CAN signal transmission circuit, chip and equipment

Abstract

According to the CAN signal transmission circuit, the chip and the equipment provided by the embodiment of the invention, the transmission module is combined with the gating module, so that multiple paths of CAN networks can be connected to the transmission module through one channel, convenience is provided for realizing signal transmission of the multiple paths of parallel CAN networks, and the utilization rate of the transmission module can also be improved.

Description

Technical Field

[0001] The present application belongs to the field of communication testing technology, and in particular, relates to a CAN signal transmission circuit, chip and device. Background Art

[0002] With the development of science and technology, cars have become an indispensable means of transportation in people's daily lives. Due to the requirements of vehicle safety, comfort and convenience, various electronic control systems have been developed. In order to achieve communication between electronic control devices in the vehicle and reduce the number of signal lines, relevant technicians have designed a single network bus, on which all peripheral devices can be connected, thereby achieving communication between electronic devices.

[0003] With the continuous development of new energy vehicle technology, the requirements for controller debugging and testing will become higher and higher. In related technologies, USB-CAN can be used to debug and test controllers. However, in the scenario of multi-channel parallel controller area network (CAN) network, how to improve the utilization rate of USB-CAN is an urgent problem to be solved. Summary of the invention

[0004] The embodiments of the present application provide a CAN signal transmission circuit, chip and device. By connecting a gating module with a transmission module, the gating module can be used to test each line in a multi-channel parallel CAN network, thereby avoiding frequent equipment debugging processes and improving the utilization rate of the test equipment.

[0005] In the first aspect, an embodiment of the present application provides a CAN signal transmission circuit, characterized in that it includes a transmission module and a gating module, the first end of the gating module is connected to the first end of the transmission module, the multiple second ends of the gating module are connected one-to-one with the multi-channel controller area network CAN signals, and the second end of the transmission module is used to connect to a personal computer PC.

[0006] In one embodiment, the gating module includes a plurality of switch devices, the first ends of the plurality of switch devices are connected to each other as the first end of the gating module, and the second ends of the plurality of switch devices are respectively used as the second ends of the gating module.

[0007] In one embodiment, the switch device comprises a mechanical switch.

[0008] In one embodiment, the mechanical switch includes a double-pole single-throw switch, which includes two pairs of contact groups, each pair of contact groups includes a static contact and a moving contact; the moving contact of the first pair of contact groups of the double-pole single-throw switch is connected to the positive pole of the first end of the transmission module, and the static contact is connected to the negative pole of the first end of the transmission module; the moving contact of the second pair of contact groups of the double-pole single-throw switch is connected to the positive pole of the CAN signal, and the static contact is connected to the negative pole of the CAN signal.

[0009] In one embodiment, the mechanical switch includes a single-pole single-throw switch group, and the single-pole single-throw switch group includes a first single-pole single-throw switch and a second single-pole single-throw switch, the first end of the first single-pole single-throw switch is connected to the positive pole of the first end of the transmission module, and the second end of the first single-pole single-throw switch is connected to the positive pole of the CAN; the first end of the second single-pole single-throw switch is connected to the negative pole of the first end of the transmission module, and the second end of the second single-pole single-throw switch is connected to the negative pole of the CAN.

[0010] In one embodiment, the switch device includes an electrically controlled switch, and the circuit further includes a control module, and the control module is used to control the state of the electrically controlled switch.

[0011] In one embodiment, the electrically controlled switch comprises a transistor.

[0012] In one implementation, the transmission module includes a USB-CAN card.

[0013] In a second aspect, an embodiment of the present application provides a CAN signal transmission chip, comprising the CAN signal transmission circuit described in the first aspect or any one of the embodiments of the first aspect.

[0014] In a third aspect, an embodiment of the present application provides a CAN signal transmission device, including:

[0015] A CAN detection chip comprises the CAN signal transmission circuit described in the first aspect or any one of the embodiments of the first aspect; and a PC.

[0016] The CAN signal transmission circuit, chip and device of the embodiments of the present application combine the transmission module with the selection module, so that multiple CAN networks can be connected to the transmission module through one channel, which facilitates the signal transmission of multiple parallel CAN networks and can also improve the utilization rate of the transmission module. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 A schematic diagram of a CAN signal transmission circuit provided by an embodiment of the present application is shown;

[0019] Figure 2 A schematic diagram of another CAN signal transmission circuit provided by an embodiment of the present application is shown;

[0020] Figure 3 A schematic diagram of a CAN signal transmission circuit using a double-pole single-throw switch as a switch device provided by an embodiment of the present application is shown;

[0021] Figure 4 A schematic diagram of a CAN signal transmission circuit using a single-pole single-throw switch group as a switch device provided by an embodiment of the present application is shown;

[0022] Figure 5 A schematic diagram of another CAN signal transmission circuit provided by an embodiment of the present application is shown;

[0023] Figure 6 A schematic diagram of a CAN signal transmission circuit using an N-MOS tube as a switch device provided by an embodiment of the present application is shown;

[0024] Figure 7 A schematic diagram of a CAN signal transmission chip architecture provided by an embodiment of the present application is shown;

[0025] Figure 8 A schematic structural diagram of a CAN signal transmission device provided in one embodiment of the present application is shown. DETAILED DESCRIPTION

[0026] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0027] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device 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 device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0028] With the continuous advancement of science and technology and the increasing awareness of environmental protection, new energy vehicles have gradually become the development direction of the automotive field. Before new energy vehicles are put into use, it is usually necessary to test the functions of various controllers in new energy vehicles. It can be understood that each controller in a new energy vehicle can correspond to a CAN network, thereby realizing the control and coordination of different controllers or control systems. In related technologies, technicians can transfer data in the CAN network to a personal computer (PC) through a USB-CAN card, and adjust and test the controller through the PC.

[0029] However, with the continuous development of new energy vehicles, their functions are gradually enriched, and the number of controllers used to control various functions is also gradually increasing. Therefore, the number of CAN networks is also increasing. For testing multiple controllers, that is, when multiple parallel CAN networks need to transmit data, each CAN network can usually be connected to a USB-CAN card to achieve testing of multiple controllers. However, at this time, the utilization rate of the USB-CAN card is low and the testing cost is high. Alternatively, in the related art, the signal transmission of the dual-channel CAN network can be achieved by using a device that supports dual-channel CAN network signal transmission, such as ZLG USBCAN-2E-U. However, in the related art, when more than two controllers need to be tested, that is, when more than two multi-channel parallel CAN networks need to transmit CAN signals, the connection line can only be adjusted manually, which causes inconvenience to the user operation.

[0030] Therefore, the embodiment of the present application provides a CAN signal transmission circuit, which combines the transmission module with the selection module, so that multiple CAN networks can be connected to the transmission module through one channel, thereby facilitating the signal transmission of multiple parallel CAN networks and improving the utilization rate of the transmission module.

[0031] The following first introduces a CAN signal transmission circuit provided in an embodiment of the present application.

[0032] Figure 1 FIG. 1 is a schematic diagram of a CAN signal transmission circuit provided by an embodiment of the present application. Figure 1 As shown, the CAN signal transmission circuit 100 includes:

[0033] The transmission module 110 and the gating module 120 .

[0034] In the embodiment of the present application, the first end of the transmission module 110 can be connected to the first end of the selection module 120, and the second end of the transmission module 110 is used to connect to the PC end.

[0035] In an embodiment of the present application, the transmission module can be used to transmit signals in the CAN network to the PC, so that the signals in the CAN network can be viewed, analyzed, and processed through the PC to implement testing of the controller.

[0036] In the embodiment of the present application, the signal in the CAN network may be a CAN message.

[0037] In the embodiment of the present application, the transmission module 110 may be a USB-CAN card. Through the USB-CAN card, the signal in the CAN network is transmitted to the PC through the Universal Serial Bus (USB) interface. It is understandable that the transmission module can convert the CAN message into a USB signal and transmit the corresponding USB signal to the PC through the USB interface.

[0038] Further, it can be understood that in the embodiment of the present application, the transmission module 110 can also include other devices, and the other devices can transmit the signals in the CAN network to the PC through other interfaces or in other forms.

[0039] In the embodiment of the present application, the gating module 120 may include multiple second terminals. Moreover, each second terminal may be connected to each CAN network in the multi-channel CAN network in a one-to-one correspondence. In one example, if the gating module has three second terminals, each second terminal may be connected to a different CAN network. For example, the three second terminals may include interface 1, interface 2, and interface 3, and interface 1 may be connected to the powertrain CAN; interface 2 may be connected to the chassis control CAN; and interface 3 may be connected to the body control CAN.

[0040] In the embodiment of the present application, the gating module 120 can be used to control the conduction of each of the multiple second ends, that is, the gating module 120 can be used to control whether any one of the multiple CAN networks can transmit CAN signals to the transmission module 110. In one example, if the gating module has three second ends including interface 1, interface 2 and interface 3, and interface 1 can be connected to the powertrain CAN; interface 2 can be connected to the chassis control CAN; interface 3 can be connected to the body control CAN. At the first moment, interface 2 can be controlled to be turned on, and interface 1 and interface 3 can be disconnected, that is, the chassis control CAN is controlled to be connected for signal transmission; at the second moment, interface 3 can be controlled to be turned on, and interface 1 and interface 2 can be disconnected, that is, the body control CAN is controlled to be connected for data transmission.

[0041] In the embodiment of the present application, the transmission module 110 can transmit the received CAN signal to the PC end, thereby realizing signal transmission for the controller corresponding to the CAN signal.

[0042] In an embodiment of the present application, by combining the transmission module with the selection module, multiple CAN networks can be connected to the transmission module through one channel, which facilitates the signal transmission of multiple parallel CAN networks and improves the utilization rate of the transmission module.

[0043] In the embodiment of the present application, whether the second end can transmit the CAN signal can be controlled by the switch device.

[0044] Figure 2 FIG. 2 is a schematic diagram of another CAN signal transmission circuit provided by an embodiment of the present application. Figure 2 As shown, as another implementation of the present application, in order to control the conduction conditions of multiple second terminals, there may be multiple switch devices 121 in the gating module 120.

[0045] In the embodiment of the present application, the first ends of the plurality of switch devices 121 are connected to each other as the first end of the gating module 120 , and the second ends of the plurality of switch devices 121 are respectively used as the second ends of the gating module 120 .

[0046] In the embodiment of the present application, it is understood that the first end of each switch device in the plurality of switch devices 121 can be connected to the transmission module 110. Furthermore, the second ends of different switch devices 121 can be connected to each CAN network in the multi-channel CAN network in a one-to-one correspondence.

[0047] In the embodiment of the present application, the switch device 121 may be used to control whether the signal of the CAN network connected to the second end can be transmitted. It is understood that the control of the switch device 121 can be controlled by a technician, or the control of the switch device 121 can be realized by a PC. Therefore, the switch device 121 in the embodiment of the present application may be a mechanical switch 122, or the switch device may also be an electrically controlled switch 123.

[0048] Furthermore, the signal of the CAN network may include one positive signal and one negative signal. Therefore, it can be understood that the second end of the gating module may include one positive wiring port and one negative wiring port, so that the positive signal in the CAN network can be received through the positive wiring port, and the negative signal in the CAN network can be received through the negative wiring port. Furthermore, the first end of the transmission module may also include one positive wiring port and one negative wiring port, so that the positive and negative signals of the CAN network transmitted by the gating module can be received through the positive and negative wiring ports.

[0049] In the embodiment of the present application, when the switch device 121 is a mechanical switch 122 , the mechanical switch device may be a double-pole single-throw switch 124 .

[0050] In the embodiment of the present application, the double-pole single-throw switch includes two pairs of contact groups, each pair of contact groups includes a static contact and a moving contact. The moving contact of the first pair of contact groups of the double-pole single-throw switch is connected to the positive pole of the transmission module 110, and the static contact is connected to the positive pole of the CAN network; the moving contact of the second pair of contact groups of the double-pole single-throw switch is connected to the negative pole of the transmission module 110, and the static contact is connected to the negative pole of the CAN network.

[0051] In the embodiment of the present application, the state of the double-pole single-throw switch may include an open state and a closed state. When the double-pole single-throw switch is in the open state, each pair of moving contacts and static contacts in the two pairs of contact groups of the double-pole single-throw switch are separated, that is, it can be understood that the paths for transmitting positive and negative signals in the CAN network are in an open state. When the double-pole single-throw switch is in the closed state, each pair of moving contacts and static contacts in the two pairs of contact groups of the double-pole single-throw switch are connected, that is, it can be understood that the paths for transmitting positive and negative signals in the CAN network are in a conductive state.

[0052] In the embodiment of the present application, the state of the double-pole single-throw switch can be changed by the technician's manipulation, wherein the state of the double-pole single-throw switch can be changed from an open state to a closed state, or the state of the double-pole single-throw switch can be changed from a closed state to an open state.

[0053] In one example, Figure 3 FIG. 1 is a schematic diagram showing a CAN signal transmission circuit using a double-pole single-throw switch as a switch device according to an embodiment of the present application. Figure 3 As shown, if there are N CAN networks, where N is a positive integer, the CAN network can be controlled by N double-pole single-throw switches 124 .

[0054] Furthermore, in an embodiment of the present application, a double-pole single-throw switch is a device for simultaneously controlling the transmission status of positive signals and negative signals in a CAN network signal. Therefore, in an embodiment of the present application, a device for simultaneously controlling the transmission status of positive signals and negative signals in a CAN network signal can also be implemented by other devices, for example, a double-pole double-throw switch, etc.

[0055] In an embodiment of the present application, a double-pole single-throw switch is used to switch the transmission signals of multiple parallel CAN networks, so that multiple parallel CAN networks can transmit signals through one channel, avoiding the inconvenience of adjusting the CAN network wiring problems during the debugging process.

[0056] In the embodiment of the present application, when the switch device is a mechanical switch 122 , the mechanical switch device may be a single-pole single-throw switch group 125 .

[0057] In an embodiment of the present application, the single-pole single-throw switch group may include two single-pole single-throw switches, that is, a first single-pole single-throw switch and a second single-pole single-throw switch. In addition, each single-pole single-throw switch may include a pair of contact groups, including a static contact and a moving contact. The moving contact of the first single-pole single-throw switch is connected to the positive pole of the transmission module, and the static contact of the first single-pole single-throw switch is connected to the positive pole of the CAN network. The moving contact of the second single-pole single-throw switch is connected to the negative pole of the transmission module, and the static contact of the second single-pole single-throw switch is connected to the negative pole of the CAN network.

[0058] In an embodiment of the present application, the single-pole single-throw switch may include an open state and a closed state. When the first single-pole single-throw switch is in the open state, the moving contact and the static contact in the contact group corresponding to the first single-pole single-throw switch are separated, that is, it can be understood that the path for transmitting the positive signal in the CAN network is in an open state. When the second single-pole single-throw switch is in the open state, the path for transmitting the negative signal in the CAN network is in an open state. When the first single-pole single-throw switch is in the closed state, the moving contact and the static contact in the contact group corresponding to the first single-pole single-throw switch are connected, that is, it can be understood that the path for transmitting the positive signal in the CAN network is in a conductive state. When the second single-pole single-throw switch is in the closed state, the path for transmitting the negative signal in the CAN network is in a conductive state.

[0059] In the embodiment of the present application, the status of each switch in the single-pole single-throw switch group can be adjusted by a technician.

[0060] In one example, Figure 4FIG. 1 is a schematic diagram showing a CAN signal transmission circuit using a single-pole single-throw switch group as a switch device according to an embodiment of the present application. Figure 4 As shown, if there are N CAN networks, where N is a positive integer, the CAN network can be controlled by using N single-pole single-throw switch groups 125 .

[0061] In the embodiment of the present application, by adjusting the conduction state of the single-pole single-throw switch, the switching of the transmission signals of multiple parallel CAN networks is achieved, so that the multiple parallel CAN networks can transmit signals through one channel, avoiding inconvenience in the debugging process.

[0062] In the embodiment of the present application, when the switch device is an electrically controlled switch, the CAN signal transmission circuit may further include a control module for controlling the electrically controlled switch.

[0063] Figure 5 FIG. 2 shows a schematic diagram of another CAN signal transmission circuit provided by an embodiment of the present application. Figure 5 As shown, the CAN signal transmission circuit includes:

[0064] The transmission module 110 , a plurality of electrically controlled switches 123 and a control module 130 .

[0065] The first end of the electric-controlled switch 123 is connected to the first end of the transmission module 110, and the multiple second ends of the electric-controlled switch 123 are connected to the multi-channel controller area network CAN network in a one-to-one correspondence, and the second end of the transmission module 110 is used to connect to the PC. The multiple first ends of the control module 130 are respectively connected to the multiple electric-controlled switches 123, and the second end of the control module 130 is used to connect to the PC.

[0066] In the embodiment of the present application, the control module 130 can be controlled by a PC, thereby controlling the conduction state of multiple electrically controlled switches 123. In one example, the control module 130 can be controlled by a PC to change any electrically controlled switch 123 from an on state to an off state. In one example, the control module 130 can be controlled by a PC to change any electrically controlled switch 123 from an off state to an on state.

[0067] In the embodiment of the present application, a technician can select the conduction status of each CAN network in the multi-channel CAN network according to corresponding requirements on the PC side. Alternatively, a corresponding timing controller can be designed to determine the conduction sequence and conduction duration of each CAN network in the multi-channel CAN network.

[0068] In the embodiment of the present application, the electrically controlled switch 123 may be a transistor 126. The conduction of the transistor is controlled by the control module 130. In one example, the transistor may be an N-type metal oxide semiconductor 127 (N-Metal-Oxide-Semiconductor, N-MOS), that is, an N-MOS tube. Figure 6 FIG. 1 is a schematic diagram of a CAN signal transmission circuit using an N-MOS tube as a switch device according to an embodiment of the present application. Figure 6 As shown, if there are N CAN networks, N is a positive integer, then the control of signal transmission in the CAN network can be achieved through N N-MOS tubes. In addition, the drains of multiple N-MOS tubes can be connected to each CAN network in the multi-channel controller area network CAN network in a one-to-one correspondence, and the sources of multiple N-MOS tubes can be connected to each other and connected to the gating module. The gates of multiple N-MOS tubes can be connected to the control module, and the control module can be used to control the conduction of multiple N-MOS tubes. It can be understood that when the control module provides a high level to the gate of a certain N-MOS tube, the N-MOS tube is turned on, and the signal of the CAN network corresponding to the branch can be transmitted to the transmission module. When the control module provides a low level to the gate of a certain N-MOS tube, the N-MOS tube is turned off, that is, the signal of the CAN network corresponding to the branch cannot be transmitted to the transmission module.

[0069] It can be understood that in the embodiments of the present application, there is no specific limitation on the type of transistor, and other types of transistors can be used to implement the CAN signal transmission circuit in the present application.

[0070] In the embodiment of the present application, the module can be controlled to adjust the state of the electronically controlled switch, thereby realizing the switching of transmission signals of multiple parallel CAN networks, so that multiple parallel CAN networks can transmit signals through one channel, avoiding inconveniences during the debugging process and improving the utilization rate of the transmission module.

[0071] Based on the CAN signal transmission circuit provided in the above embodiment, the present application also provides a CAN signal transmission chip accordingly. The CAN signal transmission circuit described in any of the above embodiments can be implemented in the CAN signal transmission chip architecture.

[0072] Figure 7 FIG. 1 is a schematic diagram showing a CAN signal transmission chip architecture provided by an embodiment of the present application. Figure 7 As shown, the CAN signal transmission chip 700 includes a CAN signal transmission circuit 100 .

[0073] In the embodiment of the present application, the CAN signal transmission chip 700 can realize parallel connection of multiple CAN networks, provide convenience for realizing signal transmission of multiple parallel CAN networks, and also improve the utilization rate of the transmission module.

[0074] Furthermore, the present application also provides a CAN signal transmission device, through which any CAN signal transmission circuit described in the above embodiments can be implemented.

[0075] Figure 8 FIG. 1 is a schematic diagram showing the structure of a CAN signal transmission device provided by an embodiment of the present application. Figure 8 As shown, the CAN signal transmission device 800 includes a CAN signal transmission circuit 100 and a PC 801 .

[0076] In the embodiment of the present application, the CAN network signal entering and exiting the CAN signal transmission circuit 100 can be detected by a PC, thereby implementing a test of the controller corresponding to the CAN network signal.

[0077] In the embodiment of the present application, the CAN signal transmission device 800 transmits the signals of multiple CAN networks through one channel, avoiding the tedious steps of constantly adjusting the connection lines, and providing convenience for users.

[0078] It should also be noted that the exemplary embodiments mentioned in this application describe some circuits or devices based on a series of steps or devices. However, this application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

[0079] Aspects of the present disclosure are described above with reference to the flowchart and / or block diagram of the method, device (system) and computer program product according to the embodiment of the present disclosure. It should be understood that each box in the flowchart and / or block diagram and the combination of each box in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine so that these instructions executed by the processor of the computer or other programmable data processing device enable the implementation of the function / action specified in one or more boxes of the flowchart and / or block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field programmable logic circuit. It can also be understood that each box in the block diagram and / or flowchart and the combination of boxes in the block diagram and / or flowchart can also be implemented by dedicated hardware that performs a specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0080] The above is only a specific implementation of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, modules and units described above can refer to the corresponding processes in the aforementioned method embodiments, and will not be repeated here. It should be understood that the protection scope of the present application is not limited to this. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in this application, and these modifications or replacements should be included in the protection scope of this application.

Claims

1. A CAN signal transmission circuit, characterized in that: It includes a transmission module and a gating module, wherein the first end of the gating module is connected to the first end of the transmission module, the multiple second ends of the gating module are connected one-to-one with a multi-channel controller area network CAN network, and the second end of the transmission module is used to connect to a personal computer PC.

2. The CAN signal transmission circuit according to claim 1, characterized in that: The gating module comprises a plurality of switch devices, the first ends of the plurality of switch devices are connected to each other as the first end of the gating module, and the second ends of the plurality of switch devices are respectively used as the second ends of the gating module.

3. The circuit according to claim 2, characterized in that The switch device comprises a mechanical switch.

4. The circuit according to claim 3, characterized in that The mechanical switch comprises a double-pole single-throw switch, which comprises two pairs of contact groups, each pair of contact groups comprises a static contact and a moving contact; the moving contact of the first pair of contact groups of the double-pole single-throw switch is connected to the positive pole of the transmission module, and the static contact is connected to the positive pole of the CAN network; the moving contact of the second pair of contact groups of the double-pole single-throw switch is connected to the negative pole of the transmission module, and the static contact is connected to the negative pole of the CAN network.

5. The circuit according to claim 3, characterized in that The mechanical switch comprises a single-pole single-throw switch group, the single-pole single-throw switch group comprises a first single-pole single-throw switch and a second single-pole single-throw switch, and each pair of single-pole single-throw switches comprises a pair of contact groups, the contact groups comprise a static contact and a moving contact; The moving contact of the first single-pole single-throw switch is connected to the positive pole of the transmission module, and the static contact of the first single-pole single-throw switch is connected to the positive pole of the CAN network; The moving contact of the second single-pole single-throw switch is connected to the cathode of the transmission module, and the static contact of the second single-pole single-throw switch is connected to the cathode of the CAN network.

6. The circuit according to claim 2, characterized in that The switch device includes an electrically controlled switch, and the circuit further includes a control module, wherein the control module is used to control the state of the electrically controlled switch.

7. The circuit according to claim 6, characterized in that The electrically controlled switch includes a transistor.

8. The CAN signal transmission circuit according to claim 1, characterized in that: The transmission module includes a USB-CAN card.

9. A CAN signal transmission chip, characterized in that: The CAN signal transmission circuit comprises the CAN signal transmission circuit described in any one of claims 1 to 5.

10. A CAN signal transmission device, characterized in that: include: A CAN detection chip, comprising the CAN signal transmission circuit according to any one of claims 1 to 5; PC.

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