Switch protection circuit and electric vehicle

Abstract

The embodiment of the application provides a kind of switch protection circuit and electric automobile, the switch protection circuit includes first switch module, second switch module, first current sensor, first drive circuit, second drive circuit, first overcurrent protection circuit, second overcurrent protection circuit, power supply circuit and control module;DC / DC converter is connected with the first battery by switch protection circuit;In the case where first current sensor detects current anomaly, first overcurrent protection circuit controls first switch module to be in the off state by first drive circuit and / or second overcurrent protection circuit controls second switch module to be in the off state by second drive circuit, control module controls first switch module to be in the off state by first drive circuit and / or controls second switch module to be in the off state by second drive circuit.The embodiment of the application can improve the power supply safety of DC / DC converter.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, specifically to a switch protection circuit and an electric vehicle. Background Technology

[0002] In electric vehicle applications, the DC / DC converter on the vehicle powers low-voltage batteries (e.g., 12V batteries) and has high reliability requirements. With the development of electrification and intelligentization, the safety requirements for DC / DC converters are becoming increasingly stringent. Improving the power supply safety of DC / DC converters in the event of internal or external failures has become an urgent problem to be solved. Summary of the Invention

[0003] This application provides a switch protection circuit and an electric vehicle, which can improve the power supply safety of DC / DC converters.

[0004] A first aspect of this application provides a switch protection circuit, which includes a first switch module, a second switch module, a first current sensor, a first drive circuit, a second drive circuit, a first overcurrent protection circuit, a second overcurrent protection circuit, a power supply circuit, and a control module; a DC / DC converter is connected to a first battery through the switch protection circuit;

[0005] The output port of the DC / DC converter is connected to the first terminal of the first current sensor; the second terminal of the first current sensor is connected to the first terminal of the first switching module; the second terminal of the first switching module is connected to the first terminal of the second switching module; and the second terminal of the second switching module is connected to the input port of the first battery. The third terminal of the first current sensor is connected to the first input terminal of the first overcurrent protection circuit, the first input terminal of the second overcurrent protection circuit, and the first input terminal of the control module. The output terminal of the first overcurrent protection circuit is connected to the first input terminal of the first drive circuit; the output terminal of the second overcurrent protection circuit is connected to the first input terminal of the second drive circuit. The first output terminal of the control module is connected to the input terminal of the first drive circuit; the second output terminal of the control module is connected to the input terminal of the second drive circuit; the output terminal of the first drive circuit is connected to the third terminal of the first switching module; and the output terminal of the second drive circuit is connected to the third terminal of the second switching module. The power supply circuit supplies power to the first drive circuit and the second drive circuit.

[0006] When the first current sensor detects an abnormal current, the first overcurrent protection circuit controls the first switch module to be in an open state through the first drive circuit and / or the second overcurrent protection circuit controls the second switch module to be in an open state through the second drive circuit. The control module controls the first switch module to be in an open state through the first drive circuit and / or controls the second switch module to be in an open state through the second drive circuit.

[0007] Optionally, the switch protection circuit further includes: a first voltage sensor and a second voltage sensor; a first terminal of the first voltage sensor is connected to the output port of the DC / DC converter, and a first terminal of the second voltage sensor is connected to the input port of the first battery; the second terminals of the first voltage sensor and the second voltage sensor are grounded, and a third terminal of the first voltage sensor is connected to the second input terminal of the control module, and a third terminal of the second voltage sensor is connected to the third input terminal of the control module.

[0008] When the first voltage sensor detects an abnormal voltage, the control module controls the first switch module to be in an open state via the first drive circuit; when the second voltage sensor detects an abnormal voltage, the control module controls the second switch module to be in an open state via the second drive circuit.

[0009] Optionally, the third output terminal of the control module is connected to the second input terminal of the first overcurrent protection circuit, and the fourth output terminal of the control module is connected to the second input terminal of the second overcurrent protection circuit.

[0010] When both the first switch module and the second switch module are turned on, the control module injects a first fault signal into the first overcurrent protection circuit. 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.

[0011] When both the first and second switch modules are turned on, the control module injects a second fault signal into the second overcurrent protection circuit. 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.

[0012] Optionally, the control module determines whether the first overcurrent protection circuit is functioning properly, including:

[0013] The control module determines whether the first overcurrent protection circuit is functioning properly based on the difference between the voltage signal detected by the first voltage sensor and the voltage signal detected by the second voltage sensor.

[0014] The control module determines whether the second overcurrent protection circuit is functioning properly, including:

[0015] The control module determines whether the second overcurrent protection circuit is functioning properly based on the difference between the voltage signal detected by the first voltage sensor and the voltage signal detected by the second voltage sensor.

[0016] Optionally, the fourth input terminal of the control module is connected to the output terminal of the first overcurrent protection circuit, and the fifth input terminal of the control module is connected to the output terminal of the second overcurrent protection circuit.

[0017] The control module determines whether the first overcurrent protection circuit is functioning properly, including:

[0018] The control module determines whether the first overcurrent protection circuit is functioning properly based on the output signal of the first overcurrent protection circuit.

[0019] The control module determines whether the second overcurrent protection circuit is functioning properly, including:

[0020] The control module determines whether the second overcurrent protection circuit is functioning properly based on the output signal of the second overcurrent protection circuit.

[0021] Optionally, the sixth input terminal of the control module is connected to the output terminal of the first driving circuit, and the seventh input terminal of the control module is connected to the output terminal of the second driving circuit.

[0022] The control module determines whether the first overcurrent protection circuit is functioning properly, including:

[0023] The control module determines whether the first overcurrent protection circuit is functioning properly based on the output signal of the first drive circuit.

[0024] The control module determines whether the second overcurrent protection circuit is functioning properly, including:

[0025] The control module determines whether the second overcurrent protection circuit is functioning properly based on the output signal of the second drive circuit.

[0026] Optionally, the switch protection circuit further includes an over / under voltage protection circuit, wherein the first input terminal of the over / under voltage protection circuit is connected to the third terminal of the first voltage sensor, the second input terminal of the over / under voltage protection circuit is connected to the third terminal of the second voltage sensor, and the output terminal of the over / under voltage protection circuit is connected to the input terminal of the power supply circuit.

[0027] If the first voltage sensor detects a voltage abnormality or the second voltage sensor detects a voltage abnormality, the over / under voltage protection circuit sends a power-off signal to the power supply circuit. The power-off signal is used to shut off the power supply to the first drive circuit and the second drive circuit.

[0028] Optionally, the switch protection circuit further includes a third voltage sensor and an alarm device. The first end of the third voltage sensor is connected to the second end of the first switch module, the second end of the third voltage sensor is grounded, and the third end of the third voltage sensor is connected to the eighth input terminal of the control module.

[0029] When the control module detects that the first switch module is in an open state and that the voltage difference between the first and second terminals of the first switch module is less than a first threshold, the control module sends a first alarm signal to the alarm device. The first alarm signal is used to trigger the alarm device to issue a first type of alarm, which is used to alert the driver that the first switch module is abnormal. The first threshold is: current I * on-resistance of the first switch module * coefficient, where current I is the current value sampled by the first current sensor, and the coefficient is greater than or equal to 1.

[0030] When the control module detects that the first switch module is in a conducting state and detects that the voltage difference between the first and second terminals of the first switch module is greater than the first threshold, the control module reduces the output power of the DC / DC converter and / or the control module sends a second alarm signal to the alarm device; wherein, the second alarm signal is used to trigger the alarm device to issue a second type of alarm, and the second type of alarm is used to indicate to the driver that the first switch module is abnormal.

[0031] Optionally, the switch protection circuit further includes a fourth voltage sensor, the first end of which is connected to the target terminal, the second end of which is grounded, and the third end of which is connected to the ninth input terminal of the control module. The target terminal includes 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.

[0032] Optionally, the first switching module includes M switching transistors connected in parallel, and the second switching module includes N switching transistors connected in parallel, where M and N are both positive integers. The negative terminals of the parasitic diodes of the M switching transistors are connected to the negative terminals of the parasitic diodes of the N switching transistors.

[0033] Optionally, the first current sensor detects an abnormal current, including:

[0034] The first current sensor detects a first current. If the direction of the first current is from 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, it is determined that the first current sensor has detected an abnormal current.

[0035] The first current sensor detects a second current. If the direction of the second current is from the output port of the DC / DC converter to the input port of the first battery, and the second current is greater than a third threshold, the first current sensor determines that it has detected an abnormal current.

[0036] Optionally, the switch protection circuit further includes a second current sensor, the first end of which is connected to the second end of the second switch module, the second end of which is connected to the input port of the first battery, and the third end of which is connected to the tenth input terminal of the control module.

[0037] A second aspect of this application provides an electric vehicle, including a switch protection circuit, a DC / DC converter, and a first battery as described in any of the first aspects of this application, wherein the DC / DC converter is connected to the first battery through the switch protection circuit.

[0038] In this embodiment of the switch protection circuit, when the first current sensor detects an abnormal current, the first overcurrent protection circuit controls the first switch module to be in an open state via the first drive circuit, and / or the second overcurrent protection circuit controls the second switch module to be in an open state via the second drive circuit. The switch protection circuit control module controls the first switch module to be in an open state via the first drive circuit, and / or the second switch module to be in an open state via the second drive circuit. When an abnormal current is detected, the first and / or second switch modules can be turned off via hardware circuits (the first and / or second overcurrent protection circuits), or via software modules (the control module). In the event of a hardware circuit failure, the switch module can be controlled via software in the event of an abnormal current. Conversely, in the event of a software module failure, the switch module can be turned off via hardware circuits in the event of an abnormal current. This improves the power supply safety of the DC / DC converter in the event of a fault (e.g., an abnormal current). Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of a switch protection circuit provided in an embodiment of this application;

[0041] Figure 2a This is a schematic diagram of the structure of an isolated DC / DC converter provided in an embodiment of this application;

[0042] Figure 2b This is a schematic diagram of the structure of a non-isolated DC / DC converter provided in an embodiment of this application;

[0043] Figure 3 This is a schematic diagram of another switch protection circuit provided in an embodiment of this application;

[0044] Figure 4 This is a schematic diagram of another switch protection circuit provided in an embodiment of this application;

[0045] Figure 5 This is a schematic diagram of another switch protection circuit provided in an embodiment of this application;

[0046] Figure 6 This is a schematic diagram of another switch protection circuit provided in an embodiment of this application;

[0047] Figure 7 This is a schematic diagram of another switch protection circuit provided in an embodiment of this application;

[0048] Figure 8 This is a schematic diagram of another switch protection circuit provided in an embodiment of this application;

[0049] Figure 9 This is a schematic diagram of another switch protection circuit provided in an embodiment of this application;

[0050] Figure 10 This is a schematic diagram of another switch protection circuit provided in an embodiment of this application;

[0051] Figure 11 This is a schematic diagram of the structure of an electric vehicle provided in an embodiment of this application. Detailed Implementation

[0052] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0053] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, system, product, or apparatus that comprises a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, products, or apparatuses.

[0054] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0055] Please see Figure 1 , Figure 1 This is a schematic diagram of a switch protection circuit provided in an embodiment of this application. Figure 1 As shown, the switch protection circuit 100 may include a first switch module 11, a second switch module 12, a first current sensor 21, a first drive circuit 31, a second drive circuit 32, a first overcurrent protection circuit 41, a second overcurrent protection circuit 42, a power supply circuit 51, and a control module 61; the DC / DC converter is connected to the first battery through the switch protection circuit 100.

[0056] The output port of the DC / DC converter is connected to the first terminal of the first current sensor 21. The second terminal of the first current sensor 21 is connected to the first terminal of the first switching module 11. The second terminal of the first switching module 11 is connected to the first terminal of the second switching module 12. The second terminal of the second switching module 12 is connected to the input port of the first battery. The third terminal of the first current sensor 21 is connected to the first input terminal of the first overcurrent protection circuit 41, the first input terminal of the second overcurrent protection circuit 42, and the first input terminal of the control module 61. The output terminal of the first overcurrent protection circuit 41 is connected to the first input terminal of the first drive circuit 31. The output terminal of the second overcurrent protection circuit 42 is connected to the first input terminal of the second drive circuit 32. The first output terminal of the control module 61 is connected to the input terminal of the first drive circuit 31. The second output terminal of the control module 61 is connected to the input terminal of the second drive circuit 32. The output terminal of the first drive circuit 31 is connected to the third terminal of the first switching module 11. The output terminal of the second drive circuit 32 is connected to the third terminal of the second switching module 12. The power supply circuit 51 supplies power to the first drive circuit 31 and the second drive circuit 32. The first switching module 11 and the second switching module 12 are the same type of switching transistors.

[0057] When the first current sensor 21 detects an abnormal current, the first overcurrent protection circuit 41 controls the first switch module 11 to be in the off state through the first drive 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 drive circuit 32. The control module 61 controls the first switch module 11 to be in the off state through the first drive circuit 31 and / or controls the second switch module 12 to be in the off state through the second drive circuit 32.

[0058] The switch protection circuit 100 can be a component of the DC / DC converter or a stand-alone circuit.

[0059] A DC-DC converter, also known as a DC-DC converter, is a device that converts a DC power source into another DC voltage. A DC-DC converter can convert high voltage to low voltage and vice versa.

[0060] DC / DC converters can also be divided into isolated DC / DC converters (such as...) Figure 2a (as shown) and non-isolated DC / DC converters (such as Figure 2b(As shown). The isolated DC / DC converter includes an isolation transformer that enables electrical isolation between the high-voltage battery and the low-voltage battery (first battery).

[0061] A DC / DC converter can be either a unidirectional or bidirectional converter. A unidirectional DC / DC converter can perform unidirectional DC / DC conversion; for example, it can convert the high voltage from the high-voltage battery side to a low voltage to power the low-voltage battery. A bidirectional DC / DC converter can perform bidirectional DC / DC conversion; for example, it can convert the high voltage from the high-voltage battery side to a low voltage to power the low-voltage battery, and vice versa.

[0062] The DC / DC converter draws power from the high-voltage battery (also known as the power battery) and converts it to power the low-voltage battery (the primary battery) and the vehicle's electronic control unit (ECU). The low-voltage battery can be a lead-acid battery or a lithium battery, and its voltage is generally around 12V. The ECU can include the vehicle's infotainment system, music player, windshield wipers, etc.

[0063] The first current sensor 21 is used to sample the current output by the DC / DC converter; if the DC / DC converter is a bidirectional DC / DC converter, it can sample bidirectional current. The first current sensor 21 can be a Hall sensor or a sampling resistor plus an operational amplifier for sampling.

[0064] The first switching module 11 includes M switching transistors connected in parallel, and the second switching module 12 includes N switching transistors connected in parallel, where M and N are both positive integers. The negative terminals of the parasitic diodes of the M switching transistors are connected to the negative terminals of the parasitic diodes of the N switching transistors. A parasitic diode can also be called a body diode.

[0065] The first switch module 11 and the second switch module 12 can each represent a single switch transistor, or multiple switch transistors connected in parallel. Figure 1 The first switching module 11 and the second switching module 12 are illustrated using a single switching transistor as an example. The switching transistor can include a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), which can be simply referred to as a MOS transistor. Since the power supply circuit 51 needs to supply power to both the first driving circuit 31 and the second driving circuit 32 simultaneously, to ensure the driving effect of both circuits, the first switching module 11 and the second switching module 12 use the same type of switching transistor. For example... Figure 1As shown, the first switching module 11 can use an N-channel MOSFET, and the second switching module 12 can also use an N-channel MOSFET; alternatively, the first switching module 11 can use a P-channel MOSFET, and the second switching module 12 can also use a P-channel MOSFET. The body diodes of the first switching module 11 and the second switching module 12 are back-to-back (e.g., Figure 1 As shown, the positive terminal of the body diode of the first switching module 11 is connected to the positive terminal of the body diode of the second switching module 12, which can achieve bidirectional protection. When both the first switching module 11 and the second switching module 12 use N-channel MOSFETs, their source (S) terminals are connected. That is, the second terminal of the first switching module 11 is the S terminal, and the first terminal of the second switching module 12 is the S terminal; the first terminal of the first switching module 11 is the D terminal, and the second terminal of the second switching module 12 is the D terminal; the third terminal of the first switching module 11 is the G terminal, and the third terminal of the second switching module 12 is the G terminal.

[0066] It should be noted that the driving circuit for a P-channel MOSFET is different from that for an N-channel MOSFET.

[0067] The power supply circuit 51 is used to supply power to the first drive circuit 31 and the second drive circuit 32. The power supply circuit 51 can be powered by a bootstrap circuit or an auxiliary power supply.

[0068] The power supply circuit 51 can draw power from any one of the first end of the first current sensor 21, the first end of the first switch module 11, and the second end of the second switch module 12. Figure 1 The power supply circuit 51 draws power from the first terminal of the second switch module 12.

[0069] The first output terminal of the power supply circuit 51 is connected to the power supply terminal of the first drive circuit 31, and the second output terminal of the power supply circuit 51 is connected to the power supply terminal of the second drive circuit 32.

[0070] When the first driving circuit 31 and the second driving circuit 32 require the same power supply voltage, the voltage output from the first output terminal of the power supply circuit 51 can be equal to the voltage output from the second output terminal of the power supply circuit 51, both being equal to the power supply voltage of the first driving circuit 31 and the second driving circuit 32.

[0071] When the first driving circuit 31 and the second driving circuit 32 require different power supply voltages, the voltage output from the first output terminal of the power supply circuit 51 may be different from the voltage output from the second output terminal of the power supply circuit 51. The voltage output from the first output terminal of the power supply circuit 51 is equal to the power supply voltage required by the first driving circuit 31, and the voltage output from the second output terminal of the power supply circuit 51 is equal to the power supply voltage required by the second driving circuit 32. In this embodiment, one power supply circuit can power two driving circuits, reducing the number of power supply circuits required, simplifying the structure of the switch protection circuit, reducing the size of the switch protection circuit, and facilitating integration.

[0072] The first driving circuit 31 is used to drive the first switching module 11. The control module 61 can control the optocoupler in the first driving circuit 31, so that the first driving circuit 31 provides drive to the first switching module 11. The first driving circuit 31 can also provide drive to the first switching module 11 using an isolated driving method.

[0073] The second drive circuit 32 is used to drive the second switch module 12. The control module 61 can control the optocoupler in the second drive circuit 32, so that the second drive circuit 32 provides drive to the second switch module 12. The second drive circuit 32 can also provide drive to the second switch module 12 using an isolated drive method.

[0074] Overcurrent protection circuit, also known as short-circuit protection circuit.

[0075] When the DC / DC converter operates in reverse (current flows from the first battery to the DC / DC converter), if the current is too large, the first overcurrent protection circuit 41 will generate a protection signal to shut down the first switching module 11, thereby cutting off the reverse current. The first overcurrent protection circuit 41 can be implemented using a comparator or a precision voltage reference integrated circuit (e.g., TC431). A large reverse current will be generated when an internal short circuit occurs in the DC / DC converter.

[0076] When the DC / DC converter is operating in the forward direction (current flows from the DC / DC converter to the first battery), if the current is too high, the second overcurrent protection circuit 42 will generate a protection signal to shut down the second switching module 12, thereby cutting off the forward current. The second overcurrent protection circuit 42 can be implemented using a comparator or a precision voltage reference integrated circuit (e.g., TC431). The forward current will become excessive when the DC / DC converter experiences an external short circuit or is overloaded.

[0077] The control module 61 can obtain the current sampling results from the current sensor and execute the protection logic of the software. For example, the control module 61 can control the first switch module 11 to be in a conducting or disconnected state through the first drive circuit 31, and can control the second switch module 12 to be in a conducting or disconnected state through the second drive circuit 32. The control module 61 can be a microcontroller unit (MCU).

[0078] The first switch module 11 may have an anti-backflow function to prevent current from flowing from the first battery into the internal workings of the DC / DC converter.

[0079] When an internal short circuit occurs in the DC / DC converter, the control module 61 or the first overcurrent protection circuit 41 detects current flowing from the first battery to the inside of the DC / DC converter through the first current sensor 21. When the current reaches the overcurrent protection threshold, the control module 61 or the first overcurrent protection circuit 41 disconnects the drive of the first switch module 11 and uses the body diode of the first switch module 11 to cut off the connection between the internal short circuit fault of the DC / DC converter and the external first battery, so as to avoid the first battery being pulled down and causing the ECU of the whole vehicle to lose power, thus avoiding the loss of control of the vehicle during driving and causing a safety accident.

[0080] The first switch module 11 can have a reverse connection protection function, which can prevent the positive and negative terminals of the first battery from being reversed. When the positive and negative terminals of the first battery are reversed, a short circuit will occur.

[0081] When an external short circuit or overload occurs in the DC / DC converter, the control module 61 or the second overcurrent protection circuit 42 detects current flowing from the DC / DC converter's interior to the first battery via the first current sensor 21. When the current reaches the overcurrent protection threshold, the drive of the second switching module 12 is disconnected. The body diode of the second switching module 12 cuts off the connection between the DC / DC converter and the external short-circuit or overload, ensuring that the DC / DC converter can still supply power to safety-related ECUs. The DC / DC converter can be configured with two power supply circuits (a first power supply circuit and a second power supply circuit) to power the vehicle's ECUs. For example, the DC / DC converter can supply power to safety-related ECUs through the first power supply circuit and to non-safety-related ECUs through the second power supply circuit. The first and second power supply circuits do not affect each other. When an external short circuit or overload occurs in the DC / DC converter, the DC / DC converter can disconnect the second power supply circuit and connect the first power supply circuit. This prevents safety-related ECUs from losing power, thus preventing loss of control and potential safety accidents during vehicle operation.

[0082] In this embodiment, the control module 61 and the overcurrent protection circuit (including the first overcurrent protection circuit 41 and the second overcurrent protection circuit 42) are redundant shutdown paths, which increases the effectiveness of protection.

[0083] The first current sensor 21 detected an abnormal current, including:

[0084] The first current sensor 21 detects a first current. If the current flows from 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, the first current sensor 21 determines that an abnormal current has been detected. At this time, the first overcurrent protection circuit 41 controls the first switch module 11 to be in the off state through the first drive circuit 31, and the control module 61 controls the first switch module 11 to be in the off state through the first drive circuit 31.

[0085] The first current sensor 21 detects a second current. If the direction of the second current is from the output port of the DC / DC converter to the input port of the first battery, and the second current is greater than a third threshold, the first current sensor 21 determines that an abnormal current has been detected. At this time, the second overcurrent protection circuit 42 controls the second switch module 12 to be in the off state through the second drive circuit 32, and the control module 61 controls the second switch module 12 to be in the off state through the second drive circuit 32.

[0086] In this embodiment of the switch protection circuit 100, when the first current sensor 21 detects an abnormal current, the first overcurrent protection circuit 41 controls the first switch module 11 to be in an open state through the first drive circuit 31 and / or the second overcurrent protection circuit 42 controls the second switch module 12 to be in an open state through the second drive circuit 32. The control module 61 controls the first switch module 11 to be in an open state through the first drive circuit 31 and / or controls the second switch module 12 to be in an open state through the second drive circuit 32. When an abnormal current is detected, the first switch module 11 and / or the second switch module 12 can be turned off through hardware circuits (first overcurrent protection circuit 41 and / or second overcurrent protection circuit 42), or through software modules (control module 61). In the event of a hardware circuit failure, the switch modules can be controlled by the software module in the case of an abnormal current. In the event of a software module failure, the switch modules can be turned off by the hardware circuit in the case of an abnormal current. This improves the power supply safety of the DC / DC converter in the event of a fault (e.g., an abnormal current).

[0087] Please see Figure 3 , Figure 3 This is a schematic diagram of another switch protection circuit 100 provided in an embodiment of this application. Figure 3 Is Figure 1 This was further derived from [the previous work]. Figure 1 On this basis, Figure 3 The switch protection circuit 100 shown further includes: a first voltage sensor 71 and a second voltage sensor 72; the first end of the first voltage sensor 71 is connected to the output port of the DC / DC converter, and the first end of the second voltage sensor 72 is connected to the input port of the first battery; the second ends of the first voltage sensor 71 and the second end of the second voltage sensor 72 are grounded, the third end of the first voltage sensor 71 is connected to the second input terminal of the control module 61, and the third end of the second voltage sensor 72 is connected to the third input terminal of the control module 61;

[0088] When the first voltage sensor 71 detects an abnormal voltage, the control module 61 controls the first switch module 11 to be in an open state through the first drive circuit 31 and controls the second switch module 12 to be in an open state through the second drive circuit 32; when the second voltage sensor 72 detects an abnormal voltage, the control module 61 controls the second switch module 12 to be in an open state through the second drive circuit 32 and controls the first switch module 11 to be in an open state through the first drive circuit 31.

[0089] The first voltage sensor 71 is used to sample the voltage at the output port of the DC / DC converter. The first voltage sensor 71 can sample the voltage using a resistor divider method.

[0090] The second voltage sensor 72 is used to sample the voltage at the input port of the first battery. The second voltage sensor 72 can sample the voltage using a resistor divider method.

[0091] The first voltage sensor 71 detects a voltage abnormality, which may include:

[0092] If the first voltage sensor 71 detects a voltage lower than the fourth threshold, it is determined that the first voltage sensor 71 has detected a voltage anomaly.

[0093] If the first voltage sensor 71 detects a voltage greater than the eighth threshold, it is determined that the first voltage sensor 71 has detected a voltage anomaly.

[0094] The fourth threshold can be preset. Specifically, if the internal voltage output by the DC / DC converter is 12V, the fourth threshold can be set to any value less than 10V.

[0095] The eighth threshold can be preset. Specifically, if the internal voltage output by the DC / DC converter is 12V, the eighth threshold can be set to any value greater than 14V.

[0096] Compared to the first current sensor 21, the first voltage sensor 71 can quickly detect an internal short circuit in the DC / DC converter. This embodiment of the application can quickly detect an internal short circuit in the DC / DC converter using the first voltage sensor 71.

[0097] The second voltage sensor 72 detects a voltage abnormality and may include:

[0098] If the second voltage sensor 72 detects a voltage lower than the fifth threshold, it is determined that the second voltage sensor 72 has detected a voltage anomaly.

[0099] If the second voltage sensor 72 detects a voltage greater than the ninth threshold, it is determined that the second voltage sensor 72 has detected a voltage anomaly.

[0100] The fifth threshold can be preset. Specifically, if the voltage at the input port of the first battery is 12V, the fifth threshold can be set to any value less than 10V. The fifth threshold can be equal to or different from the fourth threshold.

[0101] The ninth threshold can be preset. Specifically, if the voltage at the input port of the first battery is 12V, the ninth threshold can be set to any value greater than 14V.

[0102] Compared to the first current sensor 21, the second voltage sensor 72 can quickly detect external short circuits or overloads in the DC / DC converter. This embodiment of the application can quickly detect external short circuits or overloads in the DC / DC converter using the second voltage sensor 72.

[0103] Please see Figure 4 , Figure 4 This is a schematic diagram of another switch protection circuit 100 provided in an embodiment of this application. Figure 4 Is Figure 3 This was further derived from [the previous work]. Figure 3 On this basis, Figure 4 The third output terminal of the control module 61 shown is connected to the second input terminal of the first overcurrent protection circuit 41, and the fourth output terminal of the control module 61 is connected to the second input terminal of the second overcurrent protection circuit 42.

[0104] When 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 less 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. 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.

[0105] When 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. 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.

[0106] If the first overcurrent protection circuit 41 and the second overcurrent protection circuit 42 malfunction, the reliability of the entire switch protection circuit 100 will be affected. When both the first switch module 11 and the second switch module 12 are on, the control module 61 injects a first fault signal into the first overcurrent protection circuit 41. After the first fault signal is injected into the first overcurrent protection circuit 41, the first switch module 11 should be turned off. If the first switch module 11 is detected to be off, the first overcurrent protection circuit 41 is considered normal and without fault; if the second switch module 12 is detected to still be on, the first overcurrent protection circuit 41 is considered abnormal and has malfunctioned.

[0107] In this embodiment of the application, the overcurrent protection circuit can be tested for normal operation by injecting a fault signal into it. This allows for accurate identification of the fault location in the switch protection circuit 100, thereby improving the reliability of the switch protection circuit 100.

[0108] Optionally, the control module 61 determines whether the first overcurrent protection circuit 41 is functioning properly, including:

[0109] The control module 61 determines whether the first overcurrent protection circuit 41 is normal based on the difference between the voltage signal detected by the first voltage sensor 71 and the voltage signal detected by the second voltage sensor 72.

[0110] The control module 61 determines whether the second overcurrent protection circuit 42 is functioning properly, including:

[0111] The control module 61 determines whether the second overcurrent protection circuit 42 is normal based on the difference between the voltage signal detected by the first voltage sensor 71 and the voltage signal detected by the second voltage sensor 72.

[0112] To detect whether the first overcurrent protection circuit 41 is functioning correctly, with both the first switch module 11 and the second switch module 12 turned on, the control module 61 injects a first fault signal into the first overcurrent protection circuit 41. After injecting the first fault signal, the control module 61 determines whether the first overcurrent protection circuit 41 is functioning correctly. The control module 61 can determine whether the first overcurrent protection circuit 41 is functioning correctly based on the difference between the voltage signal detected by the first voltage sensor 71 and the voltage signal detected by the second voltage sensor 72. If the difference is greater than a sixth threshold, the first overcurrent protection circuit 41 is considered to be functioning correctly; if the difference is less than the sixth threshold, the first overcurrent protection circuit 41 is considered to be malfunctioning. The sixth threshold can be set to any value less than 2V and greater than a specified value.

[0113] To detect whether the second overcurrent protection circuit 42 is functioning correctly, with both the first switch module 11 and the second switch module 12 conducting, the control module 61 injects a second fault signal into the second overcurrent protection circuit 42. 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 functioning correctly. The control module 61 can determine whether the second overcurrent protection circuit 42 is functioning correctly based on the difference between the voltage signal detected by the first voltage sensor 71 and the voltage signal detected by the second voltage sensor 72. If the difference is greater than a seventh threshold, the second overcurrent protection circuit 42 is considered to be functioning correctly; if the difference is less than a sixth threshold, the second overcurrent protection circuit 42 is considered to be malfunctioning. The seventh threshold can be set to any value less than 2V. The sixth and seventh thresholds can be preset; the sixth threshold can be equal to or different from the seventh threshold.

[0114] In this embodiment, the control module 61 can accurately determine whether the first overcurrent protection circuit 41 is functioning correctly based on the difference between the voltage signal detected by the first voltage sensor 71 and the voltage signal detected by the second voltage sensor 72. Similarly, the control module 61 can accurately determine whether the second overcurrent protection circuit 42 is functioning correctly based on the difference between the voltage signal detected by the first voltage sensor 71 and the voltage signal detected by the second voltage sensor 72.

[0115] Please see Figure 5 , Figure 5 This is a schematic diagram of another switch protection circuit 100 provided in an embodiment of this application. Figure 5 Is Figure 4 This was further derived from [the previous work]. Figure 4 On this basis, Figure 5 The fourth input terminal of the control module 61 shown is connected to the output terminal of the first overcurrent protection circuit 41, and the fifth input terminal of the control module 61 is connected to the output terminal of the second overcurrent protection circuit 42.

[0116] The control module 61 determines whether the first overcurrent protection circuit 41 is functioning properly, including:

[0117] The control module 61 determines whether the first overcurrent protection circuit 41 is functioning properly based on the output signal of the first overcurrent protection circuit 41.

[0118] The control module 61 determines whether the second overcurrent protection circuit 42 is functioning properly, including:

[0119] The control module 61 determines whether the second overcurrent protection circuit 42 is functioning properly based on the output signal of the second overcurrent protection circuit 42.

[0120] In this embodiment, to detect whether the first overcurrent protection circuit 41 is functioning correctly, when both the first switch module 11 and the second switch module 12 are turned on, the control module 61 injects a first fault signal into the first overcurrent protection circuit 41. 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 functioning correctly. The control module 61 can determine whether the first overcurrent protection circuit 41 is functioning correctly based on its output signal. If the output signal of the first overcurrent protection circuit 41 is a first drive shutdown signal, the first overcurrent protection circuit 41 is considered to be functioning correctly; if the output signal of the first overcurrent protection circuit 41 is not a first drive shutdown signal, the first overcurrent protection circuit 41 is considered to be functioning incorrectly. The first drive shutdown signal is a signal used to turn off the first drive circuit 31. For example, the first drive shutdown signal can be a level trigger signal (e.g., a high-level trigger signal).

[0121] To detect whether the second overcurrent protection circuit 42 is functioning correctly, with both the first switch module 11 and the second switch module 12 on, the control module 61 injects a second fault signal into the second overcurrent protection circuit 42. 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 functioning correctly. The control module 61 can determine whether the second overcurrent protection circuit 42 is functioning correctly based on its output signal. If the output signal of the second overcurrent protection circuit 42 is a second drive shutdown signal, the second overcurrent protection circuit 42 is considered to be functioning correctly; if the output signal of the second overcurrent protection circuit 42 is not a second drive shutdown signal, the second overcurrent protection circuit 42 is considered to be functioning incorrectly. The second drive shutdown signal is a signal used to shut down the second drive circuit 32; for example, the second drive shutdown signal can be a level-triggered signal (e.g., a high-level trigger signal).

[0122] In this embodiment, the control module 61 can determine whether the first overcurrent protection circuit 41 is functioning properly based on the output signal of the first overcurrent protection circuit 41, and can directly determine whether the first overcurrent protection circuit 41 is functioning properly. Similarly, the control module 61 can determine whether the second overcurrent protection circuit 42 is functioning properly based on the output signal of the second overcurrent protection circuit 42, and can directly determine whether the second overcurrent protection circuit 42 is functioning properly.

[0123] Please see Figure 6 , Figure 6 This is a schematic diagram of another switch protection circuit 100 provided in an embodiment of this application. Figure 6 Is Figure 4 This was further derived from [the previous work]. Figure 4 On this basis, Figure 6 The sixth input terminal of the control module 61 shown is connected to the output terminal of the first drive circuit 31, and the seventh input terminal of the control module 61 is connected to the output terminal of the second drive circuit 32.

[0124] The control module 61 determines whether the first overcurrent protection circuit 41 is functioning properly, including:

[0125] The control module 61 determines whether the first overcurrent protection circuit 41 is normal based on the output signal of the first drive circuit 31.

[0126] The control module 61 determines whether the second overcurrent protection circuit 42 is functioning properly, including:

[0127] The control module 61 determines whether the second overcurrent protection circuit 42 is normal based on the output signal of the second drive circuit 32.

[0128] In this embodiment, to detect whether the first overcurrent protection circuit 41 is functioning correctly, when both the first switch module 11 and the second switch module 12 are turned on, the control module 61 injects a first fault signal into the first overcurrent protection circuit 41. 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 functioning correctly. The control module 61 determines whether the first overcurrent protection circuit 41 is functioning correctly based on the output signal of the first drive circuit 31. If the output signal of the first drive circuit 31 is a first turn-off signal, the first overcurrent protection circuit 41 is considered to be functioning correctly; if the output signal of the first drive circuit 31 is not a first turn-off signal, the first overcurrent protection circuit 41 is considered to be functioning incorrectly. The first turn-off signal is a signal used to turn off the first switch module 11. For example, if the first switch module 11 is a PMOS transistor, the first turn-off signal can be a high-level signal (a high-level signal can turn off the PMOS transistor).

[0129] To detect whether the second overcurrent protection circuit 42 is functioning correctly, with both the first switch module 11 and the second switch module 12 on, the control module 61 injects a second fault signal into the second overcurrent protection circuit 42. 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 functioning correctly. The control module 61 determines whether the second overcurrent protection circuit 42 is functioning correctly based on the output signal of the second drive circuit 32. If the output signal of the second drive circuit 32 is a second turn-off signal, the second overcurrent protection circuit 42 is considered to be functioning correctly; if the output signal of the second drive circuit 32 is not a second turn-off signal, the second overcurrent protection circuit 42 is considered to be functioning incorrectly. The second turn-off signal is used to turn off the second switch module 12. For example, if the second switch module 12 is an NMOS transistor, the second turn-off signal can be a low-level signal (a low-level signal can turn off the NMOS transistor).

[0130] In this embodiment, the control module 61 can determine whether the first overcurrent protection circuit 41 is functioning properly based on the output signal of the first driving circuit 31, and can directly determine whether the first overcurrent protection circuit 41 is functioning properly. Similarly, the control module 61 can determine whether the second overcurrent protection circuit 42 is functioning properly based on the output signal of the second driving circuit 32, and can directly determine whether the second overcurrent protection circuit 42 is functioning properly.

[0131] Please see Figure 7 , Figure 7 This is a schematic diagram of another switch protection circuit 100 provided in an embodiment of this application. Figure 7 Is Figure 4 This was further derived from [the previous work]. Figure 4 On this basis, Figure 7 The switch protection circuit 100 shown also includes an over / under voltage protection circuit 81. The first input terminal of the over / under voltage protection circuit 81 is connected to the third terminal of the first voltage sensor 71, the second input terminal of the over / under voltage protection circuit 81 is connected to the third terminal of the second voltage sensor 72, and the output terminal of the over / under voltage protection circuit 81 is connected to the input terminal of the power supply circuit 51.

[0132] If the first voltage sensor 71 detects a voltage abnormality or the second voltage sensor 72 detects a voltage abnormality, the over / under voltage protection circuit 81 sends a power-off signal to the power supply circuit 51. The power-off signal is used to shut off the power supply to the first drive circuit 31 and the second voltage sensor 72.

[0133] The first voltage sensor 71 detects a voltage abnormality, which may include:

[0134] If the first voltage sensor 71 detects a voltage lower than the fourth threshold, it is determined that the first voltage sensor 71 has detected a voltage anomaly.

[0135] The fourth threshold can be preset. Specifically, if the output voltage of the DC / DC converter is 12V, the fourth threshold can be set to any value less than 10V.

[0136] The second voltage sensor 72 detects a voltage abnormality and may include:

[0137] If the second voltage sensor 72 detects a voltage lower than the fifth threshold, it is determined that the second voltage sensor 72 has detected a voltage anomaly.

[0138] The fifth threshold can be preset. Specifically, if the output voltage of the DC / DC converter is 12V, the fifth threshold can be set to any value less than 10V. The fifth threshold can be equal to or different from the fourth threshold.

[0139] In this embodiment, when either the first voltage sensor 71 or the second voltage sensor 72 detects a voltage abnormality, the power supply circuit 51 is de-energized. This is achieved by shutting off the power supply to the first drive circuit 31 and the second drive circuit 32, causing them to stop operating and thus shutting off the first switch module 11 and the second switch module 12. This avoids the safety risks associated with the first switch module 11 or the second switch module 12 not being shut down in time when either the first voltage sensor 71 or the second voltage sensor 72 detects a voltage abnormality. If both the first overcurrent protection circuit 41 and the control module 61 malfunction, the first drive circuit 31 may not shut down in time, posing a safety risk to the first switch module 11. Similarly, if both the second overcurrent protection circuit 42 and the control module 61 malfunction, the second drive circuit 32 may not shut down in time, posing a safety risk to the second switch module 12. This embodiment can avoid the safety risks associated with the first switch module 11 not shutting down in time even when both the first overcurrent protection circuit 41 and the control module 61 malfunction. This embodiment of the application can avoid the safety risks caused by the second switch module 12 not being turned off in time, even if both the second overcurrent protection circuit 42 and the control module 61 fail.

[0140] Please see Figure 8 , Figure 8 This is a schematic diagram of another switch protection circuit 100 provided in an embodiment of this application. Figure 8 Is Figure 7 This was further derived from [the previous work]. Figure 7 On this basis, Figure 8The switch protection circuit 100 shown also includes a third voltage sensor 73 and an alarm device. The first end of the third voltage sensor 73 is connected to the second end of the first switch module 11, the second end of the third voltage sensor 73 is grounded, and the third end of the third voltage sensor 73 is connected to the eighth input terminal of the control module 61.

[0141] When the control module 61 detects that the first switch module 11 is in an open state (the first switch module 11 should be in an open state), and the control module 61 detects that the voltage difference between the first terminal and the second terminal of the first switch module 11 is less than a first threshold, the control module 61 sends a first alarm signal to the alarm device. The first alarm signal is used to trigger the alarm device to issue a first type of alarm, which is used to alert the driver that the first switch module 11 is abnormal. The first threshold is: current I * on-resistance of the first switch module * coefficient, where current I is the current value sampled by the first current sensor, and the coefficient is greater than or equal to 1.

[0142] If the first switch module 11 is detected to be in a conducting state (the first switch module 11 should be in a conducting state), and the control module 61 detects that the voltage difference between the first terminal and the second terminal of the first switch module 11 is greater than the first threshold, the control module 61 reduces the output power of the DC / DC converter and / or the control module 61 sends a second alarm signal to the alarm device; wherein, the second alarm signal is used to trigger the alarm device to issue a second type of alarm, and the second type of alarm is used to indicate to the driver that the first switch module 11 is abnormal.

[0143] In this embodiment of the application, the on / off state (conduction state or off state) of the first switch module 11 and the second switch module 12 can be determined by detecting the voltage drop across the two ends of the first switch module 11 and the voltage drop across the two ends of the second switch module 12 respectively.

[0144] When the switching module (first switching module 11 or second switching module 12) needs to perform a protection action (shut down the drive, disconnect the switching module), if the switching module does not disconnect, the driver can be prompted to take emergency measures (e.g., issue an alarm signal to prompt the driver to manually shut off the switching module). For the first switching module 11, the trigger condition for issuing a first-type alarm is |Vsample1-Vsample3| divided by the current I being less than the on-resistance (Rdson) of the first switching module 11 * a coefficient (the first threshold is current I * on-resistance of the first switching module 11 * a coefficient). For the second switching module 12, the trigger condition for issuing a second-type alarm is |Vsample2-Vsample3| divided by the current I being less than the on-resistance (Rdson) of the second switching module 12 * a coefficient. Multiplying by a coefficient is to avoid false triggering, and a margin can be left according to the actual situation. The above coefficient is greater than or equal to 1.

[0145] When the switching module (first switching module 11 or second switching module 12) does not need to perform protection actions (driven, closing the switching module), if the switching module is not fully turned on, the large current output by the DC / DC converter flows to the body diode of the switching module, which may eventually damage the switching module. In this embodiment, when this problem is detected, the output power of the DC / DC converter can be reduced and the driver can be notified to take emergency measures (e.g., the driver manually turns on the switching module). For the first switching module 11, the trigger condition is |Vsample1-Vsample3| divided by the current I, which is greater than the on-resistance (Rdson) * coefficient of the first switching module 11. For the second switching module 12, the trigger condition is |Vsample2-Vsample3| divided by the current I, which is greater than the on-resistance (Rdson) * coefficient of the second switching module 12. Multiplying by a coefficient is to avoid false triggering, and a margin can be left according to the actual situation. The above coefficient is greater than or equal to 1.

[0146] Wherein, Vsample1 is the voltage at the first terminal of the first switching module 11 sampled by the first voltage sensor 71, Vsample3 is the voltage at the second terminal of the first switching module 11 (i.e., the voltage at the first terminal of the second switching module 12) sampled by the first voltage sensor 71, and Vsample2 is the voltage at the second terminal of the second switching module 12 sampled by the first voltage sensor 71. The current I is the current sampled by the first current sensor 21.

[0147] In this embodiment, the on / off state of the first switch module 11 and the second switch module 12 can be determined by detecting the voltage drop across the two ends of the first switch module 11 and the voltage drop across the two ends of the second switch module 12, respectively. This can proactively inform the driver to take emergency measures and further improve safety when the control of the switch module malfunctions.

[0148] Optional, please refer to Figure 9 , Figure 9 This is a schematic diagram of another switch protection circuit 100 provided in an embodiment of this application. Figure 9 Is Figure 7 This was further derived from [the previous work]. Figure 7 On this basis, Figure 9 The switch protection circuit 100 shown also includes a fourth voltage sensor 74. The first end of the fourth voltage sensor 74 is connected to the target end, the second end of the fourth voltage sensor 74 is grounded, and the third end of the fourth voltage sensor 74 is connected to the ninth input end of the control module 61. 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. Figure 9 The target terminal is taken as the second terminal of the second switch module 12 as an example.

[0149] In this embodiment, when the target terminal is the first terminal of the first current sensor 21, the control module 61 can 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 malfunctioned. Generally, a smaller difference indicates that no malfunction has occurred, while a larger difference indicates that a malfunction has occurred.

[0150] When the target terminal is the second terminal of the second switch module 12, the control module 61 can 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 malfunctioned. Generally speaking, a smaller difference indicates that no malfunction has occurred, while a larger difference indicates that a malfunction has occurred.

[0151] The embodiments of this application can accurately determine whether the first voltage sensor 71 and the second voltage sensor 72 have failed, thereby improving the safety of the switch protection circuit 100.

[0152] Optional, please refer to Figure 10 , Figure 10 This is a schematic diagram of another switch protection circuit 100 provided in an embodiment of this application. Figure 10 Is Figure 9 This was further derived from [the previous work]. Figure 9 On this basis, Figure 10The switch protection circuit 100 shown also includes a second current sensor 22. The first end of the second current sensor 22 is connected to the second end of the second switch module 12, the second end of the second current sensor 22 is connected to the input port of the first battery, and the third end of the second current sensor 22 is connected to the tenth input terminal of the control module 61.

[0153] In this embodiment, the current between the second terminal of the second switch module 12 and the input port of the first battery can be sampled by the second current sensor 22. When both the first switch module 11 and the second switch module 12 are turned on, the difference between the current sampled by the first current sensor 21 and the current sampled by the second current sensor 22 can be used to determine whether the first current sensor 21 and the second current sensor 22 are faulty. Generally, a smaller difference indicates no fault, while a larger difference indicates that at least one of the first current sensor 21 and the second current sensor 22 is faulty. This can further improve the accuracy of fault detection.

[0154] Furthermore, when both the first switch module 11 and the second switch module 12 are turned on, the difference between the voltage sampled by the first voltage sensor 71 and the voltage sampled by the second voltage sensor 72 can be used to determine whether the first voltage sensor 71 and the second voltage sensor 72 are faulty. Generally, a smaller difference indicates that no fault has occurred, while a larger difference indicates that at least one of the first voltage sensor 71 and the second voltage sensor 72 has failed. This can further improve the accuracy of fault detection.

[0155] Please see Figure 11 , Figure 11 This is a schematic diagram of the structure of an electric vehicle provided in an embodiment of this application. Figure 11 As shown, the electric vehicle may include a switch protection circuit, a DC / DC converter, and a first battery, wherein the DC / DC converter is connected to the first battery through the switch protection circuit.

[0156] The DC / DC converter draws power from the power battery and then supplies power to the first battery and the vehicle's ECU via a switching protection circuit.

[0157] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0158] In the several embodiments provided in this application, it should be understood that the disclosed switch protection circuit and vehicle-mounted DC-DC converter can be implemented in other ways. For example, the switch protection circuit embodiments described above are merely illustrative. For instance, the division of the units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed.

Claims

1. A switch protection circuit, characterized in that, The switch protection circuit includes a first switch module, a second switch module, a first current sensor, a first drive circuit, a second drive circuit, a first overcurrent protection circuit, a second overcurrent protection circuit, a power supply circuit, and a control module; the DC / DC converter is connected to the first battery through the switch protection circuit; The output port of the DC / DC converter is connected to the first terminal of the first current sensor; the second terminal of the first current sensor is connected to the first terminal of the first switching module; the second terminal of the first switching module is connected to the first terminal of the second switching module; and the second terminal of the second switching module is connected to the input port of the first battery. The third terminal of the first current sensor is connected to the first input terminal of the first overcurrent protection circuit, the first input terminal of the second overcurrent protection circuit, and the first input terminal of the control module. The output terminal of the first overcurrent protection circuit is connected to the first input terminal of the first drive circuit; the output terminal of the second overcurrent protection circuit is connected to the first input terminal of the second drive circuit. The first output terminal of the control module is connected to the input terminal of the first drive circuit; the second output terminal of the control module is connected to the input terminal of the second drive circuit; the output terminal of the first drive circuit is connected to the third terminal of the first switching module; and the output terminal of the second drive circuit is connected to the third terminal of the second switching module. The power supply circuit supplies power to the first driving circuit and the second driving circuit; The first switching module and the second switching module are of the same type of switching transistor; When the first current sensor detects an abnormal current, the first overcurrent protection circuit controls the first switch module to be in the off state through the first drive circuit and / or the second overcurrent protection circuit controls the second switch module to be in the off state through the second drive circuit, and the control module controls the first switch module to be in the off state through the first drive circuit and / or controls the second switch module to be in the off state through the second drive circuit. 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 to the output port of the DC / DC converter, and a first end of the second voltage sensor is connected to the input port of the first battery; the second ends of the first voltage sensor and the second end of the second voltage sensor are grounded, and a third end of the first voltage sensor is connected to the second input terminal of the control module, and a third end of the second voltage sensor is connected to the third input terminal of the control module. When the first voltage sensor detects an abnormal voltage, the control module controls the first switch module to be in an open state through the first drive circuit; when the second voltage sensor detects an abnormal voltage, the control module controls the second switch module to be in an open state through the second drive circuit. The third output terminal of the control module is connected to the second input terminal of the first overcurrent protection circuit, and the fourth output terminal of the control module is connected to the second input terminal of the second overcurrent protection circuit. When both the first switch module and the second switch module are turned on, the control module injects a first fault signal into the first overcurrent protection circuit. 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. When both the first switch module and the second switch module are turned on, the control module injects a second fault signal into the second overcurrent protection circuit. 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. The control module determines whether the first overcurrent protection circuit is functioning properly, including: The control module determines whether the first overcurrent protection circuit is functioning properly based on the difference between the voltage signal detected by the first voltage sensor and the voltage signal detected by the second voltage sensor; or, the control module determines whether the first overcurrent protection circuit is functioning properly based on the output signal of the first overcurrent protection circuit; or, the control module determines whether the first overcurrent protection circuit is functioning properly based on the output signal of the first drive circuit. The control module determines whether the second overcurrent protection circuit is functioning properly, including: The control module determines whether the second overcurrent protection circuit is normal based on the difference between the voltage signal detected by the first voltage sensor and the voltage signal detected by the second voltage sensor; or, the control module determines whether the second overcurrent protection circuit is normal based on the output signal of the second overcurrent protection circuit; or, the control module determines whether the second overcurrent protection circuit is normal based on the output signal of the second drive circuit.

2. The switch protection circuit according to claim 1, characterized in that, The switch protection circuit also includes an over / under voltage protection circuit. The first input terminal of the over / under voltage protection circuit is connected to the third terminal of the first voltage sensor, the second input terminal of the over / under voltage protection circuit is connected to the third terminal of the second voltage sensor, and the output terminal of the over / under voltage protection circuit is connected to the input terminal of the power supply circuit. If the first voltage sensor detects a voltage abnormality or the second voltage sensor detects a voltage abnormality, the over / under voltage protection circuit sends a power-off signal to the power supply circuit. The power-off signal is used to shut off the power supply to the first drive circuit and the second drive circuit.

3. The switch protection circuit according to claim 2, characterized in that, The switch protection circuit also includes a third voltage sensor and an alarm device. The first end of the third voltage sensor is connected to the second end of the first switch module, the second end of the third voltage sensor is grounded, and the third end of the third voltage sensor is connected to the eighth input terminal of the control module. When the control module detects that the first switch module is in an open state and that the voltage difference between the first and second terminals of the first switch module is less than a first threshold, the control module sends a first alarm signal to the alarm device. The first alarm signal is used to trigger the alarm device to issue a first type of alarm, which is used to alert the driver that the first switch module is abnormal. The first threshold is: current I * on-resistance of the first switch module * coefficient, where current I is the current value sampled by the first current sensor, and the coefficient is greater than or equal to 1. When the control module detects that the first switch module is in a conducting state and detects that the voltage difference between the first and second terminals of the first switch module is greater than the first threshold, the control module reduces the output power of the DC / DC converter and / or the control module sends a second alarm signal to the alarm device; wherein, the second alarm signal is used to trigger the alarm device to issue a second type of alarm, and the second type of alarm is used to indicate to the driver that the first switch module is abnormal.

4. The switch protection circuit according to any one of claims 1 to 3, characterized in that, The switch protection circuit further includes a fourth voltage sensor. The first end of the fourth voltage sensor is connected to the target end, the second end of the fourth voltage sensor is grounded, and the third end of the fourth voltage sensor is connected to the ninth input end of the control module. The target end includes 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 includes a second current sensor, the first end of which is connected to the second end of the second switch module, the second end of which is connected to the input port of the first battery, and the third end of which is connected to the tenth input terminal of the control module.

5. An electric vehicle, characterized in that, It includes a switch protection circuit as described in any one of claims 1 to 4, a DC / DC converter, and a first battery, wherein the DC / DC converter is connected to the first battery through the switch protection circuit.

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