Brush motor control circuit and control method

Abstract

The invention relates to the field of motor control, in particular to a brush motor control circuit and a control method. The circuit comprises a first single-pole double-throw relay, a second single-pole double-throw relay, a third single-pole double-throw relay and a fourth single-pole double-throw relay, wherein a movable contact of the first single-pole double-throw relay is connected to a first electric brush of a brush motor; a normally open contact of the first single-pole double-throw relay is connected to an anode of a direct-current power supply; a normally closed contact of the first single-pole double-throw relay is connected to a cathode of the direct-current power supply; a movable contact of the second single-pole double-throw relay is connected to a second electric brush of the brush motor, a normally open contact of the second single-pole double-throw relay is connected to the anode of the direct-current power supply, a normally closed contact of the second single-pole double-throw relay is connected to the cathode of the direct-current power supply, and a first end and a second end of a coil of the second single-pole double-throw relay are connected to the anode of the direct-current power supply; the high-side driving circuit comprises a first control switch; the low-side driving circuit comprises a second control switch and a third control switch; and a main control chip. By adopting the brush motor control circuit, the working reliability of the motor control circuit can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of motor control. More specifically, this invention relates to a brushed motor control circuit and control method. Background Technology

[0002] A brushed DC motor (BDC) is a type of DC motor that uses carbon brushes and a commutator to switch the direction of current. It is the most common type of DC motor and is widely used in various household appliances, power tools, toys, automobiles, and other equipment. The forward and reverse rotation, starting, and stopping of a brushed motor are all achieved through a control circuit.

[0003] like Figure 1 As shown, the brushed motor control circuit in the prior art includes a dual-coil relay LS4, a first control switch Q1, a second control switch Q2, a third control switch Q3, and a fourth control switch Q4. The first moving contact 6 and the second moving contact 1 of the dual-coil relay LS4 are respectively connected to the two brushes of the brushed motor. The first normally open contact 3 and the second normally open contact 8 are both connected to the motor power output terminal. The first normally closed contact 9 and the second normally closed contact 4 are both grounded through the first grounding resistor R109. The first end of its first coil is connected to the coil power output terminal VCC_1, and the second end is connected to the first end of the second control switch Q2 and the first end of the first control switch Q1, respectively. The second end of the second control switch Q2 is grounded. The second end of the first control switch Q1 is grounded through the second grounding resistor R378 and connected to the controlled end of the second control switch Q2. The controlled end of the first control switch Q1 is connected to the main control chip through the current limiting resistor R374. The first end of the second coil is connected to the coil power output terminal VCC_1, and the second end is connected to the first end of the fourth control switch Q4 and the first end of the third control switch Q3. The second end of the fourth control switch Q4 is grounded, and the second end of the third control switch Q3 is grounded through the third grounding resistor R379 and connected to the controlled end of the fourth control switch Q4. The controlled end of the third control switch Q3 is connected to the main control chip through the current limiting resistor R375. The main control chip achieves forward rotation of the brushed motor by sending a high-level signal to the controlled end of the third control switch Q3 and a low-level signal to the controlled end of the first control switch; and achieves reverse rotation of the brushed motor by sending a low-level signal to the controlled end of the third control switch Q3 and a high-level signal to the controlled end of the first control switch.

[0004] Because the control circuit for achieving forward and reverse rotation of the motor is built with a large number of discrete components, the number of fault points increases. At the same time, discrete components are easily affected by ambient temperature and humidity, resulting in unstable operation and malfunctions.

[0005] In summary, the existing brushed motor control circuits have numerous fault points and poor operational reliability. Summary of the Invention

[0006] To address the technical problems of numerous fault points and poor reliability in existing brushed motor control circuits, this invention provides solutions in the following aspects.

[0007] In a first aspect, the present invention provides a brushed motor control circuit, comprising: The first single-pole double-throw relay has its moving contact connected to the first brush of the brushed motor, its normally open contact connected to the positive terminal of the DC power supply, its normally closed contact connected to the negative terminal of the DC power supply, and its coil has its first end connected to the positive terminal of the DC power supply and its second end connected to the negative terminal of the DC power supply. The second single-pole double-throw relay has its moving contact connected to the second brush of the brushed motor, its normally open contact connected to the positive terminal of the DC power supply, its normally closed contact connected to the negative terminal of the DC power supply, and its coil has its first end connected to the positive terminal of the DC power supply and its second end connected to the negative terminal of the DC power supply. The high-side drive circuit includes: a first control switch, which is connected in series between the normally open contact of the first single-pole double-throw relay and the positive terminal of the DC power supply, for connecting or disconnecting the normally open contact of the first single-pole double-throw relay to the positive terminal of the DC power supply; and is also connected in series between the normally open contact of the second single-pole double-throw relay and the positive terminal of the DC power supply, for connecting or disconnecting the normally open contact of the second single-pole double-throw relay to the positive terminal of the DC power supply. The low-side drive circuit includes a second control switch and a third control switch. The second control switch is connected in series between the second terminal of the first single-pole double-throw relay coil and ground to control the operation of the first single-pole double-throw relay. The third control switch is connected in series between the second terminal of the second single-pole double-throw relay coil and ground to control the operation of the second single-pole double-throw relay. The main control chip controls the first control switch, the second control switch, and the third control switch respectively. By controlling the conduction state of the first control switch, the second control switch, and the third control switch, the chip controls the forward rotation, reverse rotation, start-up, and stop of the brushed motor.

[0008] Preferably, the high-side drive circuit further includes a current detection circuit and a current comparator. The current detection circuit is connected to the brushed motor to collect the current flowing through the brushed motor. The input terminal of the current comparator is connected to the output terminal of the current detection circuit, and its output terminal is connected to the controlled terminal of the first control switch, which is used to control the first control switch to turn off when the current flowing through the brushed motor exceeds a first current threshold.

[0009] Preferably, it further includes: a voltage detection circuit for detecting the magnitude of the voltage output from the positive terminal of the DC power supply, so as to disconnect the power supply to the brushed motor when the output voltage exceeds a voltage threshold.

[0010] Preferably, the voltage detection circuit is a voltage divider circuit connected in series between the positive terminal of the DC power supply and ground. The voltage divider circuit includes a first voltage divider resistor and a second voltage divider resistor connected in series, and the voltage divider point of the voltage divider circuit is connected to the control chip.

[0011] Preferably, the control chip is a microcontroller of model HC32A448.

[0012] Preferably, the high-side drive circuit uses a power module chip of model RM77050DS, and the low-side drive circuit uses a motor drive chip of model MCS4230L7.

[0013] In a second aspect, the present invention provides a brushed motor control method, comprising: controlling the brushed motor to rotate forward, controlling the brushed motor to rotate in reverse, controlling the brushed motor to stop while rotating forward, and controlling the brushed motor to stop while rotating in reverse. Controlling the brushed motor to rotate forward includes: Receive forward rotation commands in real time; In response to receiving a forward rotation command, the first control switch is turned off, the second control switch is turned on, and the third control switch is turned off. When the second control switch is in the on state for a preset duration, the first control switch is turned on, thereby realizing the forward rotation of the motor.

[0014] Preferably, controlling the brushed motor to stop while it is rotating in the forward direction includes: Receive stop commands in real time; In response to receiving a stop command, the duty cycle of the drive signal at the controlled end of the first control switch is adjusted so that the current flowing through the brushed motor gradually decreases. In response to the situation where the current flowing through the brushed motor is less than the second current threshold for a preset duration, the first control switch is turned off. In response to the first control switch being in the off state for a preset duration, the second control switch is turned off.

[0015] Preferably, controlling the brushed motor to reverse includes: Receive inversion commands in real time; In response to receiving a reversal command, the first control switch is turned off, the second control switch is turned off, and the third control switch is turned on. When the duration of the conduction state at the third control switch reaches a preset duration, the first control switch is turned on, thereby achieving the reverse rotation of the motor.

[0016] Preferably, controlling the brushed motor to stop when the brushed motor is reversing includes: Receive stop commands in real time; In response to receiving a stop command, the duty cycle of the drive signal at the controlled end of the first control switch is adjusted so that the current flowing through the brushed motor gradually decreases. In response to the current flowing through the brushed motor being less than the second current threshold for a preset duration, the first control switch is turned off. In response to the first control switch being in the off state for a preset duration, the third control switch is controlled to turn off.

[0017] The beneficial effects of the present invention are as follows: the brushed motor control circuit of the present invention has fewer components and a simpler circuit structure, and does not require too many discrete components, which greatly reduces the number of failure points, thereby effectively improving the working reliability of the motor control circuit. At the same time, it is easier to detect failure points in the manufacturing stage using existing technology, thereby greatly improving the detectability of the product and reducing the number of outsourced faulty components. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the principle of a brushed motor control circuit in the prior art; Figure 2 This is a schematic diagram illustrating the principle of a brushed motor control circuit according to an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the voltage detection circuit according to an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the connection relationship between the high-side drive circuit, the low-side drive circuit, the control chip, and the relay according to an embodiment of the present invention. Figure 5 This is a schematic flowchart illustrating a method for controlling the forward rotation of a brushed motor according to an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0021] Example of a brushed motor control circuit: like Figure 2 As shown, the brushed motor control circuit of the present invention includes: The first single-pole double-throw relay R1 has its moving contact connected to the first brush of the brushed motor M, its normally open contact connected to the positive terminal BATT+ of the DC power supply, its normally closed contact connected to the negative terminal of the DC power supply, and the first end of its coil connected to the positive terminal BATT+ of the DC power supply and the second end connected to the negative terminal BATT- of the DC power supply. The second single-pole double-throw relay R2 has its moving contact connected to the second brush of the brushed motor, its normally open contact connected to the positive terminal of the DC power supply, its normally closed contact connected to the negative terminal of the DC power supply, and its coil has its first end connected to the positive terminal of the DC power supply and its second end connected to the negative terminal of the DC power supply. The high-side drive circuit includes: a first control switch Q1, which is connected in series between the normally open contact of the first single-pole double-throw relay and the positive terminal BATT+ of the DC power supply, for connecting or disconnecting the normally open contact of the first single-pole double-throw relay to the positive terminal of the DC power supply; and is also connected in series between the normally open contact of the second single-pole double-throw relay and the positive terminal BATT+ of the DC power supply, for connecting or disconnecting the normally open contact of the second single-pole double-throw relay to the positive terminal of the DC power supply. The low-side drive circuit includes a second control switch Q2 and a third control switch Q3. The second control switch Q2 is connected in series between the second terminal of the first single-pole double-throw relay coil and ground GND to control the operation of the first single-pole double-throw relay. The third control switch Q2 is connected in series between the second terminal of the second single-pole double-throw relay coil and ground GND to control the operation of the second single-pole double-throw relay. The main control chip controls the first control switch, the second control switch, and the third control switch respectively. By controlling the conduction state of the first control switch, the second control switch, and the third control switch, the chip controls the forward rotation, reverse rotation, start-up, and stop of the brushed motor.

[0022] In this embodiment, the control chip is a microcontroller with the model number HC32A448.

[0023] The working principle of the brushed motor control circuit in this embodiment is as follows: the main control chip controls the conduction state of the first control switch, the second control switch, and the third control switch; when the first control switch is on, the second control switch is on, and the third control switch is off, the brushed motor rotates forward; when the first control switch is on, the second control switch is off, and the third control switch is on, the brushed motor rotates in reverse; when the first control switch is off, the brushed motor stops rotating.

[0024] The brushed motor control circuit of this embodiment has fewer components and a simpler circuit structure, requiring fewer discrete components. This greatly reduces the number of failure points, thereby effectively improving the reliability of the motor control circuit. At the same time, it is easier to detect failure points during the manufacturing stage using existing technologies, which greatly improves the detectability of the product and reduces the number of outsourced faulty components.

[0025] In one embodiment, the high-side drive circuit further includes a current detection circuit and a current comparator. The current detection circuit is connected to the brushed motor to collect the current flowing through the brushed motor. The input terminal of the current comparator is connected to the output terminal of the current detection circuit, and its output terminal is connected to the controlled terminal of the first control switch. When the current flowing through the brushed motor exceeds a first current threshold, the comparator outputs a low level to the controlled terminal of the first control switch to control its shutdown.

[0026] The first current threshold can be set to 1.2 to 1.5 times the rated current of the brushed motor, so that the motor can withstand occasional current peaks or starting currents for a short period of time without damaging the motor.

[0027] Existing technologies implement motor overcurrent (locked rotor) protection through software. After collecting the current (with debouncing), the collected data is compared with the design threshold to obtain a failure flag. The MCU then shuts off the relay output based on the failure flag to protect the motor and the relay. The overall response time is in the tens of milliseconds, resulting in a long protection time that can easily cause motor burnout, as well as damage to the power devices and relays inside the controller. In contrast, the brushed motor control circuit of this embodiment uses a current detection circuit and a current comparator to automatically control the first control switch to shut off when the current flowing through the brushed motor is too high, thus achieving overcurrent protection for the brushed motor without the need for software programming. This effectively shortens the protection time, avoids brushed motor burnout or insulation damage caused by high temperature, and also prevents the burnout of components in the control circuit.

[0028] The current detection circuit and current comparator set inside the high-side drive circuit form an overcurrent protection circuit, which can easily solve the problem of long overcurrent protection time and improve the motor overcurrent (stalled rotor) protection time from the millisecond level to the microsecond level. This will greatly reduce the failure rate of relays inside the motor and controller.

[0029] In one embodiment, the brushed motor control circuit further includes a voltage detection circuit for detecting the magnitude of the voltage output from the positive terminal of the DC power supply, so as to disconnect the power supply to the brushed motor when the output voltage exceeds a voltage threshold.

[0030] In one embodiment, such as Figure 3 As shown, the voltage detection circuit is a voltage divider circuit connected in series between the positive terminal of the DC power supply and ground. The voltage divider circuit includes a first voltage divider resistor R7 and a second voltage divider resistor R8 connected in series. The voltage divider point of the voltage divider circuit is connected to the control chip U3.

[0031] In one embodiment, the high-side drive circuit uses a power module chip of model RM77050DS, and the low-side drive circuit uses a motor drive chip of model MCS4230L7. Figure 4 As shown, when the high-side drive circuit uses a power module chip of model RM77050DS and the low-side drive circuit uses a motor driver chip of model MCS4230L7, the circuit connection is as follows: the IN and DEN pins of the power module chip U1 are connected to the O_S_PWRCTL pin of the control chip U3 through the first current-limiting resistor R3; the IS pin is connected to the I_A_VCC pin of the control chip U3; the VS pin is connected to the positive terminal BATT+ of the DC power supply; the OUT pin is connected to the normally open contact of the first single-pole double-throw relay R1 and the normally open contact of the second single-pole double-throw relay R2; the normally closed contact of the first single-pole double-throw relay R1 and the normally closed contact of the second single-pole double-throw relay R2 are both connected to the negative terminal of the DC power supply; the moving contact of the first single-pole double-throw relay is connected to the first brush of the brushed motor M; and the moving contact of the second single-pole double-throw relay is connected to the second brush of the brushed motor M. The first terminal of the coil of the first single-pole double-throw relay and the first terminal of the coil of the second single-pole double-throw relay are both connected to the positive terminal BATT+ of the DC power supply. The second terminal of the coil of the first single-pole double-throw relay is connected to the OUT1 pin of the motor driver chip U2, and the second terminal of the coil of the second single-pole double-throw relay is connected to the OUT2 pin of the motor driver chip U2. The IN1 pin of the motor driver chip U2 is connected to the O_S_R1CTL pin of the control chip U3 through the third current-limiting resistor R5, and the IN2 pin of the motor driver chip U2 is connected to the O_S_R2CTL pin of the control chip U3 through the fourth current-limiting resistor R6.

[0032] When the O_S_PWRCTL pin outputs a high-level signal, the first control switch inside the power module chip U1 is turned on, and the OUT pin of the power module chip U1 outputs a high-level signal. The voltage of the high-level signal is basically the same as the voltage of the positive terminal VBATT+ of the DC power supply. At this time, the 5th contact of relays R1 and R2 receives a high voltage. When O_S_R1CTL outputs a high level and O_S_R2CTL outputs a low level, the second control switch inside the motor driver chip U2 is turned on and turned off. The OUT1 pin of the motor driver chip U2 outputs a low level, and the OUT2 pin outputs a high level. The coil of the first single-pole double-throw relay is energized, and its moving contact is connected to the normally open contact. At this time, the current flows out from the OUT pin of U1, passes through the 5th and 3rd contacts of the first single-pole double-throw relay R1, and enters the motor M. After flowing out from the motor M, it passes through the 3rd and 4th contacts of the second single-pole double-throw relay R2 and returns to the negative terminal VBATT- of the battery, thereby realizing the forward rotation of the motor. Similarly, when O_S_R1CTL outputs a low level and O_S_R2CTL outputs a high level, the second control switch inside the motor driver chip U2 is turned off and turned on. The OUT1 pin of the motor driver chip U2 outputs a high level and the OUT2 pin outputs a low level. The coil of the second single-pole double-throw relay is energized, and its moving contact is connected to the normally open contact. At this time, the current flows out from the OUT pin of U1, passes through the 5th and 3rd contacts of the second single-pole double-throw relay R1, and enters the motor M. After flowing out from the motor M, it passes through the 3rd and 4th contacts of the first single-pole double-throw relay R2 and returns to the negative terminal VBATT- of the battery, thereby realizing the reverse rotation of the motor.

[0033] The first single-pole double-throw relay R1 has a normally open contact (contact 5), a moving contact (contact 3), and a normally closed contact (contact 4).

[0034] Example of brushed motor control method: This invention also provides a brushed motor control method based on the brushed motor control circuit in the above embodiments, including controlling the brushed motor to rotate forward, controlling the brushed motor to rotate in reverse, controlling the brushed motor to stop when rotating forward, and controlling the brushed motor to stop when rotating in reverse, wherein, as... Figure 5 As shown, controlling the forward rotation of the brushed motor includes: S101, Real-time reception of forward rotation commands; S102. In response to receiving a forward rotation command, control the first control switch to turn off, the second control switch to turn on, and the third control switch to turn off. The first control switch is turned off, thereby cutting off the power supply to the brushed motor; the second control switch is turned on, causing the coil of the first single-pole double-throw relay to be energized, thus activating the first single-pole double-throw relay (its moving contact connects with the normally open contact), keeping the first brush of the brushed motor connected to the first control switch; the third control switch is turned off, causing the coil of the first single-pole double-throw relay to be de-energized (its moving contact connects with the normally closed contact), thus connecting the second brush of the brushed motor to the negative terminal of the DC power supply.

[0035] S103. In response to the second control switch being in the on state for a preset duration, the first control switch is turned on, thereby realizing the forward rotation of the motor.

[0036] With the first brush of the brushed motor connected to the first control switch, the power supply to the brushed motor is turned on by controlling the first control switch to conduct.

[0037] By ensuring the second control switch remains in the ON state for a preset duration—that is, by controlling the first control switch to turn on only after the first single-pole double-throw relay has activated—it is possible to prevent the first single-pole double-throw relay from closing under voltage, reduce the corrosion of the relay contacts by sparks during relay operation, and also reduce electromagnetic interference to other devices during relay operation, thereby improving the electromagnetic stability of the product.

[0038] In this embodiment, the preset duration can be 500ms.

[0039] In one embodiment, controlling the brushed motor to stop while it is rotating in the forward direction includes: S201, Real-time reception of stop commands; S202. In response to receiving a stop command, adjust the duty cycle of the drive signal at the controlled end of the first control switch so that the current flowing through the brushed motor gradually decreases. S203. In response to the situation where the current flowing through the brushed motor is less than the second current threshold for a preset duration, the first control switch is turned off. The second current threshold can be 50% to 70% of the rated current of the brushed motor.

[0040] S204. In response to the first control switch being in the off state for a preset duration, the second control switch is controlled to turn off.

[0041] In this embodiment, the preset duration can be 500ms.

[0042] By gradually reducing the current flowing through the motor, the motor can be stopped smoothly, avoiding vibration or impact caused by directly cutting off the power supply, thus enhancing the accuracy of motor control.

[0043] By controlling the second control switch to turn off only after the first control switch has been in the off state for a preset time, the contacts of the first single-pole double-throw relay are avoided from being directly disconnected when current is flowing. This reduces the corrosion of the relay contacts by sparks during the reset process of the first single-pole double-throw relay, and also reduces the electromagnetic interference to other devices during the reset process of the first single-pole double-throw relay, thereby improving the electromagnetic stability of the product.

[0044] This method controls the current during the stopping process by monitoring the current changes in real time, ensuring that the motor will not cause damage to the circuit or the motor itself when it stops.

[0045] In one embodiment, controlling the brushed motor to reverse includes: S301, Real-time reception of reversal commands; S302. In response to receiving a reversal command, control the first control switch to turn off, the second control switch to turn off, and the third control switch to turn on. S303, in response to the third control switch being in the on state for a preset duration, the first control switch is turned on, thereby achieving motor reversal.

[0046] By ensuring that the first control switch is turned on only after the second single-pole double-throw relay has operated for a preset duration at the third control switch, the voltage-carrying contact of the second single-pole double-throw relay is prevented from closing. This reduces the corrosion of the relay contacts by sparks during relay operation and also reduces electromagnetic interference to other devices during relay operation, thereby improving the electromagnetic stability of the product.

[0047] In one embodiment, controlling the brushed motor to stop when the brushed motor is reversing includes: S401, Real-time reception of stop commands; S402. In response to receiving a stop command, adjust the duty cycle of the drive signal at the controlled end of the first control switch so that the current flowing through the brushed motor gradually decreases. S403. In response to the current flowing through the brushed motor being less than the second current threshold for a preset duration, the first control switch is turned off. The preset duration can be 500ms.

[0048] S404. In response to the first control switch being in the off state for a preset duration, the third control switch is controlled to turn off.

[0049] The method in this embodiment ensures a smooth motor stop by gradually reducing the motor current and controlling the stopping process according to a current threshold. This method avoids motor damage or other mechanical problems caused by sudden power outages, while the duration setting during the control process ensures a safe and successful stop.

[0050] While this specification has shown and described numerous embodiments of the invention, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and essence of the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in the practice of this invention.

Claims

1. A brushed motor control circuit, characterized by, Comprise: The first single-throw double-throw relay, the moving contact is connected to the first brush of the brush motor, the normally open contact is connected to the positive pole of the DC power supply, the normally closed contact is connected to the negative pole of the DC power supply, the first end of the coil is connected to the positive pole of the DC power supply, and the second end is connected to the negative pole of the DC power supply; The second single-throw double-throw relay, the moving contact is connected to the second brush of the brush motor, the normally open contact is connected to the positive pole of the DC power supply, the normally closed contact is connected to the negative pole of the DC power supply, the first end of the coil is connected to the positive pole of the DC power supply, and the second end is connected to the negative pole of the DC power supply; The high-side drive circuit comprises: a first control switch, the first control switch is connected in series between the normally open contact of the first single-throw double-throw relay and the positive pole of the DC power supply, for making the normally open contact of the first single-throw double-throw relay connect or disconnect the positive pole of the DC power supply, also connected in series between the normally open contact of the second single-throw double-throw relay and the positive pole of the DC power supply, for making the normally open contact of the second single-throw double-throw relay connect or disconnect the positive pole of the DC power supply; The low-side drive circuit comprises a second control switch and a third control switch, wherein the second control switch is connected in series between the second end of the coil of the first single-throw double-throw relay and the ground, for controlling the action of the first single-throw double-throw relay, and the third control switch is connected in series between the second end of the coil of the second single-throw double-throw relay and the ground, for controlling the action of the second single-throw double-throw relay; The master control chip controls the first control switch, the second control switch and the third control switch respectively, and controls the forward rotation, reverse rotation, starting and stopping of the brush motor by controlling the conduction state of the first control switch, the second control switch and the third control switch.

2. The brushed motor control circuit of claim 1, wherein, The high-side drive circuit further comprises a current detection circuit and a current comparator, the current detection circuit is connected to the brush motor to collect the current flowing through the brush motor; the input end of the current comparator is connected to the output end of the current detection circuit, and the output end is connected to the controlled end of the first control switch, for controlling the first control switch to be turned off when the current flowing through the brush motor exceeds the first current threshold.

3. The brushed motor control circuit of claim 1, wherein, Further comprising: A voltage detection circuit for detecting the voltage output by the positive pole of the DC power supply, so as to disconnect the power supply of the brush motor when the output voltage exceeds the voltage threshold.

4. The brushed motor control circuit of claim 3, wherein, The voltage detection circuit is a voltage dividing circuit connected in series between the positive pole of the DC power supply and the ground, and the voltage dividing circuit comprises a first voltage dividing resistor and a second voltage dividing resistor connected in series, and the voltage dividing point of the voltage dividing circuit is connected to the control chip.

5. A brushed motor control circuit according to any one of claims 1 to 4, wherein The control chip adopts a microcontroller with model HC32A448.

6. A brushed motor control circuit according to any one of claims 1 to 4, wherein The high-side drive circuit adopts a power module chip with model RM77050DS, and the low-side drive circuit adopts a motor drive chip with model MCS4230L7.

7. A brush motor control method based on the brush motor control circuit according to any one of claims 1 to 6, comprising: The control of the brush motor forward rotation, the control of the brush motor reverse rotation, the control of the brush motor stopping in the case of brush motor forward rotation, and the control of the brush motor stopping in the case of brush motor reverse rotation, characterized in that the control of the brush motor forward rotation comprises: Real-time receiving of forward rotation instruction; In response to receiving the forward rotation instruction, the first control switch is turned off, the second control switch is turned on, and the third control switch is turned off; In response to the time length of the first control switch being in the on state reaching a preset time length, the second control switch is controlled to be on, so as to realize forward rotation of the motor.

8. The brushed motor control method of claim 7, wherein, The control of the brush motor to stop in the case of forward rotation of the brush motor comprises: receiving a stop instruction in real time; in response to receiving the stop instruction, adjusting the duty cycle of the driving signal of the controlled end of the first control switch, so that the current flowing through the brush motor gradually decreases; in response to the current flowing through the brush motor being less than the second current threshold for a preset time length, controlling the first control switch to be off; in response to the time length of the first control switch being in the off state reaching a preset time length, controlling the second control switch to be off.

9. The brushed motor control method of claim 7, wherein, The control of the brush motor to reverse comprises: receiving a reverse instruction in real time; in response to receiving the reverse instruction, controlling the first control switch to be off, the second control switch to be off, and the third control switch to be on; in response to the time length of the third control switch being in the on state reaching a preset time length, controlling the first control switch to be on, so as to realize reverse rotation of the motor.

10. A brushed motor control method according to any one of claims 7 to 9, characterized in that, The control of the brush motor to stop in the case of reverse rotation of the brush motor comprises: receiving a stop instruction in real time; in response to receiving the stop instruction, adjusting the duty cycle of the driving signal of the controlled end of the first control switch, so that the current flowing through the brush motor gradually decreases; in response to the current flowing through the brush motor being less than the second current threshold for a preset time length, controlling the first control switch to be off; in response to the time length of the first control switch being in the off state reaching a preset time length, controlling the third control switch to be off.

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