Safety control circuits and electric vehicles

Abstract

This application provides a safety control circuit and an electric vehicle. The safety control circuit includes a pre-charging circuit, a switch protection circuit, and a control module. The pre-charging circuit includes a first switch module, a first drive circuit, a current limiting module, and a capacitor. The switch protection circuit includes a second switch module, a second drive circuit, a first current sensor, and a first voltage sampling circuit. A DC / DC converter is connected to a load through the switch protection circuit. The control module controls the first switch module to be in a conducting state through the first drive circuit. When the first switch module is in a conducting state, the control module detects whether the DC / DC converter is short-circuited by sampling the voltage through the first voltage sampling circuit. If the DC / DC converter is not short-circuited, the power supply charges the capacitor through the current limiting module. This application can improve the safety of DC / DC converter startup.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, specifically to a safety control 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.

[0003] If a DC / DC converter experiences an internal short circuit, it can pull down the voltage of the low-voltage battery, affecting the vehicle's low-voltage power supply. Typically, a MOSFET to prevent reverse current flow is placed between the DC / DC output and the low-voltage battery. However, before the DC / DC converter is turned on, because it contains an internal capacitor, if the converter is short-circuited and shut down, and if this capacitor was in a zero-state (no energy) before the converter was turned on, then at the moment of power-on, the capacitor is effectively short-circuited, resulting in a very large current flowing through it, which can damage the converter's components. Summary of the Invention

[0004] This application provides a safety control circuit and an electric vehicle that can precharge the capacitor of a DC / DC converter, thereby avoiding damage to the components of the DC / DC converter and improving the safety of the DC / DC converter during startup.

[0005] A first aspect of this application provides a safety control circuit, which includes a pre-charging circuit, a switch protection circuit, and a control module. The pre-charging circuit includes a first switch module, a first drive circuit, a current limiting module, and a capacitor. The switch protection circuit includes a second switch module, a second drive circuit, a first current sensor, and a first voltage sampling circuit. A DC / DC converter is connected to a load through the switch protection circuit.

[0006] The output port of the DC / DC converter is connected to the first terminal of the capacitor, the first terminal of the first voltage sampling circuit, the first terminal of the current limiting module, and the first terminal of the first current sensor. The second terminal of the first current sensor 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 load. The third terminal of the first current sensor is connected to the first input terminal of the control module. The first output terminal of the control module is connected to the input terminal of the first driving circuit, and the output terminal of the first driving circuit is connected to the third terminal of the first switching module. The first terminal of the first switching module is connected to the power supply, the second terminal of the first switching module is connected to the second terminal of the current limiting module, and the third terminal of the first voltage sampling circuit is connected to the second input terminal of the control module. The second output terminal of the control module is connected to the input terminal of the second driving circuit, and the output terminal of the second driving circuit is connected to the third terminal of the second switching module. The second terminal of the capacitor and the second terminal of the first voltage sampling circuit are grounded.

[0007] The control module controls the first switch module to be in the conducting state through the first drive circuit. When the first switch module is in the conducting state, the control module detects whether the DC / DC converter is short-circuited by the voltage sampled by the first voltage sampling circuit.

[0008] If the DC / DC converter is not short-circuited, the power supply charges the capacitor through the current limiting module.

[0009] Optionally, the control module detects whether the capacitor has completed pre-charging by sampling the voltage through the first voltage sampling circuit;

[0010] Upon detecting that the capacitor has completed pre-charging, the control module controls the DC / DC converter to power on.

[0011] Optionally, the load may include a passive load, and the power supply may include an auxiliary power supply for the DC / DC converter.

[0012] Optionally, the load includes a battery, and the power supply includes the battery.

[0013] Optionally, the first voltage sampling circuit includes a first resistor and a second resistor. The first end of the first resistor is connected to the output port of the DC / DC converter, the second end of the first resistor is connected to the first end of the second resistor and the second input terminal of the control module, and the second end of the second resistor is grounded.

[0014] Optionally, the current limiting module includes a constant current source or a resistor module.

[0015] Optionally, the resistor module includes a third resistor and a fourth resistor; the first end of the third resistor is connected to the second end of the first switch module, the second end of the third resistor is connected to the first end of the fourth resistor and the first end of the capacitor, and the second end of the fourth resistor is grounded.

[0016] Optionally, the switch protection circuit further includes a second voltage sampling circuit, wherein the second terminal of the first switch module is connected to the first terminal of the second voltage sampling circuit, and the second terminal of the second voltage sampling circuit is grounded; the third input terminal of the control module is connected to the third terminal of the second voltage sampling circuit.

[0017] Optionally, the switch protection circuit further includes a third drive circuit, a third switch module, and a third voltage sampling circuit; the first terminal of the third switch module is connected to the input port of the battery, the second terminal of the third switch module is connected to the first terminal of the third voltage sampling circuit, and the second terminal of the third voltage sampling circuit is grounded; the third input terminal of the control module is connected to the third terminal of the third voltage sampling circuit, the third output terminal of the control module is connected to the input terminal of the third drive circuit, and the output terminal of the third drive circuit is connected to the third terminal of the third switch module.

[0018] Optionally, the second switching module includes: a first switching transistor and a second switching transistor; the second driving circuit includes: a first driving sub-circuit and a second driving sub-circuit; the first end of the first switching transistor is connected to the second end of the first current sensor, the second end of the first switching transistor is connected to the first end of the second switching transistor, and the second end of the second switching transistor is connected to the input port of the battery.

[0019] Optionally, the safety control circuit further includes a second current sensor, the first end of which is connected to the second end of the second switching transistor, the second end of which is connected to the input port of the battery, and the third end of which is connected to the fourth input terminal of the control module.

[0020] A second aspect of this application provides an electric vehicle, including the safety control circuit, DC / DC converter, and load described in any of the first aspects of this application.

[0021] In the safety control circuit of this application embodiment, when the first switch module is in the ON state, the control module detects whether the DC / DC converter is short-circuited by sampling the voltage through the first voltage sampling circuit. If the DC / DC converter is not short-circuited, the power supply charges the capacitor through the current limiting module. Charging the capacitor through the current limiting module when the DC / DC converter is not short-circuited pre-charges the capacitor, preventing a large current from being generated at the moment the DC / DC converter is turned on, thereby avoiding damage to the components of the DC / DC converter and improving the safety of the DC / DC converter's start-up. Attached Figure Description

[0022] 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.

[0023] Figure 1 This is a schematic diagram of the structure of a safety control circuit provided in an embodiment of this application;

[0024] Figure 2a This is a schematic diagram of the structure of an isolated DC / DC converter provided in an embodiment of this application;

[0025] Figure 2b This is a schematic diagram of the structure of a non-isolated DC / DC converter provided in an embodiment of this application;

[0026] Figure 3 This is a schematic diagram of another safety control circuit provided in an embodiment of this application;

[0027] Figure 4 This is a schematic diagram of another safety control circuit provided in an embodiment of this application;

[0028] Figure 5 This is a schematic diagram of another safety control circuit provided in an embodiment of this application;

[0029] Figure 6 This is a schematic diagram of another safety control circuit provided in an embodiment of this application;

[0030] Figure 7 This is a schematic diagram of another safety control circuit provided in an embodiment of this application;

[0031] Figure 8 This is a schematic diagram of another safety control circuit provided in an embodiment of this application;

[0032] Figure 9This is a schematic diagram of the structure of an electric vehicle provided in an embodiment of this application. Detailed Implementation

[0033] 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.

[0034] 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.

[0035] 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.

[0036] Please see Figure 1 , Figure 1 This is a schematic diagram of a safety control circuit provided in an embodiment of this application. Figure 1 As shown, the safety control circuit may include a pre-charging circuit 10, a switch protection circuit 20, and a control module 30; the pre-charging circuit 10 includes a first switch module 11, a first drive circuit 12, a current limiting module 13, and a capacitor C1; the switch protection circuit 20 includes a second switch module 21, a second drive circuit 22, a first current sensor 23, and a first voltage sampling circuit 24; the DC / DC converter is connected to the load through the switch protection circuit 20.

[0037] The output port of the DC / DC converter is connected to the first terminal of the capacitor C1, the first terminal of the first voltage sampling circuit 24, the first terminal of the current limiting module 13, and the first terminal of the first current sensor 23. The second terminal of the first current sensor 23 is connected to the first terminal of the second switching module 21, and the second terminal of the second switching module 21 is connected to the input port of the load. The third terminal of the first current sensor 23 is connected to the first input terminal of the control module 30. The first output terminal of the control module 30 is connected to the input terminal of the first driving circuit 12, and the output terminal of the first driving circuit 12 is connected to the third terminal of the first switching module 11. The first terminal of the first switching module 11 is connected to the power supply, and the second terminal of the first switching module 11 is connected to the second terminal of the current limiting module 13. The third terminal of the first voltage sampling circuit 24 is connected to the second input terminal of the control module 30. The second output terminal of the control module 30 is connected to the input terminal of the second driving circuit 22, and the output terminal of the second driving circuit 22 is connected to the third terminal of the second switching module 21. The second terminal of the capacitor C1 and the second terminal of the first voltage sampling circuit 24 are grounded.

[0038] The control module 30 controls the first switch module 11 to be in the on state through the first drive circuit 12. When the first switch module 11 is in the on state, the control module 30 detects whether the DC / DC converter is short-circuited by the voltage sampled by the first voltage sampling circuit 24.

[0039] Among them, such as Figure 1 As shown, the first voltage sampling circuit 24 may include a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to the output port of the DC / DC converter, the second end of the first resistor R1 is connected to the first end of the second resistor R2 and the second input terminal of the control module 30, and the second end of the second resistor R2 is grounded.

[0040] If the DC / DC converter is not short-circuited, the power supply charges the capacitor C1 through the current limiting module 13.

[0041] The safety control circuit 100 can be a component of the DC / DC converter or a separate circuit.

[0042] 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.

[0043] 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). An isolated DC / DC converter includes an isolation transformer that enables electrical isolation between the high-voltage battery and the load (e.g., a low-voltage battery).

[0044] 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.

[0045] A DC / DC converter draws power from a high-voltage battery (also known as a power battery) and converts it to power a low-voltage battery and the vehicle's electronic control unit (ECU). The low-voltage battery can be a lead-acid battery or a lithium battery, typically with a voltage of around 12V. The ECU can include components such as the infotainment system, music player, and windshield wipers. The high-voltage battery typically has a voltage of 100V or higher.

[0046] The first current sensor 23 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 23 can be a Hall sensor or a sampling resistor plus an operational amplifier for sampling.

[0047] The first switching module 11 may include a switching transistor.

[0048] The second switching module 21 may include M switching transistors connected in parallel, where M is a positive integer. The negative terminals of the M individual diodes point to the input port of the load, and the positive terminals of the M individual diodes point to the output port of the DC / DC converter.

[0049] The second switch module 21 can represent a single switch transistor or multiple switch transistors connected in parallel. Figure 1 The second switching module 21 takes a single switching transistor as an example. The switching transistor may include a metal-oxide-semiconductor field-effect transistor (MOSFET), which can be simply referred to as a MOS transistor.

[0050] The first driving circuit 12 is used to drive the first switching module 11. The control module 30 can control the optocoupler in the first driving circuit 12, so that the first driving circuit 12 provides drive to the first switching module 11. The first driving circuit 12 can also provide drive to the first switching module 11 using an isolated driving method. When the control module 30 controls the first driving circuit 12 to provide drive to the first switching module 11, the first switching module 11 is in the on state; when the control module 30 controls the first driving circuit 12 not to provide drive to the first switching module 11, that is, when the drive to the first switching module 11 is disconnected, the first switching module 11 is in the off state.

[0051] The second driving circuit 22 is used to drive the second switching module 21. The control module 30 can control the optocoupler in the second driving circuit 22, so that the second driving circuit 22 provides drive to the second switching module 21. The second driving circuit 22 can also provide drive to the second switching module 21 in an isolated driving mode. When the control module 30 controls the second driving circuit 22 to provide drive to the second switching module 21, the second switching module 21 is in the on state; when the control module 30 controls the second driving circuit 22 not to provide drive to the second switching module 21, that is, when the drive to the second switching module 21 is disconnected, the second switching module 21 is in the off state.

[0052] The second switch module 21 may have a backflow prevention function to prevent current from flowing from the load (e.g., a low-voltage battery) into the internal circuitry of the DC / DC converter.

[0053] When an internal short circuit occurs in the DC / DC converter, the control module 30 can detect the current flowing from the load (e.g., the low-voltage battery) to the inside of the DC / DC converter through the first current sensor 23. When the current reaches the overcurrent protection threshold, the control module 30 disconnects the drive of the second switch module 21 and uses the body diode of the second switch module 21 to cut off the connection between the internal short circuit fault of the DC / DC converter and the external load (e.g., the low-voltage battery), so as to avoid pulling down the low-voltage battery and causing the ECU of the whole vehicle to lose power, thus avoiding loss of control of the vehicle during driving and causing a safety accident.

[0054] The control module 30 can obtain the current sampling results from the first current sensor 23 and execute the software's protection logic. For example, if the first current sensor 23 detects that the current flows from the load's input port to the DC / DC converter's output port, and this current is greater than a first set threshold, it determines that the first current sensor 23 has detected an abnormal current. The control module 30 then controls the second switch module 21 to be in the off state via the second drive circuit 22. The first set threshold can be preset.

[0055] The control module 30 can be a microcontroller unit (MCU).

[0056] The power supply can be the auxiliary power supply of the DC / DC converter or a battery (i.e., the low-voltage battery mentioned above).

[0057] The current limiting module 13 includes a constant current source or a resistor module. When the current limiting module 13 includes a constant current source, a charging circuit is formed between the power supply, the constant current source, the capacitor C1, and ground when the first switch module 11 is in the on state. The constant current source can provide a stable current, and the power supply charges the capacitor C1 with a stable current through the constant current source, avoiding damage to the components of the DC / DC converter caused by the large current generated when the capacitor C1 is charging, and improving the safety of the DC / DC converter when it is turned on.

[0058] When the current limiting module 13 includes a resistor module, a charging circuit is formed between the power supply, the resistor module, capacitor C1, and ground when the first switch module 11 is in the ON state. The resistor module can limit the current charging capacitor C1, preventing damage to the components of the DC / DC converter caused by large currents during capacitor C1 charging, thus improving the safety of the DC / DC converter during startup. The resistor module can be a single resistor, multiple resistors connected in series, multiple resistors connected in parallel, or a combination of parallel and series resistors.

[0059] A short circuit occurs in the DC / DC converter, indicating an internal short circuit or a short-circuit connection between the converter's output port and ground.

[0060] The control module 30 detects whether the DC / DC converter is short-circuited by sampling the voltage from the first voltage sampling circuit 24. Specifically:

[0061] When the first switch module 11 is in the ON state, a loop is formed between the power supply, the current limiting module 13, the capacitor C1, and ground. At this time, if the DC / DC converter is short-circuited, the output port of the DC / DC converter is short-circuited to ground, and the voltage sampled by the first voltage sampling circuit 24 is close to 0. For example, a voltage threshold can be set. If the voltage sampled by the first voltage sampling circuit 24 is less than this threshold, it is considered that the output port of the DC / DC converter is short-circuited to ground, and the DC / DC converter is short-circuited. If the voltage sampled by the first voltage sampling circuit 24 is greater than or equal to the voltage threshold, it is considered that the output port of the DC / DC converter is not short-circuited to ground, and the DC / DC converter is not short-circuited. This voltage threshold can be set to a value less than or equal to 1V.

[0062] If the DC / DC converter is not short-circuited, the power supply charges the capacitor C1 through the current limiting module 13.

[0063] In the safety control circuit of this application embodiment, when the first switch module is in the ON state, the control module detects whether the DC / DC converter is short-circuited by sampling the voltage through the first voltage sampling circuit. If the DC / DC converter is not short-circuited, the power supply charges the capacitor through the current limiting module. Charging the capacitor through the current limiting module when the DC / DC converter is not short-circuited pre-charges the capacitor, preventing a large current from being generated at the moment the DC / DC converter is turned on, thereby avoiding damage to the components of the DC / DC converter and improving the safety of the DC / DC converter's start-up.

[0064] When the DC / DC converter is not short-circuited, the power supply charges the capacitor through the current limiting module 13. Whether the capacitor has completed pre-charging can be detected by the voltage sampled by the first voltage sampling circuit 24. If the pre-charging of the capacitor is detected to be complete, the control module 30 controls the DC / DC converter to power on.

[0065] In this embodiment, when the first switch module is in the ON state, a loop is formed between the power supply, the current limiting module 13, the capacitor C1, and ground. Simultaneously, a loop is formed between the power supply, the current limiting module 13, the first voltage sampling circuit 24, and ground. The first voltage sampling circuit 24... Figure 1 Taking R1 and R2 as examples, and the current limiting module 13 as an example of a resistor module, if R1 = 20KΩ, R2 = 30KΩ, the resistance of the resistor module is 10KΩ, and the power supply voltage is 12V, then when the voltage sampled by the first voltage sampling circuit 24 reaches 6V, it indicates that the capacitor is fully charged. When the voltage of the capacitor reaches 10V, it can be confirmed that the capacitor has completed pre-charging when the voltage sampled by the first voltage sampling circuit 24 reaches 5V. At this time, the voltage of the capacitor reaches more than 8V, and no large current will be generated at the moment the DC / DC converter is turned on, so as not to damage the components of the DC / DC converter.

[0066] The load can be either a passive load or an active load.

[0067] Please see Figure 3 , Figure 3 This is a schematic diagram of another safety control circuit provided in an embodiment of this application. Figure 3 Is Figure 1 It is derived further from this. For example, Figure 3 As shown, the load includes a passive load, and the power supply includes the auxiliary power supply of the DC / DC converter.

[0068] In this embodiment, when the load is a passive load, the power supply can be the auxiliary power supply of the DC / DC converter, which can also power the control module 30. Pre-charging the capacitor using the auxiliary power supply of the DC / DC converter can improve the reliability of the power supply.

[0069] Please see Figure 4 , Figure 4 This is a schematic diagram of another safety control circuit provided in an embodiment of this application. Figure 4 Is Figure 1 It is derived further from this. For example, Figure 4 As shown, the load includes a battery, and the power supply includes the battery. The first terminal of the first switch module 11 is connected to the input port of the load (i.e., the input port of the battery).

[0070] In this embodiment of the application, when the load is a battery, the power supply can be a battery. The battery can be the low-voltage battery mentioned above. For example, a 12V battery in an electric vehicle (e.g., a lead-acid battery). The capacitor can be pre-charged by the load (low-voltage battery), which can make full use of the battery and improve its utilization rate.

[0071] Please see Figure 5 , Figure 5 This is a schematic diagram of another safety control circuit provided in an embodiment of this application. Figure 5 Is Figure 4 It is derived further from this. For example, Figure 5 As shown, when the current limiting module 13 includes a resistor module, the resistor module includes a third resistor R3 and a fourth resistor R4; the first end of the third resistor R3 is connected to the second end of the first switch module 11, the second end of the third resistor R3 is connected to the first end of the fourth resistor R4 and the first end of the capacitor C1, and the second end of the fourth resistor R4 is grounded.

[0072] The third resistor R3 can be a single resistor, a resistor composed of multiple resistors connected in series, a resistor composed of multiple resistors connected in parallel, or a resistor composed of multiple resistors connected in series and in parallel.

[0073] Please see Figure 6 , Figure 6 This is a schematic diagram of another safety control circuit provided in an embodiment of this application. Figure 6 Is Figure 5This is further derived from the above. The switch protection circuit 20 also includes a second voltage sampling circuit 25, the second terminal of the first switch module 11 is connected to the first terminal of the second voltage sampling circuit 25, and the second terminal of the second voltage sampling circuit 25 is grounded; the third input terminal of the control module 30 is connected to the third terminal of the second voltage sampling circuit 25.

[0074] The second voltage sampling circuit 25 may include a fifth resistor R5 and a sixth resistor R6. The first end of the fifth resistor R5 is connected to the second end of the first switch module 11, and the second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6 and the third input terminal of the control module 30. The second end of the sixth resistor R6 is grounded. The control module 30 can obtain the sampled voltage through the third input terminal to detect whether a short circuit has occurred in the battery.

[0075] Please see Figure 7 , Figure 7 This is a schematic diagram of another safety control circuit provided in an embodiment of this application. Figure 7 Is Figure 5 This is further derived from the above. The switch protection circuit 20 also includes a third drive circuit 26, a third switch module 27, and a third voltage sampling circuit 28; the first end of the third switch module 27 is connected to the input port of the battery, the second end of the third switch module 27 is connected to the first end of the third voltage sampling circuit 28, and the second end of the third voltage sampling circuit 28 is grounded; the third input end of the control module 30 is connected to the third end of the third voltage sampling circuit 28, the third output end of the control module 30 is connected to the input end of the third drive circuit 26, and the output end of the third drive circuit 26 is connected to the third end of the third switch module 27.

[0076] The third voltage sampling circuit 28 may include a seventh resistor R7 and an eighth resistor R8. The first end of the seventh resistor R7 is connected to the second end of the third switch module 27, and the second end of the seventh resistor R7 is connected to the first end of the eighth resistor R8 and the third input terminal of the control module 30. The second end of the eighth resistor R8 is grounded. The control module 30 can obtain the sampled voltage through the third input terminal to detect whether the battery is short-circuited.

[0077] Please see Figure 8 , Figure 8 This is a schematic diagram of another safety control circuit provided in an embodiment of this application. Figure 8 Is Figure 6This is further derived from the above. The second switching module 21 includes: a first switching transistor T1 and a second switching transistor T2; the second driving circuit 22 includes: a first driving sub-circuit 221 and a second driving sub-circuit 222. The first end of the first switching transistor T1 is connected to the second end of the first current sensor 23, the second end of the first switching transistor T1 is connected to the first end of the second switching transistor T2, and the second end of the second switching transistor T2 is connected to the input port of the battery.

[0078] The second output terminal of the control module 30 includes a first sub-output terminal and a second sub-output terminal. The first sub-output terminal of the control module 30 is connected to the input terminal of the first driving sub-circuit 221, and the output terminal of the first driving sub-circuit 221 is connected to the third terminal of the first switching transistor T1. The second sub-output terminal of the control module 30 is connected to the input terminal of the second driving sub-circuit 222, and the output terminal of the second driving sub-circuit 222 is connected to the third terminal of the second switching transistor T2.

[0079] The first switch T1 and the second switch T2 are different types of switches, such as Figure 8 As shown, the first switch T1 is a P-channel MOSFET, and the second switch T2 is an N-channel MOSFET. The cathode of the body diode of the first switch T1 (i.e., the second terminal of the first switch T1) is connected to the cathode of the body diode of the second switch T2 (i.e., the first terminal of the second switch T2). It should be noted that the driving circuits for the P-channel MOSFET and the N-channel MOSFET are different; that is, the first driving sub-circuit 221 and the second driving sub-circuit 222 are different.

[0080] like Figure 8 As shown, the control module 30 can obtain the current sampling result of the first current sensor 23 and execute the software protection logic. For example, if the first current sensor 23 detects that the current flows from the input port of the load to the output port of the DC / DC converter, and the current is greater than a first set threshold, it is determined that the first current sensor 23 has detected an abnormal current. The control module 30 then controls the first switch T1 to be in the off state through the first drive sub-circuit 221. The first set threshold can be preset. As another example, if the first current sensor 23 detects that the current flows from the output port of the DC / DC converter to the input port of the load, and the current is greater than a second set threshold, it is determined that the first current sensor 23 has detected an abnormal current. The control module 30 then controls the second switch T2 to be in the off state through the second drive sub-circuit 222.

[0081] Optionally, the safety control circuit further includes a second current sensor, the first end of which is connected to the second end of the second switching transistor, the second end of which is connected to the input port of the battery, and the third end of which is connected to the fourth input terminal of the control module.

[0082] In this embodiment, the current between the second terminal of the second switch T2 and the input port of the battery can be sampled using a second current sensor. When both the first switch T1 and the second switch T2 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 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 is faulty. This can further improve the accuracy of fault detection.

[0083] Please see Figure 9 , Figure 9 This is a schematic diagram of the structure of an electric vehicle provided in an embodiment of this application. Figure 9 As shown, the electric vehicle may include a safety control circuit, a DC / DC converter, and a load, wherein the DC / DC converter is connected to the load through the safety control circuit.

[0084] The DC / DC converter draws power from the battery and then supplies power to the load and the vehicle's ECU via a safety control circuit. The load can be the battery.

[0085] Figure 9 The safety control circuit described above can be referred to in the above embodiments, and will not be repeated here.

[0086] 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.

[0087] In the several embodiments provided in this application, it should be understood that the disclosed safety control circuit and electric vehicle can be implemented in other ways. For example, the safety control 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 safety control circuit, characterized in that, It includes a pre-charging circuit, a switch protection circuit, and a control module; the pre-charging circuit includes a first switch module, a first drive circuit, a current limiting module, and a capacitor; the switch protection circuit includes a second switch module, a second drive circuit, a first current sensor, and a first voltage sampling circuit; the DC / DC converter is connected to the load through the switch protection circuit; The output port of the DC / DC converter is connected to the first terminal of the capacitor, the first terminal of the first voltage sampling circuit, the first terminal of the current limiting module, and the first terminal of the first current sensor. The second terminal of the first current sensor 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 load. The third terminal of the first current sensor is connected to the first input terminal of the control module. The first output terminal of the control module is connected to the input terminal of the first driving circuit, and the output terminal of the first driving circuit is connected to the third terminal of the first switching module. The first terminal of the first switching module is connected to the power supply, the second terminal of the first switching module is connected to the second terminal of the current limiting module, and the third terminal of the first voltage sampling circuit is connected to the second input terminal of the control module. The second output terminal of the control module is connected to the input terminal of the second driving circuit, and the output terminal of the second driving circuit is connected to the third terminal of the second switching module. The second terminal of the capacitor and the second terminal of the first voltage sampling circuit are grounded. The control module controls the first switch module to be in the conducting state through the first drive circuit. When the first switch module is in the conducting state, the control module detects whether the DC / DC converter is short-circuited by the voltage sampled by the first voltage sampling circuit. If the DC / DC converter is not short-circuited, the power supply charges the capacitor through the current limiting module.

2. The safety control circuit according to claim 1, characterized in that, The control module detects whether the capacitor has completed pre-charging by sampling the voltage through the first voltage sampling circuit; Upon detecting that the capacitor has completed pre-charging, the control module controls the DC / DC converter to power on.

3. The safety control circuit according to claim 1, characterized in that, The load includes a passive load, and the power supply includes the auxiliary power supply of the DC / DC converter.

4. The safety control circuit according to claim 1, characterized in that, The load includes a battery, and the power supply includes the battery.

5. The safety control circuit according to claim 3 or 4, characterized in that, The first voltage sampling circuit includes a first resistor and a second resistor. The first end of the first resistor is connected to the output port of the DC / DC converter, the second end of the first resistor is connected to the first end of the second resistor and the second input terminal of the control module, and the second end of the second resistor is grounded.

6. The safety control circuit according to claim 3 or 4, characterized in that, The current limiting module includes a constant current source or a resistor module.

7. The safety control circuit according to claim 6, characterized in that, The resistor module includes a third resistor and a fourth resistor; the first end of the third resistor is connected to the second end of the first switch module, the second end of the third resistor is connected to the first end of the fourth resistor and the first end of the capacitor, and the second end of the fourth resistor is grounded.

8. The safety control circuit according to claim 4 or 7, characterized in that, The switch protection circuit further includes a second voltage sampling circuit, the second terminal of the first switch module is connected to the first terminal of the second voltage sampling circuit, and the second terminal of the second voltage sampling circuit is grounded; the third input terminal of the control module is connected to the third terminal of the second voltage sampling circuit.

9. The safety control circuit according to claim 4, characterized in that, The switch protection circuit further includes a third drive circuit, a third switch module, and a third voltage sampling circuit; the first terminal of the third switch module is connected to the input port of the battery, the second terminal of the third switch module is connected to the first terminal of the third voltage sampling circuit, and the second terminal of the third voltage sampling circuit is grounded; the third input terminal of the control module is connected to the third terminal of the third voltage sampling circuit, the third output terminal of the control module is connected to the input terminal of the third drive circuit, and the output terminal of the third drive circuit is connected to the third terminal of the third switch module.

10. An electric vehicle, characterized in that, Includes the safety control circuit, DC / DC converter, and load as described in any one of claims 1 to 9.

Images