LIN communication system

Abstract

A LIN communication system is provided for communication between a high-voltage system and a low-voltage system. The LIN communication system includes: a master node located on the low-voltage system side and a slave node located on the high-voltage system side; and a LIN adapter connected to the master node via a low-voltage domain bus and to the slave node via a high-voltage domain bus, enabling bidirectional signal transmission between the master node and the slave node via the LIN adapter. The LIN adapter includes: a first optocoupler configured to enable downlink communication from the master node to the slave node, and a second optocoupler configured to enable uplink communication from the slave node to the master node. By employing the LIN adapter, the LIN communication system becomes compatible with high-voltage domain applications.

Description

Technical Field

[0001] This application relates to a LIN (Local Area Network) communication system compatible with high-voltage domain applications. Background Technology

[0002] Electronic battery sensors (EBS) in automotive applications can measure current with high accuracy over an extended dynamic range. In particular, current battery sensor devices utilize a shunt resistor-based sensing principle, achieving typical accuracy of ±0.5% in the low current range (1mA to 1A) and approximately ±1.0% in the high current range (1A to 1600A). These performance characteristics make battery sensor technology suitable for high-voltage power supply system applications where accurate battery current monitoring is required to estimate battery state and manage energy.

[0003] When integrating electronic battery sensors into high-voltage automotive architectures used for high-voltage current measurement, critical voltage domain incompatibility issues arise in the communication interface. Directly connecting a high-voltage domain LIN bus to a low-voltage domain poses safety and functional risks. For example, low-voltage electronic components connected to a low-voltage domain LIN bus lack the ability to withstand high voltages and may be immediately damaged due to insulation failure or semiconductor junction overvoltage. A direct conductive path created between the high-voltage and low-voltage domains could expose maintenance personnel or vehicle occupants to lethal high voltage potentials (typically >60V). Furthermore, the different voltage levels of the high-voltage and low-voltage domain LIN buses violate the LIN2.x physical layer specification (typically 0V / 12V logic levels), leading to signal integrity distortion, bit error propagation, and communication network malfunction. Utility Model Content

[0004] One objective of this application is to provide a LIN communication system compatible with high-voltage domain applications.

[0005] Therefore, this application provides a LIN communication system in one aspect for communication between a high-voltage system and a low-voltage system, the LIN communication system comprising: The master node is located on the low-voltage system side, and the slave node is located on the high-voltage system side; and A LIN adapter is connected to the master node via a low-voltage domain bus and to the slave node via a high-voltage domain bus to enable bidirectional signal transmission between the master node and the slave node via the LIN adapter. The LIN adapter includes: a first optocoupler configured to enable downlink communication from the master node to the slave node, and a second optocoupler configured to enable uplink communication from the slave node to the master node.

[0006] In one embodiment, the first optocoupler includes: a first infrared LED driven by the low-voltage domain bus, and a first phototransistor activated by the first infrared LED to pull down the level of the high-voltage domain bus; the second optocoupler includes: a second infrared LED driven by the high-voltage domain bus, and a second phototransistor activated by the second infrared LED to pull down the level of the low-voltage domain bus.

[0007] In one embodiment, the high-voltage domain bus is connected to the positive terminal of the auxiliary power supply in the high-voltage system via a high-voltage domain pull-up resistor, and the low-voltage domain bus is connected to the positive terminal of the low-voltage battery in the low-voltage system via a low-voltage domain pull-up resistor.

[0008] In one embodiment, a first diode is provided in the high-voltage domain bus, and the high-voltage domain pull-up resistor includes: a first high-voltage side resistor connected between the positive terminal of the first diode and the positive terminal of the auxiliary power supply, and a second high-voltage side resistor connected between the negative terminal of the first diode and the positive terminal of the auxiliary power supply.

[0009] In one embodiment, a second diode is provided in the low-voltage domain bus, and the low-voltage domain pull-up resistor includes: a first low-voltage side resistor connected between the positive terminal of the second diode and the positive terminal of the low-voltage battery, and a second low-voltage side resistor connected between the negative terminal of the second diode and the positive terminal of the low-voltage battery.

[0010] In one embodiment, the positive terminal of the first infrared LED of the first optocoupler is connected to the low-voltage domain bus on the negative terminal side of the second diode, and the negative terminal of the first infrared LED is connected to the low-voltage domain bus on the positive terminal side of the second diode. The collector of the first phototransistor of the first optocoupler is connected to the high-voltage bus on the negative side of the first diode, and the emitter of the first phototransistor is connected to the negative terminal of the auxiliary power supply.

[0011] In one embodiment, the positive electrode of the second infrared LED of the second optocoupler is connected to the high-voltage domain bus on the negative side of the first diode, and the negative electrode of the second infrared LED is connected to the high-voltage domain bus on the positive side of the first diode; the collector of the second phototransistor of the second optocoupler is connected to the low-voltage domain bus on the negative side of the second diode, and the emitter of the second phototransistor is connected to the ground of the low-voltage system.

[0012] In one embodiment, the auxiliary power supply is provided by a high-voltage battery in the high-voltage system via a DC-DC converter.

[0013] In one embodiment, during signal transmission, either the low-voltage domain bus or the high-voltage domain bus is a transmit bus and the other is a receive bus, wherein the level of the transmit bus is pulled low and the transmit bus drives the corresponding infrared LED to turn on, so that the phototransistor in the optocoupler containing the turned infrared LED turns on and pulls the level of the receive bus low.

[0014] In one embodiment, the slave node is an electronic battery sensor configured to measure the operating state of the high-voltage battery in the high-voltage system.

[0015] In one embodiment, the electronic battery sensor is mounted between the negative terminal of the high-voltage battery and the negative terminal cable.

[0016] The LIN communication system of this application uses a LIN adapter, which solves the problem of bidirectional voltage level conversion between high-voltage domain LIN networks and low-voltage domain LIN networks, enabling the LIN communication system to be compatible with high-voltage domain applications. Attached Figure Description

[0017] The foregoing and other aspects of this application will be more fully understood and appreciated through the following detailed description with reference to the accompanying drawings, in which: Figure 1 A schematic diagram of the basic structure of the LIN communication system in this application; Figure 2 This is a circuit diagram of the LIN adapter in the LIN communication system of this application. Detailed Implementation

[0018] This application generally relates to a LIN communication system compatible with high-voltage domain applications, which enables electrical isolation and bidirectional signal transmission between high-voltage and low-voltage domain LIN networks in electric vehicles (such as hybrid or pure electric vehicles).

[0019] One embodiment of the basic structure of the LIN communication system of this application is as follows: Figure 1 The illustration is shown in the image. See also... Figure 1 The LIN communication system is configured for bidirectional communication between the vehicle's high-voltage (HV) system (or high-voltage domain) SHV and low-voltage (LV) system (or low-voltage domain) SLV.

[0020] The LIN communication system includes a LIN master device (hereinafter referred to as the master device) M located on the SLV side of the low-voltage system, a LIN slave device (hereinafter referred to as the slave device) S located on the SHV side of the high-voltage system, and a LIN adapter A located between the master device M and the slave device S.

[0021] High-voltage systems (SHV) include high-voltage batteries (BP) in automobiles, such as the traction battery that powers a vehicle. The nominal voltage of a high-voltage battery (BP) is, for example, 400-800V.

[0022] The high-voltage battery BP supplies power to the high-voltage load CHV through a high-voltage circuit. The high-voltage circuit is equipped with the slave device S, which is powered by the auxiliary power supply of the high-voltage system SHV. Figure 1 (Not shown, its nominal voltage is, for example, 12V) is used for power supply. The auxiliary power supply for the high-voltage system SHV can be achieved by the high-voltage battery BP via a DC-DC converter.

[0023] A specific example of device S is an electronic battery sensor used to detect the operating state of a high-voltage battery BP to provide accurate battery state parameters. An electronic battery sensor typically includes: a clamp for securing the sensor to the negative terminal of the high-voltage battery BP, a connector for connecting to the negative terminal of the high-voltage battery BP, and a LIN interface, which enables bidirectional communication via the high-voltage domain bus LIN_HV.

[0024] The low-voltage system (SLV) includes a low-voltage battery (BLV), which is a rechargeable battery with the same nominal voltage as the auxiliary power supply of the high-voltage system (SHV). The low-voltage battery (BLV) supplies power to the low-voltage load (CLV) and the low-voltage domain master control device (M) via a low-voltage circuit. The low-voltage domain master control device (M) achieves bidirectional communication through the low-voltage domain bus (LIN_LV).

[0025] The auxiliary rail of the high-voltage system SHV floats above the negative terminal potential of the high-voltage battery, and is at most higher than the nominal voltage of the high-voltage battery BP compared to the vehicle ground. The rail of the low-voltage system SLV uses either the vehicle ground or the low-voltage battery rail as a reference potential (0V). Although the high-voltage domain bus LIN_HV and the low-voltage domain bus LIN_LV are nominally operating at the same logic level, the potential difference between them is almost equal to the full voltage of the high-voltage battery due to the difference in ground reference potential. According to the voltage domain isolation requirements, the LIN interface of the slave device S cannot be directly connected to the low-voltage domain master device M.

[0026] To achieve electrical isolation and bidirectional signal transmission between the high-voltage domain bus LIN_HV and the low-voltage domain bus LIN_LV, this application provides a hardware-based LIN adapter A. This LIN adapter A is connected to the LIN interface of the slave device S via the high-voltage domain bus LIN_HV, and to the master device M via the low-voltage domain bus LIN_LV.

[0027] In the LIN communication system of this application, the master device M in the low-voltage domain can be a vehicle body control module, with 0V vehicle ground or low-voltage battery rail as the reference potential. The slave device S in the high-voltage domain can be an electronic battery sensor or other electronic equipment, with the auxiliary power rail floating above the high-voltage battery BP as the reference potential.

[0028] In a LIN communication system, one of the high-voltage bus LIN_HV and the low-voltage bus LIN_LV serves as the transmit bus (input) and the other as the receive bus (output). Signals transmitted between the high-voltage bus LIN_HV and the low-voltage bus LIN_LV are either high or low level. The signal transmitted by the transmit bus has the same level as the signal received by the receive bus; that is, both are either high or both are low. A high-level signal is a dominant signal (logic 0), and a low-level signal is a recessive signal (logic 1).

[0029] An exemplary structure of LIN adapter A is in Figure 2 The LIN adapter A, as shown in the image, mainly comprises two optocouplers, or simply optocouplers, namely the first optocoupler OC1 and the second optocoupler OC2, which are used to provide bidirectional electrical isolation between the high-voltage system SHV and the low-voltage system SLV.

[0030] The first optocoupler OC1 is used to handle downlink communication from the master device M to the slave device S. The second optocoupler OC2 is used to handle uplink communication from the slave device S to the master device M.

[0031] Each optocoupler is preferably a high-speed optocoupler with nanosecond-level uplink and downlink response speeds.

[0032] Each optocoupler has an infrared input LED (light-emitting diode) driven by the transmit bus. The output is a phototransistor (e.g., a phototriode) used to control the pull-down level of the receive bus. The isolation barrier in the optocoupler is an optical coupling medium, typically with a withstand voltage greater than 1.5kV. There is no electrical coupling path between the input and output of the optocoupler.

[0033] Each phototransistor has a base, an emitter, and a collector. When the base is illuminated by an input LED, the emitter and collector of the phototransistor are connected; when the base is not illuminated by an input LED, the emitter and collector of the phototransistor are turned off.

[0034] The following reference Figure 2 Describe the specific wiring of the first optocoupler OC1 and the second optocoupler OC2 in LIN adapter A.

[0035] A first diode D1 is configured in the high-voltage domain bus LIN_HV. Diode D1 divides the high-voltage domain bus LIN_HV into an upstream segment and a downstream segment. The upstream segment of the high-voltage domain bus LIN_HV is connected between the slave device S and the positive terminal of the first diode D1, and the downstream segment is connected between the negative terminal of the first diode D1 and the collector of the phototransistor of the first optocoupler OC1. The emitter of the phototransistor of the first optocoupler OC1 is connected to the negative terminal BHV- of the auxiliary power supply.

[0036] The positive terminal BHV+ of the auxiliary power supply of the high-voltage system SHV is connected to the upstream and downstream segments of the high-voltage domain bus LIN_HV via the first high-voltage side resistor RHV1 and the second high-voltage side resistor RHV2, respectively. The upstream segment of the high-voltage domain bus LIN_HV is connected to the negative terminal of the input LED of the second optocoupler OC2. The downstream segment of the high-voltage domain bus LIN_HV is also connected to the positive terminal of the input LED of the second optocoupler OC2.

[0037] A second diode D2 is configured in the low-voltage domain bus LIN_LV. Diode D2 divides the LIN_LV into an upstream and downstream segment. The upstream segment of the LIN_LV is connected between the master control device M and the anode of the second diode D2, while the downstream segment is connected between the cathode of the second diode D2 and the collector of the second optocoupler OC2. The emitter of the second optocoupler OC2 is connected to the ground (vehicle ground) of the low-voltage system SLV, the GLV (0V), or the cathode of the low-voltage battery BLV.

[0038] The positive terminal BLV+ of the low-voltage battery BLV is connected to the upstream and downstream segments of the low-voltage domain bus LIN_LV via the first low-voltage side resistor RLV1 and the second low-voltage side resistor RLV2, respectively.

[0039] The upstream segment of the low-voltage domain bus LIN_LV is connected to the negative terminal of the input LED of the first optocoupler OC1, and the downstream segment of the low-voltage domain bus LIN_LV is connected to the positive terminal of the input LED of the first optocoupler OC1.

[0040] The resistors mentioned above are pull-up resistors used to pull up the level of the upstream and downstream segments of the corresponding bus, and the two optocouplers form a pull-down path used to pull down the level of the upstream and downstream segments of the corresponding bus.

[0041] Using the above-described structure of LIN adapter A, bidirectional data transmission modes can be achieved. In the first data transmission mode, the high-voltage domain bus LIN_HV acts as the transmitting bus to transmit signals to the low-voltage domain bus LIN_LV, which acts as the receiving bus. In this mode, the second optocoupler OC2 is active (controlled to be on and off), while the first optocoupler OC1 is off. In the second data transmission mode, the low-voltage domain bus LIN_LV acts as the transmitting bus to transmit signals to the high-voltage domain bus LIN_HV, which acts as the receiving bus. In this mode, the first optocoupler OC1 is active (controlled to be on and off), while the second optocoupler OC2 is off.

[0042] Specifically, in the first data transmission mode, when the high-voltage domain bus LIN_HV is high, the positive and negative voltages of the input LED of the second optocoupler OC2 are at equal high levels, therefore the input LED is off, and thus the second optocoupler OC2 is off. At this time, due to the pull-up effect of the first resistor RLV1 and the second resistor RLV2 on the low-voltage side, the upstream and downstream voltages of the low-voltage domain bus LIN_LV are both high, causing the positive and negative voltages of the input LED of the first optocoupler OC1 to be at equal high levels, therefore the input LED is off, and thus the first optocoupler OC1 is off. The low-voltage domain bus LIN_LV generates a high-level signal.

[0043] In the first data transmission mode, when the high-voltage domain bus LIN_HV is low, the negative voltage of the input LED of the second optocoupler OC2 is low, while the positive voltage is high (pulled up by the second high-voltage side resistor RHV2 to the positive terminal BHV+ of the auxiliary power supply). Therefore, the input LED is turned on, and consequently, the second optocoupler OC2 is turned on. This pulls the downstream voltage of the low-voltage domain bus LIN_LV to a low level (GLV level of the ground terminal of the low-voltage system SLV). The positive and negative voltages of the input LED of the first optocoupler OC1 become reverse biased, i.e., the negative voltage is higher than the positive voltage. Therefore, the input LED is turned off, and consequently, the first optocoupler OC1 is turned off. The low-voltage domain bus LIN_LV generates a low-level signal. The output of the first optocoupler OC1 does not affect the high-voltage domain bus LIN_HV, ensuring that the transmitted signal is not fed back to the high-voltage domain bus LIN_HV, which serves as the input bus.

[0044] In the second data transmission mode, when the low-voltage domain bus LIN_LV is high, the positive and negative voltages of the input LED of the first optocoupler OC1 are at equal high levels, therefore the input LED is off, and thus the first optocoupler OC1 is off. At this time, due to the pull-up effect of the first resistor RHV1 and the second resistor RHV2 on the high-voltage side, the voltages of both the upstream and downstream segments of the high-voltage domain bus LIN_HV are high, and the positive and negative voltages of the input LED of the second optocoupler OC2 are at equal high levels, therefore the input LED is off, and thus the second optocoupler OC2 is off. The high-voltage domain bus LIN_HV generates a high-level signal.

[0045] In the second data transmission mode, when the low-voltage domain bus LIN_LV is low (GLV level of the ground terminal of the low-voltage system SLV), the negative voltage of the input LED of the first optocoupler OC1 is low, while the positive voltage is high (BLV+ of the low-voltage battery BLV pulled up through the second resistor RLV2 on the low-voltage side). Therefore, the input LED is turned on, and thus the first optocoupler OC1 is turned on. Consequently, the downstream voltage of the high-voltage domain bus LIN_HV is pulled down to low (BHV- of the auxiliary power supply), and the positive and negative voltages of the input LED of the second optocoupler OC2 become reverse biased, i.e., the negative voltage is higher than the positive voltage. Therefore, the input LED is turned off, and thus the second optocoupler OC2 is turned off. The high-voltage domain bus LIN_HV generates a low-level signal. The output of the second optocoupler OC2 does not affect the low-voltage domain bus LIN_LV, ensuring that the transmitted signal is not fed back to the low-voltage domain bus LIN_LV, which serves as the input bus.

[0046] In the LIN communication system of this application, the bidirectional voltage level conversion problem between the LIN networks of the high-voltage system (SHV) and the low-voltage system (SLV) is solved by using LIN adapter A. Furthermore, the LIN communication system of this application is designed to meet LIN protocol compliance (ISO 17987 / LIN 2.x specification). The LIN network adopts a master-slave architecture, for example, the master node is the master control device M in the low-voltage domain, and the slave nodes are the slave devices S in the high-voltage domain. It is based on a Time Division Multiple Access (TDMA) communication model, where the master node is responsible for scheduling frame transmission, and the slave nodes respond within designated time slots.

[0047] The LIN communication system of this application is designed to implement bidirectional bus arbitration, wherein the master and slave nodes must declare a dominant state (low level) and a non-dominant state (high level) on the shared bus within their respective transmission windows.

[0048] The voltage conversion scheme of the LIN communication system in this application must meet the following requirements to maintain the integrity of bit timing (nominal transmission rate of 1kbps to 20kbps): It will not introduce bus contention (i.e., simultaneous drive conflict); The propagation delay must not exceed 10% of the bit time; It does not produce signal edge distortion that violates the rise / fall time requirements of the LIN physical layer (typical time is 1-10μs).

[0049] The LIN communication system in this application is designed to meet the requirements of bidirectional single-wire communication: The LIN protocol uses a single-wire bus for half-duplex communication, and the same physical line can be used for both sending and receiving functions simultaneously. The voltage conversion circuit supports bidirectional signal transmission and does not allow for mode switching delays; Electrical isolation must be maintained between the high-voltage and low-voltage domains to meet safety standards (such as ISO 6469, FMVSS305), where the isolation voltage rating between the input and output terminals is greater than or equal to the maximum voltage of the high-voltage system (typically 400-800VDC).

[0050] The LIN communication system of this application employs LIN Adapter A, which is a hardware-based LIN electrical adapter used to achieve seamless protocol-transparent communication between the following two: The main control device M in the low-voltage domain is usually the vehicle control module, with 0V vehicle ground or low-voltage battery rail as the reference potential; The slave device S in the high-voltage domain, such as a battery current sensor, uses the 12V (or other nominal voltage) auxiliary power rail in the high-voltage domain, which is suspended at a potential of approximately 800V (or other nominal voltage), as a reference potential.

[0051] In LIN adapter A, downlink and uplink paths are provided. The downlink path enables the conversion and isolation of the low-voltage domain bus LIN_LV (e.g., 0V-12V relative to vehicle ground) to the high-voltage domain bus LIN_HV (e.g., 0V-12V relative to the HV battery negative terminal). The uplink path enables the conversion and isolation of the high-voltage domain bus LIN_HV to the low-voltage domain bus LIN_LV.

[0052] In LIN adapter A, two high-speed optocouplers (OC1 and OC2) are used to provide bidirectional electrical isolation between the high-voltage domain and the low-voltage domain. The first optocoupler OC1 handles downlink communication (low-voltage domain master device → high-voltage domain slave device), and the second optocoupler OC2 handles uplink communication (high-voltage domain slave device → low-voltage domain master device).

[0053] Each optocoupler's input is an infrared LED driven by the transmit bus. The typical withstand voltage of the optical coupling medium in the optocoupler is >1.5kV. Each optocoupler's output is a phototransistor used to control the pull-down level of the receive bus.

[0054] The input LED is referenced relative to the emitter domain ground (low-voltage ground or the 12V auxiliary power rail in the high-voltage domain); the output transistor is referenced relative to the receiver domain ground; there is no electrical coupling path between the input and output circuits. Thus, the LIN adapter A achieves voltage domain decoupling.

[0055] LIN Adapter A provides self-disabling transmission path logic, where during dominant state transmission (one side pulls the bus potential low), i.e., the active transmitter pulls its LIN bus (transmit bus) to approximately 0V, the LIN bus (receive bus) on the opposite side is also pulled low by the output of the reverse optocoupler (where the reverse optocoupler LED presents the same potential on the anode and cathode), causing the forward voltage drop to approximately 0V, achieving no current between the two LIN buses and thus disabling the reverse path.

[0056] During the recessive state (bus released to high level), both LIN buses are pulled high by their respective pull-up resistors (e.g., 12V), and both optocoupler LEDs present the same high potential, resulting in no optocoupler conduction, thus forming a high-impedance bidirectional link. Therefore, no external control logic is required, achieving completely passive direction detection; zero loopback is achieved, and the output signal will not feed back to the input during active transmission; the protocol is compliant, maintaining LIN master-slave arbitration without adding additional latency.

[0057] In LIN adapter A, the first optocoupler OC1 in the downlink path provides low-to-high voltage isolation. The voltages connected to the two sides of its input LED are respectively the high level (e.g., 12V) in the low-voltage domain and the low-voltage ground, and the voltages connected to the two sides of its output transistor are respectively the high level (e.g., 12V) in the high-voltage domain and the negative terminal of the high-voltage battery.

[0058] The second optocoupler OC2 used in the uplink path provides high-voltage to low-voltage isolation. The voltages connected to the two sides of its input LED are respectively the high level of the high-voltage domain (e.g., 12V) / the negative terminal of the high-voltage battery, and the voltages connected to the two sides of its output transistor are respectively the high level of the low-voltage domain (e.g., 12V) / the low-voltage ground.

[0059] The low-voltage side pull-up resistor is used to pull the recessive state of the low-voltage domain LIN to a high level in the low-voltage domain (e.g., 12V), and the high-voltage side pull-up resistor is used to pull the recessive state of the high-voltage domain LIN to a high level in the high-voltage domain (e.g., 12V).

[0060] The signal conversion mechanism of LIN adapter A is as follows: Dominant state (logic 0): The phototransistor in the optocoupler is turned on, thereby pulling the receive bus to its respective ground (low voltage ground or high voltage battery negative terminal). Recessive state (logic 1): Optocoupler is off, and pull-up resistors restore the receive bus to its respective high level (e.g., 12V) battery rail.

[0061] The LIN adapter A in this application is entirely implemented in hardware. No transformers or active components are required. Furthermore, no software modifications are necessary. It meets automotive-grade reliability standards (due to mature optocoupler technology). The sensor hardware is wirelessly redesigned. A LIN transceiver supporting high-voltage systems has been developed. It is capable of implementing complex isolation protocols.

[0062] The LIN adapter A provides electrical isolation with a withstand voltage of ≥1.5kV, meeting the requirements of ISO 6469-3 for high-voltage systems; and has an insulation resistance >10MΩ under operating conditions.

[0063] The bidirectional data stream transmission provided by LIN Adapter A offers automatic direction detection without the need for external control signals; loopback prevention by disabling the receive path at the input to prevent bus reflections; protocol transparency without requiring modifications to the LIN master / slave software stack; baud rate support of 1kbps~20kbps (typically 19.2kbps); propagation delay <5μs, ensuring compliance with LIN bit timing integrity; rise / fall times of 1-10μs, conforming to the LIN 2.x physical layer specification.

[0064] In summary, the LIN adapter A in the LIN communication system of this application adopts a dual optical coupler topology and, combined with intelligent transmission path management, achieves the following technical effects: Electrical isolation is achieved through optical coupling; Signal transmission in different directions is achieved through parallel-operating optocouplers, thereby supporting bidirectional signal flow; It provides automatic direction detection, eliminating the need for explicit TX / RX mode control signals; It provides self-disable logic to prevent signal loopback during active transmission.

[0065] While this application has been described herein with reference to specific exemplary embodiments, the scope of this application is not limited to the details shown. Various modifications may be made to these details without departing from the basic principles of this application.

Claims

1. A LIN communication system for communication between a high voltage system and a low voltage system, characterized in that The LIN communication system includes: The master node is located on the low-voltage system side, and the slave node is located on the high-voltage system side; and A LIN adapter is connected to the master node via a low-voltage domain bus and to the slave node via a high-voltage domain bus to enable bidirectional signal transmission between the master node and the slave node via the LIN adapter. The LIN adapter includes: a first optocoupler configured to enable downlink communication from the master node to the slave node, and a second optocoupler configured to enable uplink communication from the slave node to the master node.

2. The LIN communication system of claim 1, wherein The first optocoupler includes: a first infrared LED configured to be driven by the low-voltage domain bus, and a first phototransistor configured to be activated by the first infrared LED to pull down the level of the high-voltage domain bus; The second optocoupler includes: a second infrared LED configured to be driven by the high-voltage domain bus, and a second phototransistor configured to be activated by the second infrared LED to pull down the level of the low-voltage domain bus.

3. The LIN communication system as described in claim 2, characterized in that, The high-voltage domain bus is connected to the positive terminal of the auxiliary power supply in the high-voltage system via a high-voltage domain pull-up resistor, and the low-voltage domain bus is connected to the positive terminal of the low-voltage battery in the low-voltage system via a low-voltage domain pull-up resistor.

4. The LIN communication system as described in claim 3, characterized in that, A first diode is provided in the high-voltage domain bus, and the high-voltage domain pull-up resistor includes: a first high-voltage side resistor connected between the positive terminal of the first diode and the positive terminal of the auxiliary power supply, and a second high-voltage side resistor connected between the negative terminal of the first diode and the positive terminal of the auxiliary power supply.

5. The LIN communication system as described in claim 4, characterized in that, The low-voltage domain bus is provided with a second diode, and the low-voltage domain pull-up resistor includes: a first low-voltage side resistor connected between the positive terminal of the second diode and the positive terminal of the low-voltage battery, and a second low-voltage side resistor connected between the negative terminal of the second diode and the positive terminal of the low-voltage battery.

6. The LIN communication system as described in claim 5, characterized in that, The positive terminal of the first infrared LED of the first optocoupler is connected to the low-voltage domain bus on the negative terminal side of the second diode, and the negative terminal of the first infrared LED is connected to the low-voltage domain bus on the positive terminal side of the second diode. The collector of the first phototransistor of the first optocoupler is connected to the high-voltage bus on the negative side of the first diode, and the emitter of the first phototransistor is connected to the negative terminal of the auxiliary power supply.

7. The LIN communication system as described in claim 6, characterized in that, The positive terminal of the second infrared LED of the second optocoupler is connected to the high-voltage domain bus on the negative terminal side of the first diode, and the negative terminal of the second infrared LED is connected to the high-voltage domain bus on the positive terminal side of the first diode. The collector of the second phototransistor of the second optocoupler is connected to the low-voltage bus on the negative side of the second diode, and the emitter of the second phototransistor is connected to the ground of the low-voltage system.

8. The LIN communication system as described in any one of claims 3-7, characterized in that, The auxiliary power supply is provided by the high-voltage battery in the high-voltage system via a DC-DC converter.

9. The LIN communication system as described in any one of claims 2-7, characterized in that, During signal transmission, either the low-voltage domain bus or the high-voltage domain bus is a transmitting bus and the other is a receiving bus. The transmitting bus is pulled low and drives the corresponding infrared LED to turn on, so that the phototransistor in the optocoupler containing the turned infrared LED turns on and pulls the receiving bus low.

10. The LIN communication system as described in any one of claims 1-7, characterized in that, The slave node is an electronic battery sensor configured to measure the operating status of the high-voltage battery in the high-voltage system.

11. The LIN communication system as described in claim 10, characterized in that, The electronic battery sensor is installed between the negative terminal of the high-voltage battery and the negative terminal cable.

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