is connected to the power supply terminal 108, the second end of the first switching device is used to connect the load 110, and the control end of the switching device is connected to the output terminal of the switch control module 104. It should be noted that in order to improve the response speed of the switch and reduce the power consumption, a transistor is used as the switching element in this embodiment.

[0049] Please refer to Figure 3 , optionally, the switch control module 104 includes a first voltage dividing circuit 1042 and a main control circuit.

[0050] The first voltage dividing circuit 1042, whose input terminal receives the external control signal 112 and whose output terminal is connected to the input terminal of the main control circuit, is used to divide the high level input externally and transmit it to the subsequent main control circuit.

[0051] The main control circuit, whose output terminal is connected to the control terminal of the first switching circuit 102, is used to output a switching control signal 112 to the first switching circuit 102 in response to the external control signal 112, so as to turn on or off the first switching circuit 102.

[0052] Optionally, the main control circuit includes a first voltage dividing circuit 1044 and a second switching circuit 1046.

[0053] The first voltage dividing circuit 1044, whose first end is connected to the power supply terminal 108, whose second end is connected to the first end of the second switching circuit 1046, whose output terminal is connected to the control terminal of the first switching circuit 102, whose second end of the second switching circuit 1046 is grounded, and whose control terminal is connected to the output terminal of the first voltage dividing circuit 1042. The first voltage dividing circuit 1042 transmits the divided high level to the control terminal of the second switching circuit 1046 to turn on the second switching circuit 1046, and then inputs it to the control terminal of the first switching circuit 102 after being divided by the first voltage dividing circuit 1044.

[0054] Optionally, the first voltage dividing circuit 1042 includes a second resistor and a third resistor. The first end of the second resistor is the input terminal of the first voltage dividing circuit 1042, the second end of the second resistor is connected to the first end of the third resistor, the node between the second resistor and the third resistor is the output terminal of the first voltage dividing circuit 1042, and the second end of the third resistor is grounded.

[0055] Optionally, the first voltage dividing circuit 1044 includes a fourth resistor and a fifth resistor. The first end of the fourth resistor is the first end of the first voltage dividing circuit 1044, the second end of the fourth resistor is connected to the first end of the fifth resistor, the connection node between the fourth resistor and the fifth resistor is the output terminal of the first voltage dividing circuit 1044, and the second end of the fifth resistor is the second end of the first voltage dividing circuit 1044.

[0056] Optionally, the second switching circuit 1046 includes a second switching device. The first end of the second switching device is connected to the second end of the first voltage dividing circuit 1044, the second end of the second switching device is grounded, and the control terminal of the second switching device is connected to the output terminal of the first voltage dividing circuit 1042.

[0057] Please refer to Figure 4 and the following in combination with Figure 4 to describe in detail the working principle of the protection circuit of the present application. Among them, Figure 4VIN in it represents the positive pole of the power supply terminal; VCC also represents the positive pole of the power supply terminal. The separate marking here is for convenience of explanation. In actual applications, the data of VIN and VCC can be the same or different. VO represents the external load; Driv represents the external control signal, and this signal is provided by the single-chip microcomputer.

[0058] Further, the short-circuit protection module 106 includes a diode D1 and a pull-up circuit R1; the first voltage-dividing circuit 1044 includes a second resistor R2 and a third resistor R3; the second switching circuit 1046 includes a second switching device T1; the second voltage-dividing circuit 1044 includes a fourth resistor R4 and a fifth resistor R5; the first switching circuit includes a first switching device M1.

[0059] When the single-chip microcomputer pulls down the Driv signal, the voltage at node ⑥ is a low-level signal, close to 0V. Both node ⑥ and node ⑤ are low-level signals, and the triode T1 is turned off; node ④, node ③ and node ① are at the same potential, no current flows through the fourth resistor R4 and the fifth resistor R5, there is no voltage difference between the gate and the source of the transistor M1, the transistor M1 is turned off, and there is no output at node ②, and there is also no output at VO.

[0060] When the single-chip microcomputer releases the Driv signal, the voltage at node ⑥ is pulled up to VCC through R1, which is a high level. This high level reaches the turn-on current after being divided by the second resistor R2 and the third resistor R3, driving the triode T1 to conduct. The current passes through the fourth resistor R4, the fifth resistor R5, the collector of the triode T1, the emitter of the triode T1 to the ground, turning on the transistor M1. The VIN current passes through the drain of the transistor M1 and the source of the transistor M1 and then outputs to VO, and the load gets powered on and operates.

[0061] When the single-chip microcomputer releases the Driv signal but the load is short-circuited, VO is directly connected to the ground wire GND. The cathode of the diode D1 is pulled down to GND. The magnitude of the short-circuit current is (VCC - D1 voltage drop) / R1 resistance value, and the voltage at node ⑥ is about 0.2 - 0.7V. After the voltage at node ⑥ is divided by the second resistor R2 and the third resistor R3, the base voltage of the triode T1 is lower than the turn-on voltage, and the triode T1 is cut off. At this time, the potential at node ④ is the same as VIN, the transistor M1 is turned off, and the output is turned off.

[0062] When the short-circuit fault is eliminated and the single-chip microcomputer releases the Driv signal, node ⑤ and node ⑥ return to the turn-on level, M1 is turned on, and the output is restored.

[0063] In the above protection circuit, when the load is in a normal working state, the switch control module responds to an external control signal and outputs a switch control signal to the control end of the first switch circuit, so that the power supply terminal provides a working voltage for the load through the first switch circuit; at the same time, during the operation of the load, if a load short - circuit occurs, the short - circuit protection module can make the switch control module output a switch control signal for disconnecting the first switch circuit, thereby disconnecting the power supply loop between the power supply terminal and the load, preventing the voltage of the power supply terminal from being pulled down by the load short - circuit, ensuring the safety of the circuit; and automatically resumes power supply to the load after the short - circuit fault is eliminated. The structure of this application is simple, with low power consumption, and has the advantages of long service life and fast response speed.

[0064] Please refer to Figure 5 , in one embodiment, the present application further provides a power supply circuit 500, including the protection circuit 100 disclosed in the above - mentioned embodiment, a power supply module 502, and a power - on control module 504.

[0065] The output end of the power supply module 502 is connected to the input end of the first switch circuit 102, and the power - on control module 504 is connected to the input end of the switch control module 104. The power - on control module 504 is used to output an external control signal.

[0066] Further, when a load short - circuit fault occurs, the voltage at node ⑥ is about 0.2 - 0.7V. This low - level signal will be fed back to the power - on control module 504 as a short - circuit signal, so that the power - on control module 504 can obtain the state of the load short - circuit and monitor and process it in a timely manner.

[0067] In the above power supply circuit, when the load is in a normal working state, the switch control module responds to the control signal of the power - on control module and outputs a switch control signal to the control end of the first switch circuit, so that the power supply module provides a working voltage for the load through the first switch circuit; at the same time, during the operation of the load, if a load short - circuit occurs, the short - circuit protection module can make the switch control module output a switch control signal for disconnecting the first switch circuit, thereby disconnecting the power supply loop between the power supply module and the load, preventing the voltage of the power supply module from being pulled down by the load short - circuit, ensuring the safety of the circuit; and automatically resumes power supply to the load after the short - circuit fault is eliminated. The structure of this application is simple, with low power consumption, and has the advantages of long service life and fast response speed.

[0068] Please refer to Figure 6 , in one embodiment, the present application further provides a vehicle 600, including a vehicle body and the power supply circuit 500 disclosed in the above - mentioned embodiment located inside the vehicle body.

[0069] For the above vehicle, when the internal power supply circuit has a load in a normal operating state, the switch control module responds to the control signal of the power-on control module and outputs a switch control signal to the control end of the first switch circuit, so that the power supply module provides a working voltage for the load through the first switch circuit; at the same time, during the operation of the load, if a load short circuit occurs, the short-circuit protection module can cause the switch control module to output a switch control signal for disconnecting the first switch circuit, thereby disconnecting the power supply loop between the power supply module and the load, preventing the voltage of the power supply module from being pulled down by the load short circuit and affecting the normal use of the entire vehicle; after the short-circuit fault is eliminated, the power supply to the load is automatically restored. The power supply circuit of the present application has a simple structure and low power consumption, and has the advantages of long life and fast response speed, greatly increasing the safety and service life of the vehicle.

[0070] It should be understood that although the steps in the flowcharts involved in the above embodiments are sequentially shown according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least some of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least some of the steps or stages in other steps or other steps.

[0071] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combinations of these technical features do not conflict, they should be considered as the scope described in this specification.

[0072] The above-described embodiments only represent several implementation manners of the present application. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A protection circuit, characterized in that: It includes: a first switch circuit, a switch control module and a short circuit protection module; The input end of the first switch circuit is connected to the power supply end, and the output end is used to connect to the load; The input end of the switch control module is used to receive an external control signal, and the output end of the switch control module is connected to the control end of the first switch circuit; The short-circuit protection module is connected between the output end of the first switch circuit and the input end of the switch control module. After the load is short-circuited, the short-circuit protection module enables the switch control module to output a switch control signal for disconnecting the first switch circuit.

2. The protection circuit according to claim 1, characterized in that: The short circuit protection module includes a diode and a pull-up circuit; The cathode of the diode is connected to the output end of the first switch circuit, and the anode of the diode is connected to the input end of the switch control module; the first end of the pull-up circuit is connected to the power supply end, and the second end is connected to the input end of the switch control module; After the load is short-circuited, the voltage at the input end of the switch control module is pulled down by the diode, and after the load short-circuit fault is removed, the pull-up circuit raises the voltage at the output end of the switch control module.

3. The protection circuit according to claim 2, characterized in that: The pull-up circuit includes a first resistor, a first end of the first resistor is connected to the power supply end, and a second end of the first resistor is connected to the input end of the switch control module.

4. The protection circuit according to any one of claims 1 to 3, characterized in that: The first switch circuit comprises: a first switch device; The first end of the first switch device is connected to the power supply end, the second end of the first switch device is used to connect to the load, and the control end of the switch device is connected to the output end of the switch control module.

5. The protection circuit according to claim 2, characterized in that: The switch control module includes a first voltage dividing circuit and a main control circuit; The input end of the first voltage divider circuit receives the external control signal, the output end is connected to the input end of the main control circuit, and the output end of the main control circuit is connected to the control end of the first switch circuit.

6. The protection circuit according to claim 5, characterized in that: The main control circuit includes a second voltage divider circuit and a second switch circuit; The first end of the second voltage divider circuit is connected to the power supply end, the second end of the second voltage divider circuit is connected to the first end of the second switch circuit, the output end of the second voltage divider circuit is connected to the control end of the first switch circuit, the second end of the second switch circuit is grounded, and the control end of the second switch circuit is connected to the output end of the first voltage divider circuit.

7. The protection circuit according to claim 5, characterized in that: The first voltage divider circuit includes a second resistor and a third resistor, the first end of the second resistor is the input end of the first voltage divider circuit, the second end of the second resistor is connected to the first end of the third resistor, the node between the second resistor and the third resistor is the output end of the first voltage divider circuit, and the second end of the third resistor is grounded.

8. The protection circuit according to claim 6, characterized in that: The second voltage divider circuit includes a fourth resistor and a fifth resistor, the first end of the fourth resistor is the first end of the second voltage divider circuit, the second end of the fourth resistor is connected to the first end of the fifth resistor, the connection node between the fourth resistor and the fifth resistor is the output end of the second voltage divider circuit, and the second end of the fifth resistor is the second end of the second voltage divider circuit.

9. The protection circuit according to claim 6, characterized in that: The second switch circuit includes a second switch device, a first end of the second switch device is connected to the second end of the second voltage divider circuit, a second end of the second switch device is grounded, and a control end of the second switch device is connected to the output end of the first voltage divider circuit.

10. A power supply circuit, characterized in that: It comprises a protection circuit, a power supply module and a power-on control module as described in any one of claims 1 to 9, wherein the output end of the power supply module is connected to the input end of the first switch circuit, the power-on control module is connected to the input end of the switch control module, and the power-on control module is used to output the external control signal.

11. A vehicle, characterized in that: The invention comprises a vehicle body and the power supply circuit according to claim 10 located in the vehicle body.

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