A three-wire controlled motor drive circuit

Abstract

This utility model relates to the field of motor drive circuits, specifically to a three-wire controlled motor drive circuit, including a power supply module, a control module, a detection module, a voltage sampling module, a current sampling module, and interfaces K+, M+, and M-. The output terminal of the control module and the input terminal of the detection module are electrically connected to interface K+. A toggle switch is connected between interface K+ and interface M+. The input terminal of the voltage sampling module is electrically connected to interface M+, and interface M- is electrically connected to the input terminal of the current sampling module. A toggle switch is connected in series between interface K+ and interface M+. When the toggle switch is turned on, interface K+ and interface M+ are short-circuited, controlling the motor to work. When the toggle switch is turned off, interface K+ and interface M+ are disconnected, controlling the motor not to work. The other wire of the toggle switch is shared with interface M+, forming a three-wire control circuit, effectively reducing the complexity of the wiring sequence and improving the stability of constant voltage control.

Description

Technical Field

[0001] This utility model relates to the field of motor drive circuits, specifically to a three-wire controlled motor drive circuit. Background Technology

[0002] The motor drive circuit is a crucial link connecting the control signal and the motor body. Its core function is to convert the low-power electrical signal output by the microcontroller into a high-power current sufficient to drive the motor, while simultaneously realizing control functions such as speed regulation, commutation, and braking. The DC motor drive circuit mainly consists of power switching devices (such as MOSFETs or IGBTs), protection circuits (such as freewheeling diodes and overcurrent detection), and logic control. The power switches use PWM (Pulse Width Modulation) technology to adjust the duty cycle to control the motor voltage, thereby achieving speed regulation. The H-bridge circuit is the core structure for the forward and reverse rotation control of the DC motor. It changes the current direction by alternating the conduction of four switching transistors, and uses dead time control to prevent short circuits between the upper and lower transistors.

[0003] In practical applications of motors, at least four wires are required for control connections and external switch connections. A messy wiring sequence leads to cumbersome control and affects the stability of constant voltage control of the motor. Utility Model Content

[0004] The purpose of this invention is to provide a three-wire controlled motor drive circuit, which aims to improve the problem that in practical applications of motors, at least four wires are required for motor control and external switch connections, resulting in messy wiring sequences, cumbersome control, and instability of constant voltage control of the motor.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A three-wire controlled motor drive circuit includes a power supply module, a control module, a detection module, a voltage sampling module, a current sampling module, a magnetic energy release module, and interfaces K+, M+, and M-.

[0007] The positive terminal of the power supply module is electrically connected to the power input terminal of the control module, and the output terminal of the control module and the input terminal of the detection module are electrically connected to interface K+; a toggle switch is connected between interface K+ and interface M+; interface M+ and interface M- are electrically connected to the positive and negative terminals of the motor, respectively, and the magnetic energy release module is electrically connected between interface M+ and interface M-; the input terminal of the voltage sampling module is electrically connected to interface M+, and interface M- is electrically connected to the input terminal of the current sampling module and the negative terminal of the power supply module;

[0008] The control terminal MOTO of the control module is electrically connected to the control output terminal of the external MCU, the detection terminal KEY of the detection module is electrically connected to the detection input terminal of the external MCU, and the output terminal V-MOTO of the voltage sampling module and the output terminal I-MOTO of the current sampling module are electrically connected to the first sampling port and the second sampling port of the external MCU, respectively.

[0009] Furthermore, the control module includes a MOSFET Q2, resistors R11, R12, and R14;

[0010] The positive terminal of the power supply module is electrically connected to the source of MOSFET Q2, one end of resistor R11, and one end of resistor R12. The drain of MOSFET Q2 and the other end of resistor R11 are both electrically connected to interface K+. The gate of MOSFET Q2 is electrically connected to the other end of resistor R12 and one end of resistor R14. The other end of resistor R14 serves as the control terminal MOTO and is electrically connected to the control output terminal of the external MCU.

[0011] Furthermore, the resistance value of the resistor R11 is greater than the internal resistance of the motor.

[0012] Furthermore, the detection module includes a resistor R15, one end of which is electrically connected to interface K+, and the other end of which serves as the detection terminal KEY and is electrically connected to the detection input terminal of an external MCU.

[0013] Furthermore, the voltage sampling module includes resistors R21, R22, and R23, and capacitor C13;

[0014] One end of resistor R21 is electrically connected to interface M+, the other end of resistor R21 is electrically connected to one end of resistor R23 and one end of resistor R22, the other end of resistor R22 is electrically connected to one end of capacitor C13, and serves as the output terminal V-MOTO, which is electrically connected to the first sampling port of the external MCU.

[0015] The other end of resistor R23 and the other end of capacitor C13 are both grounded.

[0016] Furthermore, the magnetic energy release module includes a diode D2 and a capacitor C8;

[0017] The negative terminal of diode D2 and one end of capacitor C8 are both electrically connected to interface M+, and the positive terminal of diode D2 and the other end of capacitor C8 are both electrically connected to interface M-.

[0018] Furthermore, the current sampling module includes a resistor R19 and a capacitor C12;

[0019] One end of the resistor R19 is electrically connected to the interface M-, and the other end of the resistor R19 is electrically connected to one end of the capacitor C12, and serves as the output terminal I-MOTO, which is electrically connected to the second sampling port of the external MCU.

[0020] The other end of the capacitor C12 is grounded.

[0021] Furthermore, the power supply module includes an interface BAT and a resistor R20;

[0022] Pin 1 of the interface BAT is electrically connected to the negative terminal of the external power supply battery, pin 2 of the interface BAT is electrically connected to the positive terminal of the external power supply battery, and pin 2 of the interface BAT is electrically connected to the power input terminal of the control module; the interface M- is electrically connected to one end of the resistor R20, and the other end of the resistor R20 is electrically connected to pin 1 of the interface BAT.

[0023] By adopting the above technical solution, this utility model has the following advantages compared with the prior art:

[0024] 1. The control module controls the power supply module to supply or de-energize the motor. The detection module is set at the front end of interface K+ to monitor the action of the toggle switch and identify the motor's start-up action. The voltage sampling module and the current sampling module are connected to interface M+ and interface M- respectively to sample the motor's operating current and operating voltage, identify the motor's shutdown action, and accurately obtain the motor's operating status.

[0025] 2. A toggle switch is connected in series between interface K+ and interface M+. When the toggle switch is turned up, interface K+ and interface M+ are short-circuited, controlling the motor to work; when the toggle switch is turned down, interface K+ and interface M+ are disconnected, controlling the motor not to work; the other wire of the toggle switch is shared with interface M+, forming a three-wire control circuit, which effectively reduces the complexity of the wiring sequence and improves the stability of constant voltage control. Attached Figure Description

[0026] Figure 1 This is a circuit diagram of the three-wire controlled motor drive circuit described in this utility model; Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0028] Additionally, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are all based on the orientation or positional relationship shown in the accompanying drawings. They are merely for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element of this utility model must have a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0029] When an element is referred to as being "fixed to," "set on," or "contained on" another element, it can be directly on or indirectly on that other element. When an element is referred to as being "connected to," it can be directly connected to or indirectly connected to that other element.

[0030] Unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0031] Example

[0032] Please refer to Figure 1 As shown, this embodiment provides a three-wire controlled motor drive circuit, including a power supply module, a control module, a detection module, a voltage sampling module, a current sampling module, a magnetic energy release module, and interfaces K+, M+, and M-.

[0033] The positive terminal of the power supply module is electrically connected to the power input terminal of the control module, and the output terminal of the control module and the input terminal of the detection module are electrically connected to interface K+. A toggle switch (not shown in the attached diagram) is connected between interface K+ and interface M+; interfaces M+ and M- are electrically connected to the positive and negative terminals of the motor, respectively. The magnetic energy release module is electrically connected between interface M+ and interface M-; the input terminal of the voltage sampling module is electrically connected to interface M+; interface M- is electrically connected to the input terminal of the current sampling module and the negative terminal of the power supply module. The control terminal MOTO of the control module is electrically connected to the control output terminal of the external MCU; the detection terminal KEY of the detection module is electrically connected to the detection input terminal of the external MCU; the output terminal V-MOTO of the voltage sampling module and the output terminal I-MOTO of the current sampling module are electrically connected to the first and second sampling ports of the external MCU, respectively.

[0034] The control module controls the power supply module to supply or de-energize the motor. The detection module is located at the front end of interface K+ to monitor the operation of the toggle switch and identify the motor's start-up action. The voltage sampling module and the current sampling module are connected to interfaces M+ and M- respectively to sample the motor's operating current and voltage and identify the motor's shutdown action, accurately obtaining the motor's operating status. A toggle switch is connected in series between interfaces K+ and M+. When the toggle switch is turned on, interfaces K+ and M+ are short-circuited, controlling the motor to work. When the toggle switch is turned off, interfaces K+ and M+ are disconnected, controlling the motor to stop working. The other wire of the toggle switch is shared with interface M+, forming a three-wire control circuit, effectively reducing the complexity of the wiring sequence and improving the stability of constant voltage control.

[0035] The power supply module includes an interface BAT and a resistor R20. Pin 1 of the interface BAT is electrically connected to the negative terminal of the external power supply battery, and pin 2 of the interface BAT is electrically connected to the positive terminal of the external power supply battery. Pin 2 of the interface BAT is electrically connected to the power input terminal of the control module. The interface M- is electrically connected to one end of the resistor R20, and the other end of the resistor R20 is electrically connected to pin 1 of the interface BAT. The power supply battery supplies power to the motor through the interface BAT. Pin 2 of the interface BAT is also electrically connected to the external power output terminal B+, realizing multiple power supply methods and improving the practicality of the control circuit.

[0036] Specifically, the control module includes a MOSFET Q2, resistors R11, R12, and R14. The positive terminal of the power supply module is electrically connected to the source of MOSFET Q2, one end of resistor R11, and one end of resistor R12; that is, pin 2 of interface BAT is electrically connected to the source of MOSFET Q2, one end of resistor R11, and one end of resistor R12. The drain of MOSFET Q2 and the other end of resistor R11 are both electrically connected to interface K+. The gate of MOSFET Q2 is electrically connected to the other end of resistor R12 and one end of resistor R14. The other end of resistor R14 serves as the control terminal MOTO and is electrically connected to the control output terminal of the external MCU. In this embodiment, the resistance of resistor R11 is greater than the internal resistance of the motor. Resistor R12 is a pull-up resistor, which effectively pulls the control output terminal of the external MCU high when it is initially powered on, preventing MOSFET Q2 from conducting and causing false starts of the motor.

[0037] Specifically, the detection module includes resistor R15. One end of resistor R15 is electrically connected to interface K+, and the other end of resistor R15 serves as the detection terminal KEY, which is electrically connected to the detection input terminal of the external MCU. When MOSFET Q2 is turned off, resistor R11 provides a stable high level to the detection terminal KEY.

[0038] Specifically, the voltage sampling module includes resistors R21, R22, and R23, and capacitor C13. One end of resistor R21 is electrically connected to interface M+, and the other end of resistor R21 is electrically connected to one end of resistor R23 and one end of resistor R22. The other end of resistor R22 is electrically connected to one end of capacitor C13, and serves as the output terminal V-MOTO, electrically connected to the first sampling port of the external MCU. The other ends of resistor R23 and capacitor C13 are both grounded. Resistor R22 and capacitor C13 form an RC filter to filter the voltage signal, ensuring a more stable voltage signal received by the external MCU. Resistor R21 and resistor R23 divide the motor's operating voltage, ensuring that the voltage signal is lower than the internal detection voltage of the external MCU, thus protecting the external MCU.

[0039] Specifically, the magnetic energy release module includes diode D2 and capacitor C8. The negative terminal of diode D2 and one end of capacitor C8 are both electrically connected to interface M+, while the positive terminal of diode D2 and the other end of capacitor C8 are both electrically connected to interface M-. When the power supply module stops supplying power to the motor, the motor's own magnetic energy is converted into heat energy by diode D2 for discharge, and capacitor C8 absorbs the reverse voltage pulse when the motor is turned off, protecting the circuit components.

[0040] Specifically, the current sampling module includes resistor R19 and capacitor C12. One end of resistor R19 is electrically connected to interface M-, and the other end of resistor R19 is electrically connected to one end of capacitor C12, serving as the output terminal I-MOTO, which is electrically connected to the second sampling port of the external MCU; the other end of capacitor C12 is grounded. Resistor R19 and capacitor C12 form a filter RC to filter the current signal, ensuring a more stable current signal received by the external MCU.

[0041] When the power is off, the control module's MOTO terminal receives a high level, and MOSFET Q2 is turned off. When the toggle switch connects to interfaces K+ and M+, the voltage at interface K+ is divided by resistor R11, the motor's internal resistance, and resistor R20. Because the motor's internal resistance is low, the voltage at interface K+ is pulled low. At this time, the detection module's KEY terminal detects a low level and determines that the toggle switch is closed.

[0042] An external MCU outputs a PWM signal to the control module's MOTO terminal, turning on MOSFET Q2 and causing the voltage across the motor to rise rapidly. The voltage across the motor is sampled via the output V-MOTO of the voltage sampling module. When the motor voltage is greater than the set value, the PWM duty cycle is reduced; when the motor voltage is less than the set value, the PWM duty cycle is increased until the voltage across the motor equals the set value, thus achieving constant voltage control.

[0043] Because the voltage at the detection terminal KEY of the detection module remains consistent with the motor voltage after the toggle switch is connected, it is in a fluctuating state, making it impossible to accurately identify the toggle switch's off state. In this embodiment, the voltage across the motor is detected by the output terminal V-MOTO of the voltage sampling module, and the current is detected by the output terminal I-MOTO of the current sampling module. When the voltage across the motor is less than 2.0V and the current across the motor is less than 100mA, the toggle switch is considered to be open, thus achieving accurate judgment of the disconnection action.

[0044] When the motor experiences abnormal operating conditions such as stalling, the current across the motor is sampled in real time via the I-MOTO output of the current sampling module. When the current exceeds a set value, the external MCU uses the MOTO control terminal of the control module to turn off the MOSFET Q2. At this time, because the resistance of resistor R11 is greater than the internal resistance of the motor, the power supply module cannot continuously supply power to the motor. The motor dissipates its magnetic energy as heat through diode D2, causing the KEY port of the detection module to be pulled low, preventing the toggle switch from being detected. Only when a high level is detected followed by a low level is the toggle switch considered to have been activated, thus protecting the motor.

[0045] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A three-wire controlled motor drive circuit, characterized by It includes a power supply module, a control module, a detection module, a voltage sampling module, a current sampling module, a magnetic energy release module, and interfaces K+, M+, and M-. The positive terminal of the power supply module is electrically connected to the power input terminal of the control module, and the output terminal of the control module and the input terminal of the detection module are electrically connected to interface K+; a toggle switch is connected between interface K+ and interface M+; interface M+ and interface M- are electrically connected to the positive and negative terminals of the motor, respectively, and the magnetic energy release module is electrically connected between interface M+ and interface M-; the input terminal of the voltage sampling module is electrically connected to interface M+, and interface M- is electrically connected to the input terminal of the current sampling module and the negative terminal of the power supply module; The control terminal MOTO of the control module is electrically connected to the control output terminal of the external MCU, the detection terminal KEY of the detection module is electrically connected to the detection input terminal of the external MCU, and the output terminal V-MOTO of the voltage sampling module and the output terminal I-MOTO of the current sampling module are electrically connected to the first sampling port and the second sampling port of the external MCU, respectively.

2. The three-wire controlled motor drive circuit of claim 1, wherein: The control module includes a MOSFET Q2, resistors R11, R12, and R14; The positive terminal of the power supply module is electrically connected to the source of MOSFET Q2, one end of resistor R11, and one end of resistor R12. The drain of MOSFET Q2 and the other end of resistor R11 are both electrically connected to interface K+. The gate of MOSFET Q2 is electrically connected to the other end of resistor R12 and one end of resistor R14. The other end of resistor R14 serves as the control terminal MOTO and is electrically connected to the control output terminal of the external MCU.

3. A three-wire controlled motor drive circuit according to claim 2, characterized in that: The resistance value of the resistor R11 is greater than the internal resistance of the motor.

4. The three-wire controlled motor drive circuit of claim 1, wherein: The detection module includes a resistor R15. One end of the resistor R15 is electrically connected to the interface K+, and the other end of the resistor R15 is electrically connected to the detection input terminal of an external MCU as the detection terminal KEY.

5. The three-wire controlled motor drive circuit of claim 1, wherein: The voltage sampling module includes resistors R21, R22, and R23, and capacitor C13; One end of resistor R21 is electrically connected to interface M+, the other end of resistor R21 is electrically connected to one end of resistor R23 and one end of resistor R22, the other end of resistor R22 is electrically connected to one end of capacitor C13, and serves as the output terminal V-MOTO, which is electrically connected to the first sampling port of the external MCU. The other end of resistor R23 and the other end of capacitor C13 are both grounded.

6. The three-wire controlled motor drive circuit of claim 1, wherein: The magnetic energy release module includes a diode D2 and a capacitor C8; The negative terminal of diode D2 and one end of capacitor C8 are both electrically connected to interface M+, and the positive terminal of diode D2 and the other end of capacitor C8 are both electrically connected to interface M-.

7. The three-wire controlled motor drive circuit of claim 1, wherein: The current sampling module includes a resistor R19 and a capacitor C12; One end of the resistor R19 is electrically connected to the interface M-, and the other end of the resistor R19 is electrically connected to one end of the capacitor C12, and serves as the output terminal I-MOTO, which is electrically connected to the second sampling port of the external MCU. The other end of the capacitor C12 is grounded.

8. The three-wire controlled motor drive circuit of claim 1, wherein: The power supply module comprises an interface BAT and a resistor R20; A pin 1 of the interface BAT is electrically connected with a negative electrode of an external power supply battery, a pin 2 of the interface BAT is electrically connected with a positive electrode of the external power supply battery, and the pin 2 of the interface BAT is electrically connected with a power input end of the control module; one end of the resistor R20 is electrically connected with the interface M-, and the other end of the resistor R20 is electrically connected with the pin 1 of the interface BAT.

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