A special LIN bus optical fiber transmission system for automobile lamps and lanterns and a vehicle

Abstract

The application provides a LIN bus optical fiber transmission system special for automobile lamps and a vehicle. The system effectively isolates the electrical connection between the vehicle body control end and the lamp execution end while realizing the LIN bus communication of the automobile lamps. The LIN bus optical fiber transmission system special for automobile lamps comprises a vehicle body control end and a lamp execution end. The vehicle body control end is connected with the lamp execution end through an optical fiber transmission link. The vehicle body control end converts the LIN electrical signal carrying the lamp control instruction into an optical signal. The optical signal is transmitted to the lamp execution end through the optical fiber transmission link. The lamp execution end converts the received optical signal into a LIN electrical signal and executes the lamp control based on the lamp control instruction carried in the LIN electrical signal.

Description

Technical Field

[0001] This application relates to the field of lighting control, specifically to a dedicated LIN bus fiber optic transmission system for automotive lighting and a vehicle. Background Technology

[0002] LIN (Local Interconnect Network) bus, as a low-cost, single-master, multi-slave serial communication protocol, is widely used in automotive lighting control systems. In existing automotive lighting LIN bus communication schemes, the LIN master node in the body control module (BCM) and the LIN slave nodes inside the lighting fixture are typically directly connected by copper electrical cables to transmit LIN electrical signals carrying lighting control commands.

[0003] However, automotive lighting operates in environments characterized by high voltage, high current, and strong electromagnetic interference. For example, LED driver circuits and pulse width modulation (PWM) dimming circuits generate high common-mode voltage and ground level fluctuations during operation. When the LIN master node and LIN slave node are directly connected via electrical cables, there is a lack of effective electrical isolation between them. This direct electrical connection leads to the following problems:

[0004] First, ground loop current can easily form a loop between the vehicle control terminal and the lighting actuator terminal through the LIN communication cable, introducing common-mode interference. In severe cases, this can cause LIN signal level judgment errors or communication loss.

[0005] Second, when a short circuit, high voltage crosstalk, or electrostatic discharge (ESD) occurs on the lamp side, the fault voltage will be directly conducted along the LIN communication cable to the LIN master control node at the vehicle control end, causing damage to the controller interface and even affecting other electronic control units (ECUs) of the vehicle, reducing the safety and reliability of the system.

[0006] Therefore, how to effectively isolate the electrical connection between the vehicle body control terminal and the lighting actuator terminal while realizing LIN bus communication for automotive lighting is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] This application provides a dedicated LIN bus fiber optic transmission system and vehicle for automotive lighting, which effectively isolates the electrical connection between the vehicle body control terminal and the lighting actuator terminal while realizing LIN bus communication for automotive lighting.

[0008] The technical solution of this invention is as follows:

[0009] This application provides a dedicated LIN bus fiber optic transmission system for automotive lighting, the system comprising:

[0010] The vehicle body control unit and the lighting actuator unit are connected to the lighting actuator unit via an optical fiber transmission link.

[0011] The vehicle body control terminal converts the LIN electrical signal carrying the lighting control command into an optical signal, and the optical signal is transmitted to the lighting execution terminal through the optical fiber transmission link.

[0012] The lamp actuator converts the received optical signal into a LIN electrical signal and performs lamp control based on the lamp control command carried in the LIN electrical signal.

[0013] Because the body control unit and the lighting actuator are connected via a fiber optic transmission link, and the body control unit converts the LIN electrical signal carrying the lighting control commands into an optical signal for transmission, complete electrical isolation is achieved between the body control unit and the lighting actuator due to the non-conductive nature of the fiber optic transmission link. This means that even if the lighting actuator experiences faults such as high-voltage crosstalk, short circuits, or electrostatic discharge, the fault current cannot be reversed to the body control unit through the fiber optic link. This effectively protects the body controller and other electronic units in the vehicle, solving the ground loop and high-voltage crosstalk problems caused by direct electrical cable connections in existing technologies.

[0014] After the optical signal is transmitted to the lighting actuator via the fiber optic link, it is converted back into a LIN electrical signal and used to control the lighting. Because fiber optic transmission is unaffected by electromagnetic induction, the optical signal does not couple with noise or undergo signal distortion like traditional electrical cables, even in environments with strong electromagnetic interference such as those from engines, high-current drive harnesses, and PWM dimming circuits. This ensures that the recovered LIN electrical signal maintains the same level and timing as the transmitting end, thereby improving the accuracy of lighting control commands in complex automotive electromagnetic environments.

[0015] By replacing traditional copper electrical cables with fiber optic transmission links, fiber optics, with their small size, light weight, and high flexibility, are particularly suitable for wiring in lighting fixtures with limited internal space, such as full-width headlights and ultra-thin headlights. Compared to electrical cables that require shielding and twisting, fiber optic links offer simpler routing, reducing wire diameter and installation space requirements, thereby lowering the structural complexity of the internal wiring of the lighting fixture.

[0016] In some possible embodiments, the vehicle body control terminal includes: a LIN master node, a LIN level driving circuit, and a light-emitting device connected sequentially via a LIN bus;

[0017] The LIN master control node generates a LIN electrical signal based on the received lighting control command and transmits the LIN electrical signal to the LIN level drive circuit.

[0018] The LIN level driving circuit amplifies the LIN electrical signal and enhances the driving current to drive the light-emitting device.

[0019] The light-emitting device converts the amplified LIN electrical signal into a corresponding optical pulse signal based on the high and low levels of the signal.

[0020] The LIN master node, LIN level drive circuit, and LED are connected sequentially via the LIN bus. This structure allows the standard LIN master node, which could only drive electrical cables, to indirectly control the LED through the intermediate level drive circuit. Since the LED is an electro-optical conversion element, its response speed is much higher than the level change rate of the copper cables driven by traditional LIN transceivers. Therefore, this connection provides the basic hardware architecture for realizing the electro-optical conversion of LIN signals without changing the existing LIN master node design.

[0021] The LIN master node generates a standard LIN electrical signal based on the received lighting control commands and transmits it to the LIN level drive circuit. Since the output drive capability of the LIN master node is typically limited, directly driving the light-emitting device may result in insufficient light output or signal distortion. By setting a separate LIN level drive circuit, the level of the LIN electrical signal can be amplified and the drive current enhanced, ensuring that the light-emitting device receives sufficient transient power. This results in clear on / off pulses during high / low level switching, avoiding excessive broadening of the light signal's rising / falling edges.

[0022] The light-emitting device directly converts the amplified LIN electrical signal into a corresponding optical pulse signal based on its high and low levels. This means that the binary information of the LIN signal (high level corresponds to logic 1, low level corresponds to logic 0) is mapped to the presence or absence of light as is, without involving any protocol conversion or data packetization. Compared to traditional electrical cable transmission of electrical signals, optical pulse signals are not affected by capacitive load, cable resistance, or electromagnetic coupling during subsequent fiber optic transmission, thus preserving the waveform integrity of the LIN signal after electro-optical conversion.

[0023] In some possible embodiments, the luminaire actuator includes: a photoelectric receiver, a limiting amplification and shaping circuit, and a luminaire LIN slave node connected via a LIN bus;

[0024] The photoelectric receiving device converts the received optical pulse signal into an electrical signal, the amplitude and waveform of which do not yet meet the LIN bus communication standard.

[0025] The limiting amplification and shaping circuit limits, amplifies, and shapes the electrical signal to restore a standard LIN electrical signal that is consistent with the LIN electrical signal emitted by the vehicle body control terminal.

[0026] The LIN slave node at the lighting fixture end controls the lighting fixture according to the lighting fixture control instructions in the standard LIN electrical signal.

[0027] The optical receiver, limiting amplification and shaping circuit, and LIN slave node at the lighting fixture are connected sequentially via a LIN bus. This structure allows the optical pulse signal at the end of the fiber optic link to be converted back into an electrical signal and then restored to a standard LIN electrical signal step by step. Since the electrical signals directly output by photoelectric receivers (such as photodiodes) usually have small amplitudes and distorted waveforms, they cannot be correctly recognized by the LIN slave node directly. Therefore, by setting up an independent limiting amplification and shaping circuit as an intermediate stage, the necessary processing channel for signal recovery is provided without modifying the existing standard LIN slave node.

[0028] The optoelectronic receiver converts the received optical pulse signal into an electrical signal, but it is explicitly stated that the amplitude and waveform of this electrical signal do not yet meet the LIN bus communication standard, and that signal attenuation and distortion will occur during the photoelectric conversion process. By not requiring the optoelectronic receiver to directly output a standard LIN level, the performance requirements of the optoelectronic receiver can be reduced, allowing the use of more cost-effective and moderately responsive general-purpose optoelectronic devices, thereby improving the feasibility of engineering implementation.

[0029] The limiting, amplifying, and shaping circuit limits, amplifies, and shapes the aforementioned substandard electrical signals to restore a standard LIN electrical signal consistent with the LIN electrical signal emitted by the vehicle control terminal. This means that the circuit not only compensates for signal amplitude loss during transmission but also eliminates overshoot or noise spikes, while simultaneously shaping and repairing the rising / falling edges of the waveform through Schmitt triggering or comparators. After this processing, the logic level, edge steepness, and high / low level duration of the output signal all meet the LIN 2.x series protocol specifications, thereby ensuring that subsequent LIN slave nodes can correctly parse the instruction content.

[0030] In some possible embodiments, the system further includes: a fault detection device, which is connected to the vehicle body control terminal, the fiber optic transmission link and the lamp actuator terminal respectively;

[0031] The fault detection device monitors the on / off status of the optical fiber transmission link, the communication status of the LIN slave node in the lamp actuator, and the operating parameters of the lamp load. When any abnormal parameter is detected, a standard LIN fault electrical signal is generated. The standard LIN fault electrical signal is sent to the vehicle body control terminal to drive the vehicle body control terminal to perform fault analysis.

[0032] The fault detection device can simultaneously acquire status information from the signal source, transmission, and receiving execution ends. Compared with existing technologies that can only detect bus levels or slave node responses on the LIN master node side, this structure enables independent monitoring of the entire communication chain. It can detect underlying physical faults such as link interruptions or signal loss without relying on the interaction of normal communication frames, thereby significantly improving the fault coverage.

[0033] Fault information is encoded as a standard electrical signal conforming to the LIN protocol, rather than a custom-formatted alarm level or proprietary diagnostic frame. Since the LIN protocol itself supports status response reporting from slave nodes, this standard LIN fault electrical signal can be directly received and parsed by the LIN master node in the vehicle control unit according to the conventional LIN communication mechanism, without the need to add additional diagnostic interfaces or modify the host computer software, thus achieving seamless integration of fault information with the original vehicle LIN communication architecture.

[0034] The fault detection device sends the generated standard LIN fault electrical signal to the body control terminal, driving the terminal to perform fault analysis. Because the fault detection device operates independently of the normal lighting control command transmission path, it can still report fault information via an independent backhaul path even in extreme cases such as a complete fiber optic link failure or a failure of the lighting terminal's LIN slave node. This allows the body control terminal to accurately distinguish between communication link failures and lighting unit failures, avoiding misjudgments or silent failures, and providing a reliable data source for subsequent instrument panel alarms, fault log recording, or safety degradation control.

[0035] In some possible embodiments, the system further includes a power supply isolation device, which is connected to the vehicle body control terminal, the fiber optic transmission link and the lamp actuator terminal respectively, for providing isolated power supply to the vehicle body control terminal, the fiber optic transmission link and the lamp actuator terminal.

[0036] The power supply isolation device is connected to the vehicle body control unit, the fiber optic transmission link, and the lighting actuator, respectively, and provides isolated power to all three. This means that the power circuit between the vehicle body control unit and the lighting actuator is also completely cut off, and the two no longer share the same ground (GND) or positive power terminal (VBAT). Since the fiber optic transmission link itself has already achieved electrical isolation of the signal lines, coupled with the power supply isolation device's isolation of the power path, this embodiment makes the vehicle body control unit and the lighting actuator electrically completely independent, with no direct current path, thereby fundamentally eliminating the generation of ground loop current and common-mode interference.

[0037] In some possible embodiments, the system further includes:

[0038] The timing calibration device is connected to the LIN master node of the vehicle body control end and the LIN slave node of the lamp actuator end respectively, and is used to compensate for fiber optic transmission delay in real time.

[0039] The timing calibration device dynamically measures the total transmission delay from the time the LIN master node sends a signal to the time the LIN slave node receives the corresponding signal, and actively adjusts the timing reference point on the receiving side or the start time on the sending side based on the measurement results. Unlike traditional electrical cable transmission where delays are negligible, fiber optic transmission over long distances or in plastic optical fibers can introduce delays on the order of microseconds or even tens of microseconds, which is sufficient to cause the LIN slave node to fail to respond correctly within the response timeout window. Through real-time compensation, this embodiment restores the timing relationship between the LIN master and slave nodes to a level comparable to that of electrical cable transmission, thereby ensuring that the timing parameters in the standard LIN protocol are still satisfied.

[0040] In some possible embodiments, the automotive lighting includes headlights, taillights, continuous headlights, and / or interior ambient lighting.

[0041] In some possible embodiments, the photodetector is a photodiode or a phototransistor.

[0042] In some possible embodiments, the optical fiber transmission link uses plastic optical fiber.

[0043] This application also provides a vehicle including the aforementioned automotive lighting-specific LIN bus fiber optic transmission system. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the principle of the dedicated LIN bus fiber optic transmission system for automotive lighting in this application embodiment;

[0045] Figure 2 This is a schematic diagram illustrating the signal transmission process of the automotive lighting-specific LIN bus fiber optic transmission system in this application embodiment.

[0046] Figure 3 This is a schematic diagram of fault detection in an embodiment of this application. Detailed Implementation

[0047] Reference Figure 1 This application provides a vehicle, which includes a body controller and at least one automotive lamp, wherein the body controller and the automotive lamp are connected via... Figure 1 The automotive lighting system uses a dedicated LIN bus fiber optic transmission system for communication.

[0048] The vehicle body controller serves as the vehicle body control terminal 1, and the automotive lighting fixture serves as the lighting fixture execution terminal 2. The vehicle body control terminal 1 is connected to the lighting fixture execution terminal 2 via an optical fiber transmission link 3.

[0049] The body controller is used to generate corresponding LIN bus control commands based on vehicle status signals (such as headlight switch signals, turn signal signals, daytime running light enable signals, ambient lighting mode switching signals, etc.).

[0050] Automotive lighting fixtures include, but are not limited to, one or more of the following: headlight modules, taillight modules, continuous headlights, daytime running lights, turn signals, brake lights, reversing lights, and interior ambient lights. Each automotive lighting fixture integrates a LIN slave node 23 for receiving and executing LIN bus control commands.

[0051] Fiber optic transmission link 3 uses plastic fiber (POF) or glass fiber to transmit optical signals carrying lighting control commands between the body controller and the automotive lights.

[0052] Specifically, in this embodiment, the vehicle body control terminal 1 converts the LIN electrical signal carrying the lighting control command into an optical signal, and the optical signal is transmitted to the lighting execution terminal 2 through the optical fiber transmission link 3; the lighting execution terminal 2 converts the received optical signal into a LIN electrical signal, and performs lighting control based on the lighting control command carried in the LIN electrical signal.

[0053] Because the body control terminal 1 and the lighting actuator terminal 2 are connected via an optical fiber transmission link 3, and the body control terminal 1 converts the LIN electrical signal carrying the lighting control command into an optical signal for transmission, and because the optical fiber transmission link 3 itself is non-conductive, complete electrical isolation is achieved between the body control terminal 1 and the lighting actuator terminal 2. This means that even if the lighting actuator terminal 2 experiences faults such as high-voltage crosstalk, short circuit, or electrostatic discharge, the fault current cannot be reversed to the body control terminal 1 through the optical fiber link, thereby effectively protecting the body controller and other electronic units of the vehicle, and solving the ground loop and high-voltage crosstalk problems caused by direct electrical cable connections in existing technologies.

[0054] After the optical signal is transmitted to the lamp actuator 2 via the optical fiber transmission link 3, it is converted back into a LIN electrical signal and used to control the lamp. Because optical fiber transmission is unaffected by electromagnetic induction, in environments with strong electromagnetic interference such as engines, high-current drive harnesses, and PWM dimming circuits, the optical signal will not couple with noise or undergo signal distortion during transmission, unlike traditional electrical cables. This allows the finally recovered LIN electrical signal to maintain the same level and timing as the transmitting end, thereby improving the accuracy of lamp control commands in complex automotive electromagnetic environments.

[0055] By replacing traditional copper electrical cables with fiber optic transmission links, fiber optic cables are characterized by their small size, light weight, and good flexibility, making them particularly suitable for wiring in lighting fixtures with limited internal space, such as through-type and ultra-thin automotive lights. Compared to electrical cables that require shielding and twisting, fiber optic links offer simpler routing, reducing cable diameter and installation space requirements, thereby lowering the structural complexity of the internal wiring of the lighting fixture.

[0056] The vehicle control terminal 1 includes: a LIN master control node 11, a LIN level drive circuit 12, and a light-emitting device 13 connected in sequence via a LIN bus;

[0057] The LIN master control node 11 generates a LIN electrical signal according to the received lighting control command, and transmits the LIN electrical signal to the LIN level drive circuit 12;

[0058] The LIN level driving circuit 12 amplifies the LIN electrical signal and enhances the driving current to drive the light-emitting device 13. The LIN level driving circuit 12 mainly adopts a dedicated LIN bus transceiver chip with a transistor push-pull driving architecture, with built-in level clamping resistors and current limiting resistors, and adds an ESD protection diode to suppress instantaneous high voltage pulses in the vehicle.

[0059] The light-emitting device 13 converts the electrical signal into a corresponding optical pulse signal based on the high and low levels of the amplified LIN electrical signal.

[0060] The LIN master node 11 is the master device in the LIN bus communication network, responsible for initiating bus communication, sending frame headers, scheduling frame order, and managing slave node responses. In automotive lighting applications, the LIN master node 11 is typically integrated into the body control module (BCM) or domain controller. The core of the LIN master node 11 is a microcontroller (MCU) or a dedicated chip with a LIN controller that supports the LIN protocol, working in conjunction with a separate LIN transceiver chip.

[0061] The typical circuit connection of LIN master node 11 is as follows: the microcontroller's transmit data pin (TxD) is connected to the LIN transceiver's TxD input pin, and the microcontroller's receive data pin (RxD) is connected to the LIN transceiver's RxD output pin. The LIN transceiver's LIN bus pins are directly connected to the LIN bus network.

[0062] The LIN level drive circuit 12 is the interface circuit connecting the LIN master node 11 (or the LIN transceiver output) and the light-emitting device 13. The LIN level drive circuit 12 converts the 12V level of the LIN bus into a logic level suitable for driving the light-emitting device 13. Furthermore, the output drive current of the LIN master node 11 is typically small and insufficient to directly drive the LED, therefore the LIN level drive circuit 12 needs to provide sufficient output current. Additionally, the LIN level drive circuit 12 also needs to ensure a fast switching speed between high and low or low and high electrical signals to avoid excessive broadening of the rising or falling edge of the light pulse, thereby ensuring that the light pulse accurately reflects the timing information of the LIN electrical signal.

[0063] The LIN master node 11, LIN level drive circuit 12, and light-emitting device 13 are connected sequentially via the LIN bus. This structure allows the standard LIN master node 11, which could originally only drive electrical cables, to indirectly control the light-emitting device 13 through the intermediate level drive circuit. Since the light-emitting device 13 is an electro-optical conversion element, its response speed is much higher than the level change rate of the copper cables driven by traditional LIN transceivers. Therefore, this connection provides the basic hardware architecture for realizing the electro-optical conversion of LIN signals without changing the existing LIN master node 11 design.

[0064] The LIN master node 11 generates a standard LIN electrical signal based on the received lighting control commands and transmits it to the LIN level drive circuit 12. Since the output driving capability of the LIN master node 11 is typically limited, directly driving the light-emitting device 13 may result in insufficient light output or signal distortion. By separately configuring the LIN level drive circuit 12, the level of the LIN electrical signal can be amplified and the driving current enhanced, ensuring that the light-emitting device 13 receives sufficient transient power. This results in clear on / off pulses during high / low level switching, avoiding excessive broadening of the light signal's rising / falling edges.

[0065] The light-emitting device 13 directly converts the amplified LIN electrical signal into a corresponding optical pulse signal based on its high and low levels. This means that the binary information of the LIN signal (high level corresponds to logic 1, low level corresponds to logic 0) is mapped to the presence or absence of light as is, thus without any protocol conversion or data packetization. Compared with traditional electrical cable transmission of electrical signals, optical pulse signals are not affected by capacitive load, cable resistance, or electromagnetic coupling during subsequent optical fiber transmission, thereby maintaining the waveform integrity of the LIN signal after electro-optical conversion.

[0066] Reference Figure 2 In this embodiment of the application, the lamp actuator 2 includes: a photoelectric receiver 21, a limiting amplification and shaping circuit 22, and a lamp LIN slave node 23 connected via a LIN bus;

[0067] The photoelectric receiving device 21 converts the received optical pulse signal into an electrical signal, the amplitude and waveform of which do not yet meet the LIN bus communication standard.

[0068] The limiting amplification and shaping circuit 22 limits, amplifies, and shapes the electrical signal to restore a standard LIN electrical signal that is consistent with the LIN electrical signal emitted by the vehicle control terminal 1. The limiting amplification circuit 22 mainly uses a precision operational amplifier for small signal differential amplification, and connects a bidirectional Zener diode to achieve level limiting. The back end is then equipped with a Schmitt trigger to complete waveform shaping.

[0069] The LIN slave node 23 of the lighting fixture controls the lighting fixture according to the lighting fixture control instructions in the standard LIN electrical signal.

[0070] The photoelectric receiving device 21 (e.g., a photodiode or phototransistor) receives the optical pulse signal from the optical fiber transmission link 3 and converts it into a weak photocurrent. This current forms a voltage signal across the load resistor. At this time, the amplitude of the electrical signal is small and the waveform is distorted, which does not yet meet the LIN bus communication standard. This weak electrical signal is then sent to the limiting amplifier shaping circuit 22. First, the photocurrent is converted into a voltage by the transimpedance amplifier and amplified in the primary stage. Then, the signal amplitude is increased to the logic level range by the main amplifier. At the same time, the limiter removes excessive noise spikes. Finally, the standard LIN electrical signal with steep rising and falling edges is shaped by the Schmitt trigger and output. This standard LIN electrical signal is directly sent to the LIN slave node 23 at the lamp end. The LIN protocol controller inside the slave node parses the lamp ID and control command in the signal, and then drives the corresponding lamp load (e.g., low beam headlights, turn signals or ambient lights) to perform actions such as lighting, dimming or flashing. Through the above three-level cascading, the circuit completes the entire recovery process from light pulses to standard LIN electrical signals, enabling the LIN slave node 23 at the lamp end to transparently receive and execute commands from the vehicle control terminal 1, just as in a conventional electrical cable transmission system.

[0071] The photoelectric receiver 21, the limiting amplification and shaping circuit 22, and the LIN slave node 23 at the lamp end are connected sequentially via a LIN bus. This structure allows the optical pulse signal at the end of the fiber optic link to be converted back into an electrical signal and gradually restored to a standard LIN electrical signal. Since the electrical signal directly output by the photoelectric receiver 21 (e.g., a photodiode) usually has a small amplitude and distorted waveform, it cannot be directly and correctly recognized by the LIN slave node. Therefore, by setting up an independent limiting amplification and shaping circuit 22 as an intermediate stage, the necessary processing channel for signal recovery is provided without modifying the existing standard LIN slave node.

[0072] The optoelectronic receiver 21 converts the received optical pulse signal into an electrical signal, but explicitly states that the amplitude and waveform of this electrical signal do not yet meet the LIN bus communication standard, and that signal attenuation and distortion will occur during the photoelectric conversion process. By not requiring the optoelectronic receiver 21 to directly output a standard LIN level, the performance requirements for the optoelectronic receiver 21 can be reduced, allowing the use of more cost-effective and moderately responsive general-purpose optoelectronic devices, thereby improving the feasibility of engineering implementation.

[0073] The limiting, amplifying, and shaping circuit 22 limits, amplifies, and shapes the aforementioned substandard electrical signal to restore a standard LIN electrical signal consistent with the LIN electrical signal emitted by the vehicle control terminal 1. This means that the circuit not only compensates for signal amplitude loss during transmission (i.e., amplification) but also eliminates overshoot or noise spikes (i.e., limiting), and simultaneously shapes and repairs the rising / falling edges of the waveform through Schmitt triggering or comparator (i.e., shaping). After this processing, the logic level, edge steepness, and high / low level duration of the output signal all meet the LIN2.x series protocol specifications, thereby ensuring that subsequent LIN slave nodes can correctly parse the instruction content.

[0074] Reference Figure 1 and Figure 3 In this embodiment of the application, the system further includes: a fault detection device 4, which is connected to the vehicle body control terminal 1, the optical fiber transmission link 3 and the lamp actuator terminal 2 respectively;

[0075] The fault detection device 4 monitors the on / off status of the optical fiber transmission link 3, the communication status of the LIN slave node 23 in the lamp actuator 2, and the lamp load operating parameters. When any abnormal parameter is detected, a standard LIN fault electrical signal is generated. The standard LIN fault electrical signal is sent to the vehicle body control terminal 1 to drive the vehicle body control terminal 1 to perform fault analysis.

[0076] The fault detection device 4 is an independent monitoring unit, mainly composed of an optical signal detection module, a LIN signal detection module, and a load detection module. Physically, it is connected to the vehicle control terminal 1, the fiber optic transmission link 3, and the lighting actuator terminal 2, respectively. This three-way connection structure enables the fault detection device 4 to simultaneously acquire the status information of the signal source, transmission channel, and receiving actuator, and can independently complete fault detection without relying on normal LIN communication frame interaction.

[0077] The monitoring of the continuity status of the fiber optic transmission link 3 is accomplished by the optical signal detection module of the fault detection device 4. This optical signal detection module incorporates an optical coupler or splitter in the fiber optic link, diverting a small portion of the optical energy from the main optical path to an internal photodetector. The photodetector converts the received optical signal into a current signal, which is then amplified and compared with a preset threshold voltage.

[0078] Under normal operating conditions, the amplitude of the current signal output by the photodetector is consistently higher than the threshold, and the comparator outputs a high level, indicating that the fiber optic link is working properly.

[0079] When an optical fiber breaks, is excessively bent leading to a sharp increase in optical loss, or when the light-emitting device 13 or the photodetector 21 fails, the light energy received by the photodetector drops below the threshold, and the comparator output flips from high to low. This level transition is captured by the microcontroller of the fault detection device 4, which determines that the optical fiber link is abnormal.

[0080] In addition, the optical signal detection module can detect the presence of an optical signal, but it may not be able to distinguish between the presence of light but no modulation signal and the complete absence of light.

[0081] The monitoring of the communication status of the LIN slave node 23 at the lighting fixture end is completed by the LIN signal detection module. This LIN signal detection module connects to the LIN bus pin of the LIN slave node 23 at the lighting fixture end via a high-impedance probe to acquire the LIN signals received by the slave node in a listening manner, without affecting normal communication. The specific content monitored by this LIN signal detection module includes the following three aspects: First, monitoring whether the LIN bus level is normal. A normal LIN bus should exhibit alternating recessive high and dominant low levels. If the bus remains at a fixed level for more than a preset timeout period, it is determined that the bus level is abnormal. Second, monitoring whether the LIN slave node's response frame is normal. In the LIN protocol, after the master node sends the frame header, the corresponding slave node should return a response frame within the specified response time. The fault detection device 4 listens to the LIN bus and records whether the LIN slave node sends a response frame within the expected time window. If no response from the slave node is detected for several consecutive frames, it is determined that the slave node communication is abnormal. Third, monitoring whether the signal transmission and reception timing is normal. The fault detection device 4 integrates a timing counter to measure timing parameters such as frame interval, synchronization interval length, and byte interval of the LIN signal. When the measured timing deviates from the LIN protocol specification, it is determined to be a timing anomaly.

[0082] The monitoring of the lighting load's operating parameters is accomplished by the load detection module. This module acquires the supply current and supply voltage of the lighting load in real time through a sampling resistor and an analog-to-digital converter (ADC). Specifically, a low-resistance sampling resistor is connected in series in the power supply circuit of the lighting load. The voltage drop across the sampling resistor is amplified by an operational amplifier and then converted into a digital value by the ADC to calculate the actual load current. Simultaneously, the voltage across the lighting load is acquired through a resistor divider network and also converted into a digital value by the ADC. The fault detection device 4 internally presets the normal operating current range, normal operating voltage range, and allowable fluctuation thresholds for each type of lighting load. The microcontroller compares the real-time acquired current and voltage values ​​with the preset thresholds to determine if the following abnormalities exist:

[0083] When the measured current value is close to zero and the voltage value is normal, it is determined that the lamp load is open-circuited.

[0084] When the measured current value is much greater than the upper limit of the normal operating current, it is determined that the lamp load is short-circuited or the drive circuit is short-circuited.

[0085] When the measured current value is within the normal range but the voltage value fluctuates abnormally, it is determined to be an abnormal power supply or a deterioration in the performance of the drive circuit.

[0086] When the measured current or voltage shows periodic jumps or irregular fluctuations, it is determined that the load is unstable.

[0087] The monitoring of the lighting load's operating parameters is accomplished by the load detection module. This module acquires the supply current and supply voltage of the lighting load in real time through a sampling resistor and an analog-to-digital converter.

[0088] The specific implementation method is as follows: A low-resistance sampling resistor is connected in series in the power supply circuit of the lighting load. The voltage drop across the sampling resistor is amplified by an operational amplifier and then converted into a digital value by an analog-to-digital converter to calculate the actual load current. At the same time, the voltage across the lighting load is collected through a resistor voltage divider network and also converted into a digital value by an analog-to-digital converter.

[0089] The fault detection device 4 has pre-set normal operating current range, normal operating voltage range, and allowable fluctuation thresholds for each type of lamp load. The microcontroller compares the real-time collected current and voltage values ​​with the pre-set thresholds to determine if the following abnormality types exist:

[0090] When the measured current value is close to zero and the voltage value is normal, it is determined that the lamp load is open-circuited.

[0091] When the measured current value is much greater than the upper limit of the normal operating current, it is determined that the lamp load is short-circuited or the drive circuit is short-circuited.

[0092] When the measured current value is within the normal range but the voltage value fluctuates abnormally, it is determined to be an abnormal power supply or a deterioration in the performance of the drive circuit.

[0093] When the measured current or voltage shows periodic jumps or irregular fluctuations, it is determined that the load is unstable.

[0094] The fault detection device 4 can simultaneously acquire status information from the signal source (vehicle control terminal 1), the transmission channel (fiber optic transmission link 3), and the receiving execution terminal (lamp execution terminal 2). Compared with existing technologies that can only detect bus levels or slave node responses on the LIN master control node 11 side, this structure enables independent monitoring of the entire communication chain. It can detect underlying physical faults such as link interruption or signal loss without relying on the interaction of normal communication frames, thereby significantly improving the fault coverage.

[0095] Fault information is encoded as a standard electrical signal conforming to the LIN protocol, rather than a custom-formatted alarm level or a proprietary diagnostic frame. Since the LIN protocol itself supports LIN slave nodes reporting status responses, this standard LIN fault electrical signal can be directly received and parsed by the LIN master node 11 in the vehicle control terminal 1 according to the conventional LIN communication mechanism, without the need to add additional diagnostic interfaces or modify the host computer software, thus achieving seamless integration of fault information with the original vehicle LIN communication architecture.

[0096] Reference Figure 3 The fault detection device 4 sends the generated standard LIN fault electrical signal to the LIN master node 11 of the body control terminal 1, driving the LIN master node 11 of the body control terminal 1 to perform fault analysis. Since the fault detection device 4 operates independently of the normal lighting control command transmission path, even in extreme cases where the fiber optic link is completely interrupted or the LIN slave node 23 of the lighting terminal fails, the fault detection device 4 can still report fault information through an independent backhaul path (such as a signal line directly connected to the body control terminal 1 or another backup channel). This allows the LIN master node 11 of the body control terminal 1 to accurately distinguish between communication link faults and lighting terminal faults, avoiding misjudgments or silent failures, and providing a reliable data source for subsequent instrument panel alarms, vehicle system alarms, fault log recording, or safety degradation control.

[0097] Reference Figure 1 The system further includes a power supply isolation device 5, which is connected to the vehicle body control terminal 1, the optical fiber transmission link 3 and the lamp actuator terminal 2 respectively, and is used to provide isolated power supply to the vehicle body control terminal 1, the optical fiber transmission link 3 and the lamp actuator terminal 2.

[0098] The power supply isolation device 5 establishes a magnetic or capacitive isolation path between the input and output terminals through an isolation power module, rather than a direct electrical connection. This provides independent isolated power supplies to the vehicle control terminal 1, the light-emitting device 13 and photoelectric receiver 21 in the fiber optic transmission link 3, and the limiting amplification and shaping circuit 22 and LIN slave node in the lamp actuator terminal 2. The specific working process is as follows: the isolation power module receives the DC input from the vehicle battery, converts the electrical energy into a high-frequency AC signal through an internal DC-DC converter, transfers the energy across the electrical isolation boundary through an isolation transformer, and then obtains a stable signal through rectification and filtering on the secondary side. The isolated output voltage, electrical clearances and creepage distances between different output ports and between output ports and input ports meet automotive-grade isolation requirements. Through this power supply isolation method, there is no shared positive power terminal or power ground loop between the body control terminal 1 and the lamp actuator terminal 2. Even if the lamp actuator terminal 2 experiences serious electrical faults such as high voltage crosstalk, drive short circuit or electrostatic discharge, the fault current cannot cross the isolation boundary to be conducted to the body control terminal 1. At the same time, the fiber optic transmission link 3, as a signal isolation channel, further cuts off the electrical connection on the signal path, thereby achieving complete electrical isolation between the body control terminal 1 and the lamp actuator terminal 2.

[0099] Reference Figure 1 The system in this application embodiment further includes:

[0100] The timing calibration device 6 is connected to the LIN master node 11 of the vehicle body control terminal 1 and the LIN slave node of the lamp execution terminal 2 respectively, and is used to compensate for fiber optic transmission delay in real time.

[0101] The timing calibration device 6 integrates a high-precision clock counter, which periodically sends calibration trigger signals to the LIN master node 11 and the LIN slave nodes. It measures the time difference between the time the master node sends the calibration pulse and the time the slave node receives the pulse, and then subtracts the known circuit processing delay to accurately calculate the one-way propagation delay of the fiber optic link. Based on the measured delay value, the timing calibration device 6 compensates for the delay in one of two ways: the first way is to send delay compensation parameters to the LIN slave nodes, and the timing adjustment circuit inside the slave nodes advances the frame start boundary of the received LIN signal by a corresponding compensation amount; the second way is to send an advance trigger signal to the LIN master node 11, so that the master node sends the signal one compensation amount earlier than the time when it should have sent the LIN frame. After the above real-time compensation, the signal sent by the LIN master node 11 and the signal actually received by the LIN slave nodes are basically aligned in timing, eliminating the adverse effects of the microsecond-level delay caused by fiber optic transmission on key timing parameters such as the frame gap and slave node response timeout window in the LIN protocol, so that the LIN system based on fiber optic transmission can work stably while maintaining the standard protocol.

[0102] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Those skilled in the art can understand that implementing all or part of the processes of the above embodiments and making equivalent changes according to the claims of this application still fall within the scope of this application.

Claims

1. A dedicated LIN bus fiber optic transmission system for automotive lighting, characterized in that, The system includes: The vehicle body control terminal (1) and the lighting actuator terminal (2) are connected to the lighting actuator terminal (2) via an optical fiber transmission link (3); The vehicle body control terminal (1) converts the LIN electrical signal carrying the lamp control command into an optical signal, and the optical signal is transmitted to the lamp execution terminal (2) through the optical fiber transmission link (3). The lamp actuator (2) converts the received optical signal into a LIN electrical signal and performs lamp control based on the lamp control command carried in the LIN electrical signal.

2. The automotive lighting-specific LIN bus fiber optic transmission system according to claim 1, characterized in that, The vehicle body control terminal (1) includes: a LIN master control node (11), a LIN level drive circuit (12), and a light-emitting device (13) connected in sequence via a LIN bus. The LIN master control node (11) generates a LIN electrical signal according to the received lamp control command and transmits the LIN electrical signal to the LIN level drive circuit (12). The LIN level driving circuit (12) amplifies the LIN electrical signal and enhances the driving current to drive the light-emitting device (13). The light-emitting device (13) converts the electrical signal into a corresponding light pulse signal according to the high and low levels of the amplified LIN electrical signal.

3. The automotive lighting-specific LIN bus fiber optic transmission system according to claim 1 or 2, characterized in that, The lamp actuator (2) includes: a photoelectric receiver (21), a limiting amplification and shaping circuit (22), and a lamp LIN slave node (23) connected via a LIN bus. The photoelectric receiving device (21) converts the received optical pulse signal into an electrical signal, the amplitude and waveform of which do not yet meet the LIN bus communication standard; The limiting amplification and shaping circuit (22) limits and amplifies the electrical signal to restore the standard LIN electrical signal that is consistent with the LIN electrical signal emitted by the vehicle body control terminal (1). The LIN slave node (23) of the lamp terminal controls the lamp according to the lamp control command in the standard LIN electrical signal.

4. The automotive lighting-specific LIN bus fiber optic transmission system according to claim 1, characterized in that, The system also includes: a fault detection device (4), which is connected to the vehicle body control terminal (1), the optical fiber transmission link (3) and the lamp actuator terminal (2) respectively; The fault detection device (4) monitors the on / off status of the optical fiber transmission link (3), the communication status of the LIN slave node (23) in the lamp execution terminal (2) and the lamp load operating parameters. When any abnormal parameter is detected, a standard LIN fault electrical signal is generated. The standard LIN fault electrical signal is sent to the vehicle body control terminal (1) to drive the vehicle body control terminal (1) to perform fault analysis.

5. The automotive lighting-specific LIN bus fiber optic transmission system according to claim 1, characterized in that, The system further includes a power supply isolation device (5), which is connected to the vehicle body control terminal (1), the optical fiber transmission link (3) and the lamp actuator terminal (2) respectively, and is used to provide isolated power supply to the vehicle body control terminal (1), the optical fiber transmission link (3) and the lamp actuator terminal (2).

6. The automotive lighting-specific LIN bus fiber optic transmission system according to claim 1, characterized in that, The system also includes: The timing calibration device (6) is connected to the LIN master node (11) of the vehicle body control terminal (1) and the LIN slave node of the lamp execution terminal (2) respectively, and is used to compensate for fiber optic transmission delay in real time.

7. The automotive lighting-specific LIN bus fiber optic transmission system according to claim 1, characterized in that, The automotive lighting fixtures include headlights, taillights, continuous headlights, and / or interior ambient lighting.

8. The automotive lighting-specific LIN bus fiber optic transmission system according to claim 1, characterized in that, The photoelectric receiving device (21) is a photodiode or a phototransistor.

9. The automotive lighting-specific LIN bus fiber optic transmission system according to claim 1, characterized in that, The optical fiber transmission link (3) uses plastic optical fiber.

10. A vehicle, characterized in that, Includes the dedicated LIN bus fiber optic transmission system for automotive lighting as described in any one of claims 1-9.

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