A direct current motor speed control circuit for a dental chair controller

Abstract

This invention discloses a DC motor speed control circuit for a dental chair controller, comprising an MCU unit, a Darlington drive unit, a direction control unit, a PWM modulation unit, and a current detection unit. The MCU unit is electrically connected to the Darlington drive unit, the direction control unit, the PWM modulation unit, and the current detection unit. The Darlington drive unit is electrically connected to the direction control unit, the direction control unit is electrically connected to the PWM modulation unit, and the PWM modulation unit is electrically connected to the current detection unit. The PWM modulation unit includes a MOSFET, which controls the direction control unit to perform slow speed adjustment. This control circuit has a speed regulation function. The main control chip drives the motor to rotate forward or backward through two relays, and achieves slow speed change of the motor by controlling the PWM duty cycle of the MOSFET, thereby achieving smooth operation of the dental chair, reducing noise and impact, improving the patient's user experience, and enhancing the overall performance and service life of the dental chair equipment.

Description

Technical Field

[0001] This utility model relates to the field of oral medical care and dental chair controller technology, specifically to a DC motor speed control circuit for a dental chair controller. Background Technology

[0002] In the field of oral healthcare, the dental chair, as a core diagnostic and treatment device, directly affects the patient's treatment experience and safety through the smoothness of its lifting, tilting, and other movements.

[0003] In existing technologies, most dental chair DC motor drive systems use a direct start-stop control method, lacking speed regulation functionality. When the motor starts and stops, the rapid change in speed generates significant mechanical shock. This shock not only transmits to the mechanical structure of the dental chair, accelerating component wear and reducing equipment lifespan, but also produces considerable operating noise, causing tension and discomfort for patients. This noise is particularly problematic for patients already experiencing anxiety during dental treatment, further exacerbating their psychological burden and affecting their cooperation with the treatment.

[0004] As oral healthcare services place increasing demands on patient experience and equipment performance, the shortcomings of existing dental chair motor control methods are becoming increasingly apparent. There is an urgent need for a DC motor control system that is speed-adjustable, runs smoothly, and is safe and reliable, in order to improve the patient experience and treatment outcomes. Utility Model Content

[0005] To solve the above-mentioned technical problems, this utility model proposes the following technical solution:

[0006] This utility model provides a DC motor speed control circuit for a dental chair controller, including an MCU unit, a Darlington drive unit, a direction control unit, a PWM modulation unit, and a current detection unit. The MCU unit is electrically connected to the Darlington drive unit, the direction control unit, the PWM modulation unit, and the current detection unit. The Darlington drive unit is electrically connected to the direction control unit, the direction control unit is electrically connected to the PWM modulation unit, and the PWM modulation unit is electrically connected to the current detection unit. The PWM modulation unit includes a MOSFET, which is used to control the direction control unit to perform slow speed adjustment.

[0007] Furthermore, the MCU unit includes a main control chip U1, and the first pin of U1...

[0008] ADC_HDIR_CUR is electrically connected to the current sensing unit, pin 2 of U1.

[0009] PWM_HDIR_SOFT_START is electrically connected to the PWM modulation unit. The third pin of U1 is grounded through resistor R5. The fourth pin of U1 is electrically connected to VDD through resistor R4. The fourth pin of U1 is also grounded through capacitor C1. The fifth to tenth pins of U1 are electrically connected to VDD. VDD is grounded through capacitors C2-C8. The eleventh to fifteenth pins of U1 are grounded. The sixteenth pin IOOUT_HDIR_POL1 and the seventeenth pin IOOUT_HDIR_POL2 of U1 are electrically connected to the Darlington drive unit, respectively. The eighteenth pin of U1 is electrically connected to the cathode of LED1. The anode of LED1 is electrically connected to VDD through resistor R1.

[0010] Furthermore, the Darlington drive unit includes a Darlington chip U2, and the first pin of U2...

[0011] IOOUT_HDIR_POL1 is grounded through resistor R7. The second pin of U2, IOOUT_HDIR_POL2, is grounded through resistor R8. The third pin of U2 is grounded. The fourth pin of U2 is connected to +5V and is grounded through capacitor C9. The fifth pin of U2, HDIR_POL2, and the sixth pin...

[0012] HDIR_POL1 is electrically connected to the direction control unit.

[0013] Further, the direction control unit includes a motor M1, a drive chip B1, a first relay K1, and a second relay K2. The first pin of the first relay K1 is electrically connected to the sixth pin HDIR_POL1 of U2. The second pin of the first relay K1 is electrically connected to +5V. The second pin of the first relay K1 is electrically connected to the anode of a light-emitting diode LED3 through a resistor R9. The cathode of the light-emitting diode LED3 is electrically connected to the first pin of the first relay K1. The third pin of the first relay K1 is electrically connected to +32V through a resistor R10. The fourth pin of the first relay K1 is also electrically connected to +32V. Pin 5 (HDIR_PWR1) is electrically connected to the first terminal of motor M1 and pin 3 of driver chip B1. Pin 1 of second relay K2 is electrically connected to +5V. Pin 1 of second relay K2 is electrically connected to the anode of LED2 through resistor R11. The cathode of LED2 is electrically connected to pin 2 of second relay K2. Pin 2 of second relay K2 is electrically connected to pin 5 (HDIR_POL2) of U2. Pin 3 of second relay K2 is electrically connected to +32V through resistor R10. Pin 4 of second relay K2 is electrically connected to +32V. Pin 5 of second relay K2...

[0014] HDIR_PWR2 is electrically connected to the second terminal of motor M1 and the fourth pin of driver chip B1.

[0015] The first pin of B1 is connected to +32V, and the second pin of driver chip B1 is grounded.

[0016] Furthermore, the PWM modulation unit also includes Zener diodes DZ1 and DZ2. The first pin of the MOSFET is electrically connected to the second pin of U1 (PWM_HDIR_SOFT_START), the first end of resistor R14, and the first end of Zener diode DZ2. The second end of resistor R14 and the second end of Zener diode DZ2 are grounded. The second pin of the MOSFET is electrically connected to the first end of Zener diode DZ1, the third pin of the first relay K1, and the third pin of the second relay K2. The third pin of the MOSFET is electrically connected to the current detection unit and the second end of Zener diode DZ1.

[0017] Furthermore, the current detection unit includes an optocoupler D1 and a resistor R6. The first pin of the optocoupler D1 is grounded, the second pin of the optocoupler D1 is electrically connected to +3.3V, the third pin of the optocoupler D1 is electrically connected to the first pin of U1 (ADC_HDIR_CUR), the first end of resistor R12, and the first end of capacitor C11, the second end of resistor R12 is electrically connected to the first end of capacitor C12 and the first end of resistor R13, the second end of capacitor C11 and the second end of capacitor C12 are grounded, the first end of resistor R6 is electrically connected to the second end of resistor R13 and the third pin of the MOSFET, and the second end of resistor R6 is grounded.

[0018] Beneficial effects:

[0019] (1) The DC motor speed control circuit for dental chair controller provided by this utility model has a speed control function. The main control chip drives the motor to rotate forward or reverse through two relays, and realizes the slow change of motor speed by controlling the PWM duty cycle of the MOS tube, thereby realizing the smooth operation of the dental chair, reducing noise and impact, which not only improves the user experience of patients and is conducive to doctors to perform fine diagnosis and treatment operations, but also improves the overall performance and service life of dental chair equipment.

[0020] (2) The DC motor speed control circuit for dental chair controller provided by this utility model uses an integrated Darlington chip to drive the relay, which is more stable and reliable than discrete device driving. The H-bridge circuit is composed of two single-pole double-throw relays, which is lower in cost and occupies less circuit board area compared to using four single-pole single-throw relays.

[0021] (3) The DC motor speed control circuit for dental chair controller provided by this utility model has a current monitoring function. When an overcurrent fault occurs, the main control chip can stop the motor in time, which improves the safety of the equipment operation. Attached Figure Description

[0022] Figure 1 A schematic diagram of the circuit structure provided for an embodiment of this utility model;

[0023] Figure 2 A schematic diagram of the MCU unit provided in an embodiment of this utility model;

[0024] Figure 3 A schematic diagram of the Darlington drive unit provided in an embodiment of this utility model;

[0025] Figure 4 The schematic diagram of the direction control unit, PWM modulation unit and current detection unit provided in the embodiment of this utility model. Detailed Implementation

[0026] The present solution will now be described in conjunction with the accompanying drawings and specific embodiments.

[0027] Figure 1 The circuit structure diagram provided for this embodiment of the utility model includes an MCU unit, a Darlington drive unit, a direction control unit, a PWM modulation unit, and a current detection unit. The MCU unit is electrically connected to the Darlington drive unit, the direction control unit, the PWM modulation unit, and the current detection unit, respectively. The Darlington drive unit is electrically connected to the direction control unit, the direction control unit is electrically connected to the PWM modulation unit, and the PWM modulation unit is electrically connected to the current detection unit. The PWM modulation unit includes a MOSFET, which is used to control the direction control unit to perform slow speed adjustment.

[0028] Figure 2 This is a schematic diagram of the MCU unit provided in this embodiment of the utility model. The MCU unit includes a main control chip U1. The first pin of U1, ADC_HDIR_CUR, is electrically connected to the current detection unit. The second pin of U1, PWM_HDIR_SOFT_START, is electrically connected to the PWM modulation unit. The third pin of U1 is grounded through resistor R5. The fourth pin of U1 is electrically connected to VDD through resistor R4 and capacitor C1. The fifth to tenth pins of U1 are electrically connected to VDD, which is grounded through capacitor group C2-C8. The eleventh to fifteenth pins of U1 are grounded. The sixteenth pin of U1...

[0029] Pins IOOUT_HDIR_POL1 and IOOUT_HDIR_POL2 (pin 17) are electrically connected to the Darlington driver unit, and pin 18 of U1 is electrically connected to the cathode of LED1. The anode of LED1 is electrically connected to VDD through resistor R1. In this embodiment, the MCU model is [model number missing].

[0030] GD32F105RBT6.

[0031] Figure 3 The schematic diagram of the Darlington drive unit provided in this embodiment of the present utility model is shown. The Darlington drive unit includes a Darlington chip U2. The first pin IOOUT_HDIR_POL1 of U2 is grounded through resistor R7. The second pin IOOUT_HDIR_POL2 of U2 is grounded through resistor R8. The third pin of U2 is grounded. The fourth pin of U2 is electrically connected to +5V. The fourth pin of U2 is grounded through capacitor C9. The fifth pin HDIR_POL2 and the sixth pin HDIR_POL1 of U2 are electrically connected to the direction control unit.

[0032] In this embodiment of the invention, the Darlington chip is model ULN2003D1013TR. The pins IOOUT_HDIR_POL1 and IOOUT_HDIR_POL2 of U2 are connected to the GPIO pins of the main control chip U1.

[0033] Figure 4 The schematic diagram of the direction control unit, PWM modulation unit and current detection unit provided in the embodiment of this utility model.

[0034] The direction control unit includes a motor M1, a drive chip B1, a first relay K1, and a second relay K2. The first pin of the first relay K1 is electrically connected to the sixth pin (HDIR_POL1) of U2. The second pin of the first relay K1 is electrically connected to +5V. The second pin of the first relay K1 is electrically connected to the anode of a light-emitting diode (LED3) through a resistor R9. The cathode of LED3 is electrically connected to the first pin of the first relay K1. The third pin of the first relay K1 is electrically connected to +32V through a resistor R10. The fourth pin of the first relay K1 is also electrically connected to +32V. The fifth pin of the first relay K1...

[0035] HDIR_PWR1 is electrically connected to the first terminal of motor M1 and the third pin of driver chip B1. The first pin of the second relay K2 is electrically connected to +5V. The first pin of the second relay K2 is electrically connected to the anode of LED2 through resistor R11. The cathode of LED2 is electrically connected to the second pin of the second relay K2. The second pin of the second relay K2 is electrically connected to the fifth pin HDIR_POL2 of U2. The third pin of the second relay K2 is electrically connected to +32V through resistor R10. The fourth pin of the second relay K2 is electrically connected to +32V. The fifth pin HDIR_PWR2 of the second relay K2 is electrically connected to the second terminal of motor M1 and the fourth pin of driver chip B1. The first pin of driver chip B1 is electrically connected to +32V. The second pin of driver chip B1 is grounded.

[0036] In this embodiment of the invention, the first and second relays are single-pole double-throw power relays, model G2R-1-DC24. K1 and K2 form an H-bridge drive circuit to control the forward and reverse rotation of motor M1. When the fifth and fourth pins of the first relay K1 are engaged, and the fifth and third pins of the second relay K2 are engaged, motor M1 rotates forward. When the fifth and third pins of the first relay K1 are engaged, and the fifth and fourth pins of the second relay K2 are engaged, motor M1 rotates in reverse.

[0037] The PWM modulation unit also includes Zener diodes DZ1 and DZ2. The first pin of the MOSFET is electrically connected to the second pin of U1 (PWM_HDIR_SOFT_START), the first terminal of resistor R14, and the first terminal of Zener diode DZ2. The second terminal of resistor R14 and the second terminal of Zener diode DZ2 are grounded. The second pin of the MOSFET is electrically connected to the first terminal of Zener diode DZ1, the third pin of the first relay K1, and the third pin of the second relay K2. The third pin of the MOSFET is electrically connected to the current detection unit and the second terminal of Zener diode DZ1.

[0038] The PWM modulation unit is used to regulate the motor's operating speed. The main control chip U1 is connected to the first pin of the MOSFET Q1 via a GPIO port to drive Q1 to generate a PWM signal, and the motor's operating speed is changed by adjusting the PWM duty cycle. In this embodiment, the MOSFET is of type [model number missing].

[0039] JMGG088V10A (Vdss: 100V, Id: 80A).

[0040] The current sensing unit includes an optocoupler D1 and a resistor R6. The first pin of optocoupler D1 is grounded, the second pin of optocoupler D1 is electrically connected to +3.3V, and the third pin of optocoupler D1 is connected to the first pin of U1.

[0041] The first terminal of ADC_HDIR_CUR, resistor R12, and capacitor C11 are electrically connected. The second terminal of resistor R12 is electrically connected to the first terminal of capacitor C12 and the first terminal of resistor R13. The second terminals of capacitor C11 and capacitor C12 are grounded. The first terminal of resistor R6, resistor R13, and the third pin of MOSFET are electrically connected. The second terminal of resistor R6 is grounded.

[0042] The current detection unit converts the motor's operating current into a voltage signal through a high-precision sampling resistor R6, and connects this signal to the ADC sampling channel of the main control chip U1 (i.e., the ADC_HDIR_CUR pin of U1), thereby realizing real-time monitoring of the motor's operating current and overcurrent protection.

[0043] The working principle of the control circuit provided in this embodiment of the utility model is as follows:

[0044] During startup, when the main control chip U1 controls the fifth and fourth pins of the first relay K1 to be engaged and the fifth and third pins of the second relay K2 to be engaged, the motor M1 is driven to rotate forward. At the same time, the PWM duty cycle of the MOSFET Q1 increases from 0% to 100%, causing the motor speed to increase slowly, thus achieving soft start.

[0045] During the stopping process, the main control chip U1 controls the fifth and third pins of the first relay K1 to be energized. When the fifth and fourth pins of the second relay K2 are energized, the drive motor M1 reverses. At the same time, the PWM duty cycle of the MOSFET Q1 decreases from 100% to 0%, causing the motor speed to decrease slowly, thus achieving a soft stop.

[0046] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present utility model without departing from the technical solution of the present utility model shall still fall within the protection scope of the technical solution of the present utility model.

Claims

1. A DC motor speed control circuit for a dental chair controller, characterized by, The circuit includes an MCU unit, a Darlington drive unit, a direction control unit, a PWM modulation unit, and a current detection unit. The MCU unit is electrically connected to the Darlington drive unit, the direction control unit, the PWM modulation unit, and the current detection unit, respectively. The Darlington drive unit is electrically connected to the direction control unit, the direction control unit is electrically connected to the PWM modulation unit, and the PWM modulation unit is electrically connected to the current detection unit. The PWM modulation unit includes a MOSFET, which is used to control the direction control unit to perform slow speed adjustment.

2. The DC motor speed control circuit for a dental chair controller of claim 1, wherein, The MCU unit includes a main control chip U1. The first pin of U1, ADC_HDIR_CUR, is electrically connected to the current detection unit. The second pin of U1, PWM_HDIR_SOFT_START, is electrically connected to the PWM modulation unit. The third pin of U1 is grounded through resistor R5. The fourth pin of U1 is electrically connected to VDD through resistor R4 and capacitor C1. The fifth to tenth pins of U1 are electrically connected to VDD, which is grounded through capacitors C2-C8. The eleventh to fifteenth pins of U1 are grounded. The sixteenth pin, IOOUT_HDIR_POL1, and the seventeenth pin, IOOUT_HDIR_POL2, are electrically connected to the Darlington drive unit, respectively. The eighteenth pin of U1 is electrically connected to the cathode of LED1. The anode of LED1 is electrically connected to VDD through resistor R1.

3. The DC motor speed control circuit for a dental chair controller of claim 2, wherein, The Darlington drive unit includes a Darlington chip U2. The first pin IOOUT_HDIR_POL1 of U2 is grounded through resistor R7, the second pin IOOUT_HDIR_POL2 of U2 is grounded through resistor R8, the third pin of U2 is grounded, the fourth pin of U2 is electrically connected to +5V, and the fourth pin of U2 is grounded through capacitor C9. The fifth pin HDIR_POL2 and the sixth pin HDIR_POL1 of U2 are electrically connected to the direction control unit.

4. The DC motor speed control circuit for a dental chair controller of claim 3, wherein, The direction control unit includes a motor M1, a drive chip B1, a first relay K1, and a second relay K2. The first pin of the first relay K1 is electrically connected to the sixth pin (HDIR_POL1) of U2. The second pin of the first relay K1 is electrically connected to +5V. The second pin of the first relay K1 is electrically connected to the anode of a light-emitting diode (LED3) through a resistor R9. The cathode of the LED3 is electrically connected to the first pin of the first relay K1. The third pin of the first relay K1 is electrically connected to +32V through a resistor R10. The fourth pin of the first relay K1 is also electrically connected to +32V. The fifth pin (HDIR_PWR1) of the first relay K1 is electrically connected to the first terminal of the motor M1 and the third pin of the drive chip B1. The first pin of the second relay K2 is connected to +5V. The first pin of the second relay K2 is connected to the anode of the light-emitting diode LED2 through resistor R11. The cathode of the light-emitting diode LED2 is connected to the second pin of the second relay K2. The second pin of the second relay K2 is connected to the fifth pin HDIR_POL2 of U2. The third pin of the second relay K2 is connected to +32V through resistor R10. The fourth pin of the second relay K2 is connected to +32V. The fifth pin HDIR_PWR2 of the second relay K2 is connected to the second terminal of motor M1 and the fourth pin of driver chip B1. The first pin of driver chip B1 is connected to +32V. The second pin of driver chip B1 is grounded.

5. The DC motor speed control circuit for a dental chair controller according to claim 4, characterized in that, The PWM modulation unit also includes Zener diodes DZ1 and DZ2. The first pin of the MOSFET is electrically connected to the second pin of U1 (PWM_HDIR_SOFT_START), the first end of resistor R14, and the first end of Zener diode DZ2. The second end of resistor R14 and the second end of Zener diode DZ2 are grounded. The second pin of the MOSFET is electrically connected to the first end of Zener diode DZ1, the third pin of the first relay K1, and the third pin of the second relay K2. The third pin of the MOSFET is electrically connected to the current detection unit and the second end of Zener diode DZ1.

6. The DC motor speed control circuit for a dental chair controller according to claim 5, characterized in that, The current detection unit includes an optocoupler D1 and a resistor R6. The first pin of the optocoupler D1 is grounded, the second pin of the optocoupler D1 is electrically connected to +3.3V, the third pin of the optocoupler D1 is electrically connected to the first pin of U1 (ADC_HDIR_CUR), the first end of resistor R12, and the first end of capacitor C11, the second end of resistor R12 is electrically connected to the first end of capacitor C12 and the first end of resistor R13, the second end of capacitor C11 and the second end of capacitor C12 are grounded, the first end of resistor R6 is electrically connected to the second end of resistor R13 and the third pin of the MOSFET, and the second end of resistor R6 is grounded.

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