A signal transceiving protection circuit for a vehicle air conditioning system

Abstract

This invention discloses a signal transceiver protection circuit for a vehicle air conditioning system. The circuit includes an onboard power supply, a connector, a high-speed CAN isolation transceiver, a filter, a bidirectional signal voltage regulator circuit, an overvoltage protection circuit, and a CAN bus. The connector provides power and signal connections, and the high-speed CAN isolation transceiver enables communication between the MCU and the CAN bus. The filter and resistors work together to ensure stable signal transmission. The bidirectional signal voltage regulator circuit, through a series of diodes and TVS diodes, protects the signal from voltage fluctuations, enhancing anti-interference capabilities. The overvoltage protection circuit includes a gas discharge tube, a third resistor, and a capacitor to effectively suppress overvoltage and ensure safe and stable circuit operation. This ensures the efficient and stable operation of the vehicle air conditioning system in complex electrical environments, improves the system's anti-interference capabilities and reliability, and reduces the risk of failure due to signal loss or damage.

Description

Technical Field

[0001] This invention belongs to the field of CAN communication technology, and specifically relates to a signal transmission and reception protection circuit for a vehicle air conditioning system. Background Technology

[0002] In modern vehicle air conditioning systems, data transmission and communication between the control system and the air conditioning equipment are often conducted via a CAN bus (Controller Area Network). The CAN bus is a widely used serial communication protocol between vehicle electronic control units (ECUs) due to its high efficiency, interference resistance, and real-time performance. However, with the increasing complexity of modern vehicle electronic systems, especially the signal transceiver modules in air conditioning systems, signal transmission quality and system stability face greater challenges.

[0003] In vehicle air conditioning systems, environmental factors, electrical interference, voltage fluctuations, and power supply noise can affect the reliable transmission of CAN signals, leading to data loss, incorrect transmission, or system malfunctions. For example, during vehicle operation, electromagnetic radiation, engine noise, and battery voltage fluctuations can cause instantaneous voltage fluctuations and interference, thus affecting the transmission quality of CAN bus signals. Furthermore, with continuous technological advancements, the requirements for real-time performance and accuracy in vehicle electronic systems are becoming increasingly stringent. Therefore, ensuring the stability and efficiency of CAN signals has become crucial for ensuring the normal operation of the entire system.

[0004] Transient overvoltages and voltage surges are also common sources of interference in vehicle electronic systems. During severe thunderstorms, engine startup, or sudden power outages, signals on the CAN bus can be subjected to high-voltage surges or electrostatic discharge (ESD). Without effective voltage protection, the delicate circuitry on the CAN bus transmission lines may be damaged, leading to system malfunctions or failures. Traditional voltage protection schemes often use single protective components, such as diodes or fuses. However, these schemes often suffer from incomplete protection, slow response times, or poor reliability when dealing with high-speed communication, frequent voltage changes, and complex signal environments.

[0005] To better protect the CAN signal transceiver module and signal transmission quality in vehicle air conditioning systems, it is crucial to design a protection circuit that integrates overvoltage protection, signal filtering, and voltage regulation. This circuit not only needs to handle instantaneous voltage fluctuations but also needs to clean and stabilize the CAN signal to prevent system failures caused by voltage surges, overvoltages, electrostatic discharge, and other factors. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects of the prior art and provide a signal transceiver protection circuit for a vehicle air conditioning system.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] This invention provides a signal transceiver protection circuit for a vehicle air conditioning system, including an onboard power supply, a connector, a high-speed CAN isolation transceiver, a filter, a bidirectional signal voltage regulator circuit, an overvoltage protection circuit, and a CAN bus. Pins 10 and 11 of the connector are connected to the onboard MCU of the CAN signal section of the vehicle air conditioning system. Pins 9 and 8 of the connector are connected to the positive and negative terminals of the onboard power supply, respectively. Pins 3 and 4 of the high-speed CAN isolation transceiver are connected to pins 10 and 11 of the connector, respectively. Pins 2 and 1 of the high-speed CAN isolation transceiver are connected to pins 8 and 9 of the connector, respectively. Pins 6 and 7 of the high-speed CAN isolation transceiver are connected to pins 3 and 2 of the filter, respectively. The bidirectional signal voltage regulator circuit includes a voltage regulator circuit, a first resistor, a second resistor, and a gas discharge tube. Pins 1 and 4 of the filter are connected to the voltage regulator circuit, the first resistor, and the second resistor, respectively. The first resistor and the second resistor are connected to pins 4 and 3 of the connector, respectively. Pins 4 and 3 of the connector are connected to the CAN bus.

[0009] Furthermore, the voltage regulator circuit includes a first diode, a second diode, a third diode, a fourth diode, and a TVS diode.

[0010] Furthermore, the anode of the first diode is connected to the cathode of the second diode, the anode of the third diode is connected to the cathode of the fourth diode, one terminal of the TVS diode is connected to the cathodes of the first diode and the third diode respectively, and the other terminal of the TVS diode is connected to the anodes of the second diode and the fourth diode respectively.

[0011] Furthermore, pin 1 of the filter is connected to the anode of the third diode and the cathode of the fourth diode, respectively.

[0012] Furthermore, the four pins of the filter are connected to the anode of the first diode and the cathode of the second diode, respectively.

[0013] Furthermore, the first resistor and the second resistor are respectively connected to the two input terminals of the gas discharge tube.

[0014] Furthermore, the overvoltage protection circuit includes a third resistor and a capacitor connected in parallel.

[0015] Furthermore, the output end of the gas discharge tube is connected to a third resistor and a capacitor, respectively.

[0016] Furthermore, the output end of the gas discharge tube is connected to the 6-pin connector.

[0017] Furthermore, the output of the overvoltage protection circuit is connected to pin 8 of the high-speed CAN isolated transceiver.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] (1) This invention effectively achieves electrical isolation between the CAN bus signal and the vehicle air conditioning control system by introducing a high-speed CAN isolation transceiver (CTM1051KT), reducing the impact of external electromagnetic interference and voltage fluctuations on signal transmission. Combined with a bidirectional signal voltage regulator circuit, it can stabilize the voltage level of the CAN signal, avoiding signal loss or incorrect transmission due to voltage fluctuations. This significantly improves the signal transmission quality and reliability, enhances the system's resistance to electrical interference and voltage fluctuations, and ensures stable operation of the air conditioning system.

[0020] (2) This invention designs an overvoltage protection circuit that effectively protects the CAN signal transceiver circuit from transient overvoltages and surge voltages by using a gas discharge tube (GDT) and a TVS diode. The overvoltage protection circuit can quickly absorb overvoltages and guide them to ground, thereby avoiding circuit damage caused by voltage fluctuations. The signal filter can remove high-frequency noise, ensuring clear and stable signal transmission on the CAN bus. Through rapid response protection against voltage surges and transient overvoltages, the lifespan of circuit components is extended, system failures caused by electrical interference are reduced, and the system's anti-interference capability and stability are improved.

[0021] (3) This invention effectively achieves voltage regulation and clamping functions for the CAN signal by designing a bidirectional voltage regulator circuit in the signal path, combining four diodes and a TVS diode. When the voltage exceeds the safety threshold, the diodes and TVS diodes quickly conduct, limiting the voltage within the specified safety range and ensuring that the CAN bus signal remains within its operating range. This effectively prevents overvoltage and voltage fluctuations from interfering with the CAN signal, ensuring signal stability and system reliability, especially in complex electrical environments, such as electromagnetic interference and power supply noise that may occur during vehicle operation.

[0022] (4) This invention combines an overvoltage protection circuit and a bidirectional voltage regulator circuit to achieve a more comprehensive voltage protection function. Under abnormal conditions such as high voltage, surge voltage, or voltage reversal, the circuit can automatically adjust and protect the entire system. Through this optimized combination, it can ensure that the CAN signal transceiver module in the vehicle air conditioning control system can still work normally under various voltage fluctuation environments, thus enhancing the robustness of the circuit.

[0023] (5) This invention integrates a CAN isolation transceiver, a bidirectional voltage regulator circuit, an overvoltage protection circuit, and a filter through reasonable layout and component selection, achieving multiple functions on the same circuit board. This not only simplifies circuit design but also improves system integration, reduces the number of components and system complexity. It reduces the number of external connectors, improves circuit integration and reliability, and reduces the overall system size and cost, making the installation and maintenance of the vehicle air conditioning system more convenient. Attached Figure Description

[0024] Figure 1 This is a circuit module diagram of the present invention;

[0025] Figure 2 This is a circuit diagram of the present invention;

[0026] The attached diagram is labeled as follows: GL1, high-speed CAN isolated transceiver; H1, connector; T1, filter; R1, first resistor; R2, second resistor; B1, gas discharge tube; D1, first diode; D2, second diode; D3, third diode; D4, fourth diode; D5, TVS diode; R3, third resistor; C1, capacitor. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention 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 the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] This embodiment provides a signal transceiver protection circuit for a vehicle air conditioning system, primarily used to ensure stable transmission of CAN bus signals in complex electrical environments, preventing signal loss or damage due to electromagnetic interference, overvoltage, or other factors. This circuit effectively improves system reliability and anti-interference capabilities through a rationally designed signal transmission path and protection mechanism.

[0029] A signal transceiver protection circuit for a vehicle air conditioning system, such as Figure 1 Figure 2As shown, the system includes an onboard power supply, connectors, a high-speed CAN isolated transceiver, a filter, a bidirectional signal voltage regulator circuit, an overvoltage protection circuit, and a CAN bus. Pins 10 and 11 of the connector are connected to the onboard MCU of the vehicle's air conditioning CAN signal section. Pins 9 and 8 of the connector are connected to the positive and negative terminals of the onboard power supply, respectively. Pins 3 and 4 of the high-speed CAN isolated transceiver are connected to pins 10 and 11 of the connector, respectively. Pins 2 and 1 of the high-speed CAN isolated transceiver are connected to pins 8 and 9 of the connector, respectively. Pins 6 and 7 of the high-speed CAN isolated transceiver are connected to pins 3 and 2 of the filter, respectively. The bidirectional signal voltage regulator circuit includes a voltage regulator circuit, a first resistor, a second resistor, and a gas discharge tube. Pins 1 and 4 of the filter are connected to the voltage regulator circuit, the first resistor, and the second resistor, respectively. The first resistor and the second resistor are connected to pins 4 and 3 of the connector, respectively. Pins 4 and 3 of the connector are connected to the CAN bus. The voltage regulator circuit includes a first diode, a second diode, a third diode, a fourth diode, and a TVS diode. The anode of the first diode is connected to the cathode of the second diode, and the anode of the third diode is connected to the cathode of the fourth diode. One terminal of the TVS diode is connected to the cathodes of the first and third diodes respectively, and the other terminal is connected to the anodes of the second and fourth diodes respectively. Pin 1 of the filter is connected to the anode of the third diode and the cathode of the fourth diode respectively. Pin 4 of the filter is connected to the anode of the first diode and the cathode of the second diode respectively. The first and second resistors are connected to the two input terminals of the gas discharge tube respectively. The overvoltage protection circuit includes a third resistor and a capacitor connected in parallel. The output terminal of the gas discharge tube is connected to the third resistor and the capacitor respectively. The output terminal of the gas discharge tube is connected to pin 6 of the connector. The output terminal of the overvoltage protection circuit is connected to pin 8 of the high-speed CAN isolated transceiver.

[0030] In this circuit, the onboard DC 5V power supply provides power to the high-speed CAN isolated transceiver (model CTM1051KT) through pins 8 (GND) and 9 (5V) of the connector. This power supply method ensures the stable operation of the CAN transceiver and prevents the system from being affected by unstable power supply or voltage fluctuations. The circuit converts the digital signals generated by the MCU into CAN signals through the high-speed CAN isolated transceiver and outputs them to a filter for further processing through pins 6 (CANH) and 7 (CANL). After passing through the filter, high-frequency noise in the signal is effectively removed, enhancing signal stability and improving the system's anti-interference capability in harsh electrical environments.

[0031] The filter's output is connected to pins 4 (CANH) and 3 (CANL) of the connector via a first and a second resistor, ultimately connecting to the CAN bus for data control and detection. The resistor settings effectively match the signal level, preventing signal distortion or communication errors caused by voltage mismatch. This design ensures accurate signal transmission and guarantees stable data interaction between the air conditioning control system and other peripherals.

[0032] To address potential voltage fluctuations or overvoltage issues during CAN signal transmission, this circuit incorporates a bidirectional voltage regulator. This circuit includes a first diode, a second diode, a third diode, a fourth diode, and a TVS diode. A well-designed diode connection ensures voltage stability during signal transmission. The anodes and cathodes of the first and second diodes are connected together, as are the anodes and cathodes of the third and fourth diodes. The TVS diode is connected in parallel with these diodes, collectively providing overvoltage protection. This voltage regulator effectively prevents damage from transient voltage fluctuations and excessive voltage, improves the system's anti-interference capability, and avoids signal distortion or damage, thus ensuring stable signal transmission. The TVS diode's function is to quickly respond to and absorb overvoltage, protecting the circuit from voltage surges. The advantage of this design lies in its ability to protect the system from electrical interference through transient voltage absorption, preventing system failures caused by voltage fluctuations.

[0033] In addition, this circuit includes a gas discharge tube (GDT) and an overvoltage protection circuit. The gas discharge tube rapidly conducts when the voltage exceeds a set threshold, diverting the overvoltage to ground, thus protecting the circuit. The overvoltage protection circuit includes a third resistor and a capacitor, which are connected to the input of the gas discharge tube to further enhance the circuit's overvoltage protection capability. The output of the overvoltage protection circuit is grounded through pin 6 (GND) of the connector, further stabilizing signal transmission and reducing the impact of external noise on the signal. The function of the overvoltage protection circuit is to prevent circuit failure due to external voltage surges, enhancing the stability and reliability of the system under high voltage conditions. This design effectively ensures the safe operation of the circuit under extreme voltage conditions, thereby reducing damage to the system caused by excessive voltage.

[0034] The connector (A2541WR-11P) in this invention primarily serves as a signal connector and power supply in the signal transceiver protection circuit of a vehicle air conditioning system. Specifically, as an electronic connection element, it provides an electrical connection path between different circuits, ensuring the correct transmission of CAN signals and providing a stable power supply to other critical components in the circuit. Pins 8 and 9 of the A2541WR-11P connector are connected to the positive and negative terminals of the onboard power supply, respectively, ensuring a stable power supply from the vehicle air conditioning system's power module to the high-speed CAN isolated transceiver, thereby guaranteeing its stable operation and providing the necessary power for the entire circuit. Pins 10 and 11 of the connector are connected to the MCU (Microcontroller Unit) of the vehicle air conditioning system. The MCU sends data to the high-speed CAN isolated transceiver through these pins and receives signals from the CAN bus through the receive pins. The connector provides a stable signal transmission path, ensuring the accurate transmission of CAN signals from the MCU to the transceiver. Pins 3 and 4 of the connector are connected to the first and second resistors of the CAN signal section, respectively. The signal is ultimately transmitted through these resistors to pins 4 (CANH) and 3 (CANL) of the connector and connected to the CAN bus, ensuring data communication between the vehicle's air conditioning system and other devices. Pin 6 of the connector is connected to the ground line, serving as shielding and grounding in the electrical design. The grounding connection helps suppress electromagnetic interference, ensures signal stability, and provides overvoltage protection. In summary, the A2541WR-11P connector in this invention not only provides a physical connection but is also a key component ensuring the normal operation of power supply, signal, and grounding protection functions. Through the proper design of this connector, reliable signal transmission and stable power supply can be ensured, thereby improving the overall stability and anti-interference capability of the vehicle's air conditioning system.

[0035] In summary, this circuit, through the effective coordination of multiple layers of protection mechanisms, such as a high-speed CAN isolation transceiver, filters, a bidirectional signal voltage regulator circuit, a gas discharge tube, and an overvoltage protection circuit, ensures stable transmission of CAN signals in the vehicle's air conditioning system. In this process, each protective component plays a unique role, preventing the impact of voltage fluctuations or interference on the signal and improving the circuit's anti-interference capability, thus ensuring the efficient and stable operation of the vehicle's air conditioning system. This design not only enhances system reliability and reduces the risk of failures caused by signal loss or interference but also extends the system's lifespan and improves overall performance.

[0036] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A signal transceiver protection circuit for a vehicle air conditioning system, characterized in that, The system includes an onboard power supply, connectors, a high-speed CAN isolation transceiver, a filter, a bidirectional signal voltage regulator circuit, an overvoltage protection circuit, and a CAN bus. Pins 10 and 11 of the connector are connected to the onboard MCU of the vehicle's air conditioning CAN signal section. Pins 9 and 8 of the connector are connected to the positive and negative terminals of the onboard power supply, respectively. Pins 3 and 4 of the high-speed CAN isolation transceiver are connected to pins 10 and 11 of the connector, respectively. Pins 2 and 1 of the high-speed CAN isolation transceiver are connected to pins 8 and 9 of the connector, respectively. Pins 6 and 7 of the high-speed CAN isolation transceiver are connected to pins 3 and 2 of the filter, respectively. The bidirectional signal voltage regulator circuit includes a voltage regulator circuit, a first resistor, a second resistor, and a gas discharge tube. Pins 1 and 4 of the filter are connected to the voltage regulator circuit, the first resistor, and the second resistor, respectively. The first resistor and the second resistor are connected to pins 4 and 3 of the connector, respectively. Pins 4 and 3 of the connector are connected to the CAN bus.

2. The signal transceiver protection circuit for a vehicle air conditioning system according to claim 1, characterized in that, The voltage regulator circuit includes a first diode, a second diode, a third diode, a fourth diode, and a TVS diode.

3. The signal transceiver protection circuit for a vehicle air conditioning system according to claim 2, characterized in that, The anode of the first diode is connected to the cathode of the second diode, the anode of the third diode is connected to the cathode of the fourth diode, one terminal of the TVS diode is connected to the cathodes of the first diode and the third diode respectively, and the other terminal of the TVS diode is connected to the anodes of the second diode and the fourth diode respectively.

4. A signal transceiver protection circuit for a vehicle air conditioning system according to claim 1 or 2, characterized in that, Pin 1 of the filter is connected to the anode of the third diode and the cathode of the fourth diode, respectively.

5. A signal transceiver protection circuit for a vehicle air conditioning system according to claim 1 or 2, characterized in that, The filter's four pins are connected to the anode of the first diode and the cathode of the second diode, respectively.

6. The signal transceiver protection circuit for a vehicle air conditioning system according to claim 1, characterized in that, The first resistor and the second resistor are respectively connected to the two input terminals of the gas discharge tube.

7. The signal transceiver protection circuit for a vehicle air conditioning system according to claim 1, characterized in that, The overvoltage protection circuit includes a third resistor and a capacitor connected in parallel.

8. A signal transceiver protection circuit for a vehicle air conditioning system according to claim 1 or 7, characterized in that, The output end of the gas discharge tube is connected to the third resistor and the capacitor, respectively.

9. The signal transceiver protection circuit for a vehicle air conditioning system according to claim 1, characterized in that, The output end of the gas discharge tube is connected to the 6-pin connector.

10. A signal transceiver protection circuit for a vehicle air conditioning system according to claim 1, characterized in that, The output of the overvoltage protection circuit is connected to the 8 pins of the high-speed CAN isolated transceiver.

Images