A CAN relay circuit for mobile charging of automobiles
By introducing a mobile charging CAN relay circuit into the vehicle and using a signal transformer to modulate the CAN signal onto AC power, long-distance CAN communication is achieved, solving the problem of insufficient communication distance in traditional CAN bus and realizing economical and efficient long-distance data transmission.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHANGHUI AUTOMOTIVE ELECTRICAL SYST(ANHUI) LTD
- Filing Date
- 2025-09-03
- Publication Date
- 2026-07-31
AI Technical Summary
Traditional automotive CAN buses typically have a communication distance of no more than 40 meters at high speeds, which is insufficient to meet the needs of long-distance scenarios. Existing solutions either increase costs or sacrifice real-time performance and cannot dynamically adapt to business requirements.
The vehicle mobile charging CAN relay circuit, including a microcontroller, a PLC controller and a signal transformer, is used to achieve long-distance data transmission by modulating the CAN signal onto AC power and transmitting it through ordinary wires.
With a small increase in cost, the CAN communication distance can be extended to hundreds of meters, dynamically adapting to business needs and avoiding the high cost and failure points of repeater and bridge solutions.
Smart Images
Figure CN224583184U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of automotive circuit design, and in particular to a CAN relay circuit for automotive mobile charging. Background Technology
[0002] Traditional automotive CAN buses suffer from signal propagation delays that cause arbitration mechanisms to fail, signal distortion due to attenuation and distributed capacitance over long distances, and reduced signal-to-noise ratios caused by electromagnetic interference (EMI) and ground potential differences. At high speeds (e.g., 1 Mbps), communication distances are typically limited to no more than 40 meters, making them unsuitable for long-distance applications such as the Industrial Internet of Things (IIoT), large agricultural machinery, and distributed energy systems. If two devices communicate via a high-speed CAN bus, either repeaters / bridges or fixed-speed reduction solutions must be used. Using repeaters and bridges increases costs and potential points of failure, while fixed-speed reduction sacrifices real-time performance and fails to dynamically adapt to business needs. Therefore, a circuit capable of transmitting high-speed CAN signals over long distances is needed. Utility Model Content
[0003] The purpose of this invention is to add a protection circuit to the charging protocol chip of a car, thereby solving the problem of long-distance communication between two devices via the CAN bus.
[0004] The technical solution adopted by this utility model to solve its technical problem is: A CAN relay circuit for mobile charging of automobiles, characterized in that it includes a microcontroller U1, a PLC controller U2, and a signal transmission circuit; The low-voltage signal input terminal of the PLC controller U2 is connected to the high-voltage serial port output terminal of the microcontroller U1, and the low-voltage signal output terminal of the PLC controller U2 is connected to the high-voltage serial port input terminal of the microcontroller U1. The signal transmission circuit includes a signal transformer T1 and a connector J1. The first and second ends of the secondary coil of the signal transformer T1 are connected to the positive and negative terminals of the PLC communication terminal, respectively. A first bidirectional TVS diode TVS1 is connected in parallel between the first and second ends of the secondary coil of the signal transformer T1. The third end of the primary coil of the signal transformer T1 is connected to the live wire terminal of the connector J1, and the fourth end of the primary coil of the signal transformer T1 is connected to the neutral wire terminal of the connector J1. A safety capacitor CX and a fuse FU1 are connected sequentially on the line between the third end of the primary coil of the signal transformer T1 and the live wire terminal of the connector J1. A second bidirectional TVS diode TVS2 is connected in parallel between the third end and the fourth end of the primary coil of the signal transformer T1. A varistor VDR is connected in parallel between the second end of the fuse FU1 and the neutral wire terminal of the connector J1.
[0005] Preferably, in conjunction with the above scheme, the CAN relay circuit includes a PLC power supply circuit, which includes a first capacitor C1, a second capacitor C2, and a first resistor R1. The ground terminal of the PLC controller U2 is grounded, and the power supply terminal of the PLC controller U2 is connected in sequence to the first resistor R1 and the low-voltage power supply. The first capacitor C1 and the second capacitor C2 are connected in parallel between the ground terminal of the PLC controller U2 and the first terminal of the first resistor R1.
[0006] Preferably, in conjunction with the above scheme, the CAN relay circuit includes a CAN communication circuit, which includes a CAN transceiver U3. The data receiving end of the CAN transceiver U3 is connected to the CAN data transmitting end of the microcontroller U1, and the data transmitting end of the CAN transceiver U3 is connected to the CAN data receiving end of the microcontroller U1. The enable end of the CAN transceiver U3 is connected to the enable end of the microcontroller U1. The power supply end of the CAN transceiver U3 is connected to a high-voltage power supply. The ground end of the CAN transceiver U3 is grounded. The CAN_H end of the CAN transceiver U3 is connected to the CON_CAN2_H of the device, and the CAN_L end of the CAN transceiver U3 is connected to the CON_CAN2_L of the device.
[0007] Preferably, in conjunction with the above scheme, the power supply terminal of the CAN transceiver U3 is also connected to the second terminal of the third capacitor C3, and the first terminal of the third capacitor C3 is grounded.
[0008] Preferably, in conjunction with the above scheme, the CAN relay circuit includes a power conversion circuit, which includes a power conversion chip U4. The VCCB power terminal of the power conversion chip U4 is connected to a high-voltage power supply, the VCCA power terminal of the power conversion chip U4 is connected to a low-voltage power supply, and the ground terminal of the power conversion chip U4 is grounded. The B1 input terminal of the power conversion chip U4 is connected to the high-voltage serial port output terminal of the microcontroller U1, the B2 input terminal of the power conversion chip U4 is connected to the high-voltage serial port input terminal of the microcontroller U1, the A1 output terminal of the power conversion chip U4 is connected to the low-voltage signal receiving terminal of the PLC controller U2, and the A2 output terminal of the power conversion chip U4 is connected to the low-voltage signal transmitting terminal of the PLC controller U2.
[0009] Preferably, in conjunction with the above scheme, the VCCB power supply terminal is connected to the second terminal of the fourth capacitor C4, and the first terminal of the fourth capacitor C4 is grounded; the VCCA power supply terminal is connected to the first terminal of the fifth capacitor C5, and the second terminal of the fifth capacitor C5 is grounded.
[0010] Preferably, in conjunction with the above scheme, the enable terminal OE of the power conversion chip U4 is connected to the second terminal of the second resistor R2 and the first terminal of the third resistor R3, respectively. The first terminal of the second resistor R2 is connected to the low-voltage power supply, and the second terminal of the third resistor R3 is grounded.
[0011] The beneficial effects of this invention are as follows: The circuit of this invention receives external CAN signals through a CAN transceiver and sends the CAN signals to a microcontroller. After receiving the CAN signals, the microcontroller sends the CAN data to a PLC controller via a serial port using the AT command set. The PLC controller generates an alternating current, modulates the received data onto the AC power supply, and sends the signal to an external network segment through a signal transformer. Long-distance data transmission between two devices can be achieved through ordinary electrical wires. This method can extend the CAN communication distance to hundreds of meters with only a small increase in cost.
[0012] The present invention will be described in more detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0013] Figure 1 This is the peripheral circuit diagram of the microcontroller in this utility model.
[0014] Figure 2 This is the peripheral circuit diagram of the PLC controller in this utility model.
[0015] Figure 3 This is a circuit diagram of the signal transmission circuit in this utility model.
[0016] Figure 4 This is a CAN communication circuit diagram of this utility model.
[0017] Figure 5 This is a power conversion circuit diagram of the present invention.
[0018] Figure 6 This is a connection block diagram of a CAN relay circuit for mobile charging of automobiles according to this utility model. Detailed Implementation
[0019] like Figures 1 to 6 The illustrated CAN relay circuit for mobile charging of automobiles is characterized by including a microcontroller U1, a PLC controller U2, and a signal transmission circuit. The low-voltage signal input terminal of the PLC controller U2 (i.e. Figure 2 Pin 5 (corresponding to PLC_RXD_3V3) and the high-voltage serial port output of microcontroller U1 (i.e. Figure 1 Pin 65 (corresponding to PLC_RXD_5V0) is connected to the low-voltage signal output terminal of the PLC controller U2 (i.e., Figure 2Pin 6 (corresponding to PLC_TXD_3V3) is connected to the high-voltage serial port input terminal of the microcontroller U1 (i.e., Figure 1 Pin 66 (corresponding to PLC_TXD_5V0) is connected; The signal transmission circuit includes a signal transformer T1 and a connector J1. The first and second ends of the secondary coil of the signal transformer T1 are respectively connected to the positive terminal of the PLC communication terminal (i.e., Figure 2 The PLC+ pin), the negative terminal of the PLC communication terminal (i.e. Figure 2 The PLC pins are connected in parallel. A first bidirectional TVS diode, TVS1, is connected in parallel between the first and second ends of the secondary coil of the signal transformer T1. The third end of the primary coil of the signal transformer T1 is connected to the live wire of connector J1. The fourth end of the primary coil of the signal transformer T1 is connected to the neutral wire of connector J1. A safety capacitor CX and a fuse FU1 are connected in sequence on the line between the third end of the primary coil of the signal transformer T1 and the live wire of connector J1. A second bidirectional TVS diode, TVS2, is connected in parallel between the third end of the primary coil of the signal transformer T1 and the fourth end of the primary coil. A varistor, VDR, is connected in parallel between the second end of fuse FU1 and the neutral wire of connector J1.
[0020] To power the PLC controller U2, such as Figure 2 As shown, the CAN relay circuit includes a PLC power supply circuit, which includes a first capacitor C1, a second capacitor C2, and a first resistor R1. The grounding terminal of the PLC controller U2 is grounded, and the power supply terminal of the PLC controller U2 (i.e., Figure 2 The 3V3 pin is connected in sequence to the first resistor R1 and the +3.3V low voltage power supply. The first capacitor C1 and the second capacitor C2 are connected in parallel between the ground terminal of the PLC controller U2 and the first terminal of the first resistor R1.
[0021] In order to communicate with CAN protocol devices, the CAN relay circuit includes a CAN communication circuit, which includes a CAN transceiver U3. The data receiving end of the CAN transceiver U3 (i.e., Figure 4 The RXD pin (corresponding to CAN2_RXD) is connected to the CAN data transmitter of the microcontroller U1 (i.e., Figure 1 Pin 31, corresponding to CAN2_RXD), is the data transmitting end of the CAN transceiver U3 (i.e. Figure 4 The TXD pin (corresponding to CAN2_TXD) is connected to the CAN data receiver of the microcontroller U1 (i.e., Figure 1 Pin 30 (corresponding to CAN2_TXD), the enable pin of the CAN transceiver U3 (i.e. Figure 4The STB pin (corresponding to CAN2_STB) is connected to the enable pin of the microcontroller U1 (i.e., Figure 1 Pin 73 (corresponding to CAN2_STB); the power supply terminal of the CAN transceiver U3 is connected to a +5V high-voltage power supply; the ground terminal of the CAN transceiver U3 is grounded; the CAN_H terminal of the CAN transceiver U3 is connected to the CON_CAN2_H terminal of the device, and the CAN_L terminal of the CAN transceiver U3 is connected to the CON_CAN2_L terminal of the device.
[0022] In order to achieve a filtering effect and ensure stable power supply, the power supply terminal of the CAN transceiver U3 is also connected to the second terminal of the third capacitor C3, and the first terminal of the third capacitor C3 is grounded.
[0023] To convert the serial port voltage from a high 5V to a low 3.3V, the CAN relay circuit includes a power conversion circuit. This power conversion circuit includes a power conversion chip U4. The VCCB power supply terminal of the power conversion chip U4 is connected to a +5V high-voltage power supply, and the VCCA power supply terminal of the power conversion chip U4 is connected to a +3.3V low-voltage power supply. The ground terminal of the power conversion chip U4 is grounded. The B1 input terminal of the power conversion chip U4 (i.e....) Figure 5 Pin 2 (corresponding to PLC_RXD_5V0) is connected to the high-voltage serial port output of the microcontroller U1 (i.e., Figure 1 Pin 65, corresponding to PLC_RXD_5V0, is the B2 input terminal of the power conversion chip U4 (i.e., Figure 5 Pin 3 (corresponding to PLC_TXD_5V0) is connected to the high-voltage serial port input of the microcontroller U1 (i.e., Figure 1 Pin 66, corresponding to PLC_TXD_5V0), the A1 output terminal of the power conversion chip U4 (i.e. Figure 5 Pin 7 (corresponding to PLC_RXD_3V3) is connected to the low-voltage signal input terminal of PLC controller U2 (i.e., Figure 2 Pin 5 of the power converter chip U4 (corresponding to PLC_RXD_3V3), the A2 output terminal of the power conversion chip U4 (i.e. Figure 5 Pin 6 (corresponding to PLC_TXD_3V3) is connected to the low-voltage signal output terminal of PLC controller U2 (i.e., Figure 2 Pin 6 corresponds to PLC_TXD_3V3.
[0024] To achieve a filtering effect and ensure power supply stability, the VCCB power supply terminal is connected to the second terminal of the fourth capacitor C4, and the first terminal of the fourth capacitor C4 is grounded; the VCCA power supply terminal is connected to the first terminal of the fifth capacitor C5, and the second terminal of the fifth capacitor C5 is grounded.
[0025] The enable pin OE of the power conversion chip U4 is connected to the second terminal of the second resistor R2 and the first terminal of the third resistor R3. The first terminal of the second resistor R2 is connected to the low-voltage power supply, and the second terminal of the third resistor R3 is grounded.
[0026] In this embodiment, the MCU microcontroller U1 can be the AC7811QBGE provided by AutoChips, the PLC controller U2 (PLC-IoT) can be the 3121N_ISF provided by Ouzhitong Technology Co., Ltd., the CAN transceiver U3 can be the TJA1042T provided by NXP, and the power conversion chip U4 can be the RS0102YH8 provided by Jiangsu Runshi Technology Co., Ltd.
[0027] like Figure 6 As shown, both Product 1 and Product 2 use all the circuits in this embodiment. Device A first sends CAN data to the CAN transceiver U3 of Product 1. The CAN transceiver U3 then sends the data to the microcontroller U1 of Product 1. After receiving the data, the microcontroller U1 sends the data to the PLC controller U2 (PLC-IoT module) of Product 1 via the UART serial port protocol using AT commands. The PLC controller U2 generates alternating current at the PLC+ and PLC- pins to modulate the received data onto a 50Hz, 220V AC power supply. The data is then sent to the external network segment via a 1:1 signal transformer T1. The transformer itself also acts as a protection mechanism to prevent the product from directly contacting external power. Data can be transmitted between the two sets of connectors J1 via common wires. Once the data is sent to the external network segment, it can be read on the AC power supply of that network segment.
[0028] When Product 2 receives this data from the external network segment, it first sends the signal to PLC controller U2 via signal transformer T1. PLC controller U2 demodulates the data from the 220V AC power and sends the demodulated data to microcontroller U1 via AT commands using the serial port protocol. Microcontroller U1 packages the received data into CAN data and sends the data to device B via the CAN controller. In this way, the CAN signal can be modulated onto 50Hz, 220V AC power and transmitted through traditional wires, thereby extending the communication distance.
[0029] The present invention has been described above with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any improvements made using the inventive concept and technical solution of the present invention, or any direct application to other situations without modification, fall within the protection scope of the present invention.
Claims
1. A CAN relay circuit for mobile charging in automobiles, characterized in that, Includes microcontroller U1, PLC controller U2, and signal transmission circuit; The low-voltage signal input terminal of the PLC controller U2 is connected to the high-voltage serial port output terminal of the microcontroller U1, and the low-voltage signal output terminal of the PLC controller U2 is connected to the high-voltage serial port input terminal of the microcontroller U1. The signal transmission circuit includes a signal transformer T1 and a connector J1. The first and second ends of the secondary coil of the signal transformer T1 are connected to the positive and negative terminals of the PLC communication terminal, respectively. A first bidirectional TVS diode TVS1 is connected in parallel between the first and second ends of the secondary coil of the signal transformer T1. The third end of the primary coil of the signal transformer T1 is connected to the live wire terminal of the connector J1, and the fourth end of the primary coil of the signal transformer T1 is connected to the neutral wire terminal of the connector J1. A safety capacitor CX and a fuse FU1 are connected sequentially on the line between the third end of the primary coil of the signal transformer T1 and the live wire terminal of the connector J1. A second bidirectional TVS diode TVS2 is connected in parallel between the third end and the fourth end of the primary coil of the signal transformer T1. A varistor VDR is connected in parallel between the second end of the fuse FU1 and the neutral wire terminal of the connector J1.
2. The CAN relay circuit for mobile charging of automobiles according to claim 1, characterized in that, The CAN relay circuit includes a PLC power supply circuit, which includes a first capacitor C1, a second capacitor C2, and a first resistor R1. The ground terminal of the PLC controller U2 is grounded, and the power supply terminal of the PLC controller U2 is connected in sequence to the first resistor R1 and the low-voltage power supply. The first capacitor C1 and the second capacitor C2 are connected in parallel between the ground terminal of the PLC controller U2 and the first terminal of the first resistor R1.
3. The CAN relay circuit for mobile charging of automobiles according to claim 1, characterized in that, The CAN relay circuit includes a CAN communication circuit, which includes a CAN transceiver U3. The data receiving end of the CAN transceiver U3 is connected to the CAN data transmitting end of the microcontroller U1, and the data transmitting end of the CAN transceiver U3 is connected to the CAN data receiving end of the microcontroller U1. The enable end of the CAN transceiver U3 is connected to the enable end of the microcontroller U1. The power supply end of the CAN transceiver U3 is connected to a high-voltage power supply. The ground end of the CAN transceiver U3 is grounded. The CAN_H end of the CAN transceiver U3 is connected to the CON_CAN2_H of the device, and the CAN_L end of the CAN transceiver U3 is connected to the CON_CAN2_L of the device.
4. The CAN relay circuit for mobile charging of automobiles according to claim 3, characterized in that, The power supply terminal of the CAN transceiver U3 is also connected to the second terminal of the third capacitor C3, and the first terminal of the third capacitor C3 is grounded.
5. The CAN relay circuit for mobile charging of automobiles according to claim 1, characterized in that, The CAN relay circuit includes a power conversion circuit, which includes a power conversion chip U4. The VCCB power terminal of the power conversion chip U4 is connected to a high-voltage power supply, and the VCCA power terminal of the power conversion chip U4 is connected to a low-voltage power supply. The ground terminal of the power conversion chip U4 is grounded. The B1 input terminal of the power conversion chip U4 is connected to the high-voltage serial port output terminal of the microcontroller U1, the B2 input terminal of the power conversion chip U4 is connected to the high-voltage serial port input terminal of the microcontroller U1, the A1 output terminal of the power conversion chip U4 is connected to the low-voltage signal receiving terminal of the PLC controller U2, and the A2 output terminal of the power conversion chip U4 is connected to the low-voltage signal transmitting terminal of the PLC controller U2.
6. The CAN relay circuit for mobile charging of automobiles according to claim 5, characterized in that, The VCCB power supply terminal is connected to the second terminal of the fourth capacitor C4, and the first terminal of the fourth capacitor C4 is grounded; the VCCA power supply terminal is connected to the first terminal of the fifth capacitor C5, and the second terminal of the fifth capacitor C5 is grounded.
7. The CAN relay circuit for mobile charging of automobiles according to claim 5, characterized in that, The enable pin OE of the power conversion chip U4 is connected to the second terminal of the second resistor R2 and the first terminal of the third resistor R3. The first terminal of the second resistor R2 is connected to the low-voltage power supply, and the second terminal of the third resistor R3 is grounded.