A harness open short circuit detection circuit and method for an automobile ECU

Abstract

This invention discloses a wiring harness open / short circuit detection circuit and method for automotive ECUs, comprising two parts: a circuit located at the control unit end and a circuit located at the execution unit end. The control unit end circuit periodically sends diagnostic signals to the execution unit end circuit. Upon receiving the diagnostic signals, the execution unit sends a response signal to the host unit. If the host unit receives the response signal from the execution unit, it determines that the wiring harness connection is not faulty. If no response signal is received, the host unit sends another diagnostic signal. If no response signal is received, the host unit determines that the wiring harness connection is faulty. This invention can perform status diagnosis on the vehicle's wiring harness during driving or non-driving operations without disassembling the wiring harness. Decisions are made based on the importance of the transmitted signals, and in extreme cases, timely actions such as slowing down, pulling over, or stopping the vehicle can be taken to ensure driver safety.

Description

Technical Field

[0001] This invention relates to the field of automotive electronics technology, and in particular to a wiring harness open / short circuit detection circuit and method for automotive ECUs. Background Technology

[0002] The trend of intelligent and electric vehicles is significant. Intelligent driving, smart cockpits, and the ability to remotely upgrade certain vehicle functions via OTA (Over-The-Air) updates are all impressive features that traditional engine-based vehicles cannot achieve. Some companies in the industry have already put intelligent driving technology into mass production, realizing the implementation of autonomous driving functions. However, recently, some intelligent vehicle models on the market have experienced frequent accidents, with reports of brake failure, abnormal active acceleration, touch control system malfunctions, and main unit crashes.

[0003] 2021 marked the beginning of a boom in intelligent driving products, with many automakers equipping their new models with intelligent driving domain controllers. These controllers are susceptible to external interference; for example, wiring harness failure can lead to brake failure and vehicle control malfunction. To address these issues, we propose a wiring harness open / short circuit detection circuit and method for automotive ECUs. Summary of the Invention

[0004] This invention proposes a wiring harness open / short circuit detection circuit and method for automotive ECUs, which solves the problems mentioned in the background art and provides a hardware circuit for diagnosing wiring harnesses. It can diagnose and analyze the fault causes of controller-related wiring harnesses without disassembling the vehicle or during normal driving.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A wiring harness open / short circuit detection circuit for an automotive ECU comprises two parts: a circuit located at the control unit end and a circuit located at the execution unit end. The control unit end circuit periodically sends diagnostic signals to the execution unit end circuit. Upon receiving the diagnostic signals, the execution unit sends a response signal to the host unit. If the host unit receives the response signal from the execution unit, it determines that the wiring harness is functioning correctly. If no response signal is received, the host unit sends another diagnostic signal. If no response signal is received, the host unit determines that the wiring harness is faulty. By detecting the circuit or checking for abnormal response signals, the host unit can determine whether the wiring harness is in an open / short circuit state.

[0007] The control unit is used to send signals to the execution unit and detect signal anomalies. It includes an MCU for data processing and key signals, namely VCC12V_IN, MCU_GPIO, SIGNAL_OUT, MCU_PWM_IO, and MCU_ADC. The VCC12V_IN signal is connected to the 12V DC power supply of the control unit. The MCU_GPIO signal is connected to a GPIO of the MCU. The GPIO outputs a high / low level to control the switching circuit composed of transistors VT1 and VT2, thereby controlling the conduction / switching of the VCC12V_IN DC power supply. When MCU_GPIO is high, the switching circuit is on, and 12V is output through transistor VT1. The SIGNAL_OUT signal is connected to the connector of the control unit, and then through a transmission cable to the connector of the execution unit. The SIGNAL_OUT signal contains a mixed DC-AC signal composed of the 12V DC voltage from VCC12V_IN and the AC pulse signal from MCU_PWM.

[0008] In the control unit:

[0009] DC power transmission: The VCC12V_IN network is connected to the DC power supply 12V. When MCU_GPIO is high, the switching circuit is turned on. The 12V is output through the transistor VT1, and then through the inductor L1 and the ferrite bead FB1 to the SIGNAL_OUT network. L1 and FB1 play the role of passing DC and blocking AC.

[0010] AC signal transmission: When the control unit needs to send an AC signal, the MCU can input the corresponding AC signal through the MCU_PWM_IO network. After passing through capacitor C3, the signal is output to the SIGNAL_OUT network. The SIGNAL_OUT network is connected to the connector of the control unit and the signal is transmitted to the execution unit through the connecting cable. The capacitor C3 serves to conduct AC and block DC.

[0011] Preferably, the MCU_PWM_IO signal is connected to the GPIO of an MCU with PWM function, and the MCU can output key AC control signals through the MCU_PWM_IO signal.

[0012] Preferably, the MCU_ADC signal is connected to the GPIO of the MCU with ADC function.

[0013] Preferably, the execution unit is used for data processing and signal response. It includes an MCU for data processing and control signals. The control signals include a SIGNAL_IN signal, an MCU_PWM_IO signal, a SIGNAL signal, and an MCU_ADC signal. The SIGNAL_IN signal is connected to a connector to receive signals transmitted from the control unit via SIGNAL_OUT. The MCU_PWM_IO signal is connected to the GPIO of the MCU with PWM function, and the MCU can output key AC control signals through the MCU_PWM_IO signal. The SIGNAL signal is a 12V DC voltage signal, which is ultimately provided to the key signals of the execution circuit. The MCU_ADC signal is connected to the GPIO of the MCU with ADC function.

[0014] A method for detecting open / short circuits in a wiring harness of an automotive ECU, characterized in that it is applied to the circuit described in any one of claims 1-4, and the method comprises the following:

[0015] In the control unit:

[0016] Cable detection at the control unit end: When 12V is supplied, resistors R5 and R6 divide the 12V voltage, outputting a 4V signal. This signal is connected to the MCU's ADC interface via the MCU_ADC signal for voltage detection. If the voltage on the MCU_ADC network changes:

[0017] If the MCU_ADC changes from 4V to 0V, the cable connected to the SIGNAL_OUT network can be identified as having a short circuit.

[0018] If MCU_ADC is less than 4V but not 0, it can be determined that the 12V voltage is unstable, the actual voltage is less than 12V, or the cable connected to the SIGNAL_OUT network is short.

[0019] Preferably, in the execution unit:

[0020] DC power transmission: The SIGNAL_IN signal is connected to the mixed DC and AC signal output by SIGNAL_OUT. After passing through the filter circuit composed of inductor L2 and ferrite bead FB2, the AC component is filtered out to obtain a 12V DC voltage signal, which is then supplied to the final execution circuit through the SIGNAL network.

[0021] AC signal transmission: The SIGNAL_IN signal is connected to the DC-AC mixed signal output by SIGNAL_OUT. After passing through capacitor C3, the AC signal is obtained and transmitted to the GPIO with PWM function of the MCU. The MCU analyzes the AC signal.

[0022] Cable detection at the execution unit end: When a SIGNAL_IN signal is received, resistors R7 and R8 will divide the 12V voltage, outputting a 4V signal. This signal is transmitted to the MCU's ADC interface via the MCU_ADC signal for voltage detection. Once the voltage of the MCU_ADC network changes:

[0023] If the MCU_ADC changes from 4V to 0V, the cable end connected to the SIGNAL_IN network can be determined to be either short-circuited or open-circuited.

[0024] If MCU_ADC is less than 4V but not 0, it can be determined that the 12V voltage is unstable, the actual voltage is less than 12V, or the cable connected to SIGNAL_IN is short.

[0025] Preferably, the determination of cable connection status:

[0026] If the MCU_ADC signal voltage of the control unit is 4V, the MCU_ADC signal voltage of the execution unit is 4V, and the AC signal communication between the MCUs on the control unit and execution unit sides is normal, then the cable transmission is normal.

[0027] If the MCU_ADC signal voltage of the control unit is 4V, the MCU_ADC signal voltage of the execution unit is 4V, and the AC signal communication between the MCUs on the control unit and execution unit sides is abnormal, the cable may be short-circuited to the 12V power supply.

[0028] If the MCU_ADC signal voltage of the control unit is 4V, the MCU_ADC signal voltage of the execution unit is 0V, and the AC signal communication between the MCUs on the control unit and execution unit sides is abnormal, then the cable is open.

[0029] If the MCU_ADC signal voltage of the control unit is 0V, the MCU_ADC signal voltage of the execution unit is 0V, and the AC signal communication between the MCUs on the control unit and execution unit sides is abnormal, then the cable is short-circuited to ground.

[0030] The beneficial effects of this invention are as follows: This invention provides a new solution that can perform status diagnosis on the vehicle's wiring harness during driving or non-driving processes, and without disassembling the vehicle's wiring harness. Once a wiring harness fails, the specific faulty wiring harness can be quickly and accurately located based on signal transmission, and the driver can be promptly alerted to the fault. In autonomous driving scenarios, if a control cable fails, the autonomous driving controller will know the cable fault information immediately and make decisions based on the importance of the transmitted signal. In the most extreme cases, it can promptly perform operations such as slowing down, pulling over, or stopping the vehicle to ensure the driver's safety. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall architecture of the present invention.

[0032] Figure 2 This is a circuit diagram of the control unit of the present invention.

[0033] Figure 3 This is a circuit diagram of the execution unit of the present invention.

[0034] Figure 4 This is a circuit diagram showing the connection between the control unit and the execution unit of the present invention. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0036] Example 1

[0037] Reference Figure 1-4 As shown, a wiring harness open / short circuit detection circuit for an automotive ECU comprises two parts: one part is the circuit located at the control unit end, such as an intelligent driving domain controller (or other controller), and the other part is the circuit located at the execution unit end, such as a headlight controller or a brake controller (the overall framework is shown in the figure). Figure 1 The control unit circuit periodically sends diagnostic signals to the execution unit circuit. After receiving the diagnostic signal, the execution unit sends a response signal to the host. If the host receives the response signal from the execution unit, it is determined that there is no problem with the connection harness. If no response signal is received, the diagnostic signal will be sent again. If it is still not received, it is determined that there is a fault in the connection harness. The connection harness is determined to be open or short-circuited by circuit detection or by whether the received response signal is abnormal.

[0038] like Figure 2 As shown, in the control unit, the control unit is used to send signals to the execution unit and detect signal anomalies. It includes an MCU (Microcontroller Unit) for processing data and five key signals. The five key signals are VCC12V_IN signal, MCU_GPIO signal, SIGNAL_OUT signal, MCU_PWM_IO signal and MCU_ADC signal. The VCC12V_IN signal is used to connect to the 12V DC power supply of the control unit.

[0039] The MCU_GPIO signal is used to connect to a GPIO (General-purpose input / output) of the MCU. By outputting a high / low level through the GPIO, the switching circuit composed of transistors VT1 and VT2 (hereinafter referred to as the "switching circuit") is controlled, thereby controlling the conduction / turn-off of the VCC12V_IN DC power supply. When MCU_GPIO is high, the switching circuit is turned on, and 12V is output through transistor VT1.

[0040] The SIGNAL_OUT signal is used to connect to the connector of the control unit, and then through the transmission cable to the connector of the execution unit. The SIGNAL_OUT signal contains a mixed DC-AC signal consisting of the 12V DC voltage from VCC12V_IN and the AC pulse signal emitted by MCU_PWM.

[0041] The MCU_PWM_IO signal is connected to the GPIO of the MCU with PWM (Pulse Width Modulation) function. The MCU can output key AC control signals through the MCU_PWM_IO signal.

[0042] The MCU_ADC signal is connected to the GPIO of the MCU, which has an ADC (Analog-to-Digital Converter) function.

[0043] like Figure 3 As shown, in the execution unit, the execution unit is used for data processing and signal response. It includes an MCU for data processing and four control signals. The four control signals include SIGNAL_IN signal, MCU_PWM_IO signal, SIGNAL signal and MCU_ADC signal. The SIGNAL_IN signal is connected to the connector and receives the signal transmitted from SIGNAL_OUT by the control unit.

[0044] The MCU_PWM_IO signal is connected to the GPIO of the MCU with PWM (Pulse Width Modulation) function. The MCU can output key AC control signals through the MCU_PWM_IO signal.

[0045] The SIGNAL signal, a 12V DC voltage signal, is ultimately supplied to the critical signal of the execution circuit.

[0046] The MCU_ADC signal is connected to the GPIO of the MCU, which has an ADC (Analog-to-Digital Converter) function.

[0047] Example 2

[0048] A method for detecting open / short circuits in the wiring harness of an automotive ECU, applied to the aforementioned circuit, the method comprising the following:

[0049] like Figure 2 As shown, in the control unit: DC power transmission: Figure 2 The VCC12V_IN network is connected to a 12V DC power supply. When the MCU_GPIO is high, the switching circuit is turned on. The 12V is output through the transistor VT1, and then through the inductor L1 and the ferrite bead FB1 to the SIGNAL_OUT network. L1 and FB1 serve to conduct DC and block AC.

[0050] AC signal transmission: When the control unit needs to send an AC signal, the MCU can input the corresponding AC signal through the MCU_PWM_IO network. After passing through capacitor C3, the signal is output to the SIGNAL_OUT network. The SIGNAL_OUT network is connected to the connector of the control unit and the signal is transmitted to the execution unit through the connecting cable. The capacitor C3 serves to conduct AC and block DC.

[0051] Cable detection at the control unit end: When 12V is supplied, resistors R5 and R6 divide the 12V voltage, outputting a 4V signal. This signal is connected to the MCU's ADC interface via the MCU_ADC signal for voltage detection. If the voltage on the MCU_ADC network changes:

[0052] If the MCU_ADC changes from 4V to 0V, the cable connected to the SIGNAL_OUT network can be identified as having a short circuit, or a fault in transistor VT1, capacitor C2, resistor R5, or resistor R6.

[0053] If MCU_ADC is less than 4V but not 0, it can be determined that the 12V voltage is unstable, the actual voltage is less than 12V, or the cable connected to the SIGNAL_OUT network is short.

[0054] like Figure 2 , Figure 3 As shown in Figure 4, in the execution unit: DC power supply transmission: Figure 3 The SIGNAL_IN signal is connected. Figure 2 The mixed DC and AC signal output by SIGNAL_OUT is filtered out by a filter circuit composed of inductor L2 and ferrite bead FB2 to obtain a 12V DC voltage signal, which is then sent to the final execution circuit through the SIGNAL network. L1 and FB1 play the role of conducting DC and blocking AC.

[0055] AC signal transmission: Figure 3The SIGNAL_IN signal is connected. Figure 2 The mixed DC-AC signal output by SIGNAL_OUT passes through capacitor C3 to obtain an AC signal, which is then transmitted to the GPIO with PWM function of the MCU. The MCU analyzes the AC signal. In this process, capacitor C3 serves to conduct AC and block DC.

[0056] Cable detection at the execution unit end: When a SIGNAL_IN signal is received, resistors R7 and R8 will divide the 12V voltage, outputting a 4V signal. This signal is transmitted to the MCU's ADC interface via the MCU_ADC signal for voltage detection. Once the voltage of the MCU_ADC network changes:

[0057] If the MCU_ADC changes from 4V to 0V, the cable end connected to the SIGNAL_IN network can be identified as short-circuited or open-circuited, or there may be a fault in inductor L2, ferrite bead FB2, resistor R7, resistor R8, or capacitor C5, but the latter is very, very unlikely.

[0058] If MCU_ADC is less than 4V but not 0, it can be determined that the 12V voltage is unstable, the actual voltage is less than 12V, or the cable connected to SIGNAL_IN is short.

[0059] Determining cable connection status:

[0060] If the MCU_ADC signal voltage of the control unit is 4V, the MCU_ADC signal voltage of the execution unit is 4V, and the AC signal communication between the MCUs on the control unit and execution unit sides is normal, then the cable transmission is normal.

[0061] If the MCU_ADC signal voltage of the control unit is 4V, the MCU_ADC signal voltage of the execution unit is 4V, and the AC signal communication between the MCUs on the control unit and execution unit sides is abnormal, the cable may be short-circuited to the 12V power supply, or capacitor C3 or capacitor C4 may be faulty.

[0062] If the MCU_ADC signal voltage of the control unit is 4V, the MCU_ADC signal voltage of the execution unit is 0V, and the AC signal communication between the MCUs on the control unit and execution unit sides is abnormal, then the cable is open.

[0063] If the MCU_ADC signal voltage of the control unit is 4V, the MCU_ADC signal voltage of the execution unit is 0V, and the AC signal communication between the MCUs on the control unit and execution unit sides is normal, then the fault is in one or more of the following: inductor L2, ferrite bead FB2, resistor R7, resistor R8, and capacitor C5.

[0064] If the MCU_ADC signal voltage of the control unit is 0V, the MCU_ADC signal voltage of the execution unit is 0V, and the AC signal communication between the MCUs on the control unit and execution unit sides is abnormal, then the cable is short-circuited to ground.

[0065] If the MCU_ADC signal voltage of the control unit is 0V, the MCU_ADC signal voltage of the execution unit is 0V, and the AC signal communication between the MCUs on the control unit and execution unit sides is normal, then the fault lies in one or more of the following: transistor VT1, capacitor C2, resistor R5, and resistor R6.

[0066] In summary, the main objective of this invention is to provide a new solution that allows for the diagnosis and fault analysis of controller-related wiring harnesses without disassembling the entire vehicle wiring harness during normal driving. Once a wiring harness fault is detected, the system will promptly remind the vehicle owner to inspect and maintain the faulty wiring harness. Furthermore, the system will store the causes of faults in one or more specific signal wiring harnesses, such as short circuits or open circuits, to facilitate actions such as deceleration or pulling over before the vehicle loses control. It will also allow for the retrieval of fault cause analysis data after the vehicle loses control.

[0067] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A wiring harness open / short circuit detection circuit for an automotive ECU, comprising two parts: a circuit located at the control unit end and a circuit located at the execution unit end, characterized in that, The control unit circuit periodically sends diagnostic signals to the execution unit circuit. After receiving the diagnostic signal, the execution unit sends a response signal to the host. If the host receives the response signal from the execution unit, it is determined that the connection harness is not faulty. If no response signal is received, the diagnostic signal will be sent again. If no response signal is received, it is determined that the connection harness is faulty. The connection harness is determined to be open or short-circuited by circuit detection or by whether the received response signal is abnormal. The control unit is used to send signals to the execution unit and detect signal anomalies. It includes an MCU for data processing and key signals, namely VCC12V_IN, MCU_GPIO, SIGNAL_OUT, MCU_PWM_IO, and MCU_ADC. The VCC12V_IN signal is connected to the 12V DC power supply of the control unit. The MCU_GPIO signal is connected to a GPIO of the MCU. The GPIO outputs a high / low level to control the switching circuit composed of transistors VT1 and VT2, thereby controlling the conduction / switching of the VCC12V_IN DC power supply. When MCU_GPIO is high, the switching circuit is on, and 12V is output through transistor VT1. The SIGNAL_OUT signal is connected to the connector of the control unit, and then through a transmission cable to the connector of the execution unit. The SIGNAL_OUT signal contains a mixed DC-AC signal composed of the 12V DC voltage from VCC12V_IN and the AC pulse signal from MCU_PWM. In the control unit: DC power transmission: The VCC12V_IN network is connected to the DC power supply 12V. When MCU_GPIO is high, the switching circuit is turned on. The 12V is output through the transistor VT1, and then through the inductor L1 and the ferrite bead FB1 to the SIGNAL_OUT network. L1 and FB1 play the role of passing DC and blocking AC. AC signal transmission: When the control unit needs to send an AC signal, the MCU can input the corresponding AC signal through the MCU_PWM_IO network. After passing through capacitor C3, the signal is output to the SIGNAL_OUT network. The SIGNAL_OUT network is connected to the connector of the control unit and the signal is transmitted to the execution unit through the connecting cable. The capacitor C3 serves to conduct AC and block DC.

2. The wiring harness open / short circuit detection circuit for an automotive ECU according to claim 1, characterized in that, The MCU_PWM_IO signal is connected to the GPIO of the MCU with PWM function, and the MCU can output key AC control signals through the MCU_PWM_IO signal.

3. The wiring harness open / short circuit detection circuit for an automotive ECU according to claim 1, characterized in that, The MCU_ADC signal is connected to the GPIO of the MCU that has ADC functionality.

4. The wiring harness open / short circuit detection circuit for an automotive ECU according to claim 1, characterized in that, The execution unit is used for data processing and signal response. It includes an MCU for data processing and control signals. The control signals include a SIGNAL_IN signal, an MCU_PWM_IO signal, a SIGNAL signal, and an MCU_ADC signal. The SIGNAL_IN signal is connected to a connector and receives the signal transmitted from the control unit via SIGNAL_OUT. The MCU_PWM_IO signal is connected to the GPIO of the MCU with PWM function, and the MCU can output key AC control signals through the MCU_PWM_IO signal. The SIGNAL signal is a 12V DC voltage signal, which is ultimately provided to the key signal of the execution circuit. The MCU_ADC signal is connected to the GPIO of the MCU with ADC function.

5. A method for detecting open / short circuits in the wiring harness of an automotive ECU, characterized in that, Applied to the circuit according to any one of claims 1-4, the method comprises the following: In the control unit: Cable detection at the control unit end: When 12V is supplied, resistors R5 and R6 divide the 12V voltage, outputting a 4V signal. This signal is connected to the MCU's ADC interface via the MCU_ADC signal for voltage detection. If the voltage on the MCU_ADC network changes: If the MCU_ADC changes from 4V to 0V, the cable connected to the SIGNAL_OUT network is considered to be short-circuited. If MCU_ADC is less than 4V but not 0, it indicates that the 12V voltage is unstable, the actual voltage is less than 12V, or the cable connected to the SIGNAL_OUT network is short.

6. The method for detecting open / short circuits in the wiring harness of an automotive ECU according to claim 5, characterized in that, In the execution unit: DC power transmission: The SIGNAL_IN signal is connected to the mixed DC and AC signal output by SIGNAL_OUT. After passing through the filter circuit composed of inductor L2 and ferrite bead FB2, the AC component is filtered out to obtain a 12V DC voltage signal, which is then supplied to the final execution circuit through the SIGNAL network. AC signal transmission: The SIGNAL_IN signal is connected to the DC-AC mixed signal output by SIGNAL_OUT. After passing through capacitor C3, the AC signal is obtained and transmitted to the GPIO with PWM function of the MCU. The MCU analyzes the AC signal. Cable detection at the execution unit end: When a SIGNAL_IN signal is received, resistors R7 and R8 will divide the 12V voltage, outputting a 4V signal. This signal is transmitted to the MCU's ADC interface via the MCU_ADC signal for voltage detection. Once the voltage of the MCU_ADC network changes: If the MCU_ADC changes from 4V to 0V, the cable end connected to the SIGNAL_IN network is judged to be short-circuited or open-circuited. If MCU_ADC is less than 4V but not 0, it indicates that the 12V voltage is unstable, the actual voltage is less than 12V, or the cable connected to SIGNAL_IN is short.

7. The method for detecting open / short circuits in the wiring harness of an automotive ECU according to claim 6, characterized in that, Determining cable connection status: If the MCU_ADC signal voltage of the control unit is 4V, the MCU_ADC signal voltage of the execution unit is 4V, and the AC signal communication between the MCUs on the control unit and execution unit sides is normal, then the cable transmission is normal. If the MCU_ADC signal voltage of the control unit is 4V, the MCU_ADC signal voltage of the execution unit is 4V, and the AC signal communication between the MCUs on the control unit and execution unit sides is abnormal, the cable may be short-circuited to the 12V power supply. If the MCU_ADC signal voltage of the control unit is 4V, the MCU_ADC signal voltage of the execution unit is 0V, and the AC signal communication between the MCUs on the control unit and execution unit sides is abnormal, then the cable is open. If the MCU_ADC signal voltage of the control unit is 0V, the MCU_ADC signal voltage of the execution unit is 0V, and the AC signal communication between the MCUs on the control unit and execution unit sides is abnormal, then the cable is short-circuited to ground.

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