A speed-regulating motor circuit

Abstract

This utility model discloses a speed-regulating motor circuit, including an adjustable voltage regulator circuit, an overheat protection circuit, a square wave generator, an integrator circuit, a decoding and display circuit, a multivibrator circuit, an H-bridge drive circuit, an adder output circuit, and a comparator circuit. The square wave generator output is connected to the integrator input, converting the square wave signal into a triangular wave signal. The integrator output and the adder output are connected to the comparator input, the comparator output is connected to the H-bridge drive input, and the H-bridge drive output is connected to the motor. The comparator circuit converts the triangular wave signal and different voltage signals into square waves with different duty cycles to control the motor speed. This utility model provides stable power to the entire system through an adjustable voltage regulator integrated output power supply, and features motor forward / reverse control and multi-level control via a DIP switch. It boasts advantages such as high integration, comprehensive functions, high reliability, and excellent human-machine interaction.

Description

Technical Field

[0001] This utility model relates to the field of speed-regulating motor technology, and more specifically, to a speed-regulating motor circuit. Background Technology

[0002] Traditional motor speed control circuits typically employ simple potentiometer voltage dividers or PWM (Pulse Width Modulation) control, which are limited in function and lack systematic protection measures and status feedback. For example, when the motor is overloaded or stalled, excessive current can easily burn out the drive circuit or the motor itself; the lack of visual speed indicators prevents users from intuitively understanding the current speed control status; and unstable power supply to various parts of the circuit can directly affect control accuracy and reliability.

[0003] While existing technologies include independent protection or display circuits, these are often modular, resulting in low integration, high cost, and bottlenecks in signal matching and coordination between modules. Therefore, there is an urgent need for a highly integrated, fully functional, reliable motor speed control solution with good human-machine interaction. Utility Model Content

[0004] This utility model overcomes the shortcomings of the prior art. Its structure is reasonably designed. It provides power to the entire system through an adjustable voltage regulator integrated output stable power supply. It has motor forward and reverse rotation control and DIP switch multi-level control functions. It has the advantages of high integration, complete functions, high reliability and good human-computer interaction.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A speed-regulating motor circuit includes an adjustable voltage regulator circuit, an overheat protection circuit, a square wave generator, an integrator circuit, a decoding and display circuit, a multivibrator circuit, an H-bridge drive circuit, an adder output circuit, and a comparator circuit. The square wave generator output is connected to the integrator input, converting the square wave signal into a triangular wave signal. The integrator output and the adder output are connected to the comparator input. The comparator output is connected to the H-bridge drive input, and the H-bridge drive output is connected to the motor. The comparator circuit converts the triangular wave signal and different voltage signals into square waves with different duty cycles to control the motor speed. The adjustable voltage regulator output is connected to the square wave generator input, the adder output input, the multivibrator input, and another input to the comparator circuit. The multivibrator output is connected to the decoding and display circuit input.

[0006] By adopting the above technical solution, the system is powered by a positive and negative 12V input power supply and a stable output power supply through an adjustable voltage regulator integrated circuit. The entire system has two functions: motor forward and reverse rotation control and multi-speed control via DIP switch. It also has a motor overheat protection circuit and a decoder display that can intuitively indicate the current speed level. It has the advantages of high integration, complete functions, high reliability and good human-machine interaction.

[0007] Preferably, the adjustable voltage regulator circuit includes a positive input voltage, a negative input voltage, a positive adjustable Zener diode LM317, a negative adjustable Zener diode LM337, a positive output voltage, and a negative output voltage. The input terminal of the positive adjustable Zener diode LM317 is electrically connected to the positive input voltage. A positive rheostat RP3 is electrically connected to the adjustment terminal of the positive adjustable Zener diode LM317. A positive fixed resistor R63 is connected in parallel between the adjustment terminal and the output terminal of the positive adjustable Zener diode LM317. The output terminal of the positive adjustable Zener diode LM317 is electrically connected to the positive output voltage. The input terminal of the negative adjustable Zener diode LM337 is electrically connected to the negative input voltage. The adjustment terminal 37 is electrically connected to the negative resistor RP4. A negative fixed resistor R58 is connected in parallel between the adjustment terminal and the output terminal of the negative adjustable Zener diode LM337. The output terminal of the negative adjustable Zener diode LM337 is electrically connected to the negative output voltage. Capacitors C20 and C21 are connected in parallel between the positive input voltage and the positive adjustable Zener diode LM317. Stabilizing capacitors C24 and C25 are connected in parallel between the positive output voltage and the positive adjustable Zener diode LM317. Capacitors C22 and C23 are connected in parallel between the negative input voltage and the negative adjustable Zener diode LM337. Stabilizing capacitors C4 and C2 are connected in parallel between the negative output voltage and the negative adjustable Zener diode LM337.

[0008] By adopting the above technical solution, the 12V positive voltage is adjusted to output a 5V positive voltage through an LM317 adjustable Zener diode, a variable resistor, and a fixed resistor, and then filtered by two capacitors to stabilize the output 5V positive voltage; the 12V negative voltage is adjusted to output a 5V negative voltage through an LM337 adjustable Zener diode, a variable resistor, and a fixed resistor, and then filtered by two capacitors to stabilize the output 5V negative voltage.

[0009] Preferably, the overheat protection circuit includes a thermistor RT1, a relay K1, and a comparator LM358. The third pin of the comparator LM358 is electrically connected to a resistor R61, a variable resistor RP2, a resistor R62, and a capacitor C19. The variable resistor RP2 is connected in series with the resistor R62, and the capacitor C19 is connected in parallel across the variable resistor RP2 and the resistor R62. The second pin of the comparator LM358 is electrically connected to the thermistor RT1 and the resistor R60. The first pin of the comparator LM358 is electrically connected to transistors Q14 and Q15. A resistor R59 is electrically connected between the base and collector of transistor Q14. The circuit also includes a transistor Q13. The collector of transistor Q13 is electrically connected to the first pin of the relay K1, the base of transistor Q13 is electrically connected to a resistor R57, and the emitter of transistor Q13 is grounded.

[0010] By adopting the above technical solution, the motor temperature is detected in real time by a thermistor. When the motor temperature is overheated, the resistance of the thermistor is reduced, thereby changing the output voltage of the voltage divider circuit. When the output voltage starts to change, the voltage of the third pin of the comparator circuit input changes. The second pin is a fixed input, and the change in the first pin output passes through the transistor switching circuit to control the relay to engage and switch the 12V positive voltage working power supply.

[0011] Preferably, the square wave generator and integrator circuit includes a hysteresis comparator LM358. The first pin of the hysteresis comparator LM358 is electrically connected to a resistor R13, a diode D3, and a diode D4. The second pin of the hysteresis comparator LM358 is electrically connected to a resistor R14, the other end of which is grounded. The third pin of the hysteresis comparator LM358 is electrically connected to a resistor R15 and a variable resistor RP1. The fourth pin of the hysteresis comparator LM358 is electrically connected to a capacitor C7, the other end of which is grounded. The fifth pin of the hysteresis comparator LM358 is electrically connected to a resistor R17, the other end of which is grounded. A capacitor C5 is connected in parallel between the sixth and seventh pins of the hysteresis comparator LM358. The sixth pin of the hysteresis comparator LM358 is electrically connected to a resistor R16. The eighth pin of the hysteresis comparator LM358 is electrically connected to a capacitor C6.

[0012] By adopting the above technical solution, the square wave generator circuit consists of a hysteresis comparator composed of one operational amplifier (U4) and an RC negative feedback loop composed of resistors and capacitors. The comparator output voltage is limited by two Zener diodes with identical characteristics. During the comparison process, the output voltage is kept constant by Zener diodes D3 and D4. The circuit works as follows: when the power is turned on, C5 is charged through the resistor, and the voltage rises exponentially over time. When the voltage rises to the threshold, C5 discharges through the resistor, and the voltage begins to drop, returning to the initial state. This cycle repeats, resulting in a square wave output. The integrating circuit is composed of another operational amplifier (U4) integrated into an integrating circuit, which converts the square wave output from the first pin of U4 into a triangular wave.

[0013] Preferably, the decoding and display circuit includes a driver CD4511, a digital tube DS, and a first operational amplifier LM358. The first pin of the driver CD4511 is electrically connected to the seventh pin of the first operational amplifier LM358. A resistor R8 is electrically connected to the second pin of the driver CD4511. A resistor R9 is electrically connected to the sixth pin of the driver CD4511. The thirteenth pin of the driver CD4511 is electrically connected to terminal a of the digital tube DS through a resistor R1. The twelfth pin of the driver CD4511 is electrically connected to terminal b of the digital tube DS through a resistor R2. The eleventh pin of the driver CD4511 is electrically connected to terminal c of the digital tube DS through a resistor R3. The tenth pin of the driver CD4511... Pin 1 is electrically connected to the d terminal of the digital tube DS via resistor R4. Pin 9 of driver CD4511 is electrically connected to the e terminal of digital tube DS via resistor R5. Pin 15 of driver CD4511 is electrically connected to the f terminal of digital tube DS via resistor R6. Pin 14 of driver CD4511 is electrically connected to the g terminal of digital tube DS via resistor R7. Pin 1 and pin 2 of the first operational amplifier LM358 are electrically connected to pin 7 of driver CD4511. Pin 3 of the first operational amplifier LM358 is electrically connected to resistor R10. Pin 5 of the first operational amplifier LM358 is electrically connected to resistor R11. Pin 8 of the first operational amplifier LM358 is electrically connected to capacitor C11.

[0014] By adopting the above technical solution, the decoding and display circuit is a CMOS circuit composed of CD4511, used to drive a common cathode display seven-segment decoder. It features BCD conversion, blanking and latching control, seven-segment decoding, and driving functions, providing a large pull-up current and directly driving LED displays. The second and sixth input pins of the CD4511 are directly pulled low, and the output displays switching between "1" and "2".

[0015] Preferably, the multivibrator circuit includes transistors Q10, Q9, Q11, and Q12. Transistor Q10 is connected in parallel with LED1 and resistor R46. The collector of transistor Q10 is electrically connected to resistor R47. A capacitor C14 and a tactile switch S4 are connected in parallel between the base and emitter of transistor Q10. The base of transistor Q9 is electrically connected to resistor R50. The collector of transistor Q9 is electrically connected to resistor R49 and capacitor C15. The collector of transistor Q11 is electrically connected to resistor R51. The base of transistor Q11 is electrically connected to diode D1. One end of diode D1 is electrically connected to resistor R54, and the other end of diode D1 is electrically connected to capacitor C16. The collector of transistor Q12 is electrically connected to resistor R52. The base of transistor Q12 is electrically connected to diode D2. One end of diode D2 is connected to resistor R53. The other end of diode D2 is electrically connected to capacitor C17.

[0016] By adopting the above technical solution, the multivibrator circuit consists of two parts. The first part is a debouncing circuit composed of a tactile switch and a capacitor, used to switch the output voltage of the multivibrator. The second part connects the collector output of transistor Q11 to the base input of transistor Q12, and the collector output of transistor Q12 is connected to the base input of transistor Q11. After the circuit is powered on, the base bias current is simultaneously provided to the two transistors Q11 and Q12 through the base resistors R54 and R53, causing the two transistors to enter the amplification state. Although the two transistors are of the same type and symmetrical, there will always be slight differences in the circuit parameters, including the two transistors themselves, which means that the conduction degree cannot be exactly the same. Assuming that Q11 conducts faster, the voltage will drop faster. This slight difference will be amplified by Q12 and fed back to the base of Q11. After being amplified by Q11, a chain reaction is formed, which quickly saturates Q11, cuts off Q12, and causes a change in the output voltage.

[0017] Preferably, the H-bridge driver circuit includes transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8. A resistor R28 is electrically connected to the emitter of transistor Q1. A diode D5 is connected in parallel between the base and emitter of transistor Q1. A resistor R24 ​​is electrically connected to the collector of transistor Q2. The base of transistor Q2 is connected between the emitter of transistor Q1 and the base of transistor Q4. A resistor R29 is electrically connected to the collector of transistor Q4. A series resistor R25 and R28 are electrically connected to the base of transistor Q3. 5 and R27, capacitor C10 is electrically connected to the collector of transistor Q3, resistor R32 is electrically connected to the base of transistor Q7, the collector of transistor Q7 is electrically connected to the collector of transistor Q5, resistor R33 is electrically connected to the base of transistor Q8, the collector of transistor Q8 is electrically connected to the collector of transistor Q6, the collector of transistor Q5 is electrically connected to the collector of transistor Q7, diodes D6 and D8 are connected in parallel between the emitters of transistor Q5 and Q7, and diodes D7 and D9 are connected in parallel between the emitters of transistor Q6 and Q8.

[0018] By adopting the above technical solution, in the H-bridge drive circuit, four transistors Q5, Q6, Q7, and Q8 form the four vertical legs of the H-bridge. When Q5 and Q8 are turned on, Q6 and Q7 are turned off, and the current flows from the positive terminal of the power supply through Q5 from left to right through the motor, and then through Q8 back to the negative terminal of the power supply, causing the motor to rotate forward. When Q6 and Q7 are turned on, Q5 and Q8 are turned off, and the motor rotates in reverse. D6, D7, D8, and D9 act as freewheeling diodes, providing protection.

[0019] Preferably, the adder output circuit includes a second operational amplifier LM358 and a switch S2. A resistor R41 is connected in parallel between the first and second pins of the second operational amplifier LM358. A resistor R43 is connected in series with the resistor R41. A resistor R42 is connected in parallel between the sixth and seventh pins of the second operational amplifier LM358. A capacitor C12 is electrically connected to the fourth pin of the second operational amplifier LM358. A resistor R45 is electrically connected to the fifth pin of the second operational amplifier LM358. A capacitor C13 is electrically connected to the eighth pin of the second operational amplifier LM358.

[0020] By adopting the above technical solution, the adder output circuit consists of one operational amplifier in U3 and four voltage-group circuits. By changing the position of the toggle switch, the same voltage is input to the arithmetic unit.

[0021] Preferably, the comparator circuit includes a third operational amplifier LM358, with a resistor R23 electrically connected to the first pin of the third operational amplifier LM358, a resistor R18 electrically connected to the second pin of the third operational amplifier LM358, a resistor R22 electrically connected to the third pin of the third operational amplifier LM358, and a capacitor C8 electrically connected to the eighth pin of the third operational amplifier LM358.

[0022] By adopting the above technical solution, the comparator circuit consists of another operational amplifier U3 and multiple resistors. It generates square waves with different duty cycles from the triangular wave generated by U4 and the different voltages generated by U3, thereby controlling the motor speed. Attached Figure Description

[0023] Figure 1 This is a system diagram of a specific embodiment of the present utility model; Figure 2 This is a schematic diagram illustrating an adjustable voltage regulator circuit according to a specific embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the overheat protection circuit of a specific embodiment of the present invention; Figure 4 This is a schematic diagram illustrating a square wave generator and an integrating circuit according to a specific embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the decoding and display circuit of a specific embodiment of the present invention; Figure 6 This is a schematic diagram illustrating a multivibrator circuit according to a specific embodiment of the present invention; Figure 7 This is a schematic diagram illustrating the H-bridge drive circuit of a specific embodiment of the present invention; Figure 8 This is a schematic diagram illustrating the output circuit of the adder in a specific embodiment of the present invention; Figure 9 This is a schematic diagram illustrating a comparator circuit according to a specific embodiment of the present invention. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] like Figure 1-9As shown, a speed-regulating motor circuit includes an adjustable voltage regulator circuit, an overheat protection circuit, a square wave generator, an integrator circuit, a decoding and display circuit, a multivibrator circuit, an H-bridge drive circuit, an adder output circuit, and a comparator circuit. Specifically: the output of the square wave generator is connected to the input of the integrator circuit, converting the square wave signal into a triangular wave signal; the outputs of the integrator circuit and the adder output circuit are connected to the input of the comparator circuit, the output of the comparator circuit is connected to the input of the H-bridge drive circuit, and the output of the H-bridge drive circuit is connected to the motor. The comparator circuit converts the triangular wave signal and different voltage signals into square waves with different duty cycles to control the motor speed; the output of the adjustable voltage regulator circuit is connected to the input of the square wave generator, the input of the adder output circuit, and the multivibrator circuit. The input terminal and the other input terminal of the comparator circuit, the output terminal of the multivibrator circuit are connected to the input terminal of the decoding and display circuit, and the adjustable voltage regulator circuit includes a positive input voltage, a negative input voltage, a positive adjustable Zener diode LM317, a negative adjustable Zener diode LM337, a positive output voltage, and a negative output voltage. The input terminal of the positive adjustable Zener diode LM317 is electrically connected to the positive input voltage, and the adjustment terminal of the positive adjustable Zener diode LM317 is electrically connected to a positive rheostat RP3. A positive fixed resistor R63 is connected in parallel between the adjustment terminal and the output terminal of the positive adjustable Zener diode LM317, and the output terminal of the positive adjustable Zener diode LM317 is electrically connected to the positive output voltage. The input terminal of the negative adjustable Zener diode LM337 is electrically connected to the negative input voltage, and the negative adjustable Zener diode LM317... The adjustment terminal 37 is electrically connected to the negative resistor RP4. A negative fixed resistor R58 is connected in parallel between the adjustment terminal and the output terminal of the negative adjustable Zener diode LM337. The output terminal of the negative adjustable Zener diode LM337 is electrically connected to the negative output voltage. Capacitors C20 and C21 are connected in parallel between the positive input voltage and the positive adjustable Zener diode LM317. Stabilizing capacitors C24 and C25 are connected in parallel between the positive output voltage and the positive adjustable Zener diode LM317. Capacitors C22 and C23 are connected in parallel between the negative input voltage and the negative adjustable Zener diode LM337. Stabilizing capacitors C4 and C2 are connected in parallel between the negative output voltage and the negative adjustable Zener diode LM337. The overheat protection circuit includes a thermistor RT1, a relay K1, and a comparator LM358. The third pin of the LM358 is electrically connected to resistor R61, variable resistor RP2, resistor R62, and capacitor C19. Variable resistor RP2 is connected in series with resistor R62, and capacitor C19 is connected in parallel across variable resistor RP2 and resistor R62. The second pin of the comparator LM358 is electrically connected to thermistor RT1 and resistor R60. The first pin of the comparator LM358 is electrically connected to transistors Q14 and Q15. Resistor R59 is electrically connected between the base and collector of transistor Q14. The comparator also includes transistor Q13. The collector of transistor Q13 is electrically connected to the first pin of relay K1, and resistor R57 is electrically connected to the base of transistor Q13. The emitter of transistor Q13 is grounded. The square wave generator and integrator circuit include the hysteresis comparator LM358.The first pin of the LM358 hysteresis comparator is electrically connected to resistor R13, diode D3, and diode D4. The second pin is electrically connected to resistor R14, with the other end of R14 grounded. The third pin is electrically connected to resistor R15 and variable resistor RP1. The fourth pin is electrically connected to capacitor C7, with the other end of C7 grounded. The fifth pin is electrically connected to resistor R17, with the other end of R17 grounded. A capacitor C5 is connected in parallel between the sixth and seventh pins. The sixth pin is electrically connected to resistor R16. The eighth pin... A capacitor C6 is electrically connected to the pin. The decoding and display circuit includes a driver CD4511, a digital tube DS, and a first operational amplifier LM358. The first pin of the driver CD4511 is electrically connected to the seventh pin of the first operational amplifier LM358. A resistor R8 is electrically connected to the second pin of the driver CD4511. A resistor R9 is electrically connected to the sixth pin of the driver CD4511. The thirteenth pin of the driver CD4511 is electrically connected to the a terminal of the digital tube DS through a resistor R1. The twelfth pin of the driver CD4511 is electrically connected to the b terminal of the digital tube DS through a resistor R2. The eleventh pin of the driver CD4511 is electrically connected to the c terminal of the digital tube DS through a resistor R3. The tenth pin of the driver CD4511 is electrically connected to the c terminal of the digital tube DS through a resistor R4. The circuit is electrically connected to the d terminal of the digital tube DS. The ninth pin of the driver CD4511 is electrically connected to the e terminal of the digital tube DS via resistor R5. The fifteenth pin of the driver CD4511 is electrically connected to the f terminal of the digital tube DS via resistor R6. The fourteenth pin of the driver CD4511 is electrically connected to the g terminal of the digital tube DS via resistor R7. The first and second pins of the first operational amplifier LM358 are electrically connected to the seventh pin of the driver CD4511. The third pin of the first operational amplifier LM358 is electrically connected to resistor R10. The fifth pin of the first operational amplifier LM358 is electrically connected to resistor R11. The eighth pin of the first operational amplifier LM358 is electrically connected to capacitor C11. The multivibrator circuit includes transistor Q10, transistor... Transistors Q9, Q11, and Q12 are connected in parallel. Transistor Q10 is connected in parallel with LED1 and resistor R46. Resistor R47 is connected to the collector of transistor Q10. Capacitor C14 and tactile switch S4 are connected in parallel between the base and emitter of transistor Q10. Resistor R50 is connected to the base of transistor Q9. Resistor R49 and capacitor C15 are connected to the collector of transistor Q9. Resistor R51 is connected to the collector of transistor Q11. Diode D1 is connected to the base of transistor Q11. Resistor R54 is connected to one end of diode D1, and capacitor C16 is connected to the other end of diode D1. Resistor R52 is connected to the collector of transistor Q12. Diode D2 is connected to the base of transistor Q12.One end of diode D2 is connected to resistor R53, and the other end of diode D2 is electrically connected to capacitor C17. The H-bridge driver circuit includes transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8. The emitter of transistor Q1 is electrically connected to resistor R28, and diode D5 is connected in parallel between the base and emitter of transistor Q1. The collector of transistor Q2 is electrically connected to resistor R24, and the base of transistor Q2 is electrically connected between the emitter of transistor Q1 and the base of transistor Q4. The collector of transistor Q3 is connected to resistor R29. The base of transistor Q3 is connected to resistors R25, R25, and R27 in series. The collector of transistor Q3 is connected to capacitor C10. The base of transistor Q7 is connected to resistor R32. The collector of transistor Q7 is connected to the collector of transistor Q5. The base of transistor Q8 is connected to resistor R33. The collector of transistor Q8 is connected to the collector of transistor Q6. The collector of transistor Q5 is connected to the collector of transistor Q7. The emitter of transistor Q5... Diodes D6 and D8 are connected in parallel between the emitter of transistor Q7 and the emitter of transistor Q8. Diodes D7 and D9 are connected in parallel between the emitters of transistors Q6 and Q8. The adder output circuit includes a second operational amplifier LM358 and a switch S2. A resistor R41 is connected in parallel between the first and second pins of the second operational amplifier LM358. A resistor R43 is connected in series with R41. A resistor R42 is connected in parallel between the sixth and seventh pins of the second operational amplifier LM358. The fourth pin of the second operational amplifier LM358 is electrically connected to... A capacitor C12 is connected to the first pin. A resistor R45 is electrically connected to the fifth pin of the second operational amplifier LM358, and a capacitor C13 is electrically connected to the eighth pin of the second operational amplifier LM358. The comparator circuit includes a third operational amplifier LM358. A resistor R23 is electrically connected to the first pin of the third operational amplifier LM358, a resistor R18 is electrically connected to the second pin of the third operational amplifier LM358, a resistor R22 is electrically connected to the third pin of the third operational amplifier LM358, and a capacitor C8 is electrically connected to the eighth pin of the third operational amplifier LM358.

[0026] With this setup, the circuit receives a ±12V power supply, which is then used to power the entire system via an adjustable voltage regulator. The system has two functions: motor forward and reverse rotation control and multi-speed control via DIP switches. It also includes a motor overheat protection circuit and a decoder display that clearly indicates the current speed level. The system is highly integrated, feature-rich, highly reliable, and offers excellent human-machine interaction.

[0027] Furthermore, in the adjustable voltage regulator circuit, the 12V positive voltage is adjusted to a 5V positive output through an LM317 adjustable Zener diode, a variable resistor, and a fixed resistor, and then filtered by two capacitors to stabilize the 5V positive output. Similarly, the 12V negative voltage is adjusted to a 5V negative output through an LM337 adjustable Zener diode, a variable resistor, and a fixed resistor, and then filtered by two capacitors to stabilize the 5V negative output. In the overheat protection circuit, a thermistor monitors the motor temperature in real time. When the motor overheats, the thermistor's resistance decreases, thereby altering the output of the voltage divider circuit. When the output voltage starts to change, the voltage at the third pin of the comparator circuit input changes. The second pin is a fixed input, and the change at the first pin output passes through a transistor switching circuit, controlling the relay to engage and switching the 12V positive voltage operating power supply. The square wave generator circuit consists of a hysteresis comparator composed of an operational amplifier (U4) and an RC negative feedback loop composed of resistors and capacitors. The comparator output voltage is limited by two Zener diodes with identical characteristics. During the comparison process, the output voltage is kept constant by Zener diodes D3 and D4. The circuit works as follows: when the power is turned on, C5 is charged through the resistor, and the voltage rises exponentially over time. When the voltage reaches the threshold, C5 discharges through the resistor, and the voltage begins to drop, returning to the initial state. This cycle repeats continuously, resulting in a square wave output. The integrating circuit is composed of another operational amplifier integrated with U4, which transforms the square wave output from the first pin of U4 into a triangular wave. The decoding and display circuit is a CD4511-based CMOS circuit used to drive a common cathode display seven-segment decoder. It features BCD conversion, blanking and latching control, seven-segment decoding, and driving functions, providing a large pull-up current and directly driving LED displays. The second and sixth input pins of the CD4511 are directly pulled low, and the output switches between "1" and "2". The multivibrator circuit consists of two parts. The first part is a debouncing circuit composed of a tactile switch and a capacitor, used to switch the output voltage of the multivibrator. The second part connects the collector output of transistor Q11 to the base input of transistor Q12, and the collector output of transistor Q12 is connected to the base input of transistor Q11. After the circuit is powered on, the base bias current is simultaneously provided to the two transistors Q11 and Q12 through the base resistors R54 and R53, causing the two transistors to enter the amplification state. Although the two transistors are of the same model and symmetrical, there will always be slight differences in the circuit parameters, including the two transistors themselves, which means that the conduction degree cannot be exactly the same. Assuming that Q11 conducts faster, the voltage will drop faster.This tiny difference will be amplified by Q12 and fed back to the base of Q11. After being amplified by Q11, a chain reaction occurs, quickly saturating Q11 and cutting off Q12, resulting in a voltage change in the output. In the H-bridge drive circuit, four transistors Q5, Q6, Q7, and Q8 form the four vertical legs of the H-bridge. When Q5 and Q8 are turned on, Q6 and Q7 are turned off, and the current flows from the positive terminal of the power supply through Q5 from left to right through the motor, and then back to the negative terminal of the power supply through Q8, causing the motor to rotate forward. When Q6 and Q7 are turned on, Q5 and Q8 are turned off, and the motor rotates in reverse. D6, D7, D8, and D9 act as freewheeling diodes, providing protection. The adder output circuit consists of one operational amplifier in U3 and four voltage-group circuits. By changing the position of the toggle switch, the same voltage is input to the arithmetic unit. The comparator circuit consists of the other operational amplifier in U3 and multiple resistors. It converts the triangular wave generated by U4 and the different voltages generated by U3 into square waves with different duty cycles to control the motor speed.

[0028] The circuit works as follows: First, connect the power supply (±12V), adjust RP2 to light up LED1, and relay K1 will operate. However, when the temperature sensor RT1 detects high temperature, LED1 will turn off, relay K1 will not operate, and the simulated motor will automatically shut off due to overheating. Pressing switch S4 switches the display of digital tube DS1 between "1" and "2", and simultaneously switches the rotation direction of motor M1 between "clockwise" and "counterclockwise". Adjusting DIP switch S2 changes the motor speed, with a total of 16 possible speed variations.

[0029] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A speed-regulated motor circuit, characterized by It includes an adjustable voltage regulator circuit, an overheat protection circuit, a square wave generator, an integrator circuit, a decoding and display circuit, a multivibrator circuit, an H-bridge driver circuit, an adder output circuit, and a comparator circuit, among which: The output of the square wave generator is connected to the input of the integrator circuit to convert the square wave signal into a triangular wave signal. The output of the integrator circuit and the output of the adder circuit are connected to the input of the comparator circuit. The output of the comparator circuit is connected to the input of the H-bridge drive circuit. The output of the H-bridge drive circuit is connected to the motor. The comparator circuit converts the triangular wave signal and different voltage signals into square waves with different duty cycles to control the motor speed. The output of the adjustable voltage regulator circuit is connected to the input of the square wave generator, the input of the adder output circuit, the input of the multivibrator circuit, and the other input of the comparator circuit. The output of the multivibrator circuit is connected to the input of the decoding and display circuit.

2. A motor speed regulation circuit according to claim 1, wherein The adjustable voltage regulator circuit includes a positive input voltage, a negative input voltage, a positive adjustable Zener diode LM317, a negative adjustable Zener diode LM337, a positive output voltage, and a negative output voltage. The input terminal of the positive adjustable Zener diode LM317 is electrically connected to the positive input voltage, and the adjustment terminal of the positive adjustable Zener diode LM317 is electrically connected to a positive rheostat RP3. A positive fixed resistor R63 is connected in parallel between the adjustment terminal and the output terminal of the positive adjustable Zener diode LM317, and the output terminal of the positive adjustable Zener diode LM317 is electrically connected to the positive output voltage. The input terminal of the negative adjustable Zener diode LM337 is electrically connected to the negative input voltage. The adjustment terminal is electrically connected to the negative pole rheostat RP4. A negative pole fixed resistor R58 is connected in parallel between the adjustment terminal and the output terminal of the negative pole adjustable Zener diode LM337. The output terminal of the negative pole adjustable Zener diode LM337 is electrically connected to the negative output voltage. Capacitors C20 and C21 are connected in parallel between the positive input voltage and the positive pole adjustable Zener diode LM317. Stabilizing capacitors C24 and C25 are connected in parallel between the positive output voltage and the positive pole adjustable Zener diode LM317. Capacitors C22 and C23 are connected in parallel between the negative input voltage and the negative pole adjustable Zener diode LM337. Stabilizing capacitors C4 and C2 are connected in parallel between the negative output voltage and the negative pole adjustable Zener diode LM337.

3. A motor speed regulation circuit according to claim 1, wherein The overheat protection circuit includes a thermistor RT1, a relay K1, and a comparator LM358. The third pin of the comparator LM358 is electrically connected to a resistor R61, a variable resistor RP2, a resistor R62, and a capacitor C19. The variable resistor RP2 is connected in series with the resistor R62, and the capacitor C19 is connected in parallel across the variable resistor RP2 and the resistor R62. The second pin of the comparator LM358 is electrically connected to the thermistor RT1 and a resistor R60. The first pin of the comparator LM358 is electrically connected to transistors Q14 and Q15. A resistor R59 is electrically connected between the base and collector of transistor Q14. The circuit also includes a transistor Q13. The collector of transistor Q13 is electrically connected to the first pin of the relay K1, and a resistor R57 is electrically connected to the base of transistor Q13. The emitter of transistor Q13 is grounded.

4. A speed regulating motor circuit according to claim 1, wherein The square wave generator and integrator circuit includes a hysteresis comparator LM358. The first pin of the hysteresis comparator LM358 is electrically connected to resistor R13, diode D3, and diode D4. The second pin of the hysteresis comparator LM358 is electrically connected to resistor R14, with the other end of resistor R14 grounded. The third pin of the hysteresis comparator LM358 is electrically connected to resistor R15 and variable resistor RP1. The fourth pin of the hysteresis comparator LM358 is electrically connected to capacitor C7, with the other end of capacitor C7 grounded. The fifth pin of the hysteresis comparator LM358 is electrically connected to resistor R17, with the other end of resistor R17 grounded. A capacitor C5 is connected in parallel between the sixth and seventh pins of the hysteresis comparator LM358. The sixth pin of the hysteresis comparator LM358 is electrically connected to resistor R16. The eighth pin of the hysteresis comparator LM358 is electrically connected to capacitor C6.

5. A speed regulating motor circuit according to claim 1, wherein, The decoding and display circuit includes a driver CD4511, a digital tube DS, and a first operational amplifier LM358. The first pin of the driver CD4511 is electrically connected to the seventh pin of the LM358. A resistor R8 is electrically connected to the second pin of the driver CD4511. A resistor R9 is electrically connected to the sixth pin of the driver CD4511. The thirteenth pin of the driver CD4511 is electrically connected to the a terminal of the digital tube DS through a resistor R1. The twelfth pin of the driver CD4511 is electrically connected to the b terminal of the digital tube DS through a resistor R2. The eleventh pin of the driver CD4511 is electrically connected to the c terminal of the digital tube DS through a resistor R3. The tenth pin of the driver CD4511... Resistor R4 is electrically connected to the d terminal of the digital tube DS. The ninth pin of driver CD4511 is electrically connected to the e terminal of digital tube DS through resistor R5. The fifteenth pin of driver CD4511 is electrically connected to the f terminal of digital tube DS through resistor R6. The fourteenth pin of driver CD4511 is electrically connected to the g terminal of digital tube DS through resistor R7. The first and second pins of the first operational amplifier LM358 are electrically connected to the seventh pin of driver CD4511. The third pin of the first operational amplifier LM358 is electrically connected to resistor R10. The fifth pin of the first operational amplifier LM358 is electrically connected to resistor R11. The eighth pin of the first operational amplifier LM358 is electrically connected to capacitor C11.

6. A speed regulating motor circuit according to claim 1, wherein, The multivibrator circuit includes transistors Q10, Q9, Q11, and Q12. Transistor Q10 is connected in parallel with LED1 and resistor R46. The collector of transistor Q10 is electrically connected to resistor R47. A capacitor C14 and a tactile switch S4 are connected in parallel between the base and emitter of transistor Q10. The base of transistor Q9 is electrically connected to resistor R50. The collector of transistor Q9 is electrically connected to resistor R49 and capacitor C15. The collector of transistor Q11 is electrically connected to resistor R51. The base of transistor Q11 is electrically connected to diode D1. One end of diode D1 is electrically connected to resistor R54, and the other end of diode D1 is electrically connected to capacitor C16. The collector of transistor Q12 is electrically connected to resistor R52. The base of transistor Q12 is electrically connected to diode D2. One end of diode D2 is connected to resistor R53. The other end of diode D2 is electrically connected to capacitor C17.

7. A speed regulating motor circuit according to claim 1, wherein The H-bridge driver circuit includes transistors Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8. A resistor R28 is electrically connected to the emitter of transistor Q1. A diode D5 is connected in parallel between the base and emitter of transistor Q1. A resistor R24 ​​is electrically connected to the collector of transistor Q2. The base of transistor Q2 is connected between the emitter of transistor Q1 and the base of transistor Q4. A resistor R29 is electrically connected to the collector of transistor Q4. A series resistor R25 is electrically connected to the base of transistor Q3. R27, capacitor C10 is electrically connected to the collector of transistor Q3, resistor R32 is electrically connected to the base of transistor Q7, the collector of transistor Q7 is electrically connected to the collector of transistor Q5, resistor R33 is electrically connected to the base of transistor Q8, the collector of transistor Q8 is electrically connected to the collector of transistor Q6, the collector of transistor Q5 is electrically connected to the collector of transistor Q7, diodes D6 and D8 are connected in parallel between the emitters of transistor Q5 and Q7, and diodes D7 and D9 are connected in parallel between the emitters of transistor Q6 and Q8.

8. A speed regulating motor circuit according to claim 1, wherein, The adder output circuit includes a second operational amplifier LM358 and a DIP switch S2. A resistor R41 is connected in parallel between the first and second pins of the second operational amplifier LM358. A resistor R43 is connected in series with the first pin of the second operational amplifier LM358. A resistor R42 is connected in parallel between the sixth and seventh pins of the second operational amplifier LM358. A capacitor C12 is electrically connected to the fourth pin of the second operational amplifier LM358. A resistor R45 is electrically connected to the fifth pin of the second operational amplifier LM358. A capacitor C13 is electrically connected to the eighth pin of the second operational amplifier LM358.

9. A speed-regulating motor circuit according to claim 1, characterized in that, The comparator circuit includes a third operational amplifier LM358. The first pin of the third operational amplifier LM358 is electrically connected to a resistor R23, the second pin of the third operational amplifier LM358 is electrically connected to a resistor R18, the third pin of the third operational amplifier LM358 is electrically connected to a resistor R22, and the eighth pin of the third operational amplifier LM358 is electrically connected to a capacitor C8.

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