Motor driving circuit, vehicle-mounted equipment and vehicle

Abstract

The invention discloses a motor driving circuit, vehicle-mounted equipment and a vehicle, and the motor driving circuit comprises an LPM driving module which is connected with a motor positive electrode and a motor negative electrode, and a first driving output end of the LPM driving module is connected with a control end of a speed regulation module, and is used for adjusting the conduction state of the speed regulation module; the speed regulation module is connected between a motor cathode and a grounding end, and the first control signal is used for adjusting target voltage difference between two ends of the motor; the PWM driving module is connected with the control end of the speed regulation module and is used for adjusting the conduction state of the speed regulation module; and the control module is respectively connected with the LPM driving module and the PWM driving module and is used for sending a first control signal to the LPM driving module or sending a second control signal to the PWM driving module. According to the embodiment of the invention, two mainstream driving modes of LPM and PWM can be compatible, and the compatibility of a hardware platform design circuit is improved. The response speed can be improved under the driving of the LPM, the influence of the voltage change of the control signal is avoided, and the control precision is ensured.

Description

Technical Field

[0001] This application belongs to the technical field of motor control, and particularly relates to a motor drive circuit, a vehicle-mounted device, and a vehicle. Background Art

[0002] With the continuous development of the new energy vehicle field, the popularity rate of new energy vehicles has been increasing. In the circuit architecture inside a new energy vehicle, various area controllers are usually used to control corresponding vehicle-mounted devices. For example, a blower controller is used to control the rotation speed of the air-conditioning blower, a seat controller is used to control the movement of the seat, a tailgate controller is used to control the opening of the tailgate, and a window controller is used to control the raising and lowering of the window, etc.

[0003] Taking the vehicle-mounted device as the air-conditioning blower as an example, when controlling the rotation speed of the blower, it is necessary to collect the voltage across the motor and adjust the speed control module according to the voltage difference across the two ends to keep the voltage across the motor stable.

[0004] In the related art, when an MCU (Microcontroller Unit) or a similar processing module is provided in the ECU (Electronic Control Unit) corresponding to the blower, the MCU is usually used to collect and identify the voltage difference across the motor and output a control signal to the PWM (Pulse Width Modulation) drive module to adjust the rotation speed of the motor through the PWM drive module. The response time of this closed-loop control method mainly depends on the sampling period of the MCU and the processing and response output time of the MCU, resulting in a problem of slow response speed. Moreover, there may be a voltage difference between the system ground where the MCU is located and the vehicle body ground (for example, when other loads sharing the system ground are blocked and rotated abnormally, the system ground is raised). At this time, the voltage difference between the control signal given by the MCU during closed-loop control and the vehicle body ground increases, resulting in a deviation in the rotation speed of the motor and affecting the control accuracy of the motor rotation speed. Summary of the Invention

[0005] The embodiments of this application provide a motor drive circuit, a vehicle-mounted device, and a vehicle, which can solve the problems of slow response speed and low control accuracy when adjusting the rotation speed of the motor in the related art.

[0006] In a first aspect, the embodiments of this application provide a motor drive circuit, and the motor drive circuit includes:

[0007] LPM driving module, two signal input terminals of the LPM driving module are respectively connected to the positive electrode and the negative electrode of the motor, a first driving output terminal of the LPM driving module is connected to a control terminal of the speed regulation module, and the LPM driving module is configured to adjust a conduction state of the speed regulation module according to a first control signal and voltages at two ends of the motor; wherein, the speed regulation module is connected between the negative electrode of the motor and the ground terminal, and the first control signal is used to adjust a target pressure difference between two ends of the motor;

[0008] PWM driving module, a second driving output terminal of the PWM driving module is connected to the control terminal of the speed regulation module, and the PWM driving module is configured to adjust the conduction state of the speed regulation module according to a second control signal;

[0009] Control module, which is respectively connected to the LPM driving module and the PWM driving module, and is configured to send a first control signal to the LPM driving module or send a second control signal to the PWM driving module according to a corresponding type of the speed regulation module.

[0010] In some embodiments, the first control signal includes an LPM enable signal and a first modulation signal, and the LPM driving module is configured to adjust the conduction state of the speed regulation module when receiving a valid enable signal; the LPM driving module includes:

[0011] Bias circuit, an input terminal of the bias circuit is connected to the control module, and the bias circuit is configured to generate a bias voltage according to a duty ratio of the first modulation signal;

[0012] Integral circuit, a first input terminal of the integral circuit is respectively connected to the negative electrode of the motor and an output terminal of the bias circuit, a second input terminal of the integral circuit is connected to the positive electrode of the motor, and the integral circuit is configured to generate an integral voltage signal according to an integral of a voltage difference between the first input terminal and the second input terminal over time;

[0013] Amplification circuit, a control terminal of the amplification circuit is connected to an output terminal of the integral circuit, an output terminal of the amplification circuit is connected to the control terminal of the speed regulation module, and the amplification circuit is configured to amplify the integral voltage signal to obtain a speed regulation control signal.

[0014] In some embodiments, the integral circuit includes:

[0015] First operational amplifier, a non-inverting input terminal of the first operational amplifier is connected to the negative electrode of the motor and the output terminal of the bias circuit, an inverting input terminal of the first operational amplifier is connected to the positive electrode of the motor, and an output terminal of the first operational amplifier is connected to the control terminal of the amplification circuit;

[0016] A first capacitor is connected between the output terminal and the inverting input terminal of the first operational amplifier;

[0017] A second capacitor is connected between the non-inverting input terminal and the inverting input terminal of the first operational amplifier.

[0018] In some embodiments, the bias circuit includes:

[0019] A second operational amplifier, the non-inverting input terminal of the second operational amplifier is connected to the first modulation signal output terminal of the control module, the inverting input terminal of the second operational amplifier is connected to the first power supply terminal, and the output terminal of the second operational amplifier is connected to the non-inverting input terminal of the first operational amplifier; the second operational amplifier is configured to generate a bias voltage according to the duty cycle of the first modulation signal.

[0020] In some embodiments, the LPM driving module further includes:

[0021] An enabling voltage regulating circuit, the input terminal of the enabling voltage regulating circuit is connected to the positive electrode of the motor, the output terminal of the enabling voltage regulating circuit is connected to the inverting input terminal of the first operational amplifier, and the control terminal of the enabling voltage regulating circuit is connected to the enabling signal output terminal of the control module; the enabling voltage regulating circuit is configured to adjust a first voltage of the positive electrode of the motor to a second voltage when receiving the enabling signal;

[0022] A clamping module is connected to the non-inverting input terminal of the first operational amplifier, and the clamping voltage of the clamping module is a third voltage; wherein, the first voltage is greater than the third voltage, and the second voltage is less than the third voltage.

[0023] In some embodiments, the enabling voltage regulating circuit includes:

[0024] A first resistor, the first end of the first resistor is connected to the positive electrode of the motor, and the second end of the first resistor is connected to the non-inverting input terminal of the first operational amplifier;

[0025] A second resistor, the first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is grounded;

[0026] A third resistor, the first end of the third resistor is connected to the first end of the second resistor;

[0027] A first transistor, the first end of the first transistor is connected to the second end of the third resistor, the second end of the first transistor is grounded, and the control end of the first transistor is connected to the enabling signal output terminal of the control module.

[0028] In some embodiments, the amplifier circuit includes:

[0029] A Darlington transistor, including a second transistor and a third transistor, wherein a control end of the second transistor is connected to an output end of the first operational amplifier, a first end of the second transistor is connected to a second power supply end, a second end of the second transistor is connected to a control end of the third transistor, a first end of the third transistor is connected to the second power supply end, and a second end of the third transistor is connected to a control end of a speed regulation module;

[0030] A fourth resistor, wherein a first end of the fourth resistor is connected to the second end of the third transistor, and a second end of the fourth resistor is grounded.

[0031] In some embodiments, the motor drive circuit further includes a protection module, and the protection module includes:

[0032] A first diode, wherein a positive electrode of the first diode is connected to a positive electrode of the motor, and a negative electrode of the first diode is connected to an input end of the enable voltage regulating circuit;

[0033] A second diode, wherein a positive electrode of the second diode is connected to the second end of the third transistor, and a negative electrode of the second diode is used for being connected to the control end of the speed regulation module;

[0034] A third capacitor, connected between the negative electrode of the second diode and a ground terminal;

[0035] A transient suppression diode, connected between the negative electrode of the second diode and the ground terminal.

[0036] In some embodiments, the motor drive circuit further includes:

[0037] A first sampling unit, wherein a sampling end of the first sampling unit is connected to the positive electrode of the motor, and an output end of the first sampling unit is connected to the control module;

[0038] A second sampling unit, wherein a sampling end of the second sampling unit is connected to the positive electrode of the motor, and an output end of the second sampling unit is connected to the control module;

[0039] A third sampling unit, wherein a sampling end of the third sampling unit is connected to a first drive output end of the LPM drive module, and an output end of the third sampling unit is connected to the control module.

[0040] In a second aspect, an embodiment of the present application further provides a vehicle-mounted device, and the vehicle-mounted device includes a motor and the motor drive circuit of the first aspect.

[0041] In a third aspect, an embodiment of the present application further provides a vehicle, and the vehicle includes the vehicle-mounted device of the second aspect.

[0042] The motor drive circuit, vehicle-mounted device and vehicle provided by the embodiments of the present application can, by setting an LPM drive module and a PWM drive module, when the drive mode required by the speed regulation module of the motor is the LPM drive mode, send a first control signal to the LPM drive module through a control module to specify the target voltage difference across the motor. The LPM drive module can collect the voltage across the motor by itself and perform feedback regulation on the speed regulation module so that the voltage across the motor approaches the target voltage difference. When the drive mode required by the speed regulation module of the motor is the PWM drive mode, a second control signal can be sent to the PWM drive module through the control module. At this time, the control module can adjust the conduction state of the speed regulation module through the second control signal. By being compatible with the two mainstream drive modes of LPM drive and PWM drive, the motor drive circuit can be applied to different types of motor loads, improving the compatibility of the hardware platform design of the motor drive circuit. For motor loads that require the LPM drive mode, the internal hardware circuit of the LPM drive module can be used for fast response control to improve the response speed of speed regulation control. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0044] Figure 1 is a schematic diagram of the module structure of the motor drive circuit provided by an embodiment of the present application;

[0045] Figure 2 is a schematic diagram of the module structure of the LPM drive module provided by an embodiment of the present application;

[0046] Figure 3 is a schematic diagram of the circuit structure of the LPM drive module provided by an embodiment of the present application.

[0047] In the drawings:

[0048] 10. LPM driving module; 20. PWM driving module; 30. Control module; Motor+, positive electrode of the motor; Motor-, negative electrode of the motor; OPX, first driving output terminal; 40. Speed regulation module; LPM_EN, enabling signal; PWM1, first modulation signal; 11. Bias circuit; 12. Integrating circuit; 13. Amplifying circuit; 14. Enabling voltage regulating circuit; 15. Clamping module; OP1, first operational amplifier; OP2, second operational amplifier; C1, first capacitor; C2, second capacitor; C3, third capacitor; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; Q1, first transistor; Q2, second transistor; Q3, third transistor; D1, first diode; D2, second diode; TVS, transient suppression diode; VCC, first power supply terminal; VBAT, second power supply terminal; 51. First sampling unit; 52. Second sampling unit; 53. Third sampling unit. Detailed implementation manners

[0049] In order to be able to more clearly understand the above-mentioned objects, features and advantages of the present disclosure, the solutions of the present disclosure will be further described below. It should be noted that, without conflict, the embodiments of the present disclosure and the features in the embodiments may be combined with each other.

[0050] In the following description, many specific details are set forth in order to fully understand the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only a part of the embodiments of the present disclosure, rather than all of the embodiments.

[0051] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0052] With the continuous development of the new energy vehicle field, the popularity of new energy vehicles is constantly rising. In the circuit architecture inside new energy vehicles, various area controllers are usually used to control the corresponding in-vehicle devices. For example, the blower controller is used to control the speed of the air conditioner blower, the seat controller is used to control the movement of the seat, the tailgate controller is used to control the opening of the tailgate, and the window controller is used to control the raising and lowering of the window, etc.

[0053] Taking the in-vehicle device as the air conditioner blower as an example, when controlling the speed of the blower, it is necessary to collect the voltage across the motor and control the conduction of the transistor in the speed regulation module according to the voltage difference across both ends, so as to keep the voltage across the motor stable.

[0054] In the related art, when an MCU (Microcontroller Unit) or a similar processing module is provided in the ECU (Electronic Control Unit) corresponding to the blower, the MCU is usually used to collect and identify the voltage difference across the motor, and output a control signal to the PWM drive module, so as to adjust the output voltage through the PWM drive module. The speed regulation module of the motor can adjust the speed of the motor according to the magnitude of the output voltage. The response time of this software closed-loop control method mainly depends on the sampling period of the MCU and the processing and response output time of the MCU, and there is a problem of slow response speed. Moreover, there may be a voltage difference between the system ground where the MCU is located and the body ground (for example, the system ground is raised due to abnormal situations such as the load of other common system grounds being blocked), and at this time, the control signal given by the MCU during closed-loop control increases with respect to the voltage difference between the body ground, resulting in a deviation in the motor speed and affecting the control accuracy of the motor speed.

[0055] In order to solve the above technical problems, the embodiments of the present application provide a motor drive circuit, an in-vehicle device, and a vehicle. The following will combine the drawings and elaborate on the motor drive circuit provided by the embodiments of the present application through some embodiments and their application scenarios.

[0056] Figure 1 The module structure diagram of the motor drive circuit provided by an embodiment of the present application is shown. The motor drive circuit includes an LPM (Linear Pulse Modulation) drive module 10, a PWM drive module 20, and a control module 30.

[0057] The LPM drive module 10 includes two signal input terminals, and the two signal input terminals are respectively connected to the motor positive terminal Motor+ and the motor negative terminal Motor- to respectively collect the voltage of the motor positive terminal Motor+ and the voltage of the motor negative terminal Motor-. The first drive output terminal OPX of the LPM drive module 10 can be connected to the control terminal of the speed regulation module 40.

[0058] After obtaining the positive voltage and negative voltage of the motor, the LPM driving module 10 can generate corresponding driving signals according to the voltage difference across the motor and output them to the speed regulation module 40, and the driving signals can adjust the conduction state of the speed regulation module 40.

[0059] The speed regulation module 40 can be connected between the negative pole of the motor Motor- and the ground terminal. When the speed regulation module 40 is in the saturated conduction state, the negative pole of the motor Motor- is equivalent to being grounded. At this time, the potential of the negative pole of the motor Motor- is approximately 0, and the voltage difference between the positive pole of the motor Motor+ and the negative pole of the motor Motor- is approximately the voltage of the positive pole of the motor Motor+. When the speed regulation module 40 is in the saturated cut-off state, the negative pole of the motor Motor- is disconnected from the ground terminal. At this time, the potentials of the positive pole and the negative pole of the motor Motor- are substantially the same, and the voltage difference across the motor approaches zero. Since the potential difference across the motor is 0, the motor does not operate at this time.

[0060] When the switching tube in the speed regulation module 40 operates in the constant current region, taking the switching tube as a MOSFET as an example, the output current of the MOSFET is related to the gate-source voltage difference. Since the source of the MOSFET is grounded, it is equivalent to that the output current of the MOSFET is related to the gate voltage. By adjusting the control voltage received by the gate of the MOSFET, the voltage of the negative pole of the motor Motor- relative to the ground terminal can be adjusted. At this time, the voltage difference between the positive pole of the motor Motor+ and the negative pole of the motor Motor- is greater than 0 and less than the voltage value of the positive pole of the motor Motor+. By adjusting the magnitude of the control voltage output to the speed regulation module 40, the voltage difference between the positive pole of the motor Motor+ and the negative pole of the motor Motor- can be changed, so as to keep the voltage across the motor in dynamic balance.

[0061] The second driving output terminal of the PWM driving module 20 can also be connected to the control terminal of the speed regulation module 40. The PWM driving module 20 can generate corresponding driving signals according to the second control signal sent by the control module 30 and output them to the speed regulation module 40 to adjust the conduction state of the speed regulation module 40.

[0062] The control module 30 can be respectively connected to the LPM driving module 10 and the PWM driving module 20. When the driving mode required by the speed regulation module 40 in the motor is the LPM driving mode, the control module 30 can send a first control signal to the LPM driving module 10 to balance and regulate the voltage across the motor through the LPM driving module 10. Correspondingly, when the driving mode required by the speed regulation module 40 in the motor is the PWM driving mode, the control module 30 can send a second control signal to the PWM driving module 20 to balance and regulate the voltage across the motor through the PWM driving module 20.

[0063] The above first control signal may include an LPM enable signal LPM_EN and a first modulation signal PWM1, and the second control signal may include a PWM enable signal PWM_EN and a second modulation signal PWM2.

[0064] When the control module 30 needs to drive the LPM driving module 10, the LPM enable signal LPM_EN is an active signal, and the PWM enable signal PWM_EN is an inactive signal; the first modulation signal PWM1 is output, and the second modulation signal PWM2 is not output.

[0065] When the control module 30 needs to drive the PWM driving module 20, the LPM enable signal LPM_EN is an inactive signal, and the PWM enable signal PWM_EN is an active signal; the first modulation signal PWM1 is not output, and the second modulation signal PWM2 is output. There may also be a communication connection between the control module 30 and the PWM driving module 20, for example, a communication connection is implemented through an SPI (Serial Peripheral Interface) interface or an IO port. The control module can control the operating state of the PWM driving module 20 through communication information.

[0066] When the driving mode required by the speed regulation module 40 of the motor is the LPM driving mode, the control module 30 can control the LPM driving module 10 to perform dynamic balance adjustment on the voltage across the motor. Since the LPM driving module 10 collects the voltage across the motor through an internal hardware circuit and adjusts the voltage across the motor in a hardware closed-loop control manner, the first control signal sent by the control module 30 is only used to indicate the target pressure difference across the motor to the LPM driving module 10. The LPM driving module 10 conducts control on the speed regulation module 40 through internal hardware so that the actual pressure difference across the motor approaches the target pressure difference. Compared with the software closed-loop control method in which the control module 30 collects the voltage across the motor and processes the sampling information and then outputs a control signal, the response speed of the closed-loop control process can be greatly improved. And when there is a pressure difference between the system ground of the control module 30 and the vehicle body ground connected to the motor, the LPM driving module 10 will not be affected during the adjustment process, and the adjustment accuracy of the motor speed can be guaranteed.

[0067] Due to the different driving requirements of different speed control modules, the hardware platform has a compatible design that can adapt to two different driving methods, PWM and LPM. In addition to the LPM driving module 10, the control module 30 can also use the PWM driving module 20 to adjust the voltage across the motor. During the control process of the PWM driving module 20, the PWM driving module 20 cannot achieve hardware closed-loop control. Instead, the control module 30 needs to collect the voltage across the motor and provide a corresponding second control signal to the PWM driving module 20 after processing the collected information. The PWM driving module 20 adjusts the voltage across the motor according to the second control signal. Compared with the hardware closed-loop control of the LPM driving module 10, the software closed-loop control of the PWM driving module 20 still has certain defects. The platformized design scheme of the hardware design is compatible with different user load requirements, can achieve the compatibility of PWM driving and LPM driving, and improves the adaptability of the motor driving circuit to different types of motor loads.

[0068] In this embodiment, by setting the LPM driving module 10 and the PWM driving module 20, when the driving method required by the speed control module 40 of the motor is the LPM driving method, the control module 30 can send a first control signal to the LPM driving module 10 to specify the target pressure difference across the motor. The LPM driving module 10 can collect the voltage across the motor by itself and perform feedback adjustment on the speed control module 40 to make the voltage across the motor approach the target pressure difference. When the driving method required by the speed control module 40 of the motor is the PWM driving method, the control module 30 can send a second control signal to the PWM driving module 20. At this time, the control module 30 can adjust the conduction state of the speed control module 40 through the second control signal. By being compatible with two mainstream driving methods, LPM driving and PWM driving, the motor driving circuit can be applied to motor loads with different required driving methods, improving the compatibility of the hardware platform design. For motor loads that can support the LPM driving method, the internal hardware circuit of the LPM driving module 10 can be used for fast response control to improve the response speed of the speed control.

[0069] Please refer to Figure 2 , in some embodiments, the above first control signal may include an LPM enable signal LPM_EN and a first modulation signal PWM1. The LPM enable signal LPM_EN may include a valid enable signal and a non-valid enable signal. The LPM driving module 10 can operate when receiving the valid enable signal to adjust the voltage difference across the motor.

[0070] The LPM driving module 10 may include a bias circuit 11, an integration circuit 12, and an amplification circuit 13.

[0071] The input end of the bias circuit 11 can be connected to the control module 30 to receive the first modulation signal PWM1 generated by the control module 30, and generate a bias voltage according to the duty cycle of the first modulation signal PWM1. Among them, the duty cycle of the first modulation signal PWM1 and the bias voltage can be in a positive correlation or a negative correlation.

[0072] When the control module 30 outputs the first control signal, whether the signal voltage of the LPM enable signal LPM_EN shifts or the signal voltage of the first modulation signal PWM1 shifts, it will not affect the normal regulation of the voltage across the motor by the LPM driving module 10, and can ensure the control accuracy of the LPM driving method.

[0073] The first input end of the integrating circuit 12 can be respectively connected to the negative electrode of the motor Motor- and the output end of the bias circuit 11, and the second input end of the integrating circuit 12 can be connected to the positive electrode of the motor Motor+. The integrating circuit 12 can output a corresponding integrated voltage signal according to the integral of the voltage difference between the first input end and the second input end over time, and the signal amplitude of the integrated voltage signal has a proportional relationship with the integral of the voltage difference between the two input ends over time. For example, within a certain time interval, when the voltage received by the non-inverting input end is greater than the voltage of the inverting input end, the integrated voltage signal output by the integrating circuit 12 will continuously increase to reduce the potential of the negative electrode of the motor Motor-; when the voltage received by the non-inverting input end is less than the voltage of the inverting input end, the integrated voltage signal output by the integrating circuit 12 will continuously decrease to increase the potential of the negative electrode of the motor Motor-. During the continuous change of the integrated voltage signal, the voltage received by the non-inverting input end and the voltage received by the inverting input end can be maintained in dynamic balance.

[0074] The control end of the amplifying circuit 13 can be connected to the output end of the integrating circuit 12, and the output end of the amplifying circuit 13 can be connected to the control end of the speed regulation module 40. The amplifying circuit 13 can perform amplification processing when receiving the integrated voltage signal to obtain a speed regulation control signal. The amplifying circuit 13 outputs the speed regulation control signal to the control end of the speed regulation module 40, and can control the conduction amplitude of the speed regulation module 40, thereby realizing the potential regulation of the negative electrode of the motor Motor-. By adjusting the potential of the negative electrode of the motor Motor-, the voltage difference between the positive electrode and the negative electrode of the motor can be adjusted, thereby realizing the dynamic balance regulation of the voltage across the motor.

[0075] Please refer to Figure 3 , in some embodiments, the above-mentioned integrating circuit 12 may include a first operational amplifier OP1, a first capacitor C1, and a second capacitor C2.

[0076] The non-inverting input terminal of the first operational amplifier OP1 is connected to the negative terminal of the motor Motor- and the output terminal of the bias circuit 11, the inverting input terminal of the first operational amplifier OP1 is connected to the positive terminal of the motor Motor+, and the output terminal of the first operational amplifier is connected to the control terminal of the amplifier circuit 13.

[0077] The first capacitor C1 can be connected between the output terminal and the inverting input terminal of the first operational amplifier OP1, and the second capacitor C2 can be connected between the non-inverting input terminal and the inverting input terminal of the first operational amplifier OP1.

[0078] The first operational amplifier OP1 can integrate the voltage difference between the non-inverting input terminal and the inverting input terminal and generate an integral voltage signal proportional to the integral of the voltage difference over time. In a certain time interval, if the voltage at the non-inverting input terminal is greater than the voltage at the inverting input terminal, the integral voltage signal output by the first operational amplifier OP1 will continuously increase. After the amplifier circuit 13 amplifies the continuously increasing integral voltage signal, it can be output to the control terminal of the speed regulation module 40 to adjust the conduction amplitude of the speed regulation module 40, thereby adjusting the potential of the negative terminal of the motor Motor-. When the potential of the negative terminal of the motor Motor- decreases, the voltage received by the non-inverting input terminal of the first operational amplifier OP1 decreases, thereby reducing the voltage difference between the non-inverting input terminal and the inverting input terminal until the voltage received by the non-inverting input terminal of the first operational amplifier OP1 and the voltage received by the inverting input terminal maintain dynamic balance.

[0079] Correspondingly, when the voltage received by the non-inverting input terminal of the first operational amplifier OP1 is less than the voltage at the inverting input terminal, the integral voltage signal output by the first operational amplifier OP1 will continuously decrease, thereby causing the potential of the negative terminal of the motor Motor- to continuously increase. At this time, the voltage received by the non-inverting input terminal of the first operational amplifier OP1 increases, and it can also reduce the voltage difference between the non-inverting input terminal and the inverting input terminal. That is, the first operational amplifier OP1 can generate an integral voltage signal according to the voltage received by the non-inverting input terminal and the voltage received by the inverting input terminal. After the integral voltage signal is amplified by the amplifier circuit 13, it can adjust the conduction amplitude of the speed regulation module 40, and then adjust the potential of the negative terminal of the motor Motor-, ultimately making the voltage difference between the positive terminal of the motor Motor+ and the negative terminal of the motor Motor- maintain dynamic balance.

[0080] The first capacitor C1 can be the capacitor connected between the output terminal and the inverting input terminal of the first operational amplifier OP1 in the integrating circuit. The second capacitor C2 is connected between the two input terminals and can play an anti-interference role. Based on the characteristic that the voltage across the capacitor cannot change suddenly, when an instantaneous high interference signal flows into one of the two input terminals, the second capacitor C2 can raise the voltage of the other input terminal to maintain the voltage difference between the two input terminals unchanged, so that the interference signal will not affect the comparison result of the first operational amplifier OP1.

[0081] As Figure 3 shown, in some embodiments, the above bias circuit 11 may include a second operational amplifier OP2. The non-inverting input terminal of the second operational amplifier OP2 is connected to the output terminal of the first modulation signal PWM1 of the control module 30. The inverting input terminal of the second operational amplifier OP2 is connected to the first power supply terminal VCC. The output terminal of the second operational amplifier OP2 is connected to the non-inverting input terminal of the first operational amplifier OP1.

[0082] The second operational amplifier OP2 can generate a corresponding bias voltage according to the duty cycle of the first modulation signal PWM1 and apply the bias voltage to the non-inverting input terminal of the first operational amplifier OP1. That is, the voltage at the non-inverting input terminal of the first operational amplifier OP1 is the sum of the voltage of the negative pole of the motor Motor- and the bias voltage.

[0083] In some embodiments, the above bias circuit 11 may further include a filtering unit. The filtering unit includes a resistor connected between the non-inverting input terminal of the second operational amplifier OP2 and the output terminal of the first modulation signal PWM1 and a capacitor connected between the non-inverting input terminal of the second operational amplifier OP2 and the ground terminal. The resistor and the capacitor can form an RC filtering circuit to filter the first modulation signal PWM1 to prevent the interference signal from affecting the bias voltage.

[0084] As an alternative embodiment, the way for the second operational amplifier OP2 to generate the bias voltage can be that the non-inverting input terminal of the second operational amplifier OP2 receives the first modulation signal PWM1 and the inverting input terminal receives a stable voltage signal. When the first modulation signal PWM1 is high, the voltage at the non-inverting input terminal is greater than the voltage at the inverting input terminal. At this time, the second operational amplifier OP2 outputs a high-level signal. When the first modulation signal PWM1 is low, the voltage at the non-inverting input terminal is less than the voltage at the inverting input terminal. At this time, the second operational amplifier OP2 outputs a low-level signal. By adjusting the duty cycle of the first modulation signal PWM1, the time ratio of the high-level signal output by the second operational amplifier OP2 within a unit time can be adjusted, so as to obtain a bias voltage that has a positive correlation with the duty cycle of the first modulation signal PWM1.

[0085] Please continue to refer to Figure 2, in some embodiments, the above-mentioned LPM driving module 10 may further include an enabling voltage regulating circuit 14 and a clamping module 15.

[0086] The input end of the enabling voltage regulating circuit 14 is connected to the motor positive pole Motor+, the output end of the enabling voltage regulating circuit 14 is connected to the inverting input end of the first operational amplifier OP1, and the control end of the enabling voltage regulating circuit 14 is connected to the enabling signal output end of the control module 30.

[0087] The enabling voltage regulating circuit 14 can convert the first voltage of the motor positive pole Motor+ when receiving a valid enabling signal sent by the control module 30 to obtain a second voltage.

[0088] The clamping module 15 can be connected to the non-inverting input end of the first operational amplifier OP1. The clamping voltage of the clamping module 15 can be a third voltage, and the third voltage can be set to be greater than the second voltage and less than the first voltage. As an embodiment, the clamping module 15 can be a zener diode.

[0089] When the control module 30 sends a non-valid enabling signal, the enabling voltage regulating circuit 14 will not step down the first voltage. At this time, the first voltage is greater than the clamping voltage of the clamping module 15. Since the clamping module 15 can clamp the voltage at the non-inverting input end of the first operational amplifier OP1 below the third voltage, when the first voltage is greater than the third voltage, the voltage at the inverting input end of the first operational amplifier OP1 is greater than the voltage at the non-inverting input end, and the first operational amplifier OP1 can continuously output a low-level signal to control the speed regulation module 40 to disconnect. At this time, the motor negative pole Motor- is disconnected from the ground end, and the potentials of the motor positive pole Motor+ and the motor negative pole Motor- are the same, and the motor does not operate.

[0090] When the control module 30 sends a valid enabling signal, the enabling voltage regulating circuit 14 can adjust the first voltage to a lower second voltage. Since the second voltage is lower than the clamping voltage of the clamping module 15, the second voltage can be compared with the voltage at the non-inverting input end at this time, and an integral voltage signal can be output according to the comparison result to adjust the conduction state of the speed regulation module 40.

[0091] Please continue to refer to Figure 3 , in some embodiments, the above-mentioned enabling voltage regulating circuit 14 may include a first resistor R1, a second resistor R2, a third resistor R3, and a first transistor Q1.

[0092] The first end of the first resistor R1 is connected to the positive pole of the motor, Motor+. The second end of the first resistor R1 is connected to the non-inverting input terminal of the first operational amplifier OP1. The first end of the second resistor R2 is connected to the second end of the first resistor R1. The second end of the second resistor R2 is grounded. The first end of the third resistor R3 is connected to the first end of the second resistor R2. The first end of the first transistor Q1 is connected to the second end of the third resistor R3. The second end of the first transistor Q1 is grounded. The control terminal of the first transistor Q1 is connected to the enable signal output terminal of the control module 30.

[0093] When the control module 30 outputs a non-effective enable signal, the first transistor Q1 is cut off. At this time, the first resistor R1 and the second resistor R2 form a voltage dividing circuit. The first resistor R1 is a pull-up resistor, and the second resistor R2 is a pull-down resistor. Since the resistance value of the second resistor R2 is relatively large, the voltage drop amplitude of the first voltage after voltage division is small and can still be regarded as the first voltage.

[0094] When the control module 30 outputs an effective enable signal, the first transistor Q1 is turned on. The third resistor R3 is grounded through the first transistor Q1, which is equivalent to the second resistor R2 and the third resistor R3 being connected in parallel. At this time, the first resistor R1 serves as the pull-up resistor of the voltage dividing circuit, and the second resistor R2 and the third resistor R3 connected in parallel serve as the pull-down resistor of the voltage dividing circuit. Since the resistance value decreases after the second resistor R2 and the third resistor R3 are connected in parallel, the voltage drop amplitude of the first voltage after voltage division is large, that is, the first voltage becomes the second voltage after voltage division. Since the second voltage is less than the clamping voltage, the first operational amplifier OP1 can integrate the voltage difference between the second voltage and the voltage at the non-inverting input terminal and output an integral voltage signal that has a proportional relationship with the integration result.

[0095] The above-mentioned first transistor Q1 can be an NPN-type triode. The NPN-type triode can be connected to the enable signal output terminal of the control module 30 through a current limiting resistor. A bias resistor can also be provided between the base and the collector of the NPN-type triode.

[0096] In some embodiments, the above-mentioned amplifier circuit 13 can include a Darlington transistor and a fourth resistor R4.

[0097] The Darlington transistor can include a second transistor Q2 and a third transistor Q3. The control terminal of the second transistor Q2 is connected to the output terminal of the first operational amplifier OP1. The first end of the second transistor Q2 is connected to the second power supply terminal VBAT. The second end of the second transistor Q2 is connected to the control terminal of the third transistor Q3. The first end of the third transistor Q3 is connected to the second power supply terminal VBAT. The second end of the third transistor Q3 can be connected to the control terminal of the speed control module 40.

[0098] The first end of the fourth resistor R4 is connected to the second end of the third transistor Q3, and the second end of the fourth resistor R4 is grounded.

[0099] Taking the second transistor Q2 and the third transistor Q3 as NPN bipolar transistors as an example, when the first operational amplifier OP1 outputs a low-level signal, the second transistor Q2 and the third transistor Q3 are cut off. At this time, the signal output by the amplifier circuit 13 after amplification is still a low-level signal. The switching transistor connected between the negative electrode of the motor Motor- and the ground terminal in the speed control module 40 is cut off under the low-level signal. That is, the negative electrode of the motor Motor- is disconnected from the ground terminal. At this time, the potentials of the positive electrode of the motor Motor+ and the negative electrode of the motor Motor- tend to be the same.

[0100] When the first operational amplifier OP1 outputs a high-level signal, the second transistor Q2 and the third transistor Q3 are turned on. At this time, the second transistor Q2 and the third transistor Q3 can perform secondary current amplification on the high-level signal and output the amplified current signal to the control terminal of the speed control module 40, which is beneficial to the rapid conduction of the switching transistor connected between the negative electrode of the motor Motor- and the ground terminal in the speed control module 40. That is, the negative electrode of the motor Motor- is connected to the ground terminal. At this time, the voltage difference between the positive electrode of the motor Motor+ and the negative electrode of the motor Motor- is close to the voltage of the positive electrode of the motor Motor+.

[0101] It should be noted that in the above embodiment, the voltage of the second power supply terminal VBAT is VBAT_ANTI. VBAT_ANTI can be the power supply voltage provided by an external power supply to the electronic control unit ECU where the motor drive circuit is located. VBAT_ANTI can supply power to the electronic control unit ECU through an anti-reverse connection circuit. VBAT_ANTI is usually the battery voltage provided by a battery, such as a lead-acid battery. Since the battery voltage is usually much higher than the power supply voltage required by various chips such as operational amplifiers, in order to supply power to each chip module, a voltage conversion module can also be provided on the electronic control unit ECU. The voltage conversion module can step down the higher VBAT_ANTI and supply the stepped-down voltage as the power supply voltage of the first power supply terminal VCC to the corresponding chip module. That is, the first power supply terminal VCC can be an on-board secondary power supply obtained by stepping down the voltage VBAT_ANTI of the second power supply terminal VBAT.

[0102] The switching transistor connected between the negative electrode of the motor Motor- and the ground terminal in the above speed control module 40 can be a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), or other types of transistors.

[0103] By adjusting the conduction state of the switching tube in the speed control module 40, the potential of the negative terminal of the motor Motor- can be changed, thereby adjusting the voltage across the motor. After continuous reciprocating adjustment, the voltages at the inverting input terminal and the non-inverting input terminal of the first operational amplifier OP1 will be kept consistent, and at this time, the voltage across the motor will also be kept stable.

[0104] When it is necessary to adjust the target voltage across the motor, the bias voltage can be adjusted. The voltage at the non-inverting input terminal is the sum of the voltage of the negative terminal of the motor Motor- and the bias voltage. By increasing the bias voltage, the target difference across the motor can be increased. For example, taking the motor as the blower of a vehicle air conditioner, when the user adjusts the wind speed gear, the motor speed is different at different gears, and the target difference of the voltage across the motor is also different. When the user adjusts the gear, if this adjustment needs to increase the target difference of the voltage across the motor by 0.5V, the bias voltage output by the bias circuit 11 can be increased by adjusting the first modulation signal PWM1. At this time, the voltage received by the non-inverting input terminal of the integrating circuit 12 increases, and the integrating circuit 12 will increase the output integrated voltage signal, causing the potential of the negative terminal of the motor Motor- to decrease. When the voltages at the non-inverting input terminal and the inverting input terminal of the integrating circuit 12 reach a new dynamic balance, the potential of the negative terminal of the motor Motor- will decrease, so that the voltage difference between the positive terminal of the motor Motor+ and the negative terminal of the motor Motor- increases by 0.5V.

[0105] In some embodiments, the above motor drive module may further include a protection module, and the protection module may include a first diode D1, a second diode D2, a third capacitor C3, and a transient voltage suppression diode TVS.

[0106] The positive electrode of the first diode D1 is connected to the positive terminal of the motor Motor+, and the negative electrode of the first diode D1 is connected to the input terminal of the enabling voltage regulating circuit 14. The positive electrode of the second diode D2 is connected to the second terminal of the third transistor Q3, and the negative electrode of the second diode D2 may be connected to the control terminal of the speed control module 40. The third capacitor C3 may be connected between the negative electrode of the second diode D2 and the ground terminal, and the transient voltage suppression diode TVS may be connected between the negative electrode of the second diode D2 and the ground terminal.

[0107] The first diode D1 can play a role of unidirectional conduction. When the voltage of the positive terminal of the motor Motor+ is relatively high, the first diode D1 conducts forwardly and outputs the voltage of the positive terminal of the motor Motor+ to the enabling voltage regulating circuit 14. When the anode voltage of the first diode D1 is lower than the cathode voltage, the first diode D1 is reverse-biased and cut off.

[0108] The second diode D2 can play a role in unidirectional conduction. When the voltage of the third transistor Q3 is relatively high, the second diode D2 conducts forward. When the voltage of the third transistor Q3 is relatively low, the second diode D2 can be reverse-biased and cut off, thus avoiding the influence of current on the third transistor Q3.

[0109] The third capacitor C3 can play a filtering role, filtering high-frequency interference signals to prevent the interference signals from flowing into the control terminal of the speed regulation module 40 and affecting the motor regulation.

[0110] The transient voltage suppression diode TVS can shunt when the transient current is too large to avoid damage to the devices in the circuit caused by excessive peak current.

[0111] As Figure 3 shown, after setting the relevant parameters of each device in the motor drive circuit, the two input voltages of the first operational amplifier OP1 can be calculated respectively. That is, the voltage at the non-inverting input terminal of the first operational amplifier OP1 is the sum of the voltage of the negative terminal of the motor Motor- and the bias voltage, and the voltage at the inverting input terminal of the first operational amplifier OP1 is the voltage obtained by the voltage of the positive terminal of the motor Motor+ after being divided by the first resistor R1, the second resistor R2, and the third resistor R3 in common. When the speed regulation module 40 is stable, the voltage at the non-inverting input terminal of the first operational amplifier OP1 is the same as the voltage at the inverting input terminal. Combining the above voltage expression formulas, the following formula can be obtained:

[0112] Vmotor - VF = k * Vcc * duty;

[0113] Among them, K is a constant, which is associated with the resistance values of each resistor in the motor drive circuit; Vmotor is the voltage across the motor, VCC is the on-board power supply voltage provided by the first power supply terminal, VF is the forward voltage drop of the first diode D1 in the circuit, and duty is the duty cycle of the first modulation signal PWM1. It can be understood that Vcc * duty is the magnitude of the bias voltage, and Vmotor - VF is the input voltage of the enable voltage regulation circuit 14. Since the enable voltage regulation circuit 14 can divide Vmotor - VF, the voltage division coefficient has a relevant relationship with k.

[0114] It can be seen from the above formula that within a certain range, the voltage Vmotor across the motor is only directly proportional to the duty cycle duty of the first modulation signal PWM1, and is not related to the voltage of the second power supply terminal VBAT. When there is a voltage difference between the on-board ground of the electronic control unit ECU and the body ground, it will not affect the voltage Vmotor across the motor.

[0115] Please refer to Figure 3, the above-mentioned motor drive circuit may further include a first sampling unit 51, a second sampling unit 52, and a third sampling unit 53.

[0116] The sampling terminal of the first sampling unit 51 is connected to the positive electrode of the motor Motor+, and the output terminal of the first sampling unit 51 is connected to the control module 30. The sampling terminal of the second sampling unit 52 is connected to the positive electrode of the motor Motor+, and the output terminal of the second sampling unit 52 is connected to the control module 30. The sampling terminal of the third sampling unit 53 is connected to the first drive output terminal OPX of the LPM drive module 10, and the output terminal of the third sampling unit 53 is connected to the control module 30.

[0117] The control module 30 can sample the voltage of the positive electrode of the motor Motor+, the voltage of the negative electrode of the motor Motor-, and the output voltage of the LPM drive module 10 through each sampling unit respectively. When the control module 30 dynamically adjusts the voltage across the motor through the PWM drive module 20, it can determine the actual voltage difference across the motor based on the voltage of the positive electrode of the motor Motor+ and the voltage of the negative electrode of the motor Motor-, and adjust the conduction state of the speed regulation module 40 by driving the PWM drive module 20, so that the actual voltage difference across the motor approaches the target voltage difference.

[0118] When the control module 30 dynamically adjusts the voltage across the motor by the LPM drive module 10, it can also obtain the output voltage of the LPM drive module 10. In order to realize the conduction control of the switching tube in the speed regulation module 40, the output voltage of the LPM drive module 10 should be within the tolerable voltage range of the switching tube. When the control module 30 monitors that the output voltage of the LPM drive module 10 exceeds the pressure-bearing range of the switching tube, it can determine that the LPM drive module 10 has an abnormal fault.

[0119] The above-mentioned first sampling unit 51, second sampling unit 52, and third sampling unit 53 may be a voltage division circuit formed by two resistors connected in series. By setting the resistance values of the respective resistors in the voltage division circuit, the voltage after voltage division can be made within the sampling voltage range of the control module 30, thereby realizing voltage sampling.

[0120] In some embodiments, in order to improve the stability of the circuit structure and reduce the risk of overcurrent, current-limiting resistors may be correspondingly provided at various positions in the circuit to prevent device damage due to excessive current in the loop.

[0121] The embodiment of the present application also provides a vehicle-mounted device, which may include a motor and the motor drive circuit in the above embodiment.

[0122] The embodiment of the present application also provides a vehicle, which may include the motor drive circuit in the above embodiment.

[0123] The functional blocks shown in the above structural block diagram can be implemented as hardware, software, firmware, or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, and so on. When implemented in software, the elements of the present application are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium or transmitted via a data signal carried in a carrier wave over a transmission medium or a communication link. A "machine-readable medium" can include any medium that can store or transmit information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical discs, hard disks, fiber optic media, radio frequency (RF) links, and so on. The code segment can be downloaded via a computer network such as the Internet, an intranet, and so on.

[0124] It should be noted that in this article, the terms "including", "comprising", or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article, or device.

[0125] In this article, specific examples are used to elaborate on the principles and implementation manners of the present application. The description of the above examples is only used to help understand the method and its core idea of the present application. The above are only optional implementation manners of the present application. It should be noted that due to the limited nature of literal expression and objectively infinite specific structures, for those of ordinary skill in the art, without departing from the principle of the present application, several improvements, refinements, or changes can be made, or the above technical features can be combined in an appropriate manner; these improvements, refinements, changes, or combinations, or directly applying the concept and technical solution of the present application to other occasions without improvement, shall all be regarded as the protection scope of the present application.

Claims

1. A motor drive circuit, characterized in that, the motor drive circuit includes: an LPM drive module, two signal input ends of the LPM drive module are respectively connected to the positive electrode and the negative electrode of the motor, a first drive output end of the LPM drive module is connected to a control end of a speed regulation module, and the LPM drive module is configured to adjust a conduction state of the speed regulation module according to a first control signal and voltages at two ends of the motor; wherein, the speed regulation module is connected between the negative electrode of the motor and a ground end, and the first control signal is used to adjust a target pressure difference at two ends of the motor; a PWM drive module, a second drive output end of the PWM drive module is connected to the control end of the speed regulation module, and the PWM drive module is configured to adjust the conduction state of the speed regulation module according to a second control signal; a control module, connected to the LPM drive module and the PWM drive module respectively, and configured to send the first control signal to the LPM drive module or send the second control signal to the PWM drive module according to a corresponding type of the speed regulation module.

2. The motor drive circuit according to claim 1, characterized in that, the first control signal includes an LPM enable signal and a first modulation signal, and the LPM drive module is configured to adjust the conduction state of the speed regulation module when receiving a valid enable signal; the LPM drive module includes: a bias circuit, an input end of the bias circuit is connected to the control module, and the bias circuit is configured to generate a bias voltage according to a duty ratio of the first modulation signal; an integration circuit, a first input end of the integration circuit is respectively connected to the negative electrode of the motor and an output end of the bias circuit, a second input end of the integration circuit is connected to the positive electrode of the motor, and the integration circuit is configured to generate an integration voltage signal according to an integral of a voltage difference between the first input end and the second input end over time; an amplification circuit, a control end of the amplification circuit is connected to an output end of the integration circuit, an output end of the amplification circuit is connected to the control end of the speed regulation module, and the amplification circuit is configured to amplify the integration voltage signal to obtain a speed regulation control signal.

3. The motor drive circuit according to claim 2, characterized in that, the integration circuit includes: a first operational amplifier, a non-inverting input end of the first operational amplifier is connected to the negative electrode of the motor and an output end of the bias circuit, an inverting input end of the first operational amplifier is connected to the positive electrode of the motor, and an output end of the first operational amplifier is connected to the control end of the amplification circuit; a first capacitor, connected between the output end and the inverting input end of the first operational amplifier; a second capacitor, connected between the non-inverting input end and the inverting input end of the first operational amplifier.

4. The motor drive circuit according to claim 3, characterized in that, the bias circuit includes: A second operational amplifier, the non-inverting input terminal of the second operational amplifier is connected to the first modulation signal output terminal of the control module, the inverting input terminal of the second operational amplifier is connected to the first power supply terminal, and the output terminal of the second operational amplifier is connected to the non-inverting input terminal of the first operational amplifier; the second operational amplifier is configured to generate a bias voltage according to the duty cycle of the first modulation signal.

5. The motor drive circuit according to claim 3, characterized in that the LPM drive module further includes: an enabling voltage regulating circuit, the input terminal of the enabling voltage regulating circuit is connected to the positive electrode of the motor, the output terminal of the enabling voltage regulating circuit is connected to the inverting input terminal of the first operational amplifier, and the control terminal of the enabling voltage regulating circuit is connected to the enabling signal output terminal of the control module; the enabling voltage regulating circuit is configured to adjust a first voltage of the positive electrode of the motor to a second voltage when receiving the enabling signal; a clamping module, connected to the non-inverting input terminal of the first operational amplifier, and the clamping voltage of the clamping module is a third voltage; wherein, the first voltage is greater than the third voltage, and the second voltage is less than the third voltage.

6. The motor drive circuit according to claim 5, characterized in that the enabling voltage regulating circuit includes: a first resistor, a first end of the first resistor is connected to the positive electrode of the motor, and a second end of the first resistor is connected to the non-inverting input terminal of the first operational amplifier; a second resistor, a first end of the second resistor is connected to the second end of the first resistor, and a second end of the second resistor is grounded; a third resistor, a first end of the third resistor is connected to the first end of the second resistor; a first transistor, a first end of the first transistor is connected to the second end of the third resistor, a second end of the first transistor is grounded, and a control end of the first transistor is connected to the enabling signal output terminal of the control module.

7. The motor drive circuit according to claim 5, characterized in that the amplifier circuit includes: a Darlington transistor, including a second transistor and a third transistor, a control end of the second transistor is connected to the output terminal of the first operational amplifier, a first end of the second transistor is connected to the second power supply terminal, a second end of the second transistor is connected to the control end of the third transistor, a first end of the third transistor is connected to the second power supply terminal, and a second end of the third transistor is connected to the control end of the speed regulation module; a fourth resistor, a first end of the fourth resistor is connected to the second end of the third transistor, and a second end of the fourth resistor is grounded.

8. The motor drive circuit according to claim 7, characterized in that the motor drive circuit further includes a protection module, and the protection module includes: a first diode, a positive electrode of the first diode is connected to the positive electrode of the motor, and a negative electrode of the first diode is connected to the input terminal of the enabling voltage regulating circuit; a second diode, a positive electrode of the second diode is connected to the second end of the third transistor, and a negative electrode of the second diode is connected to the control end of the speed regulation module; A third capacitor, connected between the negative electrode of the second diode and the ground terminal; A transient suppression diode, connected between the negative electrode of the second diode and the ground terminal.

9. The motor drive circuit according to claim 1, characterized in that the motor drive circuit further comprises: a first sampling unit, the sampling terminal of the first sampling unit is connected to the positive electrode of the motor, and the output terminal of the first sampling unit is connected to the control module; a second sampling unit, the sampling terminal of the second sampling unit is connected to the positive electrode of the motor, and the output terminal of the second sampling unit is connected to the control module; a third sampling unit, the sampling terminal of the third sampling unit is connected to the first drive output terminal of the LPM drive module, and the output terminal of the third sampling unit is connected to the control module.

10. A vehicle-mounted device, characterized in that the vehicle-mounted device includes a motor and the motor drive circuit according to any one of claims 1-9.

11. A vehicle, characterized in that the vehicle includes the vehicle-mounted device according to claim 10.

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