Bus protection circuit, bus protection module, bus protection device and bus interface

Abstract

The utility model discloses a bus protection circuit, module and device and a bus interface, and relates to the technical field of bus protection, the bus protection circuit is characterized in that a first end of a detection module is connected with a first signal input end and a first input end of a bus driving chip, and a second end of the detection module is connected with a second signal input end; the detection module is used for outputting a turn-off signal when detecting that the pressure difference between the first signal input end and the second signal input end is greater than a preset pressure difference threshold value; the first end of the switch module is connected with the first input end of the bus driving chip, the second end of the switch module is connected with the second signal input end, the third end of the switch module is connected with the detection module, and the switch module is used for receiving the turn-off signal and turning off the turn-off signal so as to stop transmitting the signal of the interface to the bus driving chip; and the power supply module is respectively connected with the bus driving chip and the switch module. The problem that irreversible damage occurs when the bus driving chip is protected can be solved.

Description

Technical Field

[0001] The present application relates to the field of bus protection technology, and in particular to a bus protection circuit, module, device and bus interface. Background Art

[0002] CAN (Controller Area Network) is a serial communication protocol bus used for real-time applications, which can use twisted pair cables to transmit signals.

[0003] Generally, on some devices with power ports and CAN bus ports, it is easy to cause the CAN bus to be connected to a voltage exceeding the limit voltage that the CAN bus driver chip can withstand due to unexpected reasons such as improper plugging and unplugging, resulting in damage to the CAN bus driver chip. In the prior art, a transient suppression diode is set between the CAN buses to suppress transient overvoltage to protect the CAN bus. For example, a transient suppression diode such as PESD1 CAN or PESD1 CAN is used to protect the CAN bus through the working principle of a diode array. Two reverse-parallel diodes are connected to the two signal lines of the CAN bus respectively. If the voltage on the CAN bus exceeds the breakdown voltage of the diode, the diode will be turned on and the overvoltage will be diverted to the ground, thereby protecting the CAN bus from overvoltage damage.

[0004] However, when the CAN bus is accidentally connected to an overvoltage shock with a high-energy or low-resistance power supply (such as a battery), this protection method will produce an irreversible damage due to the maximum discharge energy that exceeds the protection components such as transient suppression diodes. Utility Model Content

[0005] The main purpose of the present application is to provide a bus protection circuit, module, device and bus interface, aiming to solve the technical problem of irreversible damage when protecting the bus driver chip.

[0006] To achieve the above object, the present application provides a bus protection circuit, wherein a first end of the bus protection circuit is connected to a bus driver chip, a second end of the bus protection circuit is connected to an interface, the interface includes a first signal input end and a second signal input end, and the bus protection circuit includes:

[0007] a detection module, wherein a first end of the detection module is connected to the first signal input end and the first input end of the bus driver chip respectively, and a second end of the detection module is connected to the second signal input end, and the detection module is used to output a shutdown signal when it is detected that the voltage difference between the first signal input end and the second signal input end is greater than a preset voltage difference threshold;

[0008] a switch module, wherein a first end of the switch module is connected to a first input end of the bus driver chip, a second end of the switch module is connected to the second signal input end, and a third end of the switch module is connected to the detection module, and is used to receive the shutdown signal and shut down to stop transmitting the signal of the interface to the bus driver chip;

[0009] A power supply module is connected to the bus driver chip and the switch module respectively, and is used for adjusting the voltage of the bus driver chip and sending it to the switch module.

[0010] In one embodiment, the detection module includes:

[0011] a first resistor, wherein a first end of the first resistor is connected to the first signal input end;

[0012] a diode, a first end of the diode being connected to a second end of the first resistor;

[0013] A transistor, wherein the control end of the transistor is connected to the second end of the diode, the first end of the transistor is connected to the switch module, and the second end of the transistor is respectively connected to the second signal input end and the first output end of the power module.

[0014] In one embodiment, the detection module further includes:

[0015] A diode rectifier bridge, wherein the first end of the diode rectifier bridge is connected to the first signal input end, the second end of the diode rectifier bridge is connected to the second signal input end, the third end of the diode rectifier bridge is connected to the first end of the first resistor, and the fourth end of the diode rectifier bridge is connected to the power module.

[0016] In one embodiment, the switch module includes: a first field effect transistor, a first end of the first field effect transistor is connected to the second input end of the bus driver chip, and a control end of the first field effect transistor is respectively connected to the second input end of the power module and the first end of the transistor;

[0017] A second field effect transistor, wherein the first end of the second field effect transistor is respectively connected to the second end of the first field effect transistor and the first output end of the power module, the second end of the second field effect transistor is connected to the second signal input end, and the control end of the second field effect transistor is connected to the control end of the first field effect transistor.

[0018] In one embodiment, the switch module further includes:

[0019] A second resistor, wherein a first end of the second resistor is connected to the control end of the first field effect transistor, and a second end of the second resistor is connected to the first input end of the power module.

[0020] In one embodiment, the bus protection circuit further includes:

[0021] A first capacitor, wherein a first end of the first capacitor is respectively connected to a main power supply end of the bus driving chip and a first input end of the power module, and a second end of the first capacitor is connected to a second input end of the power module and is grounded;

[0022] a second capacitor, wherein a first end of the second capacitor is respectively connected to a preset reference voltage and a main power supply end of the bus driving chip, and a second end of the second capacitor is grounded;

[0023] A third capacitor, wherein a first end of the third capacitor is connected to the secondary power supply end of the bus driver chip, and a second end of the third capacitor is connected to the ground end of the bus driver chip.

[0024] In one embodiment, the bus protection circuit further includes:

[0025] A third resistor, wherein a first end of the third resistor is connected to the first input end of the bus driver chip, and a second end of the third resistor is connected to the second input end of the bus driver chip.

[0026] In addition, to achieve the above-mentioned purpose, the present application provides a bus protection module, which includes the bus protection circuit as described above.

[0027] In addition, to achieve the above-mentioned purpose, the present application provides a bus protection device, which includes the bus protection module as described above.

[0028] In addition, to achieve the above-mentioned purpose, the present application provides a bus interface, which includes the bus protection device as described above.

[0029] The present application provides a bus protection circuit, wherein a first end of the bus protection circuit is connected to a bus driver chip, and a second end of the bus protection circuit is connected to an interface, wherein the interface includes a first signal input end and a second signal input end, and the bus protection circuit includes: a detection module, wherein a first end of the detection module is respectively connected to the first signal input end and the first input end of the bus driver chip, and a second end of the detection module is connected to the second signal input end, wherein the detection module is configured to output a shutdown signal when a voltage difference between the first signal input end and the second signal input end is detected to be greater than a preset voltage difference threshold; a switch module, wherein a first end of the switch module is connected to the first input end of the bus driver chip, a second end of the switch module is connected to the second signal input end, and a third end of the switch module is connected to the detection module, and is configured to receive the shutdown signal and shut down to stop transmitting the signal of the interface to the bus driver chip; and a power supply module, wherein the power supply module is respectively connected to the bus driver chip and the switch module, and is configured to adjust the voltage of the bus driver chip and send it to the switch module.

[0030] Compared with the traditional protection based on transient suppression diode, in which the transient suppression diode is damaged after the low internal resistance overvoltage signal impact occurs, the present application turns off the switch module when the low internal resistance overvoltage signal impact is detected, stops transmitting the CAN signal at the interface to the bus driver chip, and then, after the low internal resistance overvoltage signal impact is restored, turns on the switch module to transmit the CAN signal at the interface to the bus driver chip, thereby avoiding irreversible damage when protecting the bus driver chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of the structure of a bus protection circuit provided in one embodiment of the present application;

[0032] Figure 2 A schematic diagram of the structure of a detection module in a bus protection circuit provided in an embodiment of the present application;

[0033] Figure 3 A schematic diagram of the structure of a switch module in a bus protection circuit provided in an embodiment of the present application;

[0034] Figure 4 A schematic diagram of the structure of a bus protection circuit provided by another embodiment of the present application;

[0035] Figure 5 A schematic diagram of the structure of a bus protection circuit provided in yet another embodiment of the present application.

[0036] Description of Figure Numbers:

[0037] T1, bus driver chip; 10, detection module; 20, switch module; 30, power module; Q1, transistor; R1, first resistor; D1, diode; R1, first resistor; D2, diode rectifier bridge; M1, first field effect transistor; M2, second field effect transistor; R2, second resistor; C1, first capacitor; C2, second capacitor; C3, third capacitor; R3, third resistor.

[0038] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0039] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0040] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0041] The main solution of the embodiment of the present application is: a bus protection circuit, wherein the first end of the bus protection circuit is connected to the bus driver chip, and the second end of the bus protection circuit is connected to the interface, the interface includes a first signal input end and a second signal input end, and the bus protection circuit includes: a detection module, wherein the first end of the detection module is respectively connected to the first signal input end and the first input end of the bus driver chip, and the second end of the detection module is connected to the second signal input end, and the detection module is used to output a shutdown signal when it detects that the voltage difference between the first signal input end and the second signal input end is greater than a preset voltage difference threshold; a switch module, wherein the first end of the switch module is connected to the first input end of the bus driver chip, the second end of the switch module is connected to the second signal input end, and the third end of the switch module is connected to the detection module, and is used to receive the shutdown signal and shut down to stop transmitting the signal of the interface to the bus driver chip; a power supply module, wherein the power supply module is respectively connected to the bus driver chip and the switch module, and is used to adjust the voltage of the bus driver chip and send it to the switch module.

[0042] CAN (Controller Area Network) is a serial communication protocol bus for real-time applications, which can use twisted pair cables to transmit signals. Generally, on some devices with power ports and CAN bus ports, it is easy to cause the CAN bus to be connected to a voltage exceeding the limit voltage that the CAN bus driver chip can withstand due to unexpected reasons such as improper plugging and unplugging, resulting in damage to the CAN bus driver chip. In the prior art, transient overvoltage suppression diodes are set between the CAN buses to protect the CAN bus. For example, transient overvoltage suppression diodes such as PESD1CAN or PESD1CAN are used to protect the CAN bus through the working principle of the diode array. Two reverse-parallel diodes are connected to the two signal lines of the CAN bus respectively. If the voltage on the CAN bus exceeds the breakdown voltage of the diode, the diode will be turned on and the overvoltage will be diverted to the ground, thereby protecting the CAN bus from overvoltage damage. However, this protection method will cause irreversible damage when the CAN bus is accidentally plugged into an overvoltage shock with a high energy or low internal resistance power supply (such as a battery), resulting in an energy discharge exceeding the maximum discharge energy that the protection element such as the transient suppression diode can withstand.

[0043] The present application stops transmitting the CAN signal at the interface to the bus driver chip by turning off the switch module when a low internal resistance overvoltage signal impact is detected. Then, after the low internal resistance overvoltage signal impact is restored, the switch module is turned on to transmit the CAN signal at the interface to the bus driver chip, thereby avoiding irreversible damage when protecting the bus driver chip.

[0044] Based on this, the present application proposes a bus protection circuit, referring to Figure 1 , Figure 1 This is a schematic diagram of the structure of a bus protection circuit provided in an embodiment of the present application. The first end of the bus protection circuit is connected to the bus driver chip T1, and the second end of the bus protection circuit is connected to the interface. The interface includes a first signal input end and a second signal input end. The bus protection circuit includes:

[0045] A detection module 10, wherein a first end of the detection module 10 is respectively connected to the first signal input end and the first input end of the bus driver chip T1, and a second end of the detection module 10 is connected to the second signal input end. The detection module 10 is configured to output a shutdown signal when it is detected that the voltage difference between the first signal input end and the second signal input end is greater than a preset voltage difference threshold;

[0046] A switch module 20, wherein a first end of the switch module 20 is connected to the first input end of the bus driver chip T1, a second end of the switch module 20 is connected to the second signal input end, and a third end of the switch module 20 is connected to the detection module 10, and is used to receive the shutdown signal and shut down to stop transmitting the signal of the interface to the bus driver chip T1;

[0047] The power module 30 is connected to the bus driver chip T1 and the switch module 20 respectively, and is used for adjusting the voltage of the bus driver chip T1 and sending it to the switch module 20 .

[0048] In this embodiment, the detection module 10 is used to detect whether the CAN bus has a low internal resistance overvoltage signal impact, that is, the detection module 10 detects whether the voltage difference between the first signal input terminal and the second signal input terminal is greater than the preset voltage difference threshold. When the preset voltage difference threshold is detected, it is confirmed that the CAN bus has a low internal resistance overvoltage signal impact, and a shutdown signal is output to the switch module 20. After receiving the shutdown signal, the switch module 20 is closed to stop transmitting the signal of the interface to the bus driver chip T1. The power module 30 provides a working voltage to the switch module 20, so that when the voltage difference between the first signal input terminal and the second signal input terminal is less than the preset voltage difference threshold, that is, when the CAN bus does not have a low internal resistance overvoltage signal impact, the switch module 20 is turned on, so that the CAN signal input by the interface is transmitted to the bus driver chip T1. In addition, the power module 30 is also connected to the detection module 10 to provide a reference voltage to the detection module 10, and the reference voltage can be specifically a ground voltage. In summary, compared with the traditional protection based on transient suppression diode, when a low internal resistance overvoltage signal impact occurs, the transient suppression diode is damaged. When a low internal resistance overvoltage signal impact is detected, the present application turns off the switch module and stops transmitting the CAN signal at the interface to the bus driver chip. Therefore, after the low internal resistance overvoltage signal impact is restored, the switch module is turned on to transmit the CAN signal at the interface to the bus driver chip, thereby avoiding irreversible damage when protecting the bus driver chip.

[0049] It should be noted that the bus of the present application is specifically a CAN bus, and the interface is used to input CAN signals. The specific model of the power module 30 may be B0505S-1W.

[0050] In some possible implementations, reference Figure 2 , Figure 2 This is a schematic diagram of the structure of a detection module in a bus protection circuit provided in an embodiment of the present application, wherein the detection module includes:

[0051] A first resistor R1, wherein a first end of the first resistor R1 is connected to the first signal input end;

[0052] A diode D1, a first end of the diode D1 is connected to a second end of the first resistor R1;

[0053] Transistor Q1, the control end of the transistor Q1 is connected to the second end of the diode D1, the first end of the transistor Q1 is connected to the switch module 20, and the second end of the transistor Q1 is respectively connected to the second signal input end and the first output end of the power module 30.

[0054] In this embodiment, the voltage of the first signal input terminal is input to the transistor Q1 through the first resistor R1 and the diode D1, and the voltage of the second signal input terminal is input to the second terminal of the transistor Q1, so that when the voltage difference between the voltage of the first signal input terminal and the voltage of the second signal input terminal is greater than the preset voltage difference threshold, that is, when a low internal resistance overvoltage signal impact occurs, the transistor Q1 is turned on, and after being turned on, the voltage of the first terminal of the transistor Q1 is lowered, wherein lowering the voltage of the first terminal of the transistor Q1 sends a shutdown signal to the switch module 20. The first resistor R1 is a current limiting resistor of the diode D1, and the diode D1 is used to set the overvoltage protection threshold of the CAN bus.

[0055] In some possible implementations, reference Figure 2 , the detection module 10 further includes:

[0056] A diode rectifier bridge D2, wherein the first end of the diode rectifier bridge D2 is connected to the first signal input end, the second end of the diode rectifier bridge D2 is connected to the second signal input end, the third end of the diode rectifier bridge D2 is connected to the first end of the first resistor R1, and the fourth end of the diode rectifier bridge D2 is connected to the power module 30.

[0057] In this embodiment, by setting a diode rectifier bridge D2, the voltage of any polarity on the CAN bus is converted to convert AC power into DC power, so that when a positive voltage overvoltage or a negative voltage overvoltage occurs, the transistor Q1 can be controlled to turn on, so that the switch module 20 is turned off to protect the bus driver chip. Pin 1 of the diode rectifier bridge D2 is connected to the second signal input terminal, pin 2 of the diode rectifier bridge D2 is connected to the first signal input terminal, pin 3 of the diode rectifier bridge D2 is connected to the first end of the first resistor R1, and pin 4 of the diode rectifier bridge D2 is respectively connected to the second end of the transistor Q1 and the power module 30.

[0058] Exemplarily, the diode D1 can be a 3.3V voltage regulator diode, and the voltage drop of the transistor Q1 is 0.7V. On this basis, the voltage drop of the diode rectifier bridge D2 is 0.7V. At this time, the preset voltage difference threshold is 4.7V (3.3+0.7+0.7). When an overvoltage exceeding 4.7V is detected between the first signal input terminal and the second signal input terminal, the diode D1 generates a voltage regulator current to cause the transistor Q1 to saturate and conduct, so that the switch module 20 is turned off.

[0059] In some possible implementations, reference Figure 3 , Figure 3 This is a schematic diagram of the structure of a switch module in a bus protection circuit provided in an embodiment of the present application. The switch module 20 includes:

[0060] A first field effect transistor M1, wherein a first end of the first field effect transistor M1 is connected to a second input end of the bus driver chip T1, and a control end of the first field effect transistor M1 is respectively connected to a first end of the transistor Q1 at a second input end of the power module 30;

[0061] A second field effect transistor M2, wherein the first end of the second field effect transistor M2 is respectively connected to the second end of the first field effect transistor M1 and the first output end of the power module 30, the second end of the second field effect transistor M2 is connected to the second signal input end, and the control end of the second field effect transistor M2 is connected to the control end of the first field effect transistor M1.

[0062] In this embodiment, when there is no low internal resistance overvoltage signal impact, the power module 30 provides voltage to the control end of the first field effect tube M1 and the second field effect tube M2 respectively, so that the first field effect tube M1 and the second field effect tube M2 are turned on, and the voltage of the second signal input end at the interface is transmitted to the bus driver chip T1 through the diode of the second field effect tube M2 and the first field effect tube M1, without affecting the transmission of normal signals. When there is a low internal resistance overvoltage signal impact, after the transistor Q1 is turned on, the voltage of the control end of the first field effect tube M1 and the second field effect tube M2 is pulled down, so that the first field effect tube M1 and the second field effect tube M2 are turned off, so that the voltage of the second signal input end cannot pass through the second field effect tube M2, and then, the voltage of the second signal input end is stopped from being transmitted to the bus driver chip T1. That is, when the low internal resistance overvoltage signal appears in the CAN bus, that is, when the power supply outside the signal interface is inserted, or when the plugging and unplugging is improper, the dual MOS tube will be turned off immediately without generating instantaneous sudden current and heating.

[0063] It should be noted that the first field effect transistor M1 and the second field effect transistor M2 are NMOS (N-Metal-Oxide-Semi conductor). The power module 30 is used to drive the first field effect transistor M1 and the second field effect transistor M2. The first output end of the power module 30 is connected to the first end of the second field effect transistor M2 and the first output end of the power module 30, respectively, so as to provide the necessary conduction conditions for the first field effect transistor M1 and the second field effect transistor M2.

[0064] In some possible implementations, reference Figure 3 , the switch module 20 further includes:

[0065] A second resistor R2 , wherein a first end of the second resistor R2 is connected to the control end of the first field effect transistor M1 , and a second end of the second resistor R2 is connected to the first input end of the power module 30 .

[0066] In this embodiment, the second resistor R2 is a current limiting resistor, which plays the role of voltage regulation and protection of the first field effect transistor M1.

[0067] It should be noted that the 4th pin of the power module 30 is connected to the second end of the second resistor R2, the 3rd pin of the power module 30 is connected to the second end of the transistor Q1, the 2nd pin of the power module 30 is connected to the bus driver chip T1, and the 1st pin of the power module 30 is grounded.

[0068] In some possible implementations, reference Figure 4 , Figure 4 A schematic diagram of the structure of a bus protection circuit provided in another embodiment of the present application, wherein the bus protection circuit further includes:

[0069] A first capacitor C1, wherein a first end of the first capacitor C1 is respectively connected to a main power supply end of the bus driver chip T1 and a first input end of the power module 30, and a second end of the first capacitor C1 is connected to a second input end of the power module 30 and is grounded;

[0070] A second capacitor C2, wherein a first end of the second capacitor C2 is respectively connected to a preset reference voltage VCC1 and a main power supply end VCC of the bus driver chip T1, and a second end of the second capacitor C2 is grounded;

[0071] A third capacitor C3, a first end of the third capacitor C3 is connected to the secondary power supply terminal VISO of the bus driver chip T1, and a second end of the third capacitor C3 is connected to the ground terminal GND2 of the bus driver chip T1.

[0072] In this embodiment, the first capacitor C1 and the second capacitor C2 are decoupling capacitors to reduce the influence of power supply noise on the circuit. The third capacitor C3 is a filter capacitor. The main power supply terminal VCC of the bus driver chip T1 is connected to the primary coil, and the secondary power supply terminal VISO of the bus driver chip T1 is connected to the secondary coil.

[0073] It should be noted that the first end of the second capacitor C2 is connected to the first pin of the bus driver chip T1, and the second end of the second capacitor C2 is grounded. The first end of the third capacitor C3 is connected to the 16th pin and the 11th pin of the bus driver chip T1, respectively, and the second end of the third capacitor C3 is connected to the 9th pin and the 10th pin of the bus driver chip T1, respectively.

[0074] In some possible implementations, reference Figure 5 , Figure 5 A schematic diagram of the structure of a bus protection circuit provided in another embodiment of the present application, wherein the bus protection circuit further includes:

[0075] A third resistor R3 , wherein a first end of the third resistor R3 is connected to the first input end of the bus driver chip T1 , and a second end of the third resistor R3 is connected to the second input end of the bus driver chip T1 .

[0076] In this embodiment, the third resistor R3 is a matching resistor, which plays a role in impedance matching of the communication line.

[0077] The present application also proposes a bus protection module, which includes a bus protection circuit. The specific structure of the bus protection circuit refers to the above-mentioned embodiment. Since the optimized bus protection module adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0078] The present application also proposes a bus protection device, which includes a bus protection module. The specific structure of the bus protection circuit in the bus protection module refers to the above-mentioned embodiment. Since the present optimized bus protection device adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0079] The present application also proposes a bus interface, which includes a bus protection device. The specific structure of the bus protection circuit in the bus interface refers to the above-mentioned embodiment. Since the optimized bus interface adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0080] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0081] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0082] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a computer storage medium (such as Flash memory, ROM / RAM, disk, CD), including several instructions for enabling a controller in a terminal device (which can be a mobile phone, computer, server, or network device, etc.) for controlling the storage medium to perform data read and write operations to execute the methods described in each embodiment of the present application.

[0083] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A bus protection circuit, characterized in that: The first end of the bus protection circuit is connected to the bus driving chip, the second end of the bus protection circuit is connected to the interface, the interface includes a first signal input end and a second signal input end, and the bus protection circuit includes: a detection module, wherein a first end of the detection module is connected to the first signal input end and the first input end of the bus driver chip respectively, and a second end of the detection module is connected to the second signal input end, and the detection module is used to output a shutdown signal when it is detected that the voltage difference between the first signal input end and the second signal input end is greater than a preset voltage difference threshold; a switch module, wherein a first end of the switch module is connected to a first input end of the bus driver chip, a second end of the switch module is connected to the second signal input end, and a third end of the switch module is connected to the detection module, and is used to receive the shutdown signal and shut down to stop transmitting the signal of the interface to the bus driver chip; A power supply module is connected to the bus driver chip and the switch module respectively, and is used for adjusting the voltage of the bus driver chip and sending it to the switch module.

2. The bus protection circuit according to claim 1, characterized in that: The detection module comprises: a first resistor, wherein a first end of the first resistor is connected to the first signal input end; a diode, a first end of the diode being connected to a second end of the first resistor; A transistor, wherein the control end of the transistor is connected to the second end of the diode, the first end of the transistor is connected to the switch module, and the second end of the transistor is respectively connected to the second signal input end and the first output end of the power module.

3. The bus protection circuit according to claim 2, characterized in that: The detection module also includes: A diode rectifier bridge, wherein the first end of the diode rectifier bridge is connected to the first signal input end, the second end of the diode rectifier bridge is connected to the second signal input end, the third end of the diode rectifier bridge is connected to the first end of the first resistor, and the fourth end of the diode rectifier bridge is connected to the power module.

4. The bus protection circuit according to claim 3, characterized in that: The switch module comprises: A first field effect transistor, wherein a first end of the first field effect transistor is connected to a second input end of the bus driver chip, and a control end of the first field effect transistor is respectively connected to a second input end of the power module and a first end of the transistor; A second field effect transistor, wherein the first end of the second field effect transistor is respectively connected to the second end of the first field effect transistor and the first output end of the power module, the second end of the second field effect transistor is connected to the second signal input end, and the control end of the second field effect transistor is connected to the control end of the first field effect transistor.

5. The bus protection circuit according to claim 4, characterized in that: The switch module also includes: A second resistor, wherein a first end of the second resistor is connected to the control end of the first field effect transistor, and a second end of the second resistor is connected to the first input end of the power module.

6. The bus protection circuit according to claim 5, characterized in that: The bus protection circuit also includes: A first capacitor, wherein a first end of the first capacitor is respectively connected to a main power supply end of the bus driving chip and a first input end of the power module, and a second end of the first capacitor is connected to a second input end of the power module and is grounded; a second capacitor, wherein a first end of the second capacitor is respectively connected to a preset reference voltage and a main power supply end of the bus driving chip, and a second end of the second capacitor is grounded; A third capacitor, wherein a first end of the third capacitor is connected to the secondary power supply end of the bus driver chip, and a second end of the third capacitor is connected to the ground end of the bus driver chip.

7. The bus protection circuit according to claim 6, characterized in that: The bus protection circuit also includes: A third resistor, wherein a first end of the third resistor is connected to the first input end of the bus driver chip, and a second end of the third resistor is connected to the second input end of the bus driver chip.

8. A bus protection module, characterized in that: The bus protection module includes the bus protection circuit as described in any one of claims 1-7.

9. A bus protection device, characterized in that: The bus protection device comprises the bus protection module as claimed in claim 8.

10. A bus interface, characterized in that: The bus interface includes the bus protection module as claimed in claim 9.

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