Circuit for diagnosing open circuit of ground wire of controller

Abstract

The utility model discloses a circuit for diagnosing open circuit of a ground wire of a controller. The system comprises a power ground wire fault detection part and a simulation ground wire fault detection part. Each of the two parts comprises a comparator and a plurality of resistors, the positive phase input ends of the two comparators are respectively connected with different power supplies through the resistors and directly connected with different power supply ground wires, the negative phase input end of the comparator U6 is respectively connected with the different power supplies and the power supply ground wires through the resistors, and the output end of the comparator U6 is connected to the MCU micro-control unit. According to the utility model, faults of the power ground wire and the simulation ground wire can be diagnosed, the influence of accidental open circuit on the brake performance of the brake-by-wire system is prevented, and the circuit design improves the function safety of the electric control brake system in use.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile electronic circuits, in particular to a circuit for diagnosing open circuit of a ground line of a controller. Background Art

[0002] Usually there are two ground wires in the ESC body stability system. One ground wire is the power PGND, which is used for the ground wire of the brushed motor. The other is the signal GND wire, which is used to power the chip in the entire controller. The ground wire plays an important role in the controller design as a power return line. In the ESC body stability system controller, the PGND power ground wire and the signal GND wire are connected to the vehicle frame through two wires respectively, and return to the negative pole of the vehicle battery through the metal frame.

[0003] With the release of the GB26262 passenger car electronic and electrical functional safety standard, higher diagnostic coverage requirements are put forward for controller design. If the ground fault is not detected, it will inevitably fail to meet the functional safety design requirements. Utility Model Content

[0004] In order to solve the problems existing in the background technology, the utility model proposes a circuit for diagnosing open circuit of the controller ground wire, which solves the technical problem of being able to detect in real time whether the connection of the two ground wires is good under the design scheme of the controller being divided into two ground wires.

[0005] The technical solution of the utility model is achieved in this way:

[0006] The utility model comprises two parts: a power ground line fault detection part and a simulation ground line fault detection part.

[0007] The power ground fault detection part includes a comparator U6, a positive phase input terminal of the comparator U6 is connected to the first power supply 5V_1 via a resistor R24, and is directly connected to the power ground line PGND; a negative phase input terminal of the comparator U6 is connected to the first power supply 5V_1 and the power ground line GND via resistors R25 and R26 respectively, and an output terminal OUT is connected to the analog-to-digital conversion interface PGND_LOSS of the MCU micro-control unit.

[0008] The analog ground fault detection part includes a comparator U7, the positive phase input terminal of the comparator U7 is connected to the second power supply 5V_2 via a resistor R27, and is directly connected to the power ground GND; the negative phase input terminal of the comparator U7 is connected to the second power supply 5V_2 and the power ground PGND via resistors R28 and R29 respectively, and the output terminal OUT is connected to the analog-to-digital conversion interface GND_LOSS of the MCU micro-control unit.

[0009] The first power supply 5V_1 and the second power supply 5V_2 are two independent power supplies. The ground referenced by the first power supply 5V_1 is the power supply ground wire GND, and the ground referenced by the second power supply 5V_1 is the power supply ground wire PGND; and the first power supply 5V_1 and the power supply ground wire GND are derived from the same power supply circuit in the vehicle controller, and the second power supply 5V_2 and the power supply ground wire PGND are derived from another identical power supply circuit in the vehicle controller.

[0010] The power supply ground line PGND and the power supply ground line GND are independent of each other inside the vehicle controller.

[0011] Beneficial effects of the utility model:

[0012] The utility model can diagnose the faults of the power ground wire and the analog ground wire, thereby preventing the influence of the accidental open circuit on the braking performance of the wire control brake system. This circuit design improves the functional safety of the electric control brake system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The schematic diagram is a circuit diagram for diagnosing an open circuit in the controller ground line. DETAILED DESCRIPTION

[0014] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0015] like Figure 1 As shown, the circuit includes two parts: MCU micro-control unit, power ground fault detection part and analog ground fault detection part;

[0016] The power ground fault detection part includes a comparator U6, wherein the positive phase input terminal of pin 3 of the comparator U6 is connected to the first power supply 5V_1 via a resistor R24, and is directly connected to the power ground line PGND; the negative phase input terminal of pin 2 of the comparator U6 is connected to the first power supply 5V_1 and the power ground line GND via resistors R25 and R26 respectively, and the output terminal OUT of pin 6 is connected to the analog-to-digital conversion interface PGND_LOSS of the MCU micro-control unit; the V+ pin 7 of the comparator U6 is also connected to the first power supply 5V_1, and the V- pin 4 is connected to the power ground line GND.

[0017] The analog ground fault detection part includes a comparator U7, wherein the positive phase input terminal of pin 3 of the comparator U7 is connected to the second power supply 5V_2 via a resistor R27, and is directly connected to the power supply ground line GND; the negative phase input terminal of pin 2 of the comparator U7 is connected to the second power supply 5V_2 and the power supply ground line PGND via resistors R28 and R29 respectively, and the output terminal OUT of pin 6 is connected to the analog-to-digital conversion interface GND_LOSS of the MCU micro-control unit; the V+ pin 7 of the comparator U7 is also connected to the second power supply 5V_2, and the V- pin 4 is connected to the power supply ground line PGND.

[0018] The first power supply 5V_1 and the second power supply 5V_2 are two independent power supplies. The ground referenced by the first power supply 5V_1 is the power supply ground wire GND, and the ground referenced by the second power supply 5V_1 is the power supply ground wire PGND; and the first power supply 5V_1 and the power supply ground wire GND are derived from the same power supply circuit in the vehicle controller, and the second power supply 5V_2 and the power supply ground wire PGND are derived from another identical power supply circuit in the vehicle controller. Therefore, the combination of the first power supply 5V_1 and the power supply ground wire GND and the combination of the second power supply 5V_2 and the power supply ground wire PGND are derived from different power supply circuits.

[0019] The power supply ground wire PGND and the power supply ground wire GND are independent of each other inside the vehicle controller, but the two ground wires are connected to the frame ground through a wiring harness.

[0020] In a specific implementation, the comparators U6 and U7 are of the model LM2903, and the resistance values ​​of the resistors R24, R25, R26, R27, R28, and R29 are 10K.

[0021] When the MCU microcontroller detects through the analog-to-digital conversion interface PGND_LOSS and the analog-to-digital conversion interface GND_LOSS respectively that the output terminals of the comparator U6 and the comparator U7 are both 0V, the power supply ground wire is not lost and there is no fault;

[0022] When the MCU micro-control unit detects through the analog-to-digital conversion interface PGND_LOSS and the analog-to-digital conversion interface GND_LOSS that one of the output ends of comparator U6 and comparator U7 is not 0V, the power supply ground wire connected to the non-0V comparator's positive input end is lost, and an open circuit fault occurs.

[0023] For example, if the output of comparator U6 is not 0V, the power ground line PGND connected to the positive input of comparator U6 is lost or open. If the output of comparator U7 is not 0V, the power ground line GND connected to the positive input of comparator U7 is lost or open.

[0024] In a specific implementation, the specific working mode of the diagnostic detection includes three modes: no-fault mode, PGND ground line loss and GND ground line loss.

[0025] In no-failure mode:

[0026] Normally, since both the power supply ground line PGND and the power supply ground line GND are connected to the frame ground, the voltage of the power supply ground line PGND=0V, and the voltage of the power supply ground line GND=0V.

[0027] When the power ground PGND is 0V, the voltage at the No. 3 positive input terminal of the comparator U6 is 0V. Since the resistance values ​​of the resistors R25 and R26 are both 10K, the voltage at its negative input terminal is:

[0028] U 5V_1 *R26 / (R25+R26)=5V*(10K / (10K+10K))=2.5V.

[0029] 0V at the non-inverting input terminal is less than 2.5V at the inverting input terminal, so the analog-to-digital conversion interface PGND_LOSS of the MCU microcontrol unit detects that the output terminal of pin 6 of the comparator U6 outputs 0V.

[0030] When the power supply ground GND is 0V, the voltage at the No. 3 positive input terminal of the comparator U7 is 0V, and the resistance values ​​of the resistors R26 and R29 are both 10K, so the voltage at its inverting input terminal is:

[0031] U 5V_2 *R29 / (R28+R29)=5V*(10K / (10K+10K))=2.5V.

[0032] 0V at the non-inverting input terminal is less than 2.5V at the inverting input terminal, so the analog-to-digital conversion interface GND_LOSS of the MCU microcontroller unit detects that the output terminal of pin 6 of the comparator U7 outputs 0V.

[0033] Therefore, when the MCU micro-control unit detects that the output terminals of the comparator U6 and the comparator U7 both output 0V, the power supply ground wire is not lost and there is no fault.

[0034] Failure mode 1:

[0035] The power supply ground line PGND is open, and the power supply ground line GND=0V.

[0036] Since the PGND ground line is disconnected, the voltage at the No. 3 positive input terminal of the comparator U6 is the voltage of the first power supply 5V_1, i.e., 5V, due to the pull-up resistor R24. The resistance values ​​of the resistors R25 and R26 are both 10K, so the voltage at its negative input terminal is:

[0037] U 5V_1 *(10K / (10K+10K))=2.5V

[0038] The 5V of the positive input terminal is greater than the 2.5V of the negative input terminal. Therefore, at this time, the analog-to-digital conversion interface PGND_LOSS of the MCU microcontrol unit detects that the output terminal of pin 6 of the comparator U6 outputs a high level (5V).

[0039] Because the voltage of the second power supply 5V_2 refers to the power ground line PGND, when the power ground line PGND is disconnected, the second power supply 5V_2 cannot establish voltage. At this time, the analog-to-digital conversion interface GND_LOSS of the MCU microcontrol unit detects that the output terminal of pin 6 of the comparator U7 outputs a low level (0V).

[0040] Failure mode 2:

[0041] The power supply ground line GND is open, and the power supply ground line PGND = 0V.

[0042] Since the GND ground line is disconnected, the voltage at the No. 3 positive input terminal of the comparator U7 is the voltage of the second power supply 5V_2, i.e., 5V, due to the pull-up resistor R27. The resistance values ​​of the resistors R28 and R29 are both 10K, so the voltage at its inverting input terminal is:

[0043] U 5V_2 *(10K / (10K+10K))=2.5V

[0044] The 5V of the positive input terminal is greater than the 2.5V of the negative input terminal. Therefore, at this time, the analog-to-digital conversion interface GND_LOSS of the MCU microcontrol unit detects that the output terminal of pin 6 of the comparator U7 outputs a high level (5V).

[0045] Because the voltage of the first power supply 5V_1 refers to the power ground line GND, when the power ground line GND is disconnected, the first power supply 5V_1 cannot establish voltage. At this time, the analog-to-digital conversion interface PGND_LOSS of the MCU microcontrol unit detects that the output end of pin 6 of the comparator U6 outputs a low level (0V).

[0046] The overall truth table is as follows:

[0047]

[0048] As can be seen from the above table, the utility model can accurately, quickly and efficiently detect the open circuit of the ground wire of the vehicle controller according to this logic.

[0049] The above specific implementation modes are used to explain the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A circuit for diagnosing an open circuit of a controller ground line, characterized in that: It includes two parts: power ground fault detection part and analog ground fault detection part; The power ground fault detection part and the analog ground fault detection part each include a comparator. The positive input terminal of the comparator is connected to a respective power supply via a resistor R24 ​​and directly connected to the respective power supply ground. The negative input terminal of the comparator is connected to the power supply and the power supply ground via a resistor, and the output terminal OUT is connected to the analog-to-digital conversion interface PGND_LOSS of the MCU microcontrol unit.

2. A circuit for diagnosing an open circuit of a controller ground line according to claim 1, characterized in that: The power ground fault detection part includes a comparator U6, the positive phase input terminal of the comparator U6 is connected to the first power supply 5V_1 through a resistor R24, and is directly connected to the power ground line PGND; the negative phase input terminal of the comparator U6 is connected to the first power supply 5V_1 and the power ground line GND through resistors R25 and R26 respectively, and the output terminal OUT is connected to the analog-to-digital conversion interface PGND_LOSS of the MCU micro-control unit; The analog ground fault detection part includes a comparator U7, the positive phase input terminal of the comparator U7 is connected to the second power supply 5V_2 via a resistor R27, and is directly connected to the power ground GND; the negative phase input terminal of the comparator U7 is connected to the second power supply 5V_2 and the power ground PGND via resistors R28 and R29 respectively, and the output terminal OUT is connected to the analog-to-digital conversion interface GND_LOSS of the MCU micro-control unit.

3. A circuit for diagnosing an open circuit of a controller ground line according to claim 1, characterized in that: The first power source 5V_1 and the second power source 5V_2 are two independent power sources.

4. A circuit for diagnosing an open circuit of a controller ground line according to claim 1, characterized in that: The ground referenced by the first power source 5V_1 is the power ground line GND, and the ground referenced by the second power source 5V_1 is the power ground line PGND.

5. A circuit for diagnosing an open circuit of a controller ground line according to claim 2, characterized in that: The first power supply 5V_1 and the power ground line GND are derived from the same power circuit in the vehicle controller, and the second power supply 5V_2 and the power ground line PGND are derived from another same power circuit in the vehicle controller.

6. A circuit for diagnosing an open circuit of a controller ground line according to claim 2, characterized in that: The power supply ground line PGND and the power supply ground line GND are independent of each other inside the vehicle controller.

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