A circuit implementation method for driving a dimming motor using a PWM signal

Abstract

The present invention proposes a circuit implementation method for driving a dimming motor with a PWM signal, so as to solve the technical problem that the dimming motor and the PWM signal output by the vehicle body module do not match. The power input signal of the present invention provides a stable power supply voltage through the power protection module, and the power supply voltage supplies power to the voltage stabilizing filter module and the driving module; at the same time, the voltage stabilizing filter module converts the PWM control signal input by the vehicle body into a linearly variable voltage stabilizing control signal, and the voltage stabilizing control signal provides a signal voltage to the driving module. The driving module simultaneously receives the feedback signal of the potentiometer, and drives the internal motor to work based on the voltage difference between the voltage stabilizing control signal and the feedback signal, thereby accurately driving the dimming motor to work. The present invention realizes the purpose of directly receiving the client PWM control signal to drive the dimming motor to work through a low-cost power protection module, a voltage stabilizing filter module and a driving module.

Description

Technical Field

[0001] The invention relates to the technical field of automobile headlamp components, and in particular to a circuit implementation method for driving a dimming motor with a PWM signal. Background Art

[0002] As the most common means of transportation, people have higher and higher requirements for the safety of cars. In terms of car headlights, in order to improve the safety of driving at night, the relevant national standards have clear requirements for the height of the headlight beam. In order to cope with the changes in the height of the headlight beam caused by the change in the weight of the vehicle body, the dimming motor is a necessary component and is generally installed in the headlight. The working principle of the dimming motor is based on the control signal given by the vehicle body. The control circuit drives the motor inside the dimming motor, and the transmission gear system inside the dimming motor converts the axial rotation of the motor into the linear motion of the output screw of the dimming motor. The output screw is connected to the reflective bowl of the headlight, and its linear motion will drive the reflective bowl to move axially, thereby realizing the height adjustment of the headlight beam to ensure driving safety.

[0003] For the control signal from the vehicle body, the manual switch on the control panel was used to give a DC voltage stabilization signal. At present, with the improvement of automobile electrification and intelligence, the control signal from the vehicle body begins to appear in the digital form of PWM. This requires the design improvement of the traditional dimming motor.

[0004] The utility model patent with application number 201920940953.4 discloses a dimming control circuit for an automobile, including a body control module that sends LIN signals, a dimming motor, and a dimming circuit board arranged in the dimming motor and connected to the body control module. The dimming circuit board includes a dimming circuit, and the dimming circuit includes a receiver that can receive LIN signals, a converter connected to the receiver, a filter connected to the converter, a control chip connected to the filter, and a drive motor connected to the control chip. The LIN signal is sent through the body control module, and then the LIN signal is transmitted to the converter through the receiver on the dimming circuit board. The converter converts the LIN signal into a PWM signal output, and then inputs the PWM signal to the control chip. Finally, the control chip controls the operation of the drive motor, and improves the switch control in the original technology to control through the center console, which is convenient for the driver to operate, has a high customer experience, and for developers, the vehicle development cycle is shortened and the development cost is reduced. However, in the above technical solution, the product assembly receives the LIN signal sent by the BCM (client), and the PWM signal is a signal generated by the internal conversion of the product, and the drive chip cannot directly receive the PWM signal, and needs to convert the signal again through the filter circuit. Therefore, the above technical solution is a solution for LIN input signals, not a solution directly for PWM input signals, which leads to an increase in the cost of the product itself. Summary of the invention

[0005] In order to solve the technical problem that the existing circuit for driving the dimming motor cannot directly receive the client PWM control signal and the PWM signal output by the dimming motor and the body module do not match, the present invention proposes a circuit implementation method for driving the dimming motor with a PWM signal, which effectively drives the dimming motor to work based on the PWM control signal through a low-cost comparator and filter circuit.

[0006] In order to achieve the above-mentioned purpose, the technical solution of the present invention is implemented as follows: a circuit implementation method for driving a dimming motor with a PWM signal, comprising: a power input signal provides a stable power supply voltage Vcc through a power protection module, and the power supply voltage Vcc supplies power to a subsequent voltage stabilizing filter module and a driving module. At the same time, the voltage stabilizing filter module converts the PWM control signal input from the vehicle body into a linearly variable voltage stabilizing control signal Vset, and the voltage stabilizing control signal Vset provides a signal voltage to the subsequent driving module. The driving module simultaneously receives the feedback signal Vfb of the potentiometer W1, and drives the internal motor to work based on the voltage difference between the voltage stabilizing control signal Vset and the feedback signal Vfb, thereby accurately driving the dimming motor to work.

[0007] Preferably, the power protection module includes a rectifier diode D1, a TVS tube D2, an electrolytic capacitor C1 and a capacitor C2, the power input signal is connected to the positive electrode of the rectifier diode D1, the negative electrode of the rectifier diode D1 is connected to the negative electrode of the TVS tube D2, and the positive electrode of the TVS tube D2 is connected to the ground; the two ends of the TVS tube D2 are connected in parallel with the electrolytic capacitor C1, and the electrolytic capacitor C1 is connected in parallel with the capacitor C2.

[0008] Preferably, the voltage stabilization filter module includes a comparator circuit and a low-pass filter circuit, the input PWM control signal is connected to the comparator circuit, the comparator circuit is connected to the low-pass filter circuit, and the low-pass filter circuit is connected to the driving module; the comparator circuit converts the input PWM signal into a PWM signal with the same potential as the power supply voltage Vcc, and then converts the PWM signal into a stable voltage stabilization control signal through the low-pass filter circuit.

[0009] Preferably, the comparator circuit includes a comparator, an inverting input terminal of the comparator is connected to the power supply voltage Vcc through a first voltage divider circuit, a non-inverting input terminal of the comparator is connected to the input PWM control signal through a second voltage divider circuit, and an output terminal of the comparator is connected to a low-pass filter circuit.

[0010] Preferably, the first voltage-dividing circuit includes a voltage-dividing resistor R6 and a voltage-dividing resistor R7, one end of the voltage-dividing resistor R6 is connected to the power supply voltage Vcc, and the other end of the voltage-dividing resistor R6 is connected to the inverting input terminal of the comparator; one end of the voltage-dividing resistor R7 is connected to the inverting input terminal of the comparator, and the other end of the voltage-dividing resistor R7 is grounded; the second voltage-dividing circuit includes a voltage-dividing resistor R4 and a voltage-dividing resistor R5, one end of the voltage-dividing resistor R4 is connected to the PWM control signal, and the other end of the voltage-dividing resistor R4 is connected to the non-inverting input terminal of the comparator; one end of the voltage-dividing resistor R5 is connected to the non-inverting input terminal of the comparator, and the other end of the voltage-dividing resistor R5 is grounded; the ground terminal of the comparator is grounded, and the power supply terminal of the comparator is connected to the power supply voltage Vcc.

[0011] Preferably, the output terminal of the comparator is connected to the power supply voltage Vcc via a pull-up resistor R8.

[0012] Preferably, the low-pass filter circuit includes a resistor R3 and a capacitor C3, one end of the resistor R3 is connected to the output end of the comparator, the other end of the resistor R3 is respectively connected to one end of the capacitor C3 and the driving module, and the other end of the capacitor C3 is grounded.

[0013] Preferably, the driving module includes a driving chip, and the driving chip compares the voltage stabilization control signal output by the voltage stabilization filter module with the feedback signal provided by the potentiometer W1, thereby driving the motor to rotate effectively.

[0014] Preferably, the SET pin of the driving chip is connected to the output end of the voltage stabilizing and filtering module through a resistor R2, the FB pin of the driving chip is connected to the adjustment end of the potentiometer W1 through a resistor R1, the two fixed ends of the potentiometer W1 are respectively connected to the power supply voltage Vcc and the ground, and a filter capacitor C4 is connected between the SET pin and the FB pin of the driving chip; the ground end of the driving chip is grounded, and the two power supply ends of the driving chip are connected to the power supply voltage Vcc.

[0015] Preferably, the two output terminals of the driving chip are respectively connected to the two ends of the capacitor C5, and the two ends of the capacitor C5 are connected in parallel with a driving motor.

[0016] Compared with the prior art, the present invention has the beneficial effects of: directly receiving the client PWM control signal to drive the dimming motor to work through a low-cost comparator, a filter circuit and a driver chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the circuit structure of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] like Figure 1As shown, a circuit implementation method for driving a dimming motor with a PWM signal includes: a power input signal provides a stable power supply voltage Vcc through a power protection module, and the power supply voltage Vcc supplies power to a subsequent voltage stabilizing filter module and a driving module. At the same time, the voltage stabilizing filter module converts the PWM control signal input by the vehicle body into a linearly variable voltage stabilizing control signal Vset, and the voltage stabilizing control signal Vset provides a signal voltage to the subsequent driving module. The driving module simultaneously receives the feedback signal Vfb of the potentiometer W1, and drives the internal motor to work based on the voltage difference between the voltage stabilizing control signal Vset and the feedback signal Vfb, thereby accurately driving the dimming motor to work. The power protection module provides the voltage stabilizing filter module and the driving module respectively, ensuring the same potential state of the above submodules. The voltage stabilizing filter module uniformly converts different external PWM signals into control signals that match the power supply signal. Through the coordinated work of the above modules, it is ensured that the dimming motor can also work stably under the action of the PWM control signal directly given by the vehicle body. The power input signal Vbat, PWM control signal and reference ground GND are all effectively electrically connected to the PCB circuit board through the plug-in, and the connector realizes the effective connection between the vehicle body signal and the product circuit.

[0021] Furthermore, if Figure 1 As shown, the power protection module includes a rectifier diode D1, a TVS tube D2, an electrolytic capacitor C1 and a capacitor C2, the power input signal Vbat is connected to the positive electrode of the rectifier diode D1, the negative electrode of the rectifier diode D1 is connected to the negative electrode of the TVS tube D2, and the positive electrode of the TVS tube D2 is connected to the ground; the two ends of the TVS tube D2 are connected in parallel with an electrolytic capacitor C1, and the electrolytic capacitor C1 is connected in parallel with the capacitor C2. The rectifier diode D1 is used to prevent reverse flow, the TVS tube D2 is used to prevent impact, and the electrolytic capacitor C1 and the capacitor C2 are used for filtering and stabilizing voltage. The entire power protection module realizes the functions of anti-reverse flow, anti-impact, filtering and stabilizing voltage, and provides a stable power supply voltage Vcc for subsequent modules.

[0022] Furthermore, if Figure 1 As shown, the voltage stabilization filter module includes a comparator circuit and a low-pass filter circuit, the input PWM control signal is connected to the comparator circuit, the comparator circuit is connected to the low-pass filter circuit, and the low-pass filter circuit is connected to the drive module. The comparator circuit is a comparator circuit with comparator U2A as the core, which converts the input PWM signal into a PWM signal with the same potential as the power supply voltage Vcc, and then converts the PWM signal into a stable voltage stabilization control signal through the low-pass filter circuit.

[0023] The comparator circuit includes a comparator, the inverting input terminal of the comparator is connected to the power supply voltage Vcc through a first voltage divider circuit, the non-inverting input terminal of the comparator is connected to the input PWM control signal through a second voltage divider circuit, and the output terminal of the comparator is connected to a low-pass filter circuit. The power supply voltage Vcc enters the voltage stabilization filter module, which, on the one hand, supplies power to the comparator U2A to ensure that the level state of its output is consistent with the power supply voltage Vcc; on the other hand, the first voltage divider circuit composed of the voltage divider resistor R6 and the voltage divider resistor R7 provides a suitable reference voltage to the comparator U2A.

[0024] The first voltage-dividing circuit includes a voltage-dividing resistor R6 and a voltage-dividing resistor R7, one end of the voltage-dividing resistor R6 is connected to the power supply voltage Vcc, and the other end of the voltage-dividing resistor R6 is connected to the inverting input terminal of the comparator; one end of the voltage-dividing resistor R7 is connected to the inverting input terminal of the comparator, and the other end of the voltage-dividing resistor R7 is grounded; the second voltage-dividing circuit includes a voltage-dividing resistor R4 and a voltage-dividing resistor R5, one end of the voltage-dividing resistor R4 is connected to the PWM control signal, and the other end of the voltage-dividing resistor R4 is connected to the non-inverting input terminal of the comparator; one end of the voltage-dividing resistor R5 is connected to the non-inverting input terminal of the comparator, and the other end of the voltage-dividing resistor R5 is grounded; the ground terminal of the comparator is grounded, and the power supply terminal of the comparator is connected to the power supply voltage Vcc.

[0025] The output end of the comparator is connected to the power supply voltage Vcc through a pull-up resistor R8. The pull-up resistor R8 improves the output capability of the comparator and ensures the rapid response of the subsequent filtering circuit.

[0026] Furthermore, the low-pass filter circuit includes a resistor R3 and a capacitor C3, one end of the resistor R3 is connected to the output end of the comparator, the other end of the resistor R3 is respectively connected to one end of the capacitor C3 and the driving module, and the other end of the capacitor C3 is grounded.

[0027] The input signals of the voltage stabilization and filtering module include PWM control signal and power supply voltage Vcc. The PWM control signal is divided by voltage-dividing resistors R4 and R5 and then input into comparator U2A. By comparing with the reference voltage obtained by voltage-dividing resistors R6 and R7, a PWM signal with the same potential as the power supply voltage Vcc is output. Then, the PWM signal is converted into a relatively stable signal voltage through a low-pass filter circuit composed of resistor R3 and capacitor C3, and the output signal voltage also changes linearly with the change of the duty cycle of the PWM signal. When the PWM signal is at a high level, the filter circuit charges capacitor C3 through resistor R3. When the PWM signal is at a low level, capacitor C3 is discharged through resistor R3. Therefore, by selecting appropriate resistors and capacitors corresponding to the frequency of the PWM signal, the capacitor terminal voltage can correspond to the PWM duty cycle, and the voltage can be stabilized and output, and directly act on the 3629-based drive module.

[0028] The driving module includes a driving chip, with the driving chip 3629 as the core. The driving chip compares the voltage stabilization control signal output by the voltage stabilization filter module with the feedback signal provided by the potentiometer W1, thereby driving the effective rotation of the motor M. The power supply voltage Vcc enters the driving module and supplies power to the 3629 driving chip in the driving module so that it can work normally. At the same time, the power supply voltage is provided to the potentiometer W1 connected to the mechanical transmission part so that it can output an effective feedback voltage.

[0029] The SET pin of the driver chip is connected to the output end of the voltage stabilizing filter module through the resistor R2, the FB pin of the driver chip is connected to the adjustment end of the potentiometer W1 through the resistor R1, the two fixed ends of the potentiometer W1 are respectively connected to the power supply voltage Vcc and the ground, and a filter capacitor C4 is connected between the SET pin and the FB pin of the driver chip; the ground end of the driver chip is grounded, and the two power supply ends of the driver chip are connected to the power supply voltage Vcc. The two output ends of the driver chip are respectively connected to the two ends of the capacitor C5, and the two ends of the capacitor C5 are connected in parallel with a driving motor. The SET pin receives a voltage stabilizing control signal, and the FB pin receives a voltage stabilizing feedback signal. The capacitor C4 avoids product jitter caused by the transient interference pressure difference between the control signal and the feedback signal, and the capacitor C5 eliminates the voltage fluctuation caused by the motor at the motor port. Capacitors C4 and C5 can effectively ensure the stability of the input signal and the output voltage.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A circuit implementation method for driving a dimming motor with a PWM signal, characterized in that: include: The power input signal provides a stable power supply voltage Vcc through the power protection module, and the power supply voltage Vcc supplies power to the subsequent voltage stabilization filter module and the drive module; at the same time, the voltage stabilization filter module converts the PWM control signal input from the vehicle body into a linearly variable voltage stabilization control signal Vset, and the voltage stabilization control signal Vset provides a signal voltage to the subsequent drive module; the drive module simultaneously receives the feedback signal Vfb of the potentiometer W1, and drives the internal motor to work based on the voltage difference between the voltage stabilization control signal Vset and the feedback signal Vfb, thereby accurately driving the dimming motor to work; The voltage stabilization filter module includes a comparator circuit and a low-pass filter circuit, the input PWM control signal is connected to the comparator circuit, the comparator circuit is connected to the low-pass filter circuit, and the low-pass filter circuit is connected to the driving module; the comparator circuit converts the input PWM signal into a PWM signal with the same potential as the power supply voltage Vcc, and then converts the PWM signal into a stable voltage stabilization control signal Vset through the low-pass filter circuit; The inverting input terminal of the comparator in the comparator circuit is connected to the power supply voltage Vcc through a first voltage divider circuit, the non-inverting input terminal of the comparator is connected to the input PWM control signal through a second voltage divider circuit, and the output terminal of the comparator is connected to a low-pass filter circuit; The first voltage-dividing circuit includes a voltage-dividing resistor R6 and a voltage-dividing resistor R7, one end of the voltage-dividing resistor R6 is connected to the power supply voltage Vcc, and the other end of the voltage-dividing resistor R6 is connected to the inverting input terminal of the comparator; one end of the voltage-dividing resistor R7 is connected to the inverting input terminal of the comparator, and the other end of the voltage-dividing resistor R7 is grounded; the second voltage-dividing circuit includes a voltage-dividing resistor R4 and a voltage-dividing resistor R5, one end of the voltage-dividing resistor R4 is connected to the PWM control signal, and the other end of the voltage-dividing resistor R4 is connected to the non-inverting input terminal of the comparator; one end of the voltage-dividing resistor R5 is connected to the non-inverting input terminal of the comparator, and the other end of the voltage-dividing resistor R5 is grounded; the ground terminal of the comparator is grounded, and the power supply terminal of the comparator is connected to the power supply voltage Vcc.

2. The circuit implementation method of the PWM signal driving dimming motor according to claim 1, characterized in that: The power protection module includes a rectifier diode D1, a TVS tube D2, an electrolytic capacitor C1 and a capacitor C2. The power input signal is connected to the positive electrode of the rectifier diode D1, the negative electrode of the rectifier diode D1 is connected to the negative electrode of the TVS tube D2, and the positive electrode of the TVS tube D2 is connected to the ground; the two ends of the TVS tube D2 are connected in parallel with the electrolytic capacitor C1, and the electrolytic capacitor C1 is connected in parallel with the capacitor C2.

3. The circuit implementation method of the PWM signal driven dimming motor according to claim 1 or 2, characterized in that: The output terminal of the comparator is connected to the power supply voltage Vcc through a pull-up resistor R8.

4. The circuit implementation method of the PWM signal driving dimming motor according to claim 3, characterized in that: The low-pass filter circuit includes a resistor R3 and a capacitor C3, one end of the resistor R3 is connected to the output end of the comparator, the other end of the resistor R3 is respectively connected to one end of the capacitor C3 and the driving module, and the other end of the capacitor C3 is grounded.

5. The circuit implementation method of the PWM signal driven dimming motor according to claim 1 or 4, characterized in that: The driving module includes a driving chip, which compares the voltage stabilization control signal Vset output by the voltage stabilization filter module with the feedback signal Vfb provided by the potentiometer W1, thereby driving the motor to rotate effectively.

6. The circuit implementation method of the PWM signal driving dimming motor according to claim 5, characterized in that: The SET pin of the driving chip is connected to the output end of the voltage stabilizing filter module through the resistor R2, the FB pin of the driving chip is connected to the adjustment end of the potentiometer W1 through the resistor R1, the two fixed ends of the potentiometer W1 are respectively connected to the power supply voltage Vcc and the ground, and a filter capacitor C4 is connected between the SET pin and the FB pin of the driving chip; the ground end of the driving chip is grounded, and the two power supply ends of the driving chip are connected to the power supply voltage Vcc.

7. The circuit implementation method of the PWM signal driving dimming motor according to claim 6, characterized in that: The two output terminals of the driving chip are respectively connected to the two ends of the capacitor C5, and the two ends of the capacitor C5 are connected in parallel with a driving motor.

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