CN116073332A

CN116073332A - Switch protection circuit and electric automobile

Info

Publication number: CN116073332A
Application number: CN202310035343.0A
Authority: CN
Inventors: 刘鹏飞; 刘登科; 李明浩; 吴壬华
Original assignee: Shenzhen Shinry Technologies Co Ltd
Current assignee: Shenzhen Shinry Technologies Co Ltd
Priority date: 2023-01-10
Filing date: 2023-01-10
Publication date: 2023-05-05

Abstract

The embodiment of the application provides a switch protection circuit and an electric automobile, wherein the switch protection circuit comprises a first switch module, a second switch module, a first current sensor, a first driving circuit, a second driving circuit, a first overcurrent protection circuit, a second overcurrent protection circuit, a first power supply circuit, a second power supply circuit and a control module; the DC/DC converter is connected with the first battery through a switch protection circuit; under the condition that the first current sensor detects current abnormality, the first overcurrent protection circuit controls the first switch module to be in an off state through the first driving circuit and/or controls the second switch module to be in an off state through the second driving circuit, and the control module controls the first switch module to be in an off state through the first driving circuit and/or controls the second switch module to be in an off state through the second driving circuit. According to the embodiment of the application, the power supply safety of the DC/DC converter can be improved.

Description

Switch protection circuit and electric automobile

Technical Field

The application relates to the technical field of electronic circuits, in particular to a switch protection circuit and an electric automobile.

Background

In an electrokinetic automotive application, a Direct current to Direct current (DC/DC) converter on a vehicle is used as a power supply for a low voltage battery (e.g., a 12V battery), and has a high reliability requirement. With the development of dynamism and intellectualization, the safety requirements for the DC/DC converter are higher and higher. When a fault occurs in the DC/DC converter or outside, how to improve the power supply safety of the DC/DC converter is a problem to be solved.

Disclosure of Invention

The embodiment of the application provides a switch protection circuit and an electric automobile, which can improve the power supply safety of a DC/DC converter.

A first aspect of the embodiments of the present application provides a switch protection circuit, where the switch protection circuit includes a first switch module, a second switch module, a first current sensor, a first driving circuit, a second driving circuit, a first overcurrent protection circuit, a second overcurrent protection circuit, a first power supply circuit, a second power supply circuit, and a control module; the DC/DC converter is connected with the first battery through the switch protection circuit;

the output port of the DC/DC converter is connected with the first end of the first current sensor, the second end of the first current sensor is connected with the first end of the first switch module, the second end of the first switch module is connected with the first end of the second switch module, and the second end of the second switch module is connected with the input port of the first battery; the third end of the first current sensor is connected with the first input end of the first overcurrent protection circuit, the first input end of the second overcurrent protection circuit and the first input end of the control module, the output end of the first overcurrent protection circuit is connected with the first input end of the first driving circuit, and the output end of the second overcurrent protection circuit is connected with the first input end of the second driving circuit; the first output end of the control module is connected with the input end of the first driving circuit, the second output end of the control module is connected with the input end of the second driving circuit, the output end of the first driving circuit is connected with the third end of the first switch module, and the output end of the second driving circuit is connected with the third end of the second switch module; the first power supply circuit supplies power to the first driving circuit, and the second power supply circuit supplies power to the second driving circuit; the first switch module and the second switch module are different types of switch tubes;

Under the condition that the first current sensor detects current abnormality, the first overcurrent protection circuit controls the first switch module to be in an off state through the first driving circuit and/or controls the second switch module to be in an off state through the second driving circuit, and the control module controls the first switch module to be in an off state through the first driving circuit and/or controls the second switch module to be in an off state through the second driving circuit.

Optionally, the switch protection circuit further includes: a first voltage sensor and a second voltage sensor; a first end of the first voltage sensor is connected with an output port of the DC/DC converter, and a first end of the second voltage sensor is connected with an input port of the first battery; the second end of the first voltage sensor and the second end of the second voltage sensor are grounded, the third end of the first voltage sensor is connected with the second input end of the control module, and the third end of the second voltage sensor is connected with the third input end of the control module;

the control module controls the first switch module to be in an off state through the first driving circuit under the condition that the first voltage sensor detects voltage abnormality; and under the condition that the second voltage sensor detects voltage abnormality, the control module controls the second switch module to be in an off state through the second driving circuit.

Optionally, a third output end of the control module is connected with a second input end of the first overcurrent protection circuit, and a fourth output end of the control module is connected with a second input end of the second overcurrent protection circuit;

under the condition that the first switch module and the second switch module are both conducted, the control module injects a first fault signal into the first overcurrent protection circuit, and after the first fault signal is injected into the first overcurrent protection circuit, the control module determines whether the first overcurrent protection circuit is normal or not;

and under the condition that the first switch module and the second switch module are both conducted, the control module injects a second fault signal into the second overcurrent protection circuit, and after the second fault signal is injected into the second overcurrent protection circuit, the control module determines whether the second overcurrent protection circuit is normal or not.

Optionally, the control module determines whether the first overcurrent protection circuit is normal, including:

the control module determines whether the first overcurrent protection circuit is normal or not according to the difference value of the voltage signal detected by the first voltage sensor and the voltage signal detected by the second voltage sensor;

The control module determining whether the second overcurrent protection circuit is normal, including:

the control module determines whether the second overcurrent protection circuit is normal according to the difference value of the voltage signal detected by the first voltage sensor and the voltage signal detected by the second voltage sensor.

Optionally, a fourth input end of the control module is connected with an output end of the first overcurrent protection circuit, and a fifth input end of the control module is connected with an output end of the second overcurrent protection circuit;

the control module determining whether the first overcurrent protection circuit is normal, including:

the control module determines whether the first overcurrent protection circuit is normal or not according to the output signal of the first overcurrent protection circuit;

and the control module determines whether the second overcurrent protection circuit is normal or not according to the output signal of the second overcurrent protection circuit.

Optionally, a sixth input end of the control module is connected with an output end of the first driving circuit, and a seventh input end of the control module is connected with an output end of the second driving circuit;

the control module determines whether the first overcurrent protection circuit is normal according to the output signal of the first driving circuit;

and the control module determines whether the second overcurrent protection circuit is normal or not according to the output signal of the second driving circuit.

Optionally, the switch protection circuit further includes an over-voltage and under-voltage protection circuit, a first input end of the over-voltage and under-voltage protection circuit is connected with a third end of the first voltage sensor, a second input end of the over-voltage and under-voltage protection circuit is connected with a third end of the second voltage sensor, a first output end of the over-voltage and under-voltage protection circuit is connected with a first input end of the first power supply circuit, and a second output end of the over-voltage and under-voltage protection circuit is connected with a first input end of the second power supply circuit;

under the condition that the first voltage sensor detects voltage abnormality, the overvoltage and undervoltage protection circuit sends a first power-off signal to the first power supply circuit, and the first power-off signal is used for turning off power supply of the first driving circuit;

And under the condition that the second voltage sensor detects voltage abnormality, the overvoltage and undervoltage protection circuit sends a second outage signal to the second power supply circuit, and the second outage signal is used for cutting off the power supply of the first driving circuit.

Optionally, the switch protection circuit further includes a third voltage sensor and an alarm device, a first end of the third voltage sensor is connected to the second end of the first switch module, a second end of the third voltage sensor is grounded, and a third end of the third voltage sensor is connected to the eighth input end of the control module;

when the first switch module is detected to be in an off state and the control module detects that the voltage difference between the first end and the second end of the first switch module is smaller than a first threshold value, the control module sends a first alarm signal to the alarm device, wherein the first alarm signal is used for triggering the alarm device to send out a first type alarm, and the first type alarm is used for prompting a driver that the first switch module is abnormal;

when the first switch module is detected to be in a conducting state and the control module detects that the voltage difference between the first end and the second end of the first switch module is larger than the first threshold value, the control module reduces the output power of the DC/DC converter and/or sends a second alarm signal to the alarm device; the second alarm signal is used for triggering the alarm device to send out a second type of alarm, and the second type of alarm is used for prompting a driver that the first switch module is abnormal.

Optionally, the switch protection circuit further includes a fourth voltage sensor, a first end of the fourth voltage sensor is connected to a target end, a second end of the fourth voltage sensor is grounded, a third end of the fourth voltage sensor is connected to a ninth input end of the control module, and the target end includes any one of a first end of the first current sensor, a first end of the first switch module, a second end of the first switch module, and a second end of the second switch module.

Optionally, the first switch module includes M switch tubes connected in parallel, the second switch module includes N switch tubes connected in parallel, and M, N is a positive integer. And the cathodes of the parasitic diodes of the M switching tubes are connected with the cathodes of the parasitic diodes of the N switching tubes.

Optionally, the first current sensor detects a current anomaly, including:

the first current sensor detects a first current, and when the current flow direction of the first current is that the input port of the first battery is towards the output port of the DC/DC converter and the first current is larger than a second threshold value, the first current sensor is determined to detect current abnormality;

The first current sensor detects a second current, and when a current flow of the second current is an input port of the output port of the DC/DC converter to the first battery and the second current is greater than a third threshold, it is determined that the first current sensor detects a current abnormality.

Optionally, the switch protection circuit further includes a second current sensor, a first end of the second current sensor is connected to a second end of the second switch module, a second end of the second current sensor is connected to the input port of the first battery, and a third end of the second current sensor is connected to a tenth input end of the control module.

A second aspect of the embodiments of the present application provides an electric vehicle, including the switch protection circuit of any one of the first aspects of the embodiments of the present application, a DC/DC converter, and a first battery, where the DC/DC converter is connected to the first battery through the switch protection circuit.

According to the switch protection circuit, under the condition that the first current sensor detects current abnormality, the first overcurrent protection circuit controls the first switch module to be in a disconnection state through the first driving circuit and/or controls the second switch module to be in a disconnection state through the second driving circuit, and the switch protection circuit control module controls the first switch module of the switch protection circuit to be in a disconnection state through the first driving circuit of the switch protection circuit and/or controls the second switch module of the switch protection circuit to be in a disconnection state through the second driving circuit of the switch protection circuit. When a current abnormality is detected, the first and/or second switching modules may be turned off by a hardware circuit (first and/or second overcurrent protection circuits), on the one hand, and may be turned off by a software module (control module), on the other hand. When the hardware circuit fails, the control of the switch module can be realized through the software module under the condition of abnormal current, when the software module fails, the switch module can be closed through the hardware circuit under the condition of abnormal current, and when faults (such as abnormal current) occur, the power supply safety of the DC/DC converter can be improved.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a switch protection circuit according to an embodiment of the present application;

fig. 2a is a schematic structural diagram of an isolated DC/DC converter according to an embodiment of the present application;

fig. 2b is a schematic structural diagram of a non-isolated DC/DC converter according to an embodiment of the present application;

FIG. 3 is a schematic diagram of another switch protection circuit according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of another switch protection circuit according to an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of another switch protection circuit according to an embodiment of the present disclosure;

FIG. 6 is a schematic diagram of another switch protection circuit according to an embodiment of the present disclosure;

fig. 7 is a schematic structural diagram of another switch protection circuit according to an embodiment of the present disclosure;

FIG. 8 is a schematic diagram of another switch protection circuit according to an embodiment of the present disclosure;

fig. 9 is a schematic structural diagram of another switch protection circuit according to an embodiment of the present disclosure;

fig. 10 is a schematic structural diagram of another switch protection circuit according to an embodiment of the present disclosure;

fig. 11 is a schematic structural diagram of an electric vehicle according to an embodiment of the present application.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

The terms first, second and the like in the description and in the claims of the present application and in the above-described figures, are used for distinguishing between different objects and not for describing a particular sequential order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed but may optionally include additional steps or elements not listed or inherent to such process, article, or apparatus.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a switch protection circuit according to an embodiment of the present application. As shown in fig. 1, the switch protection circuit 100 may include a first switch module 11, a second switch module 12, a first current sensor 21, a first driving circuit 31, a second driving circuit 32, a first overcurrent protection circuit 41, a second overcurrent protection circuit 42, a first power supply circuit 51, a second power supply circuit 52, and a control module 61; the DC/DC converter is connected to the first battery through the switch protection circuit 100;

an output port of the DC/DC converter is connected to a first end of the first current sensor 21, a second end of the first current sensor 21 is connected to a first end of the first switch module 11, a second end of the first switch module 11 is connected to a first end of the second switch module 12, and a second end of the second switch module 12 is connected to an input port of the first battery; a third terminal of the first current sensor 21 is connected to a first input terminal of the first overcurrent protection circuit 41, a first input terminal of the second overcurrent protection circuit 42, and a first input terminal of the control module 61, an output terminal of the first overcurrent protection circuit 41 is connected to a first input terminal of the first driving circuit 31, and an output terminal of the second overcurrent protection circuit 42 is connected to a first input terminal of the second driving circuit 32; a first output end of the control module 61 is connected to an input end of the first driving circuit 31, a second output end of the control module 61 is connected to an input end of the second driving circuit 32, an output end of the first driving circuit 31 is connected to a third end of the first switch module 11, and an output end of the second driving circuit 32 is connected to a third end of the second switch module 12; the first power supply circuit 51 supplies power to the first driving circuit 31, and the second power supply circuit 52 supplies power to the second driving circuit 32; the first switch module and the second switch module are different types of switch tubes;

In the case that the first current sensor 21 detects a current abnormality, the first overcurrent protection circuit 41 controls the first switch module 11 to be in an off state through the first driving circuit 31 and/or the second overcurrent protection circuit 42 controls the second switch module 12 to be in an off state through the second driving circuit 32, and the control module 61 controls the first switch module 11 to be in an off state through the first driving circuit 31 and/or controls the second switch module 12 to be in an off state through the second driving circuit 32.

The switch protection circuit 100 may be a component of a DC/DC converter or may be a separate circuit.

A Direct current to Direct current (DC/DC) converter may also be referred to as a DC-DC converter, which is a DC conversion device that converts a DC base power supply into other DC voltages. The DC/DC converter may convert a high voltage to a low voltage or a low voltage to a high voltage.

The DC/DC converter may also be divided into an isolated DC/DC converter (as shown in fig. 2 a) and a non-isolated DC/DC converter (as shown in fig. 2 b). The isolating DC/DC converter comprises an isolating transformer, which enables electrical isolation between the high voltage battery and the battery (first battery).

The DC/DC converter may be a unidirectional DC/DC converter or a bidirectional DC/DC converter. The unidirectional DC/DC converter may implement unidirectional DC/DC conversion, for example, may convert a high voltage on the high voltage battery side into a low voltage for powering the battery. The bidirectional DC/DC converter can realize bidirectional DC/DC conversion, for example, can convert high voltage at the high-voltage battery side into low voltage to supply power for the low-voltage battery, and can convert low voltage at the low-voltage battery side into high voltage to supply power for the high-voltage battery.

The DC/DC converter takes power from a high voltage battery (which may also be referred to as a power battery), and after conversion, supplies power to a low voltage battery (first battery) and an electronic control unit (Electronic Control Unit, ECU) on the vehicle. The low-voltage battery may include a lead-acid battery or a lithium battery, and the voltage of the low-voltage battery is typically about 12V, and the ECU may include a car machine, a music player, a wiper, and the like.

A first current sensor 21 for sampling a current output from the DC/DC converter; if the DC/DC converter is a bi-directional DC/DC converter, bi-directional current can be sampled. The first current sensor 21 may be sampled in the manner of a hall sensor or a sampling resistor plus an op-amp.

The first switch module 11 includes M switch tubes connected in parallel, the second switch module 12 includes N switch tubes connected in parallel, and M, N is a positive integer. And the cathodes of the parasitic diodes of the M switching tubes are connected with the cathodes of the parasitic diodes of the N switching tubes. Parasitic diodes, which may also be referred to as body diodes.

The first switching module 11 and the second switching module 12 may represent a single switching tube, or may be a plurality of switching tubes connected in parallel. The first switching module 11 and the second switching module 12 of fig. 1 take a single switching tube as an example. The switching transistor may include a Metal-Oxide-semiconductor field effect transistor (MOSFET), which may be simply referred to as a MOS transistor. The first switch module 11 and the second switch module 12 are different types of switch tubes, the first driving circuit 31 and the second driving circuit 32 are different driving circuits, and in order to ensure the power supply of the first driving circuit 31 and the second driving circuit 32, a first power supply circuit 51 needs to be provided for supplying power to the first driving circuit 31, and a second power supply circuit 52 needs to be provided for supplying power to the second driving circuit 32. As shown in fig. 1, the first switch module 11 may be a P-channel MOS transistor, and the second switch module 12 may be an N-channel MOS transistor; for another example, the first switch module 11 may be an N-channel MOS transistor, and the second switch module 12 may be a P-channel MOS transistor. The body diode of the first switch module 11 is back-to-back with the body diode of the second switch module 12 (as shown in fig. 1, the cathode of the body diode of the first switch module 11 is connected with the cathode of the body diode of the second switch module 12), so that bidirectional protection can be realized. The driving circuit of the P-channel MOS transistor is different from the driving circuit of the N-channel MOS transistor, that is, the first driving circuit and the second driving circuit are different, and the first power supply circuit 51 and the second power supply circuit 52 are different power supply circuits.

The first power supply circuit 51 is configured to supply power to the first driving circuit 31. The first power supply circuit 51 may be supplied with a bootstrap circuit or an auxiliary power supply.

The second power supply circuit 52 is configured to supply power to the second driving circuit 32. The second power supply circuit 52 may be powered by a bootstrap circuit or an auxiliary power supply.

Wherein the first power supply circuit 51 may take power from any one of the first end of the first current sensor 21, the first end of the first switch module 11, the first end of the second switch module 12, and the second end of the second switch module 12; the second power supply circuit 52 may take power from any one of the first end of the first current sensor 21, the first end of the first switch module 11, the first end of the second switch module 12, and the second end of the second switch module 12.

The first driving circuit 31 is used for driving the first switch module 11. The control module 61 may control the optocoupler in the first driving circuit 31, so that the first driving circuit 31 provides driving for the first switch module 11. The first driving circuit 31 may also provide driving to the first switch module 11 using an isolated driving mode.

The second driving circuit 32 is configured to drive the second switch module 12. The control module 61 may control the optocoupler in the second driving circuit 32, so that the second driving circuit 32 provides driving to the second switch module 12. The second drive circuit 32 may also provide drive to the second switch module 12 using an isolated drive.

The overcurrent protection circuit may also be referred to as a short-circuit protection circuit.

When the DC/DC converter is operated in reverse (current flows from the first battery to the DC/DC converter), the first overcurrent protection circuit 41 generates protection information to turn off the first switch module 11 if the current is excessive, thereby turning off the reverse current. The first over-current protection circuit 41 may be implemented with a comparator or a precision voltage reference integrated circuit (e.g., TC 431). When an internal short circuit occurs in the DC/DC converter, a large reverse current is generated.

When the DC/DC converter is operating in the forward direction (current flows from the DC/DC converter to the first battery), the second overcurrent protection circuit 42 generates protection information to turn off the second switch module 12 if the current is excessive, thereby turning off the forward current. The second over-current protection circuit 42 may be implemented with a comparator or a precision voltage reference integrated circuit (e.g., TC 431). The forward current may be excessive when an external short circuit or an excessive load occurs in the DC/DC converter.

The control module 61 may obtain the current sampling result of the current sensor and execute the protection logic of the software. For example, the control module 61 may control the first switch module 11 to be in an on state or an off state by the first driving circuit 31, and may control the second switch module 12 to be in an on state or an off state by the second driving circuit 32. The control module 61 may be a micro control unit (Microcontroller Unit, MCU).

The first switch module 11 may have a backflow preventing function to prevent current from flowing from the first battery to the inside of the DC/DC converter.

When the internal short circuit occurs in the DC/DC converter, the control module 61 or the first overcurrent protection circuit 41 detects that current flows from the first battery to the inside of the DC/DC converter through the first current sensor 21, and when the current reaches the overcurrent protection threshold, the control module 61 or the first overcurrent protection circuit 41 cuts off the driving of the first switch module 11, and the body diode of the first switch module 11 is used for cutting off the connection between the internal short circuit fault of the DC/DC converter and the external first battery, so that the ECU of the whole vehicle is prevented from losing power due to the fact that the first battery is pulled down, and the safety accident caused by out of control in the running process of the vehicle is avoided.

The first switch module 11 may have an anti-reverse connection function, and may prevent the reverse connection of the positive and negative poles of the first battery, and a short circuit may occur when the positive and negative poles of the first battery are reverse connected.

When the DC/DC converter is shorted externally or overloaded, the control module 61 or the second overcurrent protection circuit 42 detects that current flows from the inside of the DC/DC converter to the first battery through the first current sensor 21, and when the current reaches the overcurrent protection threshold, the drive of the second switch module 12 is disconnected, and the body diode of the second switch module 12 is used to disconnect the DC/DC converter from the shorted external or overloaded, so that the DC/DC converter can normally supply power to the ECU related to safety. Wherein the DC/DC converter may be provided with two supply loops (a first supply loop and a second supply loop) for supplying power to the ECU on the vehicle, e.g. the DC/DC converter may supply power to the safety-related ECU via the first supply loop and to the non-safety-related ECU via the second supply loop. The first power supply loop and the second power supply loop do not affect each other. When the DC/DC converter has external short circuit or overload, the DC/DC converter can disconnect the second power supply loop and conduct the first power supply loop. The ECU related to safety can be prevented from losing power supply, and safety accidents caused by out-of-control in the running process of the vehicle are avoided.

In this embodiment of the present application, the control module 61 and the over-current protection circuit (including the first over-current protection circuit 41 and the second over-current protection circuit 42) are redundant off paths, so as to increase the protection effectiveness.

The first current sensor 21 detects a current abnormality, including:

the first current sensor 21 detects a first current, and in the case where the current flow of the first current is the input port of the first battery to the output port of the DC/DC converter, and the first current is greater than a second threshold value, it is determined that the first current sensor 21 detects a current abnormality. At this time, the first overcurrent protection circuit 41 controls the first switch module 11 to be in the off state through the first driving circuit 31, and the control module 61 controls the first switch module 11 to be in the off state through the first driving circuit 31.

The first current sensor 21 detects a second current, and in the case where the current flow of the second current is the input port of the output port of the DC/DC converter to the first battery, and the second current is greater than a third threshold value, it is determined that the first current sensor 21 detects a current abnormality. At this time, the second overcurrent protection circuit 42 controls the second switch module 12 to be in the off state through the second driving circuit 32, and the control module 61 controls the second switch module 12 to be in the off state through the second driving circuit 32.

In the switch protection circuit 100 of the present embodiment, when the first current sensor 21 detects that the current is abnormal, the first overcurrent protection circuit 41 controls the first switch module 11 to be in the off state through the first driving circuit 31 and/or the second overcurrent protection circuit 42 controls the second switch module 12 to be in the off state through the second driving circuit 32, and the control module 61 controls the first switch module 11 to be in the off state through the first driving circuit 31 and/or controls the second switch module 12 of the switch protection circuit 100 to be in the off state through the second driving circuit 32. When a current abnormality is detected, the first switch module 11 and/or the second switch module 12 may be turned off by a hardware circuit (the first overcurrent protection circuit 41 and/or the second overcurrent protection circuit 42) on the one hand, and the first switch module 11 and the second switch module 12 may be turned off by a software module (the control module 61) on the other hand. When the hardware circuit fails, the control of the switch module can be realized through the software module under the condition of abnormal current, when the software module fails, the switch module can be closed through the hardware circuit under the condition of abnormal current, and when faults (such as abnormal current) occur, the power supply safety of the DC/DC converter can be improved.

Referring to fig. 3, fig. 3 is a schematic diagram of another switch protection circuit 100 according to an embodiment of the present application. Fig. 3 is further obtained on the basis of fig. 1. On the basis of fig. 1, the switch protection circuit 100 shown in fig. 3 further includes: a first voltage sensor 71 and a second voltage sensor 72; a first end of the first voltage sensor 71 is connected to an output port of the DC/DC converter, and a first end of the second voltage sensor 72 is connected to an input port of the first battery; a second end of the first voltage sensor 71 and a second end of the second voltage sensor 72 are grounded, a third end of the first voltage sensor 71 is connected to the second input end of the control module 61, and a third end of the second voltage sensor 72 is connected to the third input end of the control module 61;

in the case where the first voltage sensor 71 detects a voltage abnormality, the control module 61 controls the first switch module 11 to be in an off state through the first driving circuit 31, and controls the second switch module 12 to be in an off state through the second driving circuit 32; in the case where the second voltage sensor 72 detects a voltage abnormality, the control module 61 controls the second switch module 12 to be in an off state via the second driving circuit 32, and controls the first switch module 11 to be in an off state via the first driving circuit 31.

A first voltage sensor 71 for sampling the voltage of the output port of the DC/DC converter. The first voltage sensor 71 may be sampled by means of resistive voltage division.

A second voltage sensor 72 for sampling the voltage of the input port of the first battery. The second voltage sensor 72 may be sampled by means of resistive voltage division.

The first voltage sensor 71 detecting a voltage abnormality may include:

in the case where the first voltage sensor 71 detects a voltage less than the fourth threshold value, determining that the first voltage sensor 71 detects a voltage abnormality;

in the case where the first voltage sensor 71 detects that the voltage is greater than the eighth threshold value, it is determined that the first voltage sensor 71 detects a voltage abnormality.

The fourth threshold value may be set in advance. Wherein the fourth threshold value may be set to any value smaller than 10V if the internal voltage output from the DC/DC converter is 12V.

The eighth threshold may be set in advance. Wherein, if the internal voltage of the DC/DC converter output is 12V, the eighth threshold value may be set to any value greater than 14V.

The occurrence of an internal short circuit of the DC/DC converter can be detected quickly by the first voltage sensor 71 as compared with the first current sensor 21. The embodiment of the application can quickly detect the internal short circuit of the DC/DC converter through the first voltage sensor 71.

The detection of the voltage abnormality by the second voltage sensor 72 may include:

in the case where the second voltage sensor 72 detects a voltage less than the fifth threshold, determining that the second voltage sensor 72 detects a voltage abnormality;

in the case where the second voltage sensor 72 detects a voltage greater than the ninth threshold value, it is determined that the second voltage sensor 72 detects a voltage abnormality.

The fifth threshold may be set in advance. Wherein, if the voltage of the input port of the first battery is 12V, the fifth threshold may be set to any value less than 10V. The fifth threshold value and the fourth threshold value may be equal or unequal.

The ninth threshold may be set in advance. Wherein, if the voltage of the input port of the first battery is 12V, the ninth threshold may be set to any value greater than 14V.

The occurrence of an external short circuit or overload of the DC/DC converter can be detected rapidly by the second voltage sensor 72 compared to the first current sensor 21. The embodiment of the application can be used for quickly detecting the occurrence of external short circuit or overload of the DC/DC converter through the second voltage sensor 72.

Referring to fig. 4, fig. 4 is a schematic diagram of another switch protection circuit 100 according to an embodiment of the present application. Fig. 4 is further obtained on the basis of fig. 3. On the basis of fig. 3, the third output end of the control module 61 shown in fig. 4 is connected to the second input end of the first overcurrent protection circuit 41, and the fourth output end of the control module 61 is connected to the second input end of the second overcurrent protection circuit 42;

In the case where both the first switch module 11 and the second switch module 12 are turned on (when the DC/DC converter is not started or the output port voltage is smaller than the input port voltage of the first battery), the control module 61 injects a first fault signal into the first overcurrent protection circuit 41, and after the first fault signal is injected into the first overcurrent protection circuit 41, the control module 61 determines whether the first overcurrent protection circuit 41 is normal;

in the case where both the first switch module 11 and the second switch module 12 are turned on, the control module 61 injects a second fault signal into the second overcurrent protection circuit 42, and after the second fault signal is injected into the second overcurrent protection circuit 42, the control module 61 determines whether the second overcurrent protection circuit 42 is normal.

If the first and second

overcurrent protection circuits

41 and 42 fail, the reliability of the entire switch protection circuit 100 is affected. In the case where both the first switch module 11 and the second switch module 12 are turned on, the control module 61 injects the first fault signal into the first overcurrent protection circuit 41, and after the first fault signal is injected into the first overcurrent protection circuit 41, the first switch module 11 should be turned off, and if the first switch module 11 is detected to be turned off, the first overcurrent protection circuit 41 is considered to be normal without a fault; if it is detected that the second switch module 12 is still on, the first overcurrent protection circuit 41 is considered abnormal and a fault occurs.

According to the embodiment of the application, whether the overcurrent protection circuit is normal or not can be tested by injecting the fault signal into the overcurrent protection circuit, and the fault point of the switch protection circuit 100 can be accurately judged, so that the reliability of the switch protection circuit 100 is improved.

Optionally, the control module 61 determines whether the first overcurrent protection circuit 41 is normal, including:

the control module 61 determines whether the first overcurrent protection circuit 41 is normal or not according to a difference between the voltage signal detected by the first voltage sensor 71 and the voltage signal detected by the second voltage sensor 72;

the control module 61 determines whether the second overcurrent protection circuit 42 is normal, including:

the control module 61 determines whether the second overcurrent protection circuit 42 is normal according to a difference between the voltage signal detected by the first voltage sensor 71 and the voltage signal detected by the second voltage sensor 72.

In order to detect whether the first overcurrent protection circuit 41 is normal, the control module 61 injects a first fault signal into the first overcurrent protection circuit 41 in the case where both the first switch module 11 and the second switch module 12 are turned on, and after the first fault signal is injected into the first overcurrent protection circuit 41, the control module 61 determines whether the first overcurrent protection circuit 41 is normal. The control module 61 may determine whether the first overcurrent protection circuit 41 is normal according to a difference between the voltage signal detected by the first voltage sensor 71 and the voltage signal detected by the second voltage sensor 72. The first overcurrent protection circuit 41 may be considered to be normal if the difference is greater than the sixth threshold, and the first overcurrent protection circuit 41 may be considered to be abnormal if the difference is less than the sixth threshold. The sixth threshold may be set to any value less than 2V and greater than.

In order to detect whether the second overcurrent protection circuit 42 is normal, the control module 61 injects a second fault signal into the second overcurrent protection circuit 42 in the case where both the first switch module 11 and the second switch module 12 are turned on, and the control module 61 determines whether the second overcurrent protection circuit 42 is normal after the second fault signal is injected into the second overcurrent protection circuit 42. The control module 61 may determine whether the second overcurrent protection circuit 42 is normal according to a difference between the voltage signal detected by the first voltage sensor 71 and the voltage signal detected by the second voltage sensor 72. The second overcurrent protection circuit 42 can be considered normal if the difference is greater than the seventh threshold, and the second overcurrent protection circuit 42 can be considered abnormal if the difference is less than the sixth threshold. The seventh threshold may be set to any value less than 2V. The sixth threshold and the seventh threshold may be set in advance, and the sixth threshold may be equal to the seventh threshold or may be unequal.

In this embodiment, the control module 61 may accurately determine whether the first overcurrent protection circuit 41 is normal according to the difference between the voltage signal detected by the first voltage sensor 71 and the voltage signal detected by the second voltage sensor 72. The control module 61 can accurately determine whether the second overcurrent protection circuit 42 is normal according to the difference between the voltage signal detected by the first voltage sensor 71 and the voltage signal detected by the second voltage sensor 72.

Referring to fig. 5, fig. 5 is a schematic diagram of another switch protection circuit 100 according to an embodiment of the present application. Fig. 5 is further obtained on the basis of fig. 4. On the basis of fig. 4, a fourth input end of the control module 61 shown in fig. 5 is connected to an output end of the first overcurrent protection circuit 41, and a fifth input end of the control module 61 is connected to an output end of the second overcurrent protection circuit 42;

the control module 61 determines whether the first overcurrent protection circuit 41 is normal, including:

the control module 61 determines whether the first overcurrent protection circuit 41 is normal according to the output signal of the first overcurrent protection circuit 41;

the control module 61 determines whether the second overcurrent protection circuit 42 is normal according to the output signal of the second overcurrent protection circuit 42.

In this embodiment, in order to detect whether the first overcurrent protection circuit 41 is normal, the control module 61 injects a first fault signal into the first overcurrent protection circuit 41 when both the first switch module 11 and the second switch module 12 are turned on, and after the first fault signal is injected into the first overcurrent protection circuit 41, the control module 61 determines whether the first overcurrent protection circuit 41 is normal. The control module 61 may determine whether the first overcurrent protection circuit 41 is normal according to the output signal of the first overcurrent protection circuit 41. The first overcurrent protection circuit 41 can be considered normal if the output signal of the first overcurrent protection circuit 41 is the first drive off signal, and the first overcurrent protection circuit 41 can be considered abnormal if the output signal of the first overcurrent protection circuit 41 is not the first drive off signal. The first drive off signal is a signal for turning off the first drive circuit 31, and for example, the first drive off signal may be a level trigger signal (e.g., a high level trigger signal).

In order to detect whether the second overcurrent protection circuit 42 is normal, the control module 61 injects a second fault signal into the second overcurrent protection circuit 42 in the case where both the first switch module 11 and the second switch module 12 are turned on, and the control module 61 determines whether the second overcurrent protection circuit 42 is normal after the second fault signal is injected into the second overcurrent protection circuit 42. The control module 61 may determine whether the second overcurrent protection circuit 42 is normal according to the output signal of the second overcurrent protection circuit 42. The second overcurrent protection circuit 42 can be considered normal if the output signal of the second overcurrent protection circuit 42 is the second drive off signal, and the second overcurrent protection circuit 42 can be considered abnormal if the output signal of the second overcurrent protection circuit 42 is not the second drive off signal. The second driving turn-off signal is a signal for turning off the second driving circuit 32, and for example, the second driving turn-off signal may be a level trigger signal (e.g., a low level trigger signal).

In this embodiment, the control module 61 may determine whether the first overcurrent protection circuit 41 is normal according to the output signal of the first overcurrent protection circuit 41, and may directly determine whether the first overcurrent protection circuit 41 is normal. The control module 61 may determine whether the second overcurrent protection circuit 42 is normal according to the output signal of the second overcurrent protection circuit 42, and may directly determine whether the second overcurrent protection circuit 42 is normal.

Referring to fig. 6, fig. 6 is a schematic diagram of another switch protection circuit 100 according to an embodiment of the present application. Fig. 6 is further obtained on the basis of fig. 4. On the basis of fig. 4, a sixth input end of the control module 61 shown in fig. 6 is connected to an output end of the first driving circuit 31, and a seventh input end of the control module 61 is connected to an output end of the second driving circuit 32;

the control module 61 determines whether the first overcurrent protection circuit 41 is normal according to the output signal of the first driving circuit 31;

the control module 61 determines whether the second overcurrent protection circuit 42 is normal according to the output signal of the second driving circuit 32.

In this embodiment, in order to detect whether the first overcurrent protection circuit 41 is normal, the control module 61 injects a first fault signal into the first overcurrent protection circuit 41 when both the first switch module 11 and the second switch module 12 are turned on, and after the first fault signal is injected into the first overcurrent protection circuit 41, the control module 61 determines whether the first overcurrent protection circuit 41 is normal. The control module 61 determines whether the first overcurrent protection circuit 41 is normal according to the output signal of the first driving circuit 31. The first overcurrent protection circuit 41 can be considered normal if the output signal of the first drive circuit 31 is the first off signal, and the first overcurrent protection circuit 41 can be considered abnormal if the output signal of the first drive circuit 31 is not the first off signal. The first turn-off signal is a signal for turning off the first switch module 11, for example, if the first switch module 11 is a PMOS transistor, the first turn-off signal may be a high level signal (the high level signal may turn off the PMOS transistor).

In order to detect whether the second overcurrent protection circuit 42 is normal, the control module 61 injects a second fault signal into the second overcurrent protection circuit 42 in the case where both the first switch module 11 and the second switch module 12 are turned on, and the control module 61 determines whether the second overcurrent protection circuit 42 is normal after the second fault signal is injected into the second overcurrent protection circuit 42. The control module 61 determines whether the second overcurrent protection circuit 42 is normal according to the output signal of the second driving circuit 32. The second overcurrent protection circuit 42 can be considered normal if the output signal of the second drive circuit 32 is the second off signal, and the second overcurrent protection circuit 42 can be considered abnormal if the output signal of the second drive circuit 32 is not the second off signal. The second turn-off signal is a signal for turning off the second switch module 12, for example, if the second switch module 12 is an NMOS transistor, the second turn-off signal may be a low level signal (the low level signal may turn off the NMOS transistor).

In this embodiment, the control module 61 may determine whether the first overcurrent protection circuit 41 is normal according to the output signal of the first driving circuit 31, and may directly determine whether the first overcurrent protection circuit 41 is normal. The control module 61 may determine whether the second overcurrent protection circuit 42 is normal according to the output signal of the second driving circuit 32, and may directly determine whether the second overcurrent protection circuit 42 is normal.

Referring to fig. 7, fig. 7 is a schematic diagram of another switch protection circuit 100 according to an embodiment of the present application. Fig. 7 is further obtained on the basis of fig. 4. On the basis of fig. 4, the switch protection circuit 100 shown in fig. 7 further includes an over-voltage and under-voltage protection circuit 81, wherein a first input end of the over-voltage and under-voltage protection circuit 81 is connected to the third end of the first voltage sensor 71, a second input end of the over-voltage and under-voltage protection circuit 81 is connected to the third end of the second voltage sensor 72, a first output end of the over-voltage and under-voltage protection circuit 81 is connected to the first input end of the first power supply circuit 51, and a second output end of the over-voltage and under-voltage protection circuit 81 is connected to the first input end of the second power supply circuit 52;

in the case that the first voltage sensor 71 detects a voltage abnormality, the over-voltage and under-voltage protection circuit 81 sends a first power-off signal to the first power supply circuit 51, where the first power-off signal is used to turn off the power supply of the first driving circuit 31;

in the case where the second voltage sensor 72 detects a voltage abnormality, the over-voltage and under-voltage protection circuit 81 sends a second power-off signal for turning off the power supply of the first driving circuit 31 to the second power supply circuit 52.

The first voltage sensor 71 detecting a voltage abnormality may include:

in the case where the first voltage sensor 71 detects that the voltage is smaller than the fourth threshold value, it is determined that the first voltage sensor 71 detects a voltage abnormality.

The fourth threshold value may be set in advance. Wherein the fourth threshold value may be set to any value smaller than 10V if the output voltage of the DC/DC converter is 12V.

in the case where the second voltage sensor 72 detects a voltage smaller than the fifth threshold value, it is determined that the second voltage sensor 72 detects a voltage abnormality.

The fifth threshold may be set in advance. Wherein the fifth threshold may be set to any value less than 10V if the output voltage of the DC/DC converter is 12V. The fifth threshold value and the fourth threshold value may be equal or unequal.

In this embodiment, when the first voltage sensor 71 detects that the voltage is abnormal, under the condition that both the first overcurrent protection circuit 41 and the control module 61 fail, the first driving circuit 31 can be stopped by turning off the power supply of the first driving circuit 31, so that the first switch module 11 is turned off, and the safety risk caused by that the first switch module 11 is not turned off in time can be avoided under the condition that the first voltage sensor 71 detects that the voltage is abnormal. In the case that the second voltage sensor 72 detects the voltage abnormality, in the case that both the second overcurrent protection circuit 42 and the control module 61 fail, the second driving circuit 32 may be stopped by turning off the power supply of the second driving circuit 32, so as to turn off the second switch module 12, and the safety risk caused by the fact that the second switch module 12 is not turned off in time may be avoided in the case that the second voltage sensor 72 detects the voltage abnormality.

Referring to fig. 8, fig. 8 is a schematic diagram of another switch protection circuit 100 according to an embodiment of the present application. Fig. 8 is further obtained on the basis of fig. 7. On the basis of fig. 7, the switch protection circuit 100 shown in fig. 8 further includes a third voltage sensor 73 and an alarm device, a first end of the third voltage sensor 73 is connected to the second end of the first switch module 11, a second end of the third voltage sensor 73 is grounded, and a third end of the third voltage sensor 73 is connected to the eighth input end of the control module 61;

in case it is detected that the first switch module 11 is in an off-state (the first switch module 11 should be in an off-state), and the control module 61 detects that the voltage difference between the first and second ends of the first switch module 11 is smaller than a first threshold value, the control module 61 sends a first alarm signal to the alarm device, wherein the first alarm signal is used for triggering the alarm device to send out a first type of alarm, and the first type of alarm is used for prompting a driver that the first switch module 11 is abnormal;

in case it is detected that the first switch module 11 is in an on state (the first switch module 11 should be in an on state) and the control module 61 detects that the voltage difference between the first and the second end of the first switch module 11 is larger than the first threshold value, the control module 61 decreases the output power of the DC/DC converter and/or the control module 61 sends a second alarm signal to the alarm device; the second alarm signal is used for triggering the alarm device to send out a second type of alarm, and the second type of alarm is used for prompting a driver that the first switch module 11 is abnormal.

In this embodiment, the on-off state (on state or off state) of the first switch module 11 and the on-off state of the second switch module 12 may be determined by detecting the voltage drop at both ends of the first switch module 11 and the voltage drop at both ends of the second switch module 12 respectively.

When the switch module (the first switch module 11 or the second switch module 12) is required to perform the protection action (the switch module is turned off ), if the switch module is not turned off, the driver may be prompted to perform emergency treatment (for example, an alarm signal is sent to prompt the driver to manually turn off the switch module). For the first switch module 11, the triggering condition for sending out the first type alarm is that |vsample1-vsample3| divided by the current I is smaller than the on-resistance (Rdson) coefficient of the first switch module 11 (the first threshold is that the current I is that of the first switch module 11), and for the second switch module 12, the triggering condition for sending out the second type alarm is that |vsample2-vsample3| divided by the current I is smaller than the on-resistance (Rdson) coefficient of the second switch module 12, and the multiplying factor is that false triggering is avoided, so that a margin can be left according to the actual situation. Wherein the above coefficient is greater than or equal to 1.

When the switch module (the first switch module 11 or the second switch module 12) does not need to perform a protection action (to drive, close the switch module), if the switch module is not fully turned on, a large current output from the DC/DC converter flows to the body diode of the switch module, and eventually the switch module may be damaged. When this problem is detected, the output power of the DC/DC converter may be reduced and the driver may be notified to perform emergency treatment (for example, the driver manually turns on the switch module), and for the first switch module 11, the triggering condition is that |vsmple1-vsmple3| divided by the current I is greater than the on-resistance (Rdson) of the first switch module 11, and for the second switch module 12, the triggering condition is that |vsmple2-vsmple3| divided by the current I is greater than the on-resistance (Rdson) of the second switch module 12, and the multiplying factor is that false triggering is avoided, and a margin may be left according to the actual situation. Wherein the above coefficient is greater than or equal to 1.

Where Vsample1 is the voltage of the first end of the first switch module 11 sampled by the first voltage sensor 71, vsample3 is the voltage of the second end of the first switch module 11 sampled by the first voltage sensor 71 (i.e., the voltage of the first end of the second switch module 12), and Vsample2 is the voltage of the second end of the second switch module 12 sampled by the first voltage sensor 71. The current I is a current sampled by the first current sensor 21.

In this embodiment of the present application, the on-off state of the first switch module 11 and the on-off state of the second switch module 12 may be determined by detecting the voltage drop at two ends of the first switch module 11 and the voltage drop at two ends of the second switch module 12, so that the driver may be actively informed to perform emergency treatment, and the safety is further improved when the control of the switch module fails.

Optionally, referring to fig. 9, fig. 9 is a schematic diagram of another switch protection circuit 100 according to an embodiment of the present application. Fig. 9 is further obtained on the basis of fig. 7. On the basis of fig. 7, the switch protection circuit 100 shown in fig. 9 further includes a fourth voltage sensor 74, where a first end of the fourth voltage sensor 74 is connected to a target end, a second end of the fourth voltage sensor 74 is grounded, and a third end of the fourth voltage sensor 74 is connected to the ninth input end of the control module 61, and the target end includes any one of the first end of the first current sensor 21, the first end of the first switch module 11, the second end of the first switch module 11, and the second end of the second switch module 12. The target end in fig. 9 takes the second end of the second switch module 12 as an example.

In this embodiment, when the target terminal is the first terminal of the first current sensor 21, the control module 61 may compare the difference between the voltage sampled by the fourth voltage sensor 74 and the voltage sampled by the first voltage sensor 71 to determine whether the first voltage sensor 71 has a fault. In general, a small difference indicates no fault, and a large difference indicates a fault.

When the target terminal is the second terminal of the second switch module 12, the control module 61 may compare the difference between the voltage sampled by the fourth voltage sensor 74 and the voltage sampled by the second voltage sensor 72 to determine whether the second voltage sensor 72 has a fault. In general, a small difference indicates no fault, and a large difference indicates a fault.

The embodiment of the application can accurately judge whether the first voltage sensor 71 and the second voltage sensor 72 fail, thereby improving the safety of the switch protection circuit 100.

Optionally, referring to fig. 10, fig. 10 is a schematic structural diagram of another switch protection circuit 100 according to an embodiment of the present application. Fig. 10 is further obtained on the basis of fig. 9. On the basis of fig. 9, the switch protection circuit 100 shown in fig. 10 further includes a second current sensor 22, a first end of the second current sensor 22 is connected to the second end of the second switch module 12, a second end of the second current sensor 22 is connected to the input port of the first battery, and a third end of the second current sensor 22 is connected to the tenth input end of the control module 61.

In the embodiment of the present application, the current between the second end of the second switch module 12 and the input port of the first battery may be sampled by the second current sensor 22. In the case where both the first switch module 11 and the second switch module 12 are turned on, it is possible to determine whether or not the first current sensor 21 and the second current sensor 22 have failed by comparing the difference between the current sampled by the first current sensor 21 and the current sampled by the second current sensor 22. In general, a smaller difference indicates that no fault has occurred, and a larger difference indicates that at least one of the first current sensor 21 and the second current sensor 22 has failed. The accuracy of fault detection can be further improved.

Further, in the case where both the first switch module 11 and the second switch module 12 are turned on, it is possible to determine whether or not the first voltage sensor 71 and the second voltage sensor 72 have failed by comparing the difference between the voltage sampled by the first voltage sensor 71 and the voltage sampled by the second voltage sensor 72. In general, a smaller difference indicates no malfunction, and a larger difference indicates malfunction of at least one of the first voltage sensor 71 and the second voltage sensor 72. The accuracy of fault detection can be further improved.

Referring to fig. 11, fig. 11 is a schematic structural diagram of an electric vehicle according to an embodiment of the present application. As shown in fig. 11, the electric vehicle may include a switch protection circuit, a DC/DC converter, and a first battery, the DC/DC converter being connected to the first battery through the switch protection circuit.

The DC/DC converter takes electricity from the power battery, and after conversion, the power is supplied to the first battery and the ECU on the vehicle through the switch protection circuit.

In the foregoing embodiments, the descriptions of the embodiments are emphasized, and for parts of one embodiment that are not described in detail, reference may be made to related descriptions of other embodiments.

In several embodiments provided in the present application, it should be understood that the disclosed switch protection circuit and the vehicle-mounted dc conversion device may be implemented in other manners. For example, the above-described switch protection circuit embodiments are merely illustrative, such as the division of the units, merely a logical function division, and there may be additional divisions when actually implemented, such as multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed.

Claims

1. The switch protection circuit is characterized by comprising a first switch module, a second switch module, a first current sensor, a first driving circuit, a second driving circuit, a first overcurrent protection circuit, a second overcurrent protection circuit, a first power supply circuit, a second power supply circuit and a control module; the DC/DC converter is connected with the first battery through the switch protection circuit;

2. The switch protection circuit of claim 1, further comprising: a first voltage sensor and a second voltage sensor; a first end of the first voltage sensor is connected with an output port of the DC/DC converter, and a first end of the second voltage sensor is connected with an input port of the first battery; the second end of the first voltage sensor and the second end of the second voltage sensor are grounded, the third end of the first voltage sensor is connected with the second input end of the control module, and the third end of the second voltage sensor is connected with the third input end of the control module;

3. The switch protection circuit of claim 2, wherein a third output of the control module is connected to a second input of the first overcurrent protection circuit, and a fourth output of the control module is connected to a second input of the second overcurrent protection circuit;

4. The switch protection circuit of claim 3, wherein the control module determining whether the first over-current protection circuit is normal comprises:

5. A switch protection circuit according to claim 3, wherein a fourth input of the control module is connected to an output of the first overcurrent protection circuit, and a fifth input of the control module is connected to an output of the second overcurrent protection circuit;

6. A switch protection circuit according to claim 3, wherein a sixth input of the control module is connected to the output of the first drive circuit and a seventh input of the control module is connected to the output of the second drive circuit;

7. The switch protection circuit according to any one of claims 1 to 6, further comprising an over-voltage and under-voltage protection circuit, wherein a first input terminal of the over-voltage and under-voltage protection circuit is connected to a third terminal of the first voltage sensor, a second input terminal of the over-voltage and under-voltage protection circuit is connected to a third terminal of the second voltage sensor, a first output terminal of the over-voltage and under-voltage protection circuit is connected to a first input terminal of the first power supply circuit, and a second output terminal of the over-voltage and under-voltage protection circuit is connected to a first input terminal of the second power supply circuit;

8. The switch protection circuit of claim 7, further comprising a third voltage sensor and an alarm device, a first end of the third voltage sensor connected to the second end of the first switch module, a second end of the third voltage sensor grounded, a third end of the third voltage sensor connected to an eighth input of the control module;

9. The switch protection circuit of any one of claims 1-6, further comprising a fourth voltage sensor, a first end of the fourth voltage sensor connected to a target end, a second end of the fourth voltage sensor connected to ground, a third end of the fourth voltage sensor connected to a ninth input of the control module, the target end comprising any one of the first end of the first current sensor, the first end of the first switch module, the second end of the first switch module, and the second end of the second switch module;

the switch protection circuit further comprises a second current sensor, a first end of the second current sensor is connected with a second end of the second switch module, a second end of the second current sensor is connected with an input port of the first battery, and a third end of the second current sensor is connected with a tenth input end of the control module.

10. An electric vehicle comprising the switch protection circuit according to any one of claims 1 to 9, a DC/DC converter, and a first battery, the DC/DC converter being connected to the first battery through the switch protection circuit.