Protection circuit for a vehicle interface and vehicle

Abstract

The application provides a protection circuit of a vehicle-mounted interface and a vehicle. The circuit comprises: a positive electrode of a first diode is electrically connected with a first power supply end; a first end of a first resistance module is electrically connected with a negative electrode of the first diode; a positive electrode of a second diode is electrically connected with a second power supply end; a first end of a second resistance module is electrically connected with a negative electrode of the second diode; a first end of a connector is electrically connected with a second end of the first resistance module and a second end of the second resistance module respectively, a second end of the connector is used for being electrically connected with an external device, the first power supply end and the second power supply end supply power to the external device via the connector, in the case that the external device is short-circuited, the first diode is used for protecting the first power supply end from being damaged, and the second diode is used for protecting the second power supply end from being damaged. The circuit has a simple structure, the cost of the used devices is low, and on the basis of realizing reverse protection, the cost of the circuit is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle terminal, in particular to a protection circuit of vehicle interface and a vehicle. BACKGROUND

[0002] In vehicle electronic circuit, there are high requirements for reliability and functional safety, so the communication between devices generally requires the devices to have interface diagnosis function and interface protection function, and the interface protection function mainly includes reverse protection, over current protection and over voltage protection. At present, the circuit for realizing the reverse protection function is relatively complex, and the cost of the circuit is relatively high. SUMMARY

[0003] The main purpose of the present application is to provide a protection circuit of vehicle interface and a vehicle, so as to solve the problem of complex circuit for realizing reverse protection function and high cost of the circuit in the prior art.

[0004] According to an aspect of an embodiment of the present application, a protection circuit of vehicle interface is provided, which comprises a first diode, a positive electrode of the first diode being electrically connected with a first power supply end; a first resistance module having a first end and a second end, the first end of the first resistance module being electrically connected with a negative electrode of the first diode; a second diode, a positive electrode of the second diode being electrically connected with a second power supply end; a second resistance module having a first end and a second end, the first end of the second resistance module being electrically connected with a negative electrode of the second diode; a connector having a first end and a second end, the first end of the connector being electrically connected with the second end of the first resistance module and the second end of the second resistance module respectively, the second end of the connector being used for electrically connecting with an external device, the first power supply end and the second power supply end supplying power to the external device via the connector, in the case of short circuit of the external device, the first diode being used for protecting the first power supply end from being damaged, and the second diode being used for protecting the second power supply end from being damaged.

[0005] Optionally, the circuit further comprises: a triode, a base of the triode being electrically connected with the second end of the second resistance module, an emitter of the triode being electrically connected with the first end of the second resistance module; a first MOS tube, a gate of the first MOS tube being electrically connected with a collector of the triode, a source of the first MOS tube being electrically connected with the base of the triode, a drain of the first MOS tube being electrically connected with the first end of the connector, wherein, in the case that the voltage value of the triode is greater than the voltage value threshold, the emitter of the triode and the collector of the triode are turned on, the collector of the triode outputs a first level signal, and under the action of the first level signal, the source of the first MOS tube and the drain of the first MOS tube are turned off.

[0006] Optionally, the circuit further comprises: a control unit having a first end, a second end and a third end, the first end of the control unit being electrically connected with the third power supply end; a third resistance module having a first end and a second end, the first end of the third resistance module being electrically connected with the first end of the connector, the second end of the third resistance module being electrically connected with the second end of the control unit; a fourth resistance module having a first end and a second end, the first end of the fourth resistance module being electrically connected with the second end of the control unit, the second end of the fourth resistance module being grounded, wherein the control unit is used for detecting whether the cable is short-circuited to the automobile battery, and turning off the first MOS tube in the case that the cable is detected to be short-circuited to the automobile battery.

[0007] Optionally, the circuit further comprises: a fifth resistance module having a first end and a second end, the first end of the fifth resistance module being electrically connected with the negative electrode of the second diode, the second end of the fifth resistance module being electrically connected with the collector of the triode; a sixth resistance module having a first end and a second end, the first end of the sixth resistance module being electrically connected with the gate of the first MOS tube; a second MOS tube, a drain of the second MOS tube being electrically connected with the second end of the sixth resistance module, a source of the second MOS tube being grounded; a seventh resistance module having a first end and a second end, the first end of the seventh resistance module being electrically connected with the third end of the control unit, the second end of the seventh resistance module being electrically connected with the gate of the second MOS tube; an eighth resistance module having a first end and a second end, the first end of the eighth resistance module being electrically connected with the gate of the second MOS tube, the second end of the eighth resistance module being grounded.

[0008] Optionally, the circuit further comprises: a first capacitance module having a first end and a second end, the first end of the first capacitance module being electrically connected with the second end of the control unit, the second end of the first capacitance module being grounded.

[0009] Optionally, the control unit is further configured to: calculate a sum of the resistance value of the third resistance module and the resistance value of the fourth resistance module to obtain a first calculation result; calculate a quotient of the voltage value of the main battery of the vehicle and the first calculation result to obtain a second calculation result; calculate a product of the second calculation result and the resistance value of the fourth resistance module to obtain a third calculation result, and determine whether the cable is short-circuited to the automobile battery according to the third calculation result.

[0010] Optionally, the control unit is further configured to: in a case where the third calculation result is less than a first threshold value, determine that the cable is in normal operation, and continue to supply power to the external device; and in a case where the third calculation result is greater than the first threshold value, determine that the cable is short-circuited to the automobile battery, and output a first level signal from a third end of the control unit, so that the first MOS tube is turned off under the action of the first level signal.

[0011] Optionally, the control unit is further configured to: detect a voltage value of a second end of the control unit according to the resistance value of the first resistance module, and determine whether the cable is open-circuited according to the voltage value of the second end of the control unit.

[0012] Optionally, the control unit is further configured to: obtain an input impedance value of the external device; calculate a quotient of the first calculation result and the input impedance value to obtain a fourth calculation result; calculate a sum of the fourth calculation result and the resistance value of the first resistance module to obtain a fifth calculation result; calculate a quotient of the voltage value of the first power supply end and the fifth calculation result to obtain a sixth calculation result; calculate a product of the sixth calculation result and the fourth calculation result to obtain a voltage value of a first detection point, the first detection point being located between the drain of the first MOS tube and a second end of the first resistance module; calculate a voltage value of the second end of the control unit according to the voltage value of the first detection point, and determine whether the cable is open-circuited according to the voltage value of the second end of the control unit.

[0013] Optionally, the control unit is further configured to: calculate a quotient of the voltage value of the first detection point and the fourth calculation result to obtain a seventh calculation result; and calculate a product of the seventh calculation result and the resistance value of the fourth resistance module to obtain the voltage value of the second end of the control unit.

[0014] Optionally, the control unit is further configured to: in a case where it is detected that the voltage value of the second end of the control unit is a first voltage value, determine that the cable is not open-circuited; and in a case where it is detected that the voltage value of the second end of the control unit is a second voltage value, determine that the cable is open-circuited.

[0015] Optionally, the control unit is further configured to determine whether the cable is short-circuited to ground according to the input impedance value; and determine a voltage value range of the second end of the control unit in a case where it is determined that the cable is not short-circuited to ground.

[0016] Optionally, the control unit is further configured to determine that the cable is short-circuited to ground and stop supplying power or outputting a signal to the external device in a case where the input impedance value is the first resistance value, the detected voltage value of the first detection point is the third voltage value, and the detected voltage value of the second end of the control unit is the third voltage value; determine the voltage value range of the second end of the control unit according to the fifth voltage value and the seventh voltage value in a case where the input impedance value is the second resistance value, the detected voltage value of the first detection point is the fourth voltage value, and the detected voltage value of the second end of the control unit is the fifth voltage value; and determine the voltage value range of the second end of the control unit according to the third resistance value, the detected voltage value of the first detection point is the sixth voltage value, and the detected voltage value of the second end of the control unit is the seventh voltage value.

[0017] Optionally, the circuit further comprises a fuse module having a first end and a second end, the first end of the fuse module is electrically connected to the drain of the first MOS tube, and the second end of the fuse module is electrically connected to the first end of the connector; a second capacitor module having a first end and a second end, the first end of the second capacitor module is electrically connected to the first end of the connector, and the second end of the second capacitor module is grounded; and a third diode, the anode of the third diode is electrically connected to the first end of the connector, and the cathode of the third diode is grounded.

[0018] According to another aspect of the embodiments of the present application, a vehicle is also provided, which comprises a protection circuit of the vehicle-mounted interface, and the protection circuit is any one of the protection circuits.

[0019] In the embodiments of the present application, the voltage of the external device is greater than the voltage of the first power supply end and the voltage of the second power supply end, and in a case where the connector is short-circuited to the external device, the first diode can protect the first power supply end from being damaged due to the reverse voltage protection function of the diode, the second diode can protect the second power supply end from being damaged, the circuit can still work normally in a case where the external device circuit, and the circuit has a simple structure and low cost of devices used, and the cost of the circuit is reduced on the basis of realizing reverse protection. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the illustrative embodiments of the present application and their description are used to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0021] Figure 1 A structure diagram of a protection circuit of a vehicle-mounted interface is shown according to an embodiment of the present application.

[0022] In the above drawings, reference numerals include the following:

[0023] 10, connector; 20, control unit; 30, analog-digital conversion module. DETAILED DESCRIPTION

[0024] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0025] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the scope of protection of the present application.

[0026] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0027] It should be understood that when an element (such as a layer, film, region, or substrate) is described as "on" another element, it can be directly on the other element, or there can be an intermediate element. Also, in the specification and claims, when an element is described as "connected to" another element, it can be "directly connected to" the other element, or "connected to" the other element through a third element.

[0028] As mentioned in the background, the circuit of the reverse protection function in the prior art is relatively complex, and the cost of the circuit is relatively high. In order to solve the above problems, in an embodiment of the present application, a protection circuit of a vehicle-mounted interface and a vehicle are provided.

[0029] According to an embodiment of the present application, a protection circuit of a vehicle-mounted interface is provided. According to an embodiment of the present application, a protection circuit of a vehicle-mounted interface is provided.

[0030] Figure 1 is a structure diagram of a protection circuit of a vehicle-mounted interface according to an embodiment of the present application, as shown in the figure, the circuit comprises: Figure 1

[0031] a first diode D1, a positive electrode of the first diode D1 is electrically connected with a first power supply end VCC1;

[0032] a first resistor module R6, the first resistor module R6 can have a resistance value of 68kΩ, the first resistor module R6 has a first end and a second end, the first end of the first resistor module R6 is electrically connected with a negative electrode of the first diode D1;

[0033] a second diode D2, a positive electrode of the second diode D2 is electrically connected with a second power supply end VCC2;

[0034] a second resistor module R8, the second resistor module R8 can have a resistance value of 20Ω, the second resistor module R8 has a first end and a second end, the first end of the second resistor module R8 is electrically connected with a negative electrode of the second diode D2;

[0035] a connector 10, having a first end and a second end, the first end of the connector 10 is respectively electrically connected with the second end of the first resistor module R6 and the second end of the second resistor module R8, the second end of the connector 10 is used for electrically connecting with an external device, the first power supply end VCC1 and the second power supply end VCC2 supply power to the external device via the connector 10, in the case of short circuit of the external device, the first diode D1 is used for protecting the first power supply end VCC1 from being damaged, and the second diode D2 is used for protecting the second power supply end VCC2 from being damaged.

[0036] In the above-mentioned circuit, the voltage of the external device is greater than the voltage of the first power supply end and the voltage of the second power supply end, in the case of short circuit of the external device to the connector, since the diode has a reverse voltage protection function, the first diode can protect the first power supply end from being damaged, and the second diode can protect the second power supply end from being damaged, in the case of the external device circuit, the circuit can still work normally, and the structure of the circuit is simple, the cost of the devices used is low, on the basis of realizing reverse protection, the cost of the circuit is reduced.

[0037] In a specific embodiment, the battery of a passenger vehicle is generally 14V voltage, the voltage value of the first power supply end is 5V, and the voltage value of the second power supply end is 12V, in the case of short circuit of the 1 pin of the connector to the circuit, since the first diode has a reverse voltage protection function, as shown in the figure, Figure 1 ​As shown, the voltage of 14V will not damage VCC1=5V, and the voltage of 14V will not damage VCC2=12V due to the reverse voltage protection function of the second diode, so the cable will not affect the normal operation of the device on the battery circuit.

[0038] In an embodiment of the present application, as shown in Figure 1 As shown, the circuit further comprises a transistor Q5 and a first MOS tube Q4, the base of the transistor Q5 is electrically connected to the second end of the second resistance module R8, and the emitter of the transistor Q5 is electrically connected to the first end of the second resistance module R8; the gate of the first MOS tube Q4 is electrically connected to the collector of the transistor Q5, the source of the first MOS tube Q4 is electrically connected to the base of the transistor Q5, and the drain of the first MOS tube Q4 is electrically connected to the first end of the connector 10. In the case where the voltage value of the transistor Q5 is greater than the voltage value threshold, the emitter of the transistor Q5 and the collector of the transistor Q5 are turned on, the collector of the transistor Q5 outputs a first level signal, and under the action of the first level signal, the source of the first MOS tube Q4 and the drain of the first MOS tube Q4 are turned off. In this embodiment, in the case where the output current increases, the current passing through the second resistance module increases, the voltage value between the two ends of the second resistance module increases, and the voltage value between the emitter and the base of the transistor increases. According to the characteristics of the transistor, in the case where the voltage value between the emitter and the base of the transistor is greater than the voltage value threshold, the emitter and the collector of the transistor are turned on, the collector of the transistor outputs a first level signal, and the first MOS tube is turned off under the action of the first level signal. Thus, the circuit can also realize the function of overcurrent protection.

[0039] In an embodiment, in the case where the first MOS tube is a silicon tube, the voltage value threshold can be 0.7V, in the case where the first MOS tube is a germanium tube, the voltage value is 0.3V, and the first level signal can be a high level signal. In the case where the first MOS tube receives a high level signal, the voltage value of the first MOS tube is 0V. In the case where the voltage value between the emitter and the base of the transistor is less than the voltage value threshold, the collector of the transistor outputs a second level signal, and the first MOS tube continues to be turned on under the action of the second level signal.

[0040] In another embodiment of the present application, as shown in Figure 1As shown, the above circuit further comprises a control unit 20, a third resistance module R10 and a fourth resistance module R16, the control unit 20 has a first end, a second end and a third end, the resistance value of the third resistance module R10 can be 22KΩ, the resistance value of the fourth resistance module R16 can be 10KΩ, the first end of the control unit 20 is electrically connected with the third power supply end VCC3; the third resistance module R10 has a first end and a second end, the first end of the third resistance module R10 is electrically connected with the first end of the connector 10, and the second end of the third resistance module R10 is electrically connected with the second end of the control unit 20; the fourth resistance module R16 has a first end and a second end, the first end of the fourth resistance module R16 is electrically connected with the second end of the control unit 20, and the second end of the fourth resistance module R16 is grounded, wherein the control unit 20 is used for detecting whether the cable is short-circuited to the automobile battery, and turning off the first MOS tube Q4 when it is detected that the cable is short-circuited to the automobile battery. In this embodiment, the control unit can further efficiently detect whether the cable is short-circuited to the automobile battery, and the battery circuit protection function can be further efficiently realized.

[0041] In a specific embodiment, as shown in the figure, Figure 1 The voltage value of the first power supply end VCC1 is 5V, the voltage value of the second power supply end is 12V, and the voltage value of the third power supply end VCC3 is 5V. The above three power supply ends are all internal power supplies of the vehicle-mounted device, the control unit can be an MCU, the control unit 20 has an analog-to-digital conversion module 30 inside, the voltage value on the output cable can be realized through the analog-to-digital conversion module 30, and a control signal (MCU_GPIO) is output to control the opening and closing of the external output switch (the first MOS tube).

[0042] In another embodiment of the present application, as shown in the figure, Figure 1As shown, the circuit also includes a fifth resistor module R9, a sixth resistor module R13, a second MOSFET Q6, a seventh resistor module R18, and an eighth resistor module R19. The resistance value of the fifth resistor module R9 can be 100KΩ, the resistance value of the sixth resistor module R13 can be 10KΩ, the resistance value of the seventh resistor module R18 can be 1KΩ, and the resistance value of the eighth resistor module R19 can be 10KΩ. The fifth resistor module R9 has a first terminal and a second terminal. The first terminal of the fifth resistor module R9 is electrically connected to the negative terminal of the second diode D2, and the second terminal of the fifth resistor module R9 is electrically connected to the collector of the transistor Q5. The sixth resistor module R13 has a first terminal and a second terminal. The sixth resistor module R13 has a first terminal electrically connected to the gate of the first MOSFET Q4; the drain of the second MOSFET Q6 is electrically connected to the second terminal of the sixth resistor module R13, and the source of the second MOSFET Q6 is grounded; the seventh resistor module R18 has a first terminal and a second terminal, the first terminal of the seventh resistor module R18 is electrically connected to the third terminal of the control unit 20, and the second terminal of the seventh resistor module R18 is electrically connected to the gate of the second MOSFET Q6; the eighth resistor module R19 has a first terminal and a second terminal, the first terminal of the eighth resistor module R19 is electrically connected to the gate of the second MOSFET Q6, and the second terminal of the eighth resistor module R19 is grounded. In this embodiment, the fifth resistor module, sixth resistor module, second MOSFET, seventh resistor module, and eighth resistor module used are all of low cost, which can further reduce the cost of the circuit.

[0043] In another embodiment of this application, such as Figure 1 As shown, the circuit also includes a first capacitor module C1. The capacitance of the first capacitor module C1 can be 0.1uF, and the voltage of the first capacitor module C1 can be 50V. The first capacitor module C1 has a first terminal and a second terminal. The first terminal of the first capacitor module C1 is electrically connected to the second terminal of the control unit 20, and the second terminal of the first capacitor module C1 is grounded. In this embodiment, the first capacitor module can filter the electrical signal, further ensuring a high accuracy of the signal at the second terminal of the input value control unit.

[0044] In one specific embodiment of this application, the control unit is further configured to calculate the sum of the resistance values ​​of the third resistor module and the fourth resistor module to obtain a first calculation result; calculate the quotient of the voltage value of the vehicle's main battery and the first calculation result to obtain a second calculation result; calculate the product of the second calculation result and the resistance value of the fourth resistor module to obtain a third calculation result; and determine whether the cable is short-circuited to the vehicle battery based on the third calculation result. In this embodiment, the control unit can determine whether the cable is short-circuited to the vehicle battery more accurately and efficiently based on the third calculation result.

[0045] In one embodiment, the pin of the control unit generally works in the range of 0-5V, so the voltage value of the second end of the control unit is to be less than 5V, by adjusting the resistance value of the third resistance module and the resistance value of the fourth resistance module, the voltage value of the second end of the control unit is limited to below 5V, and the calculation formula for calculating the voltage value of the second end of the control unit is as follows:

[0046] Wherein, V LINE_ADC represents the voltage value of the second end of the control unit, Vbat represents the voltage value of the main battery of the vehicle, R10 represents the resistance value of the third resistance module, and R16 represents the resistance value of the fourth resistance module.

[0047] In another specific embodiment of the application, the control unit is further configured to determine that the cable is working normally and continue to supply power to the external device when the third calculation result is less than the first threshold value, and determine that the cable is short-circuited to the vehicle battery when the third calculation result is greater than the first threshold value, and the third end of the control unit outputs a first level signal, and the first MOS tube Q4 is turned off under the action of the first level signal. In this embodiment, whether the cable is short-circuited to the vehicle battery can be more efficiently determined according to the size relationship between the third calculation result and the first threshold value.

[0048] In one embodiment, V LINE_ADC = 4.375V, which is less than 5V, and is within the normal voltage acquisition range of the analog-to-digital conversion module of the control unit, so the pin of the control unit will not be damaged. If the control unit detects that the voltage on the cable is 14V, it can be determined that the cable is short-circuited to the vehicle battery circuit, and the third end of the control unit will output a first level signal, the first MOS will be turned off, and the 12V power output to the outside will be disconnected, further protecting the external device.

[0049] In another specific embodiment of the application, the control unit is further configured to detect the voltage value of the second end of the control unit according to the resistance value of the first resistance module, and determine whether the cable is open according to the voltage value of the second end of the control unit. In this embodiment, the resistance value of the first resistance module is further used to more accurately determine the voltage value of the second end of the control unit to determine whether the cable is open.

[0050] In another specific embodiment of the application, as Figure 1As shown, the control unit 20 is further configured to obtain an input impedance value of the external device; calculate a quotient of the first calculation result and the input impedance value to obtain a fourth calculation result; calculate a sum of the fourth calculation result and a resistance value of the first resistance module R6 to obtain a fifth calculation result; calculate a quotient of a voltage value of the first power supply end and the fifth calculation result to obtain a sixth calculation result; calculate a product of the sixth calculation result and the fourth calculation result to obtain a voltage value of a first detection point TP1, the first detection point TP1 being located between a drain of the first MOS Q4 and a second end of the first resistance module R6; calculate a voltage value of a second end of the control unit 20 according to the voltage value of the first detection point TP1, and determine whether the cable is open according to the voltage value of the second end of the control unit 20. In this embodiment, the voltage value of the first detection point is further accurately determined according to the resistance value of the first resistance module, the input impedance value, the resistance value of the third resistance module and the resistance value of the fourth resistance module, and then the voltage value of the second end of the control unit is more accurately calculated according to the voltage value of the first detection point.

[0051] In one embodiment, before the vehicle-mounted device is powered on, it is necessary to detect whether the cable is open, and then to confirm whether to output a signal to the cable. Before the signal is input, the first MOS will be closed, and the voltage value of the first detection point is 5V. Since the signal connection of the external device generally has an input impedance value, which is generally about several tens of KΩ. Once the cable is inserted, the impedance value of the entire cable link will change. The formula for calculating the voltage value of the first detection point is as follows:

[0052] V TP1 represents the voltage value of the first detection point, VCC1 represents the voltage value of the first power supply end, Rext represents the input impedance value, and R6 represents the resistance value of the first resistance module.

[0053] In one embodiment of the present application, the control unit is further configured to calculate a quotient of the voltage value of the first detection point and the fourth calculation result to obtain a seventh calculation result; calculate a product of the seventh calculation result and a resistance value of the fourth resistance module to obtain the voltage value of the second end of the control unit. In this embodiment, the voltage value of the second end of the control unit is more efficiently and accurately calculated according to the voltage value of the first detection point.

[0054] In one embodiment, the formula for calculating the voltage value of the second end of the control unit is as follows:

[0055] V LINE_ADC represents the voltage value of the second end of the control unit, and more specifically, as Figure 1As shown, the protection circuit further comprises a second detection point TP2 and a third detection point TP3. The second detection point TP2 is located between the second end of the second resistance module R8 and the source level of the first MOS tube Q4. The third detection point TP3 is located between the second end of the seventh resistance module R18 and the gate of the second MOS tube Q6. The base voltage of the transistor Q5 or the source voltage of the first MOS tube Q4 can be detected through the second detection point TP2. The gate voltage of the second MOS tube Q6 can be detected through the third detection point TP3.

[0056] In another embodiment of the present application, the control unit is further configured to determine that the cable is not open-circuited when the voltage value of the second end of the control unit is detected to be the first voltage value, and determine that the cable is open-circuited when the voltage value of the second end of the control unit is detected to be the second voltage value. In this embodiment, whether the cable is open-circuited can be determined more accurately according to the specific value of the detected voltage value of the second end of the control unit.

[0057] In a specific embodiment, when the external cable is connected to the connector, V TP1 = 0.503V, V LINE_ADC = 0.157V, when the external cable is disconnected from the connector, V TP1 = 1.6V, V LINE_ADC = 0.5V, and when V LINE_ADC = 0.5V is detected, the cable is disconnected, and the open-circuit diagnosis function can be realized.

[0058] In another embodiment of the present application, the control unit is further configured to determine whether the cable is short-circuited to ground according to the input impedance value, and determine the voltage value range of the second end of the control unit when it is determined that the cable is not short-circuited to ground. In this embodiment, whether the cable is short-circuited to ground is detected before the vehicle-mounted device is powered on. Since the signal connection of the external device has a certain input impedance value, generally several tens of KΩ to several hundred KΩ, once the cable is inserted, the entire cable link impedance value will change. Therefore, it is necessary to detect whether the cable is short-circuited to ground and accurately determine the voltage value range of the second end of the control unit when it is not short-circuited to ground.

[0059] In another embodiment of the present application, the control unit is further configured to determine that the cable is short-circuited to ground and stop the power supply or signal output to the external device when the input impedance value is the first resistance value, the voltage value of the first detection point is the third voltage value, and the voltage value of the second end of the control unit is the third voltage value; when the input impedance value is the second resistance value, the voltage value of the first detection point is the fourth voltage value, and the voltage value of the second end of the control unit is the fifth voltage value; when the input impedance value is the third resistance value, the voltage value of the first detection point is the sixth voltage value, and the voltage value of the second end of the control unit is the seventh voltage value; and determine the voltage value range of the second end of the control unit according to the fifth voltage value and the seventh voltage value. In this embodiment, the voltage value range of the second end of the control unit can be determined more accurately in the case where the cable is not short-circuited to ground, so that whether the cable is short-circuited to ground can be determined more accurately according to the voltage value range.

[0060] In one embodiment, when Rext=1K, V TP1 =0.07V, V LINE_ADC =0.022V=22mV, when Rext=500K, V TP1 =1.533V, V LINE_ADC =0.479V=479mV, it can be determined that the voltage value range of the second end of the control unit is between [22-479mV], and when the cable is short-circuited to ground, Rext=0Ω, V TP1 =0V, V LINE_ADC =0V, and when V LINE_ADC =0V, the cable is short-circuited to ground, the external device is prohibited from outputting a signal or power, and the circuit can realize the cable-to-ground circuit diagnosis function.

[0061] In one specific embodiment of the present application, as Figure 1As shown, the circuit further comprises a fuse module, a second capacitor module C2 and a third diode D3, the fuse module comprises a fuse FB1, the capacitor value of the second capacitor module C2 can be 10uF, the voltage value of the second capacitor C2 can be 50V, the fuse module has a first end and a second end, the first end of the fuse module is electrically connected with the drain of the first MOS tube Q4, and the second end of the fuse module is electrically connected with the first end of the connector 10; the second capacitor module C2 has a first end and a second end, the first end of the second capacitor module C2 is electrically connected with the first end of the connector 10, and the second end of the second capacitor module C2 is grounded; the anode of the third diode D3 is electrically connected with the first end of the connector 10, and the cathode of the third diode D3 is grounded. In this embodiment, the fuse module can further protect the safety of the circuit, and the second capacitor module can further filter the signal, thereby ensuring that the effectiveness of the transmitted signal is good.

[0062] The embodiments of the present application also provide a vehicle comprising the protection circuit of the vehicle-mounted interface.

[0063] In the vehicle, since the protection circuit comprises any one of the protection circuits, the voltage of the external device is greater than the voltage of the first power supply end and the voltage of the second power supply end, in the case that the connector is short-circuited with the external device, the first diode can protect the first power supply end from being damaged due to the reverse voltage protection function of the diode, the second diode can protect the second power supply end from being damaged, the circuit can still work normally in the case of the external device circuit, and the structure of the circuit is simple, the cost of the devices used is low, and the cost of the circuit is reduced on the basis of realizing the reverse protection.

[0064] In the above embodiments of the present application, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0065] In the several embodiments provided by the present application, it should be understood that the disclosed technology can be implemented in other ways. Of course, the unit division in the above device embodiment is only a logical function division, and there can be another division manner during actual implementation; for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the shown or discussed modules can be indirect coupling or communication connection through some interface, and can be electrical or other form.

[0066] The units described as separate components above can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed to multiple units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0067] In addition, each functional unit in each embodiment of the application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0068] The integrated unit, if realized in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the application, essentially or the part that contributes to the prior art, or all or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the above-mentioned method of each embodiment of the application. The foregoing storage medium includes: a U disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a mobile hard disk, a magnetic disk or an optical disk, and various program code storage media.

[0069] From the above description, it can be seen that the above-mentioned embodiments of the application achieve the following technical effects:

[0070] 1) The protection circuit of the vehicle-mounted interface of the application, the voltage of the external device is greater than the voltage of the first power supply end and the voltage of the second power supply end, in the case of short circuit of the connector to the external device, since the diode has a reverse voltage protection function, the first diode can protect the first power supply end from being damaged, the second diode can protect the second power supply end from being damaged, in the case of the external device circuit, the circuit can still work normally, and the structure of the circuit is simple, the cost of the devices used is low, on the basis of realizing reverse protection, the cost of the circuit is reduced.

[0071] 2) The vehicle of the present application, because it comprises any one of the above-mentioned protection circuits, in which the voltage of the external device is greater than the voltage of the first power supply end and the voltage of the second power supply end, in the case of short circuit of the connector to the external device, because the diode has a reverse voltage protection function, the first diode can protect the first power supply end from being damaged, the second diode can protect the second power supply end from being damaged, in the case of the external device circuit, the circuit can still work normally, and the structure of the circuit is simple, the cost of the devices used is lower, on the basis of realizing reverse protection, the cost of the circuit is reduced.

[0072] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A protection circuit for an in-vehicle interface, characterized by, The circuit comprises: a first diode, a positive electrode of the first diode being electrically connected to a first power terminal; a first resistor module having a first end and a second end, the first end of the first resistor module being electrically connected to a negative electrode of the first diode; a second diode, a positive electrode of the second diode being electrically connected to a second power terminal; a second resistor module having a first end and a second end, the first end of the second resistor module being electrically connected to a negative electrode of the second diode; a connector having a first end and a second end, the first end of the connector being electrically connected to the second end of the first resistor module and the second end of the second resistor module respectively, the second end of the connector being used for electrical connection with an external device, the first power terminal and the second power terminal supplying power to the external device via the connector, in the case of a short circuit of the external device, the first diode is used to protect the first power terminal from being damaged, and the second diode is used to protect the second power terminal from being damaged; The circuit further comprises: a transistor, a base of the transistor being electrically connected to the second end of the second resistor module, an emitter of the transistor being electrically connected to the first end of the second resistor module; a first MOS tube, a gate of the first MOS tube being electrically connected to a collector of the transistor, a source of the first MOS tube being electrically connected to the base of the transistor, a drain of the first MOS tube being electrically connected to the first end of the connector, wherein, in the case that a voltage value of the transistor is greater than a voltage value threshold, the emitter of the transistor and the collector of the transistor are turned on, the collector of the transistor outputs a first level signal, and under the action of the first level signal, the source of the first MOS tube and the drain of the first MOS tube are turned off; a control unit having a first end, a second end and a third end, the first end of the control unit being electrically connected to a third power terminal; a third resistor module having a first end and a second end, the first end of the third resistor module being electrically connected to the first end of the connector, the second end of the third resistor module being electrically connected to the second end of the control unit; a fourth resistor module having a first end and a second end, the first end of the fourth resistor module being electrically connected to the second end of the control unit, the second end of the fourth resistor module being grounded, wherein the control unit is used to detect whether a cable is short-circuited to a car battery, and in the case that the cable is detected to be short-circuited to the car battery, the first MOS tube is turned off; The control unit is further used to: calculate a sum of a resistance value of the third resistor module and a resistance value of the fourth resistor module to obtain a first calculation result; calculate a quotient of a voltage value of a main battery of a vehicle and the first calculation result to obtain a second calculation result; calculate a product of the second calculation result and the resistance value of the fourth resistor module to obtain a third calculation result, and determine whether the cable is short-circuited to the car battery according to the third calculation result.

2. The protection circuit of claim 1, wherein The circuit further comprises: a fifth resistor module having a first end and a second end, the first end of the fifth resistor module being electrically connected to the negative electrode of the second diode, and the second end of the fifth resistor module being electrically connected to the collector of the transistor; a sixth resistor module having a first end and a second end, the first end of the sixth resistor module being electrically connected to the gate of the first MOS tube; a second MOS tube, the drain of the second MOS tube being electrically connected to the second end of the sixth resistor module, and the source of the second MOS tube being grounded; a seventh resistor module having a first end and a second end, the first end of the seventh resistor module being electrically connected to the third end of the control unit, and the second end of the seventh resistor module being electrically connected to the gate of the second MOS tube; an eighth resistor module having a first end and a second end, the first end of the eighth resistor module being electrically connected to the gate of the second MOS tube, and the second end of the eighth resistor module being grounded.

3. The protection circuit of claim 1, wherein, The circuit further comprises: a first capacitor module having a first end and a second end, the first end of the first capacitor module being electrically connected to the second end of the control unit, and the second end of the first capacitor module being grounded.

4. The protection circuit of claim 1, wherein, The control unit is further configured to: in a case where the third calculation result is less than a first threshold value, determine that the cable is working normally, and continue to supply power to the external device; in a case where the third calculation result is greater than the first threshold value, determine that the cable is short-circuited to the automobile battery, and output a first level signal from the third end of the control unit, so that the first MOS tube is turned off under the action of the first level signal.

5. The protection circuit of claim 1, wherein, The control unit is further configured to: detect a voltage value of the second end of the control unit according to the resistance value of the first resistor module, and determine whether the cable is open-circuited according to the voltage value of the second end of the control unit.

6. The protection circuit of claim 5, wherein, The control unit is further configured to: obtain an input impedance value of the external device; calculate a quotient of the first calculation result and the input impedance value to obtain a fourth calculation result; calculate a sum of the fourth calculation result and the resistance value of the first resistor module to obtain a fifth calculation result; calculate a quotient of the voltage value of the first power supply end and the fifth calculation result to obtain a sixth calculation result; calculate a product of the sixth calculation result and the fourth calculation result to obtain a voltage value of a first detection point, the first detection point being located between the drain of the first MOS tube and the second end of the first resistor module; calculate a voltage value of the second end of the control unit according to the voltage value of the first detection point, and determine whether the cable is open-circuited according to the voltage value of the second end of the control unit.

7. The protection circuit of claim 6, wherein, The control unit is further configured to: calculate a quotient of the voltage value of the first detection point and the fourth calculation result to obtain a seventh calculation result; calculate a product of the seventh calculation result and the resistance value of the fourth resistor module to obtain the voltage value of the second end of the control unit.

8. The protection circuit of claim 6, wherein, The control unit is further configured to: in a case where the voltage value of the second end of the control unit is detected as a first voltage value, determine that the cable is not open-circuited; in a case where the voltage value of the second end of the control unit is detected as a second voltage value, determine that the cable is open-circuited.

9. The protection circuit of claim 6, wherein, The control unit is further configured to: determining whether the cable is short-circuited to ground according to the input impedance value; in a case where it is determined that the cable is not short-circuited to ground, determining a voltage value range of the second end of the control unit.

10. The protection circuit of claim 9, wherein, The control unit is further configured to: in a case where the input impedance value is the first resistance value, the detected voltage value of the first detection point is the third voltage value, and the detected voltage value of the second end of the control unit is the third voltage value, determining that the cable is short-circuited to ground, and stopping power supply to the external device or signal output; in a case where the input impedance value is the second resistance value, the detected voltage value of the first detection point is the fourth voltage value, and the detected voltage value of the second end of the control unit is the fifth voltage value; in a case where the input impedance value is the third resistance value, the detected voltage value of the first detection point is the sixth voltage value, and the detected voltage value of the second end of the control unit is the seventh voltage value; determining the voltage value range of the second end of the control unit according to the fifth voltage value and the seventh voltage value.

11. The protection circuit of claim 1, wherein, The circuit further comprises: a fuse module having a first end and a second end, the first end of the fuse module being electrically connected to the drain of the first MOS tube, and the second end of the fuse module being electrically connected to the first end of the connector; a second capacitor module having a first end and a second end, the first end of the second capacitor module being electrically connected to the first end of the connector, and the second end of the second capacitor module being grounded; a third diode, one end of the third diode being electrically connected to the first end of the connector, and the other end of the third diode being grounded.

12. A vehicle characterized by comprising: The protection circuit comprises a vehicle-mounted interface, and the protection circuit is any one of the protection circuits in claims 1 to 11.

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