A DC brushed motor driver

Abstract

The present invention discloses a DC brushed motor driver, comprising: a P-type MOS tube, an N-type MOS tube, a P-type MOS tube control circuit, an N-type MOS tube control circuit, a forward / reverse control circuit, a PWM control circuit, a protection circuit, a power supply interface, a motor interface, and a control interface. In order to reduce the current when the motor starts, an NTC thermistor is also provided, which can effectively extend the life of the motor commutation carbon brush. The present invention can support PWM with a frequency of more than 18kHz, can effectively reduce motor noise, and can support PWM with a duty cycle of 100%. The control circuit of the MOS tube of the present invention adopts simple and reliable triodes, resistors, diodes and capacitors, which is not only low in cost but also highly reliable, and is suitable for large-scale promotion and use.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a direct current brushed motor driver. Background Art

[0002] DC motors are widely used in daily life and industrial fields. DC motors can be divided into brushed motors and brushless motors according to different commutation methods. The commutation of brushless motors is achieved through electronic control. It has the advantages of high reliability, no commutation sparks, and low mechanical noise, but the control circuit is complex and the cost is high. It is generally used in occasions with higher requirements. The commutation of brushed motors is achieved through carbon brushes. It has the advantages of fast starting, timely braking, smooth speed regulation over a wide range, relatively simple control circuit, and low cost, but the disadvantages of brushed motors are also obvious. Its main disadvantages are high rotation noise, large starting current, and short carbon brush life. Most of the existing DC brushed motor drivers can meet the motor speed regulation and forward and reverse control, but there are few drivers that are both low-cost and can well solve the problems of high rotation noise and short carbon brush life of DC brushed motors. Summary of the invention

[0003] The purpose of the present invention is to solve the deficiencies of the prior art and provide a DC brush motor driver. The present invention can solve the disadvantage of large starting current of DC brush motor by adding NTC thermistor in the motor driver circuit, thereby extending the life of motor commutation carbon brush. The present invention can support PWM with frequency above 18kHz, can effectively reduce motor noise, and can support PWM with 100% duty cycle. The control circuit of the MOS tube of the present invention adopts simple and reliable triode, resistor, diode and capacitor, which is not only low in cost but also high in reliability, and is suitable for large-scale promotion and use.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A direct current brushed motor driver comprises: a P-type MOS tube, an N-type MOS tube, a P-type MOS tube control circuit, an N-type MOS tube control circuit, a forward / reverse control circuit, a PWM control circuit, a protection circuit, a power supply interface, a motor interface, and a control interface. The P-type MOS tube control circuit is mainly composed of a PNP triode, a resistor and a voltage-stabilizing diode, the N-type MOS tube control circuit is mainly composed of an NPN triode, a resistor and a voltage-stabilizing diode, the forward / reverse control circuit is mainly composed of a resistor, a Schottky diode and a capacitor, the PWM control circuit is mainly composed of a PNP triode, a resistor and a capacitor, the protection circuit is mainly composed of a fuse, a Schottky diode, a TVS diode and a capacitor, two groups of circuits mainly connected by the P-type MOS tube and the N-type MOS tube form an H-bridge circuit, the motor interface is connected to the middle of the upper and lower arms of the H-bridge circuit, and the control interface is connected to the forward / reverse control circuit and the PWM control circuit.

[0006] As a further solution of the present invention: an NTC thermistor is also provided, and the NTC thermistor is connected in series between the P-type MOS tube and the N-type MOS tube. The NTC thermistor is a resistor whose resistance value can decrease as the temperature rises. The resistance value of the thermistor at room temperature is generally 5-10 ohms. At the moment of motor starting, the motor coil resistance is low and there is no reverse electromotive force, so the current is often very large. When the NTC thermistor is connected in series in the circuit, the current at the moment of motor starting can be effectively reduced. After the motor starts, the temperature of the NTC thermistor will increase over time, and the resistance value can be reduced to a very low level, which will hardly affect the normal operation of the motor.

[0007] As a further solution of the present invention: the motor interface is provided with a forward / reverse LED indicator light circuit.

[0008] As a further solution of the present invention: the Schottky diode can be replaced by a fast recovery diode, an ultrafast recovery diode or a rectifier diode.

[0009] As a further solution of the present invention: the fuse of the protection circuit is a PTC resettable fuse.

[0010] As a further solution of the present invention: the fuse of the protection circuit is a fast-acting fuse.

[0011] As a further solution of the present invention: the forward / reverse control circuit and the PWM control circuit are provided with an optical coupling isolation circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematic diagram of the left half of the H-bridge circuit according to an embodiment of the present invention.

[0013] Figure 2 It is a schematic diagram of a forward / reverse control circuit according to an embodiment of the present invention.

[0014] Figure 3 It is a schematic diagram of a PWM control circuit according to an embodiment of the present invention.

[0015] Figure 4 It is a schematic diagram of a power supply and a protection circuit according to an embodiment of the present invention.

[0016] Figure 5 The diagram is a schematic diagram of a forward / reverse LED indicator light circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 making creative work are within the scope of protection of the present invention.

[0018] It should be understood by those skilled in the art that unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0019] The present invention provides a DC brushed motor driver, including: a P-type MOS tube, an N-type MOS tube, a P-type MOS tube control circuit, an N-type MOS tube control circuit, a forward / reverse control circuit, a PWM control circuit, a protection circuit, a power supply interface, a motor interface, and a control interface. The P-type MOS tube control circuit is mainly composed of a PNP triode, a resistor, and a voltage-stabilizing diode. The N-type MOS tube control circuit is mainly composed of an NPN triode, a resistor, and a voltage-stabilizing diode. The forward / reverse control circuit is mainly composed of a resistor, a Schottky diode, and a capacitor. The PWM control circuit is mainly composed of a PNP triode, a resistor, and a capacitor. The protection circuit is mainly composed of a fuse, a Schottky diode, a TVS diode, and a capacitor. Two groups of circuits mainly connected by P-type MOS tubes and N-type MOS tubes form an H-bridge circuit. The motor interface is connected to the middle of the upper and lower arms of the H-bridge circuit. The control interface is connected to the forward / reverse control circuit and the PWM control circuit. Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown. T1 is a P-type MOS tube, T2 is an N-type MOS tube, D1, D2 and D6 are voltage-stabilizing diodes, D4, D5 and D8 are Schottky diodes, D7 is a TVS diode, Q1, Q2 and Q5 are PNP transistors, Q3 and Q4 are NPN transistors, R2-R14 are metal film resistors, C1, C2 and C3 are ceramic capacitors, and C4 is an electrolytic capacitor. Figure 1 It is the left half of the H-bridge circuit. The right half of the H-bridge circuit is mirror-symmetrical to the left half, so the right half of the H-bridge circuit is omitted in the drawings of the specification.

[0020] As a preferred solution of the present invention: an NTC thermistor is further provided, and the NTC thermistor is connected in series between the P-type MOS tube and the N-type MOS tube. Figure 1 Resistor R1 is an NTC thermistor.

[0021] As a preferred solution of the present invention: the motor interface is provided with a forward / reverse LED indicator circuit. Figure 5 As shown, D9 and D10 are LED lights.

[0022] As a preferred solution of the present invention: the fuse of the protection circuit is a PTC resettable fuse. Figure 4 Fuse F1 is a PTC resettable fuse.

[0023] The control interface of the embodiment of the present invention has three ports, namely, a PWM signal port, a forward signal port, and a reverse signal port. When the motor is to rotate forward, just ground both the forward signal port and the PWM signal port. When the motor is to rotate reversely, just ground both the reverse signal port and the PWM signal port. If the motor speed is to be controlled, it can be achieved by controlling the duty cycle of the PWM signal port. The greater the proportion of low level of the PWM signal port, the faster the motor speed. If the motor is to be in a braking state, it can be achieved by grounding both the forward signal port and the reverse signal port to a low level.

[0024] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications, combinations or variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A brushed DC motor driver, characterized in that: include: P-type MOS tube, N-type MOS tube, P-type MOS tube control circuit, N-type MOS tube control circuit, forward / reverse control circuit, PWM control circuit, protection circuit, power interface, motor interface, control interface, the P-type MOS tube control circuit is mainly composed of PNP transistor, resistor and voltage-stabilizing diode, the N-type MOS tube control circuit is mainly composed of NPN transistor, resistor and voltage-stabilizing diode, the forward / reverse control circuit is mainly composed of resistor, Schottky diode and capacitor, the PWM control circuit is mainly composed of PNP transistor, resistor and capacitor, the protection circuit is mainly composed of fuse, Schottky diode, TVS diode and capacitor, two groups of circuits mainly connected by P-type MOS tube and N-type MOS tube form an H-bridge circuit, the motor interface is connected to the middle of the upper and lower arms of the H-bridge circuit, and the control interface is connected to the forward / reverse control circuit and the PWM control circuit; The protection circuit includes a Schottky diode D8, a fuse F1, a capacitor C3, a capacitor C4 and a TVS diode D7, wherein the anode of the Schottky diode D8 is connected to the power interface, the cathode of the Schottky diode D8 is connected to one end of the fuse F1, the other end of the fuse F1 is respectively connected to one end of the capacitor C4, one end of the capacitor C3 and the cathode of the TVS diode D7, and the other end of the power interface is respectively connected to the other end of the capacitor C4, the other end of the capacitor C3, the anode of the TVS diode D7 and the ground; The P-type MOS tube control circuit includes PNP transistors Q1 and Q2, resistors R2, R3, R4, R5 and a voltage regulator diode D1. The base of the PNP transistor Q2 is respectively connected to the forward / reverse control circuit and one end of the resistor R5, the emitter of the PNP transistor Q2 is respectively connected to the other end of the resistor R5 and the emitter of the PNP transistor Q1, the collector of the PNP transistor Q2 is respectively connected to one end of the resistor R4 and the base of the PNP transistor Q1, the emitter of the PNP transistor Q1 is also connected to one end of the resistor R2, the cathode of the voltage regulator diode D1 and the source of the P-type MOS tube, the collector of the PNP transistor Q1 is respectively connected to the other end of the resistor R2, one end of the resistor R3, the anode of the voltage regulator diode D1 and the gate of the P-type MOS tube, the other end of the resistor R3 is respectively connected to the other end of the resistor R4 and to ground, and the drain of the P-type MOS tube is connected to the motor interface; The N-type MOS transistor control circuit includes NPN transistors Q3 and Q4, resistors R1, R6, R7, R8, R9 and a voltage regulator diode D2. The base of the NPN transistor Q4 is respectively connected to the forward / reverse control circuit and one end of the resistor R9, the emitter of the NPN transistor Q4 is respectively connected to the other end of the resistor R9 and the emitter of the NPN transistor Q3, the collector of the NPN transistor Q4 is respectively connected to one end of the resistor R8 and the base of the NPN transistor Q3, the emitter of the NPN transistor Q3 is also connected to one end of the resistor R7, the anode of the voltage regulator diode D2 and the source of the N-type MOS transistor, the collector of the NPN transistor Q3 is respectively connected to the other end of the resistor R7, one end of the resistor R6, the cathode of the voltage regulator diode D2 and the gate of the N-type MOS transistor, the other end of the resistor R6 is respectively connected to the other end of the resistor R8 and ground, the drain of the N-type MOS transistor is connected to one end of the resistor R1, and the other end of the resistor R1 is connected to the motor interface; The forward / reverse control circuit includes a capacitor C1, resistors R10 and R11, a voltage stabilizing diode D3, and Schottky diodes D4 and D5. One end of the capacitor C1 is grounded, and the other end of the capacitor C1 is respectively connected to one end of the resistor R10 and the cathode of the Schottky diode D5. The other end of the resistor R10 is connected to the anode of the voltage stabilizing diode D3, and the cathode of the voltage stabilizing diode D3 is connected to the P-type MOS tube control circuit. One end of the resistor R11 is connected to the PWM control circuit, and the other end of the resistor R11 is respectively connected to the anodes of the Schottky diodes D4 and D5. The cathode of the Schottky diode D4 is connected to the N-type MOS tube control circuit, and the cathode of the Schottky diode D5 is connected to the forward / reverse signal control interface. The PWM control circuit includes a capacitor C2, resistors R12 and R13, a voltage-stabilizing diode D6 and a PNP transistor Q5. One end of the capacitor C2 is grounded, and the other end of the capacitor C2 is respectively connected to the PWM signal control interface and one end of the resistor R12. The other end of the resistor R12 is connected to the anode of the voltage-stabilizing diode D6. The cathode of the voltage-stabilizing diode D6 is respectively connected to one end of the resistor R13 and the base of the PNP transistor Q5. The emitter of the PNP transistor Q5 is connected to the other end of the resistor R13 and is grounded. The collector of the PNP transistor Q5 is connected to the forward and reverse circuit.

2. The DC brushed motor driver according to claim 1, characterized in that: An NTC thermistor is also provided, and the NTC thermistor is connected in series between the P-type MOS tube and the N-type MOS tube.

3. The DC brushed motor driver according to claim 1 or 2, characterized in that: The motor interface is provided with a forward / reverse LED indicator light circuit.

4. The DC brush motor driver according to claim 1 or 2, characterized in that: The Schottky diode can be replaced by a fast recovery diode, an ultrafast recovery diode or a rectifier diode.

5. The DC brush motor driver according to claim 1 or 2, characterized in that: The fuse of the protection circuit is a PTC resettable fuse.

6. The DC brush motor driver according to claim 1 or 2, characterized in that: The fuse of the protection circuit is a fast-acting fuse.

7. The DC brushed motor driver according to claim 1 or 2, characterized in that: The forward / reverse control circuit and the PWM control circuit are provided with an optical coupling isolation circuit.

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