Circuit for diagnosing fault of motor power supply anti-reverse MOS (Metal Oxide Semiconductor) tube

By designing a circuit for detecting anti-reverse MOS tubes for motor power supply and using operational amplifiers to detect voltage drop in real time, the problem of lack of monitoring of anti-reverse MOS tubes in the prior art is solved, and real-time diagnosis of anti-reverse MOS tubes is realized and Improved motor performance.

CN222482369UActive Publication Date: 2025-02-14ZHEJIANG ASIA PACIFIC MECHANICAL & ELECTRONICS CO LTD
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Patent Information

Application Number
CN202420798642.X
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-04-17
Publication Date
2025-02-14
Estimated Expiration
2034-04-17

AI Technical Summary

Technical Problem

The lack of monitoring of the anti-reverse MOS tube for the motor power supply is caused by the lack of monitoring and control modules in the circuit, which cannot ensure the correct operation of the anti-reverse module in the circuit, affects the performance of the motor and may cause controller failure.

Method used

Design a circuit to detect the voltage drop across both ends of the power-supply anti-reverse MOS tube in real time through the operational amplifier, determine whether there are problems such as excessive internal resistance of the anti-reverse MOS tube, integrate a self-test module to reduce the potential failure efficiency of the op-amp detection circuit. .

Benefits of technology

Real-time diagnosis of power supply anti-reverse MOS tubes is realized, ensuring that the anti-reverse module operates correctly in the circuit, and improving motor performance and system functional safety requirements.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model discloses a circuit for diagnosing faults of a motor power supply anti-reverse MOS tube. A source electrode and a grid electrode of the MOS tube Q3 are connected with a motor power supply line, and a drain electrode is connected with the motor; the source electrode is connected to the positive input end of the operational amplifier through resistors R6 and R15, the drain electrode is connected to the reverse input end of the operational amplifier through resistors R8 and R14, the reverse input end of the operational amplifier is connected with the output end through a resistor R10, the output end is connected with an MCU analog-to-digital conversion port ADCRVPG, and the resistor R6 and the resistor R15 as well as the resistor R8 and the resistor R14 are respectively connected to an MCU general input and output port DRVSW1 and an MCU general output port DRVSW2 through composite triodes Q2 and Q3. According to the utility model, the operational amplifier forms a circuit, the voltage drop at the two ends of the power supply anti-reverse MOS tube is detected in real time, whether the anti-reverse MOS tube has the problems of overlarge conduction internal resistance and the like is judged through the voltage drop, and the potential failure rate of the operational amplifier detection circuit is reduced, so that the functional safety requirement of electronic hardware is improved.
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Description

Technical Field

[0001] The utility model relates to the technical field of electronic hardware fault diagnosis, in particular to a circuit for diagnosing a motor power supply anti-reverse MOS tube fault. Background Art

[0002] Motor power supply reverse polarity protection is necessary in chassis controllers, such as in the electronic parking system EPB. If the controller is not designed with a reverse polarity protection circuit, the reverse connection of the power supply line will damage the bridge MOS tube circuit inside the controller, causing EPB system failure. The design has MOS tube power supply protection, but if this reverse polarity protection module is not monitored, the following problems will occur:

[0003] 1. When the controller detects that the power supply of the motor is within the normal operating voltage range, but the anti-reverse module is faulty, resulting in a large internal resistance, the voltage loaded to the motor end will be reduced, thus affecting the performance of the motor.

[0004] 2. Due to the lack of monitoring of the anti-reverse MOS tube, the correct operation of the anti-reverse module in the circuit cannot be guaranteed. Utility Model Content

[0005] In order to solve the problems existing in the background technology, the utility model discloses a circuit for diagnosing the fault of a motor power supply anti-reverse MOS tube.

[0006] The technical solution of the utility model is achieved in this way:

[0007] The utility model comprises a MOS tube Q3, a resistor R6-resistor R8, a resistor R14-resistor R15, a capacitor C6, a composite triode Q2 and a composite triode Q3; the source and the gate of the MOS tube Q3 are connected to the power supply line VBAT_MR of the motor, the drain of the MOS tube Q3 is connected to one end of the motor, and the other end of the motor is grounded; the source of the MOS tube Q3 is connected to the positive input end of an operational amplifier U1 through the resistor R6 and the resistor R15 in sequence, the positive input end of the operational amplifier U1 is grounded through the resistor R5, the drain of the MOS tube Q3 is connected to the reverse input end of the operational amplifier U1 through the resistor R8 and the resistor R14 in sequence, the reverse input end of the operational amplifier U1 is connected to its own output end through the resistor R10, the output end of the operational amplifier U1 is connected to the analog-to-digital conversion port ADC_RVPG of an MCU micro control unit through the resistor R7, and the analog-to-digital conversion port ADC_RVPG of the MCU micro control unit is grounded through the capacitor C6.

[0008] The lead between resistor R6 and resistor R15 is connected to the compound transistor Q2, the lead between resistor R8 and resistor R14 is connected to the compound transistor Q3, and the compound transistor Q2 and the compound transistor Q3 are respectively connected to the general input and output port DRV_SW1 and the general input and output port DRV_SW2 of the MCU micro control unit.

[0009] The composite transistor Q2 is mainly composed of two transistors connected in reverse arrangement, wherein the emitter of the first transistor is grounded, the base of the first transistor is connected to the general input and output port DRV_SW1 of the MCU micro control unit, the collector of the first transistor is connected to the base of the second transistor, the emitter of the second transistor is connected to the operating voltage, and the collector of the second transistor is connected between the resistor R6 and the resistor R15.

[0010] The composite transistor Q3 is mainly composed of two transistors connected in reverse arrangement, wherein the emitter of the first transistor is grounded, the base of the first transistor is connected to the general input and output port DRV_SW2 of the MCU micro control unit, the collector of the first transistor is connected to the base of the second transistor, the emitter of the second transistor is connected to the operating voltage, and the collector of the second transistor is connected between the resistor R8 and the resistor R14.

[0011] The MOS tube Q3 is a power supply anti-reverse MOS tube.

[0012] The operational amplifier U1 operates in a negative feedback mode.

[0013] Beneficial effects of the utility model:

[0014] The utility model detects the voltage drop at both ends of the power supply anti-reverse MOS tube in real time through the circuit composed of operational amplifiers, and judges whether the anti-reverse MOS tube has problems such as excessive conduction internal resistance through this voltage drop. The operational amplifier detection module integrates a self-test module, which reduces the potential failure rate of the operational amplifier detection circuit, thereby improving the functional safety requirements for electronic hardware. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention is a circuit schematic diagram for diagnosing motor power supply anti-reverse MOS tube fault. DETAILED DESCRIPTION

[0016] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0017] like Figure 1 As shown, the circuit includes an MCU microcontroller unit, a MOS tube Q3, resistors R6 to R8, resistors R14 to R15, a capacitor C6, a composite transistor Q2 and a composite transistor Q3.

[0018] The source of pin 3 and the gate of pin 2 of the MOS tube Q3 are connected to the power supply line VBAT_MR of the motor, the drain of pin 1 of the MOS tube Q3 is connected to one end of the motor, and the other end of the motor is grounded; the source of pin 3 of the MOS tube Q3 is connected to the positive input end of the operational amplifier U1 through resistors R6 and R15 in sequence, and the positive input end of the operational amplifier U1 is grounded through resistor R5, the drain of pin 1 of the MOS tube Q3 is connected to the reverse input end of the operational amplifier U1 through resistors R8 and R14 in sequence, and the reverse input end of the operational amplifier U1 is connected to its own output end through resistor R10, and the output end of the operational amplifier U1 is connected to the analog-to-digital conversion port ADC_RVPG of the MCU microcontroller unit through resistor R7, and the analog-to-digital conversion port ADC_RVPG of the MCU microcontroller unit is grounded through capacitor C6; pin 8 V+ of the operational amplifier is connected to the working voltage 5V, and pin 4 V- is grounded.

[0019] The lead between resistor R6 and resistor R15 is connected to the compound transistor Q2, the lead between resistor R8 and resistor R14 is connected to the compound transistor Q3, and the compound transistor Q2 and the compound transistor Q3 are respectively connected to the general input and output port DRV_SW1 and the general input and output port DRV_SW2 of the MCU micro control unit.

[0020] like Figure 1 As shown, the composite transistor Q2 is mainly composed of two transistors connected in reverse arrangement, wherein the emitter pin 1 of the first transistor is grounded, the base pin 2 of the first transistor is connected to the general input and output port DRV_SW1 of the MCU microcontroller unit, the collector pin 6 of the first transistor is connected to the base pin 5 of the second transistor, the emitter pin 4 of the second transistor is connected to the operating voltage 5V, and the collector pin 3 of the second transistor is connected between the resistor R6 and the resistor R15.

[0021] like Figure 1 As shown, the composite transistor Q3 is also mainly composed of two transistors connected in reverse arrangement, wherein the emitter pin 1 of the first transistor is grounded, the base pin 2 of the first transistor is connected to the general input and output port DRV_SW2 of the MCU microcontroller unit, the collector pin 6 of the first transistor is connected to the base pin 5 of the second transistor, the emitter pin 4 of the second transistor is connected to the operating voltage 5V, and the collector pin 3 of the second transistor is connected between the resistor R8 and the resistor R14.

[0022] MOS tube Q3 is a power supply anti-reverse MOS tube, which mainly uses the internal body diode for unidirectional conduction. Operational amplifier U1 works in negative feedback mode.

[0023] The composite transistors Q4 and Q2 form an operational amplifier self-test drive module, which is used for power-on self-test to verify whether the operational amplifier module has a fault. The output port OUT of the operational amplifier U1 is connected to the reverse input terminal pin 2 of the operational amplifier U1 through the resistor R10. At this time, the operational amplifier U1 works in the negative feedback mode.

[0024] There are two characteristics in this negative feedback mode. When the operational amplifier U1 is working stably, the voltages at the positive input terminal of pin 3 of the operational amplifier U1 and the negative input terminal of pin 2 are the same, similar to a short circuit. No current will flow into pins 3 and 2 of the operational amplifier U1, which is equivalent to the pins being disconnected.

[0025] In the specific implementation, the model of the operational amplifier U1 is OPA1013, the model of the composite transistor Q4 is PUMD16, and the model of the composite transistor Q2 is PUMD16; the resistance value of resistor R6 is 6K, the resistance value of resistor R8 is 5K, the resistance value of resistor R15 is 8K, the resistance value of resistor R14 is 5K, the resistance value of resistor R5 is 2K, the resistance value of resistor R10 is 10K, the resistance value of resistor R7 is 1K, the capacitance value of capacitor C6 is 100nF, and the model of the motor MOS tube Q3 is IPD50N04S4L08ATMA1.

[0026] The specific working mode includes two modes: power-on self-test mode and normal operation mode.

[0027] Power-on self-test mode:

[0028] In this mode, the two general input and output ports DRV_SW1 and DRV_SW2 of the MCU microcontroller unit both output high level, making the compound transistor Q2 and compound transistor Q3 both turned on. At this time, when the compound transistor Q2 and compound transistor Q3 are turned on, the working voltage 5V of the emitter of its own pin 4 is loaded to the collector pin of pin 3.

[0029] At this time, the voltage signal at the positive input terminal + of the operational amplifier U1 is pin 1 of the resistor R15, that is, the working voltage 5V, and the voltage signal at the negative input terminal - is pin 1 of R14.

[0030] The voltage at the connection between resistor R5 and the non-inverting input of op amp U1 is:

[0031] 5V*(R15 / (R15+R5))=5*8K / (8K+2K)=4V

[0032] Because the operational amplifier U1 works in a negative feedback mode, the voltages at the positive input terminal and the negative input terminal of the operational amplifier U1 are consistent in magnitude, so the voltage at the negative input terminal is 4V.

[0033] And because the operational amplifier U1 works in negative feedback mode, no current will flow into the inverting input terminal of pin 2 of the operational amplifier U1, making the current flowing through the resistor R14 equal to the current flowing through R10:

[0034] (5V-4V) / R14=(4V-VOUT) / R10

[0035] Specifically: (5V-4V) / 5K=(4V-VOUT) / 10K

[0036] From this solution, we can get: VOUT = 2V

[0037] In the power-on self-test mode, when the analog-to-digital conversion port ADC_RVPG of the MCU microcontroller unit obtains the output voltage VOUT of the output end of the operational amplifier U1 as 2V through the voltage read, the power supply anti-reverse MOS tube Q3 is fault-free.

[0038] Normal Mode:

[0039] In this mode, the two general input and output ports DRV_SW1 and DRV_SW2 of the MCU microcontroller unit both output low level, making the compound transistor Q2 and compound transistor Q3 disconnected. At this time, when the compound transistor Q2 and compound transistor Q3 are disconnected, the working voltage 5V of the emitter of its own pin 4 cannot be loaded to the collector pin of pin 3.

[0040] At this time, the voltage signal at the positive input terminal + of the operational amplifier U1 is pin 1 of the resistor R6, that is, the working voltage 5V, and the voltage signal at the negative input terminal - is pin 1 of R8.

[0041] The power reverse protection relies on the body diode of MOS tube Q3, so the voltage difference between the source terminal 3 and the drain terminal 1 of MOS tube Q3 is 0.7V when working normally (MOS tube has its own properties, the internal parasitic diode is about 0.7V). That is:

[0042] U3-U1=0.7V

[0043] Among them, U3 represents the voltage of the source terminal 3 of the MOS tube Q3, and U1 represents the voltage of the drain terminal 1 of the MOS tube Q3.

[0044] Because the operational amplifier U1 operates in negative feedback mode, the voltage at the positive input terminal of pin 3 of the operational amplifier U1 is consistent with the voltage at the negative input terminal of pin 2, so the voltage at the negative input terminal of pin 2 is U3*(R5 / (R5+R15+R6))=U3 / 2.

[0045] Because the operational amplifier U1 works in negative feedback mode, no current will flow into the inverting input terminal of pin 2 of the operational amplifier U1, so the voltage drop across the resistor R8 is:

[0046] (U1-U3 / 2) / (R8+R14)=(U3 / 2-VOUT) / R10

[0047] The specific calculation is (U1-U3 / 2) / 10K=(U3 / 2-VOUT) / 10K

[0048] It is concluded that U1-U3=-VOUT, VOUT=U3-U1

[0049] Because the inherent property of the parasitic diode of the MOS tube is U3-U1=0.7V.

[0050] In normal mode, when the analog-to-digital conversion port ADC_RVPG of the MCU microcontroller unit obtains the output voltage VOUT≤0.7V of the output terminal of the operational amplifier U1 through the read voltage, it is diagnosed that the power supply anti-reverse MOS tube Q3 is not faulty.

[0051] When the output voltage VOUT of the output end of the operational amplifier U1 obtained by the analog-to-digital conversion port ADC_RVPG of the MCU microcontroller unit through the read voltage is greater than 0.7V, it means that the power supply anti-reverse MOS tube Q3 is faulty.

Claims

1. A circuit for diagnosing a motor power supply anti-reverse MOS tube fault, characterized in that: It includes a MOS tube Q3, resistors R6 to R8, resistors R14 to R15, a capacitor C6, a composite triode Q2 and a composite triode Q3; the MOS tube Q3 is connected to the motor and the operational amplifier U1 respectively, the reverse input end of the operational amplifier U1 is connected to its own output end through the resistor R10, the operational amplifier U1 is connected to an external MCU micro control unit, the composite triode Q2 and the composite triode Q3 are connected between the MOS tube Q3 and the operational amplifier U1, and the composite triode Q2 and the composite triode Q3 are connected to the external MCU micro control unit.

2. A circuit for diagnosing a motor power supply anti-reverse MOS tube fault according to claim 1, characterized in that: The source and gate of the MOS tube Q3 are connected to the power supply line VBAT_MR of the motor, the drain of the MOS tube Q3 is connected to one end of the motor, and the other end of the motor is grounded; the source of the MOS tube Q3 is connected to the positive input end of the operational amplifier U1 through the resistor R6 and the resistor R15 in sequence, the positive input end of the operational amplifier U1 is grounded through the resistor R5, and the drain of the MOS tube Q3 is connected to the negative input end of the operational amplifier U1 through the resistor R8 and the resistor R14 in sequence.

3. A circuit for diagnosing a motor power supply anti-reverse MOS tube fault according to claim 1, characterized in that: The output end of the operational amplifier U1 is connected to the analog-to-digital conversion port ADC_RVPG of the MCU microcontroller unit via the resistor R7, and the analog-to-digital conversion port ADC_RVPG of the MCU microcontroller unit is grounded via the capacitor C6.

4. A circuit for diagnosing a motor power supply anti-reverse MOS tube fault according to claim 1, characterized in that: The lead between the resistor R6 and the resistor R15 is connected to the compound transistor Q2, the lead between the resistor R8 and the resistor R14 is connected to the compound transistor Q3, and the compound transistor Q2 and the compound transistor Q3 are respectively connected to the general input and output port DRV_SW1 and the general input and output port DRV_SW2 of the MCU micro control unit.

5. A circuit for diagnosing a motor power supply anti-reverse MOS tube fault according to claim 1, characterized in that: The composite transistor Q2 is mainly composed of two transistors connected in reverse arrangement, wherein the emitter of the first transistor is grounded, the base of the first transistor is connected to the general input and output port DRV_SW1 of the MCU micro control unit, the collector of the first transistor is connected to the base of the second transistor, the emitter of the second transistor is connected to the operating voltage, and the collector of the second transistor is connected between the resistor R6 and the resistor R15.

6. A circuit for diagnosing a motor power supply anti-reverse MOS tube fault according to claim 1, characterized in that: The composite transistor Q3 is mainly composed of two transistors connected in reverse arrangement, wherein the emitter of the first transistor is grounded, the base of the first transistor is connected to the general input and output port DRV_SW2 of the MCU micro control unit, the collector of the first transistor is connected to the base of the second transistor, the emitter of the second transistor is connected to the operating voltage, and the collector of the second transistor is connected between the resistor R8 and the resistor R14.

7. A circuit for diagnosing a motor power supply anti-reverse MOS tube fault according to claim 1, characterized in that: The MOS tube Q3 is a power supply anti-reverse MOS tube.

8. The circuit for diagnosing a motor power supply anti-reverse MOS tube fault according to claim 1, characterized in that: The operational amplifier U1 operates in a negative feedback mode.