A state monitoring circuit and method for vehicle-mounted electronic equipment

Abstract

A circuit and method for monitoring the status of an on-board electronic device includes a microprocessor, a serializer / deserializer, a DC / DC power module, and a camera module. The DC / DC power module is connected to the serializer / deserializer, and data communication between the microprocessor and the camera module is achieved through the serializer / deserializer. The circuit also includes a current detection module, a comparison module, and a switch module. The switch module is connected to the DC / DC power module to control the on / off of power supply. The input end of the current detection module is connected to the output end of the DC / DC power module to detect the output current and convert it into a voltage. The input end of the comparison module is connected to the output end of the current detection module to perform voltage comparison. The microprocessor is connected to the output end of the comparison module to control the state of the switch module based on the comparison result. The circuit structure of the present invention is simple, easy to implement, low in circuit cost, and highly versatile.

Description

Technical Field

[0001] The present invention relates to the field of vehicle-mounted equipment, and in particular to a circuit and method for monitoring the status of vehicle-mounted electronic equipment. Background Art

[0002] With the rapid development of the automotive market, the use of in-vehicle electronic devices is becoming increasingly widespread, and customer requirements for in-vehicle video displays, such as reversing video displays and driving recorder video monitoring, are also increasing. To meet the requirements of high-resolution in-vehicle video displays, high-definition LVDS cameras are gaining popularity. LVDS HD cameras, typically used in specialized automotive environments, require long-distance transmission and high interference immunity. They often utilize FPD-Link serializer / deserializers for remote high-speed data transmission and control. Currently, mature solutions, such as TI's, use twisted pair or coaxial cable as the transmission medium between the serializer and deserializer to achieve high-speed signal transmission, allowing in-vehicle display devices to be located several meters away from the HD camera.

[0003] In actual use, due to considerations for on-board wiring, cost savings, and reduced work hours, the connection between high-definition LVDS cameras and on-board display terminals generally uses coaxial transmission. This coaxial line must transmit both the high-definition video signal and related control signals, as well as power. Furthermore, in actual use, for the LVDS camera to function properly, it must be powered by the on-board display device and its internal serializer configuration registers must be initialized. Once the camera is functioning properly, the camera will transparently transmit the high-definition video signal to the on-board display terminal via the internal serializer for normal display. However, during the power-on and initialization process for the LVDS high-definition camera to function properly, incorrect power-on timing, serializer initialization failure, or camera failures such as internal short circuits or open circuits will cause the camera to malfunction. Summary of the Invention

[0004] The main purpose of the present invention is to overcome the above-mentioned defects in the prior art and to provide a state monitoring circuit and method for electronic equipment, which has a simple circuit structure, is easy to implement, has low circuit cost and strong versatility.

[0005] The present invention adopts the following technical solutions:

[0006] A state monitoring circuit for on-board electronic equipment includes a microprocessor, a serializer / deserializer, a DC / DC power module, and a camera module. The DC / DC power module is connected to the serializer / deserializer, and data communication between the microprocessor and the camera module is achieved through the serializer / deserializer. The circuit is characterized by further comprising a current detection module, a comparison module, and a switch module. The switch module is connected to the DC / DC power module to control the on / off of power supply. The input end of the current detection module is connected to the output end of the DC / DC power module to detect the output current and convert it into a voltage. The input end of the comparison module is connected to the output end of the current detection module to perform voltage comparison. The microprocessor is connected to the output end of the comparison module to control the state of the switch module based on the comparison result.

[0007] Preferably, the current detection module is a current detection amplifier.

[0008] Preferably, the comparison module includes a first comparator, a power supply VCC, a resistor R11, a resistor R12, a diode D3, a diode D5, a resistor R13 and a resistor R14; the positive input end of the first comparator is connected to the cathode of the diode D3, and the anode of the diode D3 is connected to the output end of the current detection module; the negative input end of the first comparator is connected to the cathode of the diode D5, one end of the resistor R12 and one end of the resistor R11; the other end of the resistor R11 is connected to the power supply VCC, and the other end of the resistor R12 and the anode of the diode D5 are grounded; one end of the resistor R13 is connected to the output end of the first comparator, and the other end is connected to one end of the resistor R14 and the microprocessor; the other end of the resistor R14 is grounded.

[0009] Preferably, the comparison module includes a second comparator, a power supply VCC, a resistor R3, a resistor R4, a resistor R, a resistor R6, a diode D4, and a diode D1; the positive input end of the second comparator is connected to the cathode of the diode D4, and the anode of the diode D4 is connected to the output end of the current detection module; the negative input end of the second comparator is connected to the cathode of the diode D1, one end of the resistor R4, and one end of the resistor R3; the other end of the resistor R3 is connected to the power supply VCC, and the other end of the resistor R4 and the anode of the diode D1 are grounded; one end of the resistor R5 is connected to the output end of the second comparator, and the other end is connected to one end of the resistor R6 and the microprocessor; the other end of the resistor R6 is grounded.

[0010] Preferably, the switch module includes a transistor Q1 and a resistor R1; the base of the transistor Q1 is connected to one end of the resistor R1, the collector is connected to the DCDC power supply module, and the emitter is grounded; the other end of the resistor R1 is connected to the microprocessor.

[0011] Preferably, the system further comprises a status indication module connected to the microprocessor.

[0012] Preferably, the status indication module includes a transistor Q2, a light-emitting diode D2 and a resistor R10; the base of the transistor Q2 is connected to the microprocessor, the collector is connected to the cathode of the light-emitting diode D2, and the emitter is grounded; the anode of the light-emitting diode D2 is connected to one end of the resistor R10, and the other end of R10 is connected to the power supply VCC.

[0013] Preferably, the status indication module includes a transistor Q3, a light-emitting diode D6 and a resistor R10; the base of the transistor Q3 is connected to the microprocessor, the collector is connected to the cathode of the light-emitting diode D6, and the emitter is grounded; the anode of the light-emitting diode D6 is connected to one end of the resistor R10, and the other end of R10 is connected to the power supply VCC.

[0014] A method for monitoring the status of an on-board electronic device is provided, for detecting the operating status of a camera module. Data communication between the camera module and a microprocessor is achieved via a serializer / deserializer, and power is supplied by a DC-DC power module. The method is characterized in that a current detection module detects the output current of the DC-DC power module and converts it into a voltage, which is input into a comparison module for comparison. Based on the comparison result, the DC-DC power module is controlled to maintain or shut down power supply, or the camera module is controlled to restart.

[0015] Preferably, the comparison result includes whether the camera is in a normal working state or is not started normally or is in a broken circuit or overcurrent state.

[0016] From the above description of the present invention, it can be seen that compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The circuit and method of the present invention utilize a current detection module, a comparison module, and a switch module to detect the output current of the DCDC power module and convert it into a voltage. The voltage is then compared and, based on the comparison result, the DCDC power module is controlled to maintain or shut down power supply, or the camera module is controlled to restart. The circuit structure is simple, easy to implement, low in cost, and highly versatile.

[0018] 2. The circuit and method of the present invention utilize the detection principle of the current detection amplifier and the voltage function characteristics of the voltage comparator, and have high-precision detection.

[0019] 3. The circuit of the present invention combines I / O port detection and control technology with FPD-Link serializer / deserializer transparent transmission control technology and POC power supply technology to realize status detection and control of vehicle-mounted LVDS high-definition cameras. This enables real-time monitoring and control of high-definition cameras when faults occur, facilitating troubleshooting of high-definition cameras in actual use.

[0020] 4. The circuit and method of the present invention are provided with a status indication module, which reminds the working status of the camera module through the light-emitting diode, facilitating the installation and debugging of the high-definition camera on the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a circuit diagram of the present invention;

[0022] Figure 2 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0023] The present invention is further described below through specific embodiments.

[0024] Figure 1 A status monitoring circuit for an on-board electronic device includes a microprocessor, a serializer / deserializer, a DC / DC power module U11, and a camera module. The DC / DC power module U11 is connected to the serializer / deserializer, and data communication between the microprocessor and the camera module is achieved through the serializer / deserializer. The serializer / deserializer includes a serializer U2 and a deserializer U3, and data exchange between the serializer U3 and the deserializer U2 is carried out via a coaxial cable. The serializer U2 can be an FPD-Link serializer (such as TI's DS90UB935-Q1), and the deserializer U3 can be an FPD-Link deserializer (such as TI's ds90ub936-q1).

[0025] The DC-DC power module U11 has an input terminal VIN, an enable terminal EN, and an output terminal VOUT. The input terminal VIN is connected to the power front end U10, which contains surge protection and front-end filtering circuits. The U10 input terminal is connected to the vehicle's power supply B+, which is typically 24V. Resistor R9 is connected between the input terminal VIN and the enable terminal EN as a pull-up resistor, and filter capacitors C1 and C2 are also connected to its output terminal. When the enable terminal EN is high, the DC-DC power module outputs voltage; when the enable terminal EN is low, the DC-DC power module has no output.

[0026] The camera module can be an LVDS high-definition camera, which includes a power module U6, an ISP module U4, a sensor module U5, etc. The power module U6 contains a DC-DC and an LDO, which respectively power U3, U4, and U5. The power module is powered by a DC-DC power module U11. Specifically, it includes two bias tee circuits for implementing POC power supply. One circuit is connected between the power module and the coaxial line of the serializer / deserializer, and includes a ferrite bead L1, a ferrite bead L6, a capacitor C4, an inductor L5, a resistor R8, a capacitor C7, and a capacitor C8. The capacitor C4 is a high-frequency coupling capacitor, one end of which is connected to the input end of the serializer U3, and the other end is connected to one end of the ferrite bead L1. The other end of the ferrite bead L1 is connected to one end of the inductor L5, and the resistor R8 is connected in parallel with the inductor L5. The other end of the inductor L5 is connected to the capacitor C7, the capacitor C8, and one end of the ferrite bead L6. The other end of the ferrite bead L6 is connected to the input end of the power module. The capacitors C7 and C8 are filter capacitors.

[0027] The other path is connected between the DCDC power module U11 and the coaxial line, and includes ferrite beads L2, ferrite beads L3, capacitor C3, inductor L4, resistor R7, capacitor C5, and capacitor C6. Capacitor C3 is a high-frequency coupling capacitor, one end of which is connected to the output of the deserializer U2, and the other end is connected to one end of ferrite bead L2, which is connected to one end of inductor L4. Resistor R7 is connected in parallel with inductor L4. The other end of inductor L4 is connected to capacitor C5, capacitor C6, and one end of ferrite bead L3. The other end of ferrite bead L3 is connected to the output of the DCDC power module U11. Capacitors C5 and C6 are filter capacitors.

[0028] The present invention also includes a current detection module, a comparison module, and a switch module. The switch module is connected to the DC-DC power module U11 to control the power supply on and off. The switch module can use an NPN transistor or other switching element. Preferably, it includes a transistor Q1 and a resistor R1; the base of transistor Q1 is connected to one end of resistor R1, the collector is connected to the enable terminal EN of the DC-DC power module U11, and the emitter is grounded; the other end of resistor R1 is connected to the microprocessor U1. R1 is a current-limiting resistor.

[0029] The input of the current sensing module is connected to the output of the DC-DC power module U11 to detect the output current and convert it into a voltage. This current sensing module can utilize a current sensing amplifier U9. In practical applications, for example, a Maxim MAX9938 can be used. Resistor R2 is installed at the output of the DC-DC power module U11 as a current sensing resistor. The input of U9 is connected to both ends of the current sensing resistor, and the output is connected to the comparator module.

[0030] The input end of the comparison module is connected to the output end of the current detection module to perform voltage comparison. It can be implemented using multiple comparator circuits, preferably two. The details are as follows:

[0031] One of the comparison circuits includes a first comparator U7, a power supply VCC, a resistor R11, a resistor R12, a diode D3, a diode D5, a resistor R13, and a resistor R14. The positive input of the first comparator U7 is connected to the cathode of diode D3, the anode of which is connected to the output of the current detection module. The negative input of the first comparator U7 is connected to the cathode of diode D5, one end of resistor R12, and one end of resistor R11. The other end of resistor R11 is connected to the power supply VCC, and the other end of resistor R12 and the anode of diode D5 are grounded. One end of resistor R13 is connected to the output of the first comparator, and the other end is connected to one end of resistor R14 and the microprocessor. The other end of resistor R14 is grounded. This comparison circuit is used to determine whether the camera module has started normally or has an internal circuit breaker.

[0032] Another comparison circuit includes a second comparator U8, resistors R3, R4, R, R6, diode D4, and diode D1. The positive input of the second comparator U8 is connected to the cathode of diode D4, the anode of which is connected to the output of the current detection module. The negative input of the second comparator U8 is connected to the cathode of diode D1, one end of resistor R4, and one end of resistor R3. The other end of resistor R3 is connected to power supply VCC, and the other end of resistor R4 and the anode of diode D1 are grounded. One end of resistor R5 is connected to the output of the second comparator U8, and the other end is connected to one end of resistor R6 and the microprocessor. The other end of resistor R6 is grounded. This comparison circuit is used to determine whether the camera module has overcurrent.

[0033] In the comparison circuit, diode D1 and diode D5 are different voltage-stabilizing diodes, resistors R3, R4, R11, and R12 are voltage-dividing resistors, and diode D3 and diode D4 are diodes with the same parameters.

[0034] Resistors R5 and R6 serve as voltage divider resistors at the output of the second comparator U8, ensuring that the high level outputted by the second comparator U8 to the I / O port of the microprocessor U1 does not exceed the I / O port supply voltage (typically 3.3V). Resistors R13 and R14 serve as voltage divider resistors at the output of the first comparator U7, ensuring that the high level outputted by the first comparator U7 to the I / O port of the microprocessor U1 does not exceed the I / O port supply voltage (typically 3.3V).

[0035] The system also includes a status indication module connected to the microprocessor. It includes at least one status indication circuit for indicating the status of the camera module. Preferably, there are two status indication circuits, as follows:

[0036] A status indication circuit includes a transistor Q2, a light-emitting diode D2 and a resistor R10; the base of the transistor Q2 is connected to the microprocessor, the collector is connected to the cathode of the light-emitting diode D2, and the emitter is grounded; the anode of the light-emitting diode D2 is connected to one end of the resistor R10, and the other end of R10 is connected to the power supply VCC.

[0037] Another status indication circuit includes a transistor Q3, a light-emitting diode D6 and a resistor R10; the base of the transistor Q3 is connected to the microprocessor, the collector is connected to the cathode of the light-emitting diode D6, and the emitter is grounded; the anode of the light-emitting diode D6 is connected to one end of the resistor R10, and the other end of R10 is connected to the power supply VCC.

[0038] Resistor R10 is a current-limiting resistor, and transistors Q2 and Q3 are NPN transistors. LED D2 can be set to flash to indicate the camera module is operating normally, LED D2 is constantly on to indicate low current and the camera module is not starting properly, and LED D6 is constantly on to indicate excessive internal current in the camera module, possibly indicating an internal short circuit.

[0039] The microprocessor U1 is connected to the output of the comparison module to control the state of the switch module based on the comparison result. Microprocessor U1 is the core system module, which contains a CPU, DDR3, EMMC, PMIC, etc. It has audio and video codec functions, includes a dual LVDS interface, an HDMI interface, a MIPI_CSI interface, and contains combination circuits such as WiFi, Bluetooth, and GPS. In practice, it runs on the Android platform. I / O1, I / O2, I / O3, and I / O4 are U1's internal GPIO ports. I / O1 and I / O2 are configured as input ports and are connected to the output of the two comparison circuits respectively. I / O3, I / O4, and I / O5 are output ports. I / O3 is connected to the base of transistor Q2, I / O4 is connected to resistor R1, and I / O5 is connected to the base of transistor Q3.

[0040] The microprocessor U1 and the serializer U2 communicate internally via I2C and MIPI_CSI interfaces. During power-on initialization, U1 initializes the deserializer U3 by configuring related registers via I2C, enabling normal communication between the camera module and the microprocessor U1.

[0041] The present invention also provides a state monitoring method for an on-board electronic device, which is used to detect the operating status of a camera module. The above-mentioned current detection module is used to detect the output current of the DC-DC power module and convert it into a voltage. The voltage is input into a comparison module for voltage comparison. Based on the comparison result, the DC-DC power module is controlled to maintain or shut down power supply, or the camera module is controlled to restart. The comparison result may include whether the camera is in normal working state, has not started normally, is in a circuit breaker state, or is in an overcurrent state. The method of the present invention is specifically as follows:

[0042] Set the total current passing through resistor R2 to be I1 when the LVDS high-definition camera is working properly; the total current passing through R2 during the current test is I2; when I2 = I1, it indicates the working state of the LVDS high-definition camera. When I2 < I1, the LVDS high-definition camera fails to start properly or there is an open circuit inside. When I2 > I1, there may be a short circuit inside the LVDS camera, resulting in excessive current.

[0043] Let the voltage at point A of the first comparator U7 be represented by VA, and the voltage at point B, which is the default lower limit of the normal voltage, be VB; let the voltage at point P of the second comparator U8 be represented by VP, and the voltage at point N, which is the default upper limit of the normal voltage, be VN; the voltage drops of D3 and D4 are V3 and V4 respectively (in actual application, V3 is approximately equal to V4), and at the same time, VN > VB is set.

[0044] In actual application, when U9 uses MAX9938 from Maxim: VA = I * R2 * Rout / Rin - V3,

[0045] VP = I * R2 * Rout / Rin - V4, where VA is approximately equal to VP.

[0046] When VA > VB and VP < VN, it indicates that the LVDS high-definition camera is in a normal working state, and U9 monitors that the current is within the normal range; when VA < VB, it indicates that the LVDS high-definition camera fails to start properly or there is an open circuit inside, and the current monitored by U9 is less than the normal working current range; when VP > VN, it indicates that there may be a short circuit inside the LVDS high-definition camera, resulting in excessive current, and the current monitored by U9 has exceeded the normal current range.

[0047] For the specific steps, refer to Figure 2

[0048] After the device is powered on and initialized, the current passing through resistor R2 is monitored by the current detection amplifier U9 and is simultaneously converted into a voltage and output to the first voltage comparator U7 and the second voltage comparator U8 for voltage comparison. When VA > VB and VP < VN, the microprocessor U1 will detect that I / O1 is at a high level and I / O2 is at a low level. At this time, the microprocessor U1 will keep the output of I / O4 low, and at the same time, the output of I / O3 will have a waveform with a fixed frequency of F, causing the light-emitting diode D2 to flash, indicating that the LVDS camera is in a normal working state.

[0049] When VA < VB, the microprocessor U1 will detect that I / O1 is at a low level and I / O2 is at a low level, indicating that the LVDS camera fails to start properly or there is an internal open circuit. The microprocessor U1 controls I / O3 to output a high level, causing the light-emitting diode D2 to light up constantly for fault reminder, and at the same time controls I / O4 to output a high level; after a time T1, I / O4 and I / O3 are pulled low. At the same time, the microprocessor U1 configures the internal relevant registers through I2C and remotely transmits them to the deserialization unit U3 by the serializer U2 to realize the re-initialization of the LVDS high-definition camera, so that the LVDS high-definition camera restarts once. The microprocessor U1 detects and processes I / O1 and I / O2, including the following:

[0050] If I / O1 is at a low level and I / O2 is at a low level, the microprocessor U1 controls I / O3 to be at a high level, causing the light-emitting diode D2 to light up constantly for fault reminder, and at the same time controls I / O4 to be at a high level, turning off the output power of the DCDC power module U11 and no longer supplying power to the LVDS camera;

[0051] If I / O1 is at a high level and I / O2 is at a low level, the microprocessor U1 keeps I / O4 at a low level, and at the same time I / O3 outputs a waveform with a fixed frequency of F, causing the light-emitting diode D2 to flash, indicating that the LVDS camera is in a normal working state;

[0052] If I / O1 is at a high level and I / O2 is at a high level, indicating that the LVDS high-definition camera is in an overcurrent state and there may be an internal short circuit, the microprocessor U1 will control I / O4 to output a high level, disconnecting the output power of the DCDC power module U11 and stopping supplying power to the LVDS high-definition camera. At the same time, the microprocessor U1 controls I / O5 to output a high level, causing the light-emitting diode D6 to light up constantly for abnormal reminder of overcurrent.

[0053] When VP > VN, the microprocessor U1 detects that I / O1 is at a high level and I / O2 is at a high level, indicating that the LVDS high-definition camera is in an overcurrent state and there may be an internal short circuit. The microprocessor U1 will control I / O4 to output a high level, disconnecting the output power of the DCDC power module U11 and stopping supplying power to the LVDS high-definition camera. At the same time, the microprocessor U1 controls I / O5 to output a high level, causing the light-emitting diode D6 to light up constantly for abnormal reminder of overcurrent.

[0054] The present invention is applied to an in-vehicle display terminal with an LVDS high-definition camera function to realize the status detection, control and fault reminder of the in-vehicle LVDS high-definition camera, facilitating the installation and debugging of the high-definition camera on the vehicle. It has the advantages of low cost, convenient application, automatic real-time monitoring and fault reminder.

[0055] The above is only a specific implementation of the present invention, but the design concept of the present invention is not limited to this. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A status monitoring circuit for an in-vehicle electronic device, comprising a microprocessor, a serializer / deserializer, a DC-DC power module, and a camera module, wherein the DC-DC power module is connected to the serializer / deserializer, and data communication between the microprocessor and the camera module is achieved via the serializer / deserializer; characterized in that: The device further comprises a current detection module, a comparison module, and a switch module; the switch module is connected to the DCDC power module to control the on or off of power supply; the input end of the current detection module is connected to the output end of the DCDC power module to detect the output current and convert it into a voltage; the input end of the comparison module is connected to the output end of the current detection module to perform voltage comparison; the microprocessor is connected to the output end of the comparison module to control the state of the switch module according to the comparison result; the comparison result includes whether the camera is in a normal working state, abnormal startup, open circuit, or overcurrent state, and the DCDC power module is controlled to maintain or shut down the power supply, or the camera module is controlled to restart according to the comparison result; The comparison module includes a first comparator, a power supply VCC, a resistor R11, a resistor R12, a diode D3, a diode D5, a resistor R13, and a resistor R14; the positive input end of the first comparator is connected to the cathode of the diode D3, and the anode of the diode D3 is connected to the output end of the current detection module; the negative input end of the first comparator is connected to the cathode of the diode D5, one end of the resistor R12, and one end of the resistor R11; the other end of the resistor R11 is connected to the power supply VCC, and the other end of the resistor R12 and the anode of the diode D5 are grounded; one end of the resistor R13 is connected to the output end of the first comparator, and the other end is connected to one end of the resistor R14 and the microprocessor; the other end of the resistor R14 is grounded; The comparison module includes a second comparator, a power supply VCC, a resistor R3, a resistor R4, a resistor R, a resistor R6, a diode D4, and a diode D1; the positive input end of the second comparator is connected to the cathode of the diode D4, and the anode of the diode D4 is connected to the output end of the current detection module; the negative input end of the second comparator is connected to the cathode of the diode D1, one end of the resistor R4, and one end of the resistor R3; the other end of the resistor R3 is connected to the power supply VCC, and the other end of the resistor R4 and the anode of the diode D1 are grounded; one end of the resistor R5 is connected to the output end of the second comparator, and the other end is connected to one end of the resistor R6 and the microprocessor; the other end of the resistor R6 is grounded.

2. The state monitoring circuit of an on-vehicle electronic device according to claim 1, wherein: The current detection module is a current detection amplifier.

3. A state monitoring circuit for an on-vehicle electronic device as claimed in claim 1, characterized in that : The switch module includes a transistor Q1 and a resistor R1; the base of the transistor Q1 is connected to one end of the resistor R1, the collector is connected to the DCDC power supply module, and the emitter is grounded; the other end of the resistor R1 is connected to the microprocessor.

4. The state monitoring circuit of an on-vehicle electronic device according to claim 1, wherein: The device also includes a status indication module, which is connected to the microprocessor.

5. The state monitoring circuit of an on-vehicle electronic device according to claim 4, characterized in that: The status indication module includes a transistor Q2, a light-emitting diode D2 and a resistor R10; the base of the transistor Q2 is connected to the microprocessor, the collector is connected to the cathode of the light-emitting diode D2, and the emitter is grounded; the anode of the light-emitting diode D2 is connected to one end of the resistor R10, and the other end of R10 is connected to the power supply VCC.

6. The state monitoring circuit of an on-vehicle electronic device according to claim 4, characterized in that: The status indication module includes a transistor Q3, a light-emitting diode D6 and a resistor R10; the base of the transistor Q3 is connected to the microprocessor, the collector is connected to the cathode of the light-emitting diode D6, and the emitter is grounded; the anode of the light-emitting diode D6 is connected to one end of the resistor R10, and the other end of R10 is connected to the power supply VCC.

7. A method for monitoring the status of an on-vehicle electronic device, for detecting the operating status of a camera module; the camera module communicates with a microprocessor via a serial / deserializer (SERD) and is powered by a DC-DC power module; characterized in that: The state monitoring circuit of a vehicle-mounted electronic device according to any one of claims 1 to 6 is used for implementation, wherein a current detection module is used to detect the output current of the DCDC power module and convert it into a voltage, the voltage is input into a comparison module for voltage comparison, and the DCDC power module is controlled to maintain or shut down the power supply, or the camera module is controlled to restart according to the comparison result.

8. The method for monitoring the status of an on-vehicle electronic device according to claim 7, wherein: The comparison result includes whether the camera is in a normal working state or not started normally or is in a circuit breaker or overcurrent state.

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