A control circuit for adjustable DC motor speed

Abstract

This utility model relates to the field of automotive electronics technology, and specifically to a control circuit for adjusting the speed of a DC motor. The control circuit includes an MCU module, a high-side output module, a motor speed control module, and a DC motor. The MCU module is connected to the high-side output module and controls the high-side output. The MCU module is also connected to the motor speed control module and sends a PWM duty cycle signal to it. The high-side output module provides power to the motor speed control module and the DC motor. The motor speed control module sends a speed control signal to the DC motor. This utility model achieves logical control of DC motor speed regulation using discrete components, reducing costs while ensuring quality.

Description

Technical Field

[0001] This utility model relates to the field of automotive electronics technology, and to a control circuit for adjusting the speed of a DC motor. Background Technology

[0002] DC motors are widely used as the core actuators in automotive intelligent lighting systems. By sensing the vehicle's status through a height position sensor, the DC motor drives a gear mechanism to automatically or manually adjust the headlight beam angle, ensuring optimal illumination and preventing glare. Alternatively, based on the steering wheel angle and vehicle speed, the DC motor adjusts the horizontal and vertical angles of the headlights in real time, ensuring the light always points in the direction the vehicle is about to travel, improving lighting safety on curves and complex road conditions.

[0003] In the market, actuators that drive DC motors are generally integrated chips. These chips can drive DC motors and adjust their speed, but they are relatively expensive. Utility Model Content

[0004] The technical problem this invention aims to solve is: the control of DC motor speed uses a high-cost integrated chip.

[0005] Therefore, this utility model provides a control circuit for adjustable DC motor speed, which uses discrete components to output the DC motor speed adjustment signal, thereby improving the utilization rate of the components and optimizing costs.

[0006] The technical solution adopted by this utility model to solve its technical problem is: A control circuit for adjusting the speed of a DC motor, comprising: MCU module, wherein the MCU module has at least two interfaces; A high-side output module is connected to one of the interfaces of the MCU module, and the MCU module controls the high-side output by outputting commands to the high-side output module. A motor speed control module is connected to another interface of the MCU module, and the MCU module sends a PWM duty cycle signal to the motor speed control module. Both the high-side output module and the motor speed control module are connected to the DC motor. The high-side output module is used to provide power to the DC motor, and the motor speed control module outputs a speed control signal to the DC motor.

[0007] By adopting the above discrete component technology solution, the high-side output module is responsible for power output, the MCU module is responsible for speed regulation signal generation, and the motor speed regulation module is implemented. The logic circuit is simple and the cost is low.

[0008] Furthermore, the high-side output module is also used to provide power to the motor speed control module.

[0009] By adopting the above technical solutions, the stability and consistency of the power supply of the motor speed control module can be guaranteed, avoiding interference from external power supply fluctuations on speed control accuracy; at the same time, the integrated design of power supply and control between modules can be realized, simplifying the system architecture, and through the power enable logic of high-side output, it can form functional synergy with speed control, improving the overall reliability and response efficiency of DC motor speed control.

[0010] Furthermore, the high-side output module includes a high-side driver chip U1.

[0011] The high-side drive chip U1 is connected to the MCU module. When the MCU module receives the instruction to start the DC motor, the MCU module sends a high-level instruction to the high-side drive chip U1. The high-side drive chip U1 receives the channel control enable signal, controls the channel to open and output.

[0012] Furthermore, the motor speed control module is connected to the high-side drive chip U1. The high-side drive chip U1 controls its own on / off state according to the speed control signal received from the motor speed control module, and adjusts the current and voltage output to the DC motor.

[0013] Furthermore, the motor speed control module is a separate circuit including transistor Q1 and transistor Q2, used to achieve stable output of speed control signal (voltage).

[0014] Furthermore, the formula for the output speed control signal voltage of the motor speed control module and the PWM duty cycle signal given by the MCU module is as follows:

[0015] in, This indicates the output speed control signal voltage (V). This indicates that the MCU provides the duty cycle percentage (%) of the PWM signal, and the PWM signal frequency is 20KHz.

[0016] The beneficial effects of this invention are that the DC motor can be speed-regulated by receiving different voltage values. When the entire system receives a command from the DC motor to speed-regulate, the MCU module can output PWM signals with fixed frequency and different duty cycles to the motor speed regulation module. After conversion by the motor speed regulation module, different stable voltage values ​​can be output. The DC motor can adjust its speed upon receiving this voltage value. The higher the duty cycle of the PWM signal output by the MCU, the higher the voltage value converted by the motor speed regulation module, and the higher the speed regulation rate of the DC motor. The solution is simple and cost-effective, eliminating the need for complex motor speed regulation chips or circuits. The motor speed regulation function can be achieved through simple logic circuits. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] Figure 1 This is a structural block diagram of the present invention; Figure 2 This is the circuit diagram of the high-side output module of this utility model; Figure 3 This is the circuit diagram of the motor speed control module of this utility model.

[0019] In the diagram: 1. MCU module; 2. High-side output module; 3. Motor speed control module; 4. DC motor. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.

[0021] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0022] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0023] Reference Figure 1 A control circuit for adjusting the speed of a DC motor includes an MCU module 1, a high-side output module 2, a motor speed control module 3, and a DC motor 4.

[0024] MCU module 1 is connected to high-side output module 2 via one general-purpose I / O port to control the high-side output; MCU module 1 is also connected to motor speed control module 3 via another general-purpose I / O port to send PWM duty cycle signals to motor speed control module 3. Furthermore, high-side output module 2 provides power to DC motor 4 and motor speed control module 3, and motor speed control module 3 outputs speed control signals to DC motor 4.

[0025] Reference Figure 2 The high-side output module 2 includes a high-side driver chip U1. The first pin of the high-side driver chip U1 is GND; the second pin is a sensor output, which, after passing through an RC filter, allows the MCU module 1 to read the voltage; the third pin is for setting fault handling behavior (latch or automatic retry); the fourth pin is for chip enable, where the MCU module 1 inputs a high-level signal to the enable pin, and the high-side driver chip U1 starts working; the fifth pin, connected to a resistor, can set the current limit threshold; the sixth to eighth pins are channel outputs; the fourteenth pin is a diagnostic selection pin, which can be combined with the second and sixteenth pins to perform fault diagnosis on the high-side driver chip U1; the sixteenth pin is a diagnostic enable pin; and the seventeenth pin is the power supply input pin for the high-side driver chip U1.

[0026] In one embodiment, the high-side output module 2 further includes resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, capacitors C1, C2, C3, C4, C5, and diode D1.

[0027] Specifically: the second pin of the high-side driver chip U1 is connected to the MCU module 1 through current-limiting resistor R4; one end of resistor R2 is connected to the second pin of the high-side driver chip U1, and the other end is connected to GND; one end of capacitor C2 is connected to the second pin of the high-side driver chip U1, and the other end is connected to GND; resistor R2 converts the detection current into a detection voltage, and capacitor C2 is a low-pass filter capacitor; the third pin of the high-side driver chip U1 is connected to the MCU module 1 through current-limiting resistor R6; the fourth pin of the high-side driver chip U1 is connected to the MCU module 1 through current-limiting resistor R7; the fourteenth pin of the high-side driver chip U1 is connected to the MCU module 1 through current-limiting resistor R5; and the sixteenth pin of the high-side driver chip U1 is connected to the MCU module 1 through current-limiting resistor R3. 1. The fifth pin of the high-side driver chip U1 is connected to the input voltage through resistor R8. The output current limit threshold can be set by adjusting the resistance value of resistor R8. The first pin of the high-side driver chip U1 is connected to GND through resistor R1, capacitor C1 and diode D1 connected in parallel. Resistor R1 plays a stabilizing role, capacitor C1 helps to improve RF immunity, and diode D1 protects the device when the battery is reverse connected. The seventeenth pin of the high-side driver chip U1 is connected to VBAT and is also connected to GND through capacitors C4 and C5 connected in parallel. This can stabilize the input power supply, filter low-frequency noise, and filter voltage transients.

[0028] The sixth, seventh, and eighth pins of the high-side driver chip U1 are shorted together and connected to a parallel pull-down resistor R9 and a filter capacitor C3, and then connected to GND. The resistor R9 acts as a pull-down resistor to stabilize the static level of the output terminal, and the C3 acts as a filter capacitor to filter out high-frequency noise in the output signal.

[0029] When MCU module 1 receives the command to start DC motor 4, MCU module 1 sends a high-level command to the fourth pin of high-side driver chip U1. High-side driver chip U1 receives the channel control enable signal, controls the channel to open and outputs power to DC motor 4, and can also provide analog power to motor speed control module 3.

[0030] It should be noted that the high-side driver chip U1 can be any existing high-side driver chip, model TPS1HB16.

[0031] Reference Figure 3The motor speed control module 3 is a discrete circuit, including transistors Q1 and Q2. When the base of transistor Q2 receives a high level, Q2 is in the conducting state, grounding the base of transistor Q1 and thus turning Q1 off. This results in a high-voltage output for the speed control signal, which, after passing through a second-order filter circuit, outputs a stable voltage value. When the base of transistor Q2 receives a low level, Q2 is in the off state, grounding the base of transistor Q1 and turning Q1 on. This results in a low-voltage output for the speed control signal, which, after passing through a second-order filter circuit, outputs a stable voltage value. The DC motor 4 receives this voltage value and can then adjust its speed.

[0032] In one embodiment, the motor speed control module 3 further includes capacitors C6, C7, and C8, and resistors R10, R11, R12, R13, R14, R15, R16, R17, and R18.

[0033] Specifically: The base of transistor Q2 is coupled to the PWM signal output pin (HS_PWM) of the chip in MCU module 1 through resistor R16. The base of transistor Q2 is also connected to one end of resistor R18, and the other end of resistor R18 is connected to GND. One end of capacitor C8 is connected to HS_PWM, and the other end is connected to GND. Capacitor C8 is the filter capacitor for the base of transistor Q2, resistor R16 is the current limiting resistor, and resistor R18 is the base bias resistor for transistor Q2. Resistor R18 and capacitor C8 together filter and stabilize the HS_PWM signal. The collector of transistor Q2 is coupled to the sixth, seventh, and eighth pins of the high-side driver chip U1 through resistor R10, and is coupled to the base of transistor Q1 through resistor R15. The emitter of transistor Q2 is connected to GND.

[0034] The base of transistor Q1 is connected to one end of resistor R17, and the other end of resistor R17 is connected to GND. Resistor R17 is the base bias resistor of transistor Q1. The collector of transistor Q1 is coupled to the sixth, seventh, and eighth pins of the high-side driver chip U1 through parallel resistors R11 and R12. At the same time, the collector of transistor Q1 also outputs the motor speed control signal (HS OUT_PWM) through series resistors R13 and R14. One end of capacitor C6 is connected to the node between resistors R13 and R14, and the other end is connected to GND. One end of capacitor C7 is connected to the node between resistor R14 and the HS_OUT_PWM signal, and the other end is connected to GND. Resistor R13 and capacitor C6 form a first-order filter circuit, and resistor R14 and capacitor C7 form a second-order filter capacitor, converting the motor speed control signal into a stable output voltage. The emitter of transistor Q1 is grounded.

[0035] It should be noted that resistor R10 can be a 10K resistor, resistor R11 can be a 2K resistor, resistor R12 can be a 2K resistor, resistor R13 can be a 20K resistor, resistor R14 can be a 20K resistor, resistor R15 can be a 4.7K resistor, resistor R16 can be a 10K resistor, resistor R17 can be a 10K resistor, and resistor R18 can be a 47K resistor; capacitor C6 can be a 10nF / 50V capacitor, capacitor C7 can be a 10nF / 50V capacitor, and capacitor C8 can be a 10nF / 50V capacitor.

[0036] When MCU module 1 receives the instruction to speed control DC motor 4, MCU module 1 sends a PWM signal with a frequency of 20KHz and a duty cycle range of 0 to 100% to motor speed control module 3, and motor speed control module 3 can output a stable voltage of 0 to 12V.

[0037] The relevant data obtained after circuit testing are shown in Table 1: Table 1 Duty Cycle and Voltage

[0038] Based on the data in Table 1, the linear formula between the output speed control signal voltage of motor speed control module 3 and the PWM signal given by the MCU is as follows:

[0039] in, This indicates the output speed control signal voltage (V). This indicates the duty cycle percentage (%) of the PWM signal provided by the MCU, with a PWM signal frequency of 20kHz. Therefore, the higher the duty cycle of the PWM signal output by MCU module 1, the higher the voltage value converted by motor speed control module 3, and the higher the corresponding speed control rate of DC motor 4.

[0040] The specific working process of this utility model is illustrated in the following example: When MCU module 1 receives a command from DC motor 4 to adjust its rotation speed to 20%, MCU module 1 sends a high-level command to the fourth pin of the high-side driver chip U1. Upon receiving the channel control enable signal, the high-side driver chip U1 controls the channel to open and output. MCU module 1 then sends a PWM signal with a frequency of 20kHz and a duty cycle of 85% to motor speed control module 3. Based on the formula between the output speed control signal voltage of motor speed control module 3 and the PWM signal given by MCU module 1, motor speed control module 3 outputs a stable voltage of 10.14V to DC motor 4. After receiving the stable voltage of 10.14V from the speed control module, DC motor 4 adjusts its rotation speed to 85%.

[0041] Detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely examples of the present invention, which can be implemented in various forms. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as the basis of the claims and as a representative basis for teaching those skilled in the art to employ the present invention differently with any suitable detailed structure contemplated. In particular, features presented and described in the individual dependent claims may be applied in combination, and any advantageous combinations of these claims are disclosed herein.

[0042] Furthermore, it is anticipated that structural elements can be generated by applying three-dimensional (3D) printing technology. Therefore, any reference to structural elements is intended to cover any computer-executable instructions that instruct a computer to generate such a structural element using 3D printing technology or similar computer-controlled manufacturing techniques. Additionally, any such reference to structural elements is also intended to cover computer-readable media carrying such computer-executable instructions.

[0043] Furthermore, the terms and phrases used herein are not intended to be restrictive, but rather to provide an understandable description of the present invention. As used herein, the term “a” or “an” is defined as one or more. As used herein, the term “multiple” is defined as two or more. As used herein, the term “another” is defined as at least a second or more. As used herein, the terms “comprising” and / or “having” are defined as including (i.e., open-ended language). As used herein, the term “connection” is defined as a link, although not necessarily a direct link.

[0044] The present invention, as thus described, can obviously be modified in many ways. These modifications should not be considered as a departure from the spirit and scope of the present invention, and all such modifications, which are obvious to those skilled in the art, are intended to be included within the scope of the appended claims.

[0045] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined by the scope of the claims.

Claims

1. A control circuit for regulating the speed of a direct current motor, characterized by, Includes MCU module (1); One of the two interfaces of the MCU module (1) is connected to the DC motor (4) through the high-side output module (2) for power supply, and the other is connected to the DC motor (4) through the motor speed control module (3); The motor speed control module (3) outputs a speed control signal to the DC motor (4).

2. The control circuit for regulating the speed of a DC motor as defined in claim 1, wherein, The high-side output module (2) also supplies power to the motor speed control module (3).

3. The control circuit for regulating the rotational speed of a DC motor according to claim 1 or 2, wherein, The speed control signal is a stable voltage value.

4. The control circuit for regulating the speed of a DC motor as defined in claim 3, wherein, The output speed control signal voltage of the motor speed control module (3) is calculated according to the PWM duty cycle signal given by the MCU module (1) using the following formula: wherein, represents the output speed regulation signal voltage, represents the duty cycle percentage of the PWM signal given by the MCU, the PWM signal frequency being 20 KHz.

5. The control circuit for adjustable DC motor speed according to claim 3, characterized in that, The motor speed control module (3) is a separate circuit.

6. The control circuit for adjustable DC motor speed according to claim 5, characterized in that, The motor speed control module (3) uses transistors Q1 and Q2 to form a separate circuit. When the base of transistor Q2 is connected to a high level, it is turned on, and the base of transistor Q1 is grounded and turned off. The speed control signal outputs a high voltage or a low voltage and is stably output after second-order filtering. When the base of transistor Q2 is connected to a low level, it is turned off, and the base of transistor Q1 is connected to a high level and is turned on. The speed control signal outputs a low voltage and is stably output after second-order filtering.

7. The control circuit for adjustable DC motor speed according to claim 6, characterized in that, The high-side output module (2) includes a high-side driver chip U1, and transistors Q1 and Q2 are both connected to the high-side driver chip U1.

Images