A CAN FD bus opto-isolation system

Abstract

The utility model discloses a kind of CAN FD bus photoelectric isolation systems, including bus signal optical fiber, power adapter, battery box and two CAN FD photoelectric isolation modules, two between the CAN FD photoelectric isolation module is connected by bus signal optical fiber, one of the CAN FD photoelectric isolation module is bidirectionally connected with measured object, and the CAN FD photoelectric isolation module is powered by battery box;Another the CAN FD photoelectric isolation module is bidirectionally connected with bus analyzer, and the CAN FD photoelectric isolation module is powered by battery box or power adapter.The utility model, correct transmission signal and to signal waveform is appropriately corrected, ensure that the interference caused by CAN FD signal after transmission through it can satisfy the limit value requirement of test standard.

Description

Technical Field

[0001] This utility model relates to the field of CAN FD bus opto-isolation technology, specifically a CAN FD bus opto-isolation system. Background Technology

[0002] With technological advancements, the proportion of electronic components in automobiles is increasing, and their designs are becoming more complex. Bus technology in automobiles coordinates the operation of various electronic components. As the most popular bus technology among car manufacturers, CAN FD bus technology covers almost all automotive products currently on the market. Automotive electronic electromagnetic compatibility testing, in addition to using traditional audio, video, antenna tower control signals, and turntable control signals, requires extensive signal monitoring of the product under test. This necessitates the installation of various automotive bus opto-isolation systems, and at least a CAN FD bus opto-isolation system is required.

[0003] According to electromagnetic compatibility (EMC) testing requirements, the product should be in normal operating condition during testing. When the product under test needs to receive commands via the CAN FD bus to operate, an opto-isolation system for the CAN FD signal is essential. The CAN bus signal waveform is close to a square wave and has abundant harmonics. If the CAN FD signal is directly transmitted into the system without any processing during frequency domain measurements, the following problems may occur: a: Insufficient noise reduction processing for the output CAN FD bus signal results in electromagnetic interference derived from the CAN FD bus signal exceeding the background noise requirements.

[0004] b: Excessive noise reduction processing on the output CAN FD bus signal leads to a serious deterioration in the quality of the CAN FD bus signal. Once the transmission rate is high, packet loss will occur, resulting in communication interruption. Utility Model Content

[0005] The purpose of this invention is to provide a CAN FD bus opto-isolation system to solve the problems in the prior art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a CAN FD bus opto-isolation system, comprising a bus signal optical fiber, a power adapter, a battery box, and two CAN FD opto-isolation modules. The two CAN FD opto-isolation modules are connected via a bus signal optical fiber. One of the CAN FD opto-isolation modules is bidirectionally connected to the device under test and is powered by the battery box. The other CAN FD opto-isolation module is bidirectionally connected to a bus analyzer and is powered by either the battery box or the power adapter.

[0007] Preferably, it also includes a CAN transceiver, inductor L1, capacitors C1, C2, C3, and C4, a resistor network, a varistor, and a D-SUB9 interface; the CANH and CANL pins of the CAN transceiver are respectively connected to the two ends of inductor L1.

[0008] Preferably, the resistor network includes 1K3 resistors, 30R resistors, and 60R resistors.

[0009] Preferably, the bus signal fiber is a multimode fiber optic cable.

[0010] Compared with the prior art, the beneficial effects of this utility model are: it can correctly transmit signals and appropriately correct the signal waveform, ensuring that the interference brought by the CAN FD signal after transmission can meet the limit requirements of the test standard. Attached Figure Description

[0011] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is the circuit diagram of this utility model; Figure 2 This is a schematic diagram of the present invention; Figure 3 This is a schematic diagram of the structure of this utility model in use. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model.

[0013] Please see Figure 2In this embodiment of the present invention, a CAN FD bus opto-isolation system includes a bus signal optical fiber, a power adapter, a battery box, and two CAN FD opto-isolation modules. The two CAN FD opto-isolation modules are connected to each other via the bus signal optical fiber. One of the CAN FD opto-isolation modules is bidirectionally connected to the device under test and is powered by the battery box. The other CAN FD opto-isolation module is bidirectionally connected to a bus analyzer and is powered by either the battery box or the power adapter.

[0014] The CAN FD opto-isolation module enables opto-isolated transmission of CAN FD signals, isolating electrical interference between different circuits and ensuring reliable transmission of CAN FD signals in environments with electrical interference. A well-designed CAN FD bus opto-isolation system can correctly transmit CAN FD signals and appropriately correct the signal waveform, ensuring that the interference introduced by the transmitted CAN FD signals meets the limits of the testing standards.

[0015] The device under test (DUT) is the source or target of the CAN FD bus signals. It is bidirectionally connected to one of the CAN FD opto-isolation modules to enable CAN FD signal interaction with that module.

[0016] Two CAN FD opto-isolation modules: These two modules are connected via a fiber optic cable to achieve opto-isolated transmission of CAN FD signals. Opto-isolation effectively isolates electrical interference between different circuits, ensuring reliable transmission of CAN FD signals even in environments with electrical interference. The module connected to the device under test is battery-powered, while the remote module can be powered by a battery or an external power adapter to adapt to different power supply scenarios.

[0017] Bus Analyzer: Connects bidirectionally to a remote CAN FD opto-isolation module to analyze and monitor signals transmitted on the CAN FD bus, helping users understand the communication status of the CAN FD bus, such as whether data transmission is normal and whether there are error frames.

[0018] Fiber optic cable: As the medium for signal transmission between two CAN FD opto-isolation modules, it utilizes the characteristics of optical signal transmission to avoid the influence of electrical interference on CAN FD signals, ensuring reliable signal transmission over long distances or in interference environments.

[0019] Preferably, the bus signal fiber is a multimode fiber cable used to transmit CAN FD signals between the two CAN FD opto-isolation modules.

[0020] like Figure 1It also includes a CAN transceiver, inductor L1, capacitors C1, C2, C3, and C4, a resistor network, a varistor, and a D-SUB9 interface; the CANH and CANL pins of the CAN transceiver are connected to the two ends of inductor L1, respectively.

[0021] The varistor is connected between the CAN bus and ground to provide overvoltage protection. When an overvoltage occurs on the CAN bus, the varistor will conduct to discharge the overvoltage and protect the CAN bus circuitry from damage.

[0022] Preferably, the resistor network includes 1K3 resistors, 30R resistors, and 60R resistors, which are used to set the CAN bus termination matching, etc., affecting the impedance matching of the bus, thereby ensuring the integrity of the CAN signal when it is transmitted on the bus and reducing signal reflection and other problems.

[0023] The D-SUB9 interface is the physical interface for connecting the CAN bus to external devices. It is used to connect the CAN bus to other devices (such as CAN analyzers, other devices with CAN interfaces, etc.) and transmit CAN bus signals.

[0024] like Figure 3 Anechoic chamber or shielded room: Module 1 inside is connected to Module 2, which is placed in the remote control room, via cables. The anechoic chamber or shielded room is mainly used to provide an electromagnetic interference shielded environment, reducing the impact of external electromagnetic interference on the relevant circuits or signals of the internal module 1, and ensuring that module 1 can work or conduct relevant tests in a relatively pure electromagnetic environment.

[0025] Module 1: Located in an anechoic chamber or shielded room, it is connected to Module 2 in the remote control room via cable. It is used to perform related signal processing, equipment control and other tasks in a shielded environment, and to transmit relevant signals or control commands to Module 2.

[0026] Module 2: Located in the remote control room, it is connected to Module 1 in the darkroom or shielded room via cable. It is used to receive signals transmitted by Module 1 or send control commands to Module 1 to realize remote control and monitoring of relevant equipment or experiments in the darkroom or shielded room.

[0027] The working principle of this invention is as follows: The device under test (DUT) is bidirectionally connected to one of the CAN FD opto-isolation modules powered by a battery box to realize CAN FD signal interaction between the DUT and the module; the CAN FD opto-isolation module connected to the DUT is connected to a remote CAN FD opto-isolation module through a multimode fiber optic cable to perform opto-isolation transmission of CAN FD signals; the remote CAN FD opto-isolation module is bidirectionally connected to a bus analyzer to analyze and monitor the signals transmitted on the CAN FD bus.

[0028] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A CAN FD bus opto-isolation system, characterized in that: The device includes a bus signal fiber optic cable, a power adapter, a battery box, and two CAN FD opto-isolation modules. The two CAN FD opto-isolation modules are connected via a bus signal fiber optic cable. One of the CAN FD opto-isolation modules is bidirectionally connected to the device under test and is powered by the battery box. The other CAN FD opto-isolation module is bidirectionally connected to a bus analyzer and is powered by either the battery box or the power adapter.

2. The CAN FD bus opto-isolation system according to claim 1, characterized in that: It also includes a CAN transceiver, inductor L1, capacitors C1, C2, C3, and C4, a resistor network, a varistor, and a D-SUB9 interface; the CANH and CANL pins of the CAN transceiver are connected to the two ends of inductor L1, respectively.

3. The CAN FD bus opto-isolation system according to claim 2, characterized in that: The resistor network includes 1K3 resistors, 30R resistors, and 60R resistors.

4. The CAN FD bus opto-isolation system according to claim 1, characterized in that: The bus signal fiber is a multimode fiber optic cable.

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