A direct current motor rotation direction controller

Abstract

The application discloses a DC motor rotation direction controller, which comprises a PCB plate with a motor direction control signal input circuit arranged in the controller, and motor direction control signal input circuit, control signal under-voltage protection circuit, circuit power under-voltage protection circuit and control signal input range adjustment circuit are arranged on the PCB plate. The application changes the polarity of the power supply by using a power electronic full-bridge power circuit, replaces the mechanical electromagnetic relay for controlling the rotation direction of the motor through the contact, improves the reliability of the DC motor rotation direction controller, and meanwhile, the control signal under-voltage protection circuit and the circuit power under-voltage protection circuit are arranged, so that the power electronic device can be prevented from being damaged due to unsaturated conduction, and in addition, the control signal input range adjustment circuit is arranged, so that the change of the optical coupling input voltage of the control signal can be realized, and the applicability of the circuit is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of motor circuit design, and particularly relates to a DC motor rotation direction controller. BACKGROUND

[0002] At present, DC motors are widely used in many occasions, such as in electric push rods, DC motors are usually used for driving control of back-and-forth movement, and the DC motor in the electric push rod is mostly controlled in rotation direction by a relay, and by controlling the attraction or disconnection of different contacts of the relay, the positive or negative polarity of the voltage applied to the DC motor can be changed, so as to realize the rotation direction control of the DC motor.

[0003] However, when the electromagnetic mechanical relay controls the on-off of the DC motor, the mechanical metal contact is easy to produce arc burning to increase the on-resistance, and the spring has problems such as elastic fatigue and contact on-off signal oscillation, which leads to high failure rate, short service life and low reliability of the relay for controlling the rotation direction of the DC motor. SUMMARY

[0004] The present application aims to provide a DC motor rotation direction controller to solve the problems in the background art.

[0005] To achieve the above purpose, one technical solution adopted by the present application is: a PCB board with a motor direction control signal input circuit is arranged in a controller, an input end of the controller is connected to an AC / DC converter so that the PCB board is connected to 24V voltage and a stable DC is passed in, an output end of the controller is connected to a motor, and the PCB board of the motor direction control signal input circuit is provided with a motor forward rotation control signal pin In_F and a motor reverse rotation control signal pin In_R for adjusting the rotation direction of the motor.

[0006] The motor direction control signal input circuit comprises a motor forward rotation control signal circuit, a motor reverse rotation control signal circuit, a two-way drive signal forming circuit and an H-bridge drive circuit, the motor forward rotation control signal circuit comprises a diode D3, a PNP triode Q0, an isolation optocoupler G1, a PNP triode Q5, voltage dividing current limiting resistors R4, R6 and R7.

[0007] Specifically, the anode of the diode at the input terminal of the isolation optocoupler G1 is connected to the collector (c) of the PNP transistor Q0, and the cathode of the diode at the input terminal of the isolation optocoupler G1 is connected to the emitter (e) of the PNP transistor Q5. The base (b) of the PNP transistor Q5 is connected to the common terminal pin COM via resistors R7 and R4. The collector (c) of the PNP transistor Q5 is connected to the common terminal COM via resistor R6. The forward rotation control signal pin In_F of the motor is connected to the anode of diode D3, and the cathode of diode D3 is connected to the emitter (e) of the PNP transistor Q0. One end of resistor R6 connected to the common terminal COM is also connected to the base (b) of the PNP transistor Q0.

[0008] The motor reverse rotation control signal circuit includes diode D2, PNP transistor Q0, isolation optocoupler G2, PNP transistor Q6, voltage divider and current limiting resistors R5, R6, and R8.

[0009] Specifically, the anode of the diode at the input terminal of the isolation optocoupler G2 is connected to the collector (c) of the PNP transistor Q0, the cathode of the diode at the input terminal of the isolation optocoupler G2 is connected to the emitter (e) of the PNP transistor Q6, the base (b) of the PNP transistor Q6 is connected to the common terminal pin COM via R8 and R5, and the collector (c) of the PNP transistor Q6 is connected to the common terminal COM via R6. The collectors of the PNP transistor Q6 and the PNP transistor Q5 are connected to the same end of R6. The motor reverse rotation control signal pin In_R is connected to the anode of D2, and the cathode of D2 is connected to the emitter (e) of the PNP transistor Q0.

[0010] In addition, In_R is connected between R7 and R4 so that the voltage signal is divided by R7 and then connected to the base of PNP transistor Q5. In_F is connected between R8 and R5 so that the voltage signal is divided by R8 and then connected to the base of PNP transistor Q6. The collector of the output terminal of the isolation optocoupler G1 is connected to a voltage divider resistor R11 and then connected to the circuit power supply. The collector of the output terminal of the isolation optocoupler G2 is connected to a voltage divider resistor R12 and then connected to the circuit power supply. Among them, diodes D2 and D3, resistors R4, R7, R5 and R8, and PNP transistors Q5 and Q6 together form the anti-short-through interlock protection circuit for the motor forward rotation control signal circuit and the motor reverse rotation control signal circuit.

[0011] The dual-path drive signal forming circuit is used to convert the signal O_G1 emitted from the emitter of the transistor at the output terminal of the isolation optocoupler G1 into a high-potential signal LB and a low-potential signal HA, and to convert the signal O_G2 emitted from the emitter of the transistor at the output terminal of the isolation optocoupler G2 into a high-potential signal LA and a low-potential signal HB.

[0012] The H-bridge drive circuit includes P-MOS transistors Q1 and Q2, and P-MOS transistors Q3 and Q4, on the same bridge arm. The source (S) of P-MOS transistors Q1 and Q3 are connected to the circuit power supply. The drain (D) of P-MOS transistor Q1 is connected to the drain of N-MOS transistor Q2, and the drain of P-MOS transistor Q3 is connected to the drain of N-MOS transistor Q4. The source (S) of N-MOS transistors Q2 and Q4 are grounded together. One end of the motor DCM is connected to the drains of Q1 and Q2. The low-potential signal HA of the isolation optocoupler G1, converted by the dual-path drive signal forming circuit, is connected to Q1, and the high-potential signal LB is connected to Q4. The low-potential signal HB of the isolation optocoupler G2, converted by the dual-path drive signal forming circuit, is connected to Q3, and the high-potential signal LA is connected to Q2.

[0013] Preferably, the dual-path drive signal forming circuit includes diodes D4, D5, D10, and D11; transistors Q7, Q8, Q9, and Q10; and voltage divider resistors R13, R14, R15, R16, R21, R22, R25, and R26. Specifically, the cathodes of diodes D4 and D5 are interconnected, the anode of diode D4 is connected to the circuit power supply via R9, and the anode of diode D5 is connected to the power supply via R10. The end of diode D4 connected to R9 is also connected to the base (b) of Q7, and the end of diode D5 connected to R10 is also connected to the base (b) of Q8. The cathodes of diodes D10 and D11 are interconnected, the anode of diode D10 is connected to the circuit power supply via R29, and the anode of diode D11 is connected to the power supply via R30. The end of diode D10 connected to R29 is also connected to the base (b) of Q9. One end of diode D11 connected to R30 is simultaneously connected to the base (b) of Q10; the emitter (e) of Q7 is grounded after passing through voltage divider resistors R13 and R15 in sequence, and the emitter of Q9 is grounded after passing through R25 and R21 in sequence. The collectors (c) of Q7 and Q9 are simultaneously connected to the circuit power supply. The emitters of Q8 and Q10 are simultaneously grounded. The collector of Q8 is connected to the power supply after passing through R14 and R16 in sequence, and the collector of Q10 is connected to the circuit power supply after passing through R26 and R22 in sequence. A shoot-through interlock protection diode D6 is connected to the end of Q8's collector connected to R21 and R25. The anode of D6 is connected to R21, and the cathode of D6 is connected to the collector of Q8. A shoot-through interlock protection diode D9 is connected between Q10's collector and R13 and R15. The anode of D9 is connected to R15, and the cathode of D9 is connected to the collector of Q10.

[0014] Specifically, the signal O_G1 output by the isolation optocoupler G1 is connected to the cathodes of D4 and D5. The high-potential signal LB converted from the signal O_G1 output by the isolation optocoupler G1 is output at the end connected by R13 and R15 and connected to the gate (G) of Q4. The low-potential signal HA is output at the end connected by R14 and R16 and connected to the gate (G) of Q1. The signal O_G2 output by the isolation optocoupler G2 is connected to the cathodes of D10 and D11. The high-potential signal LA converted from the signal O_G2 output by the isolation optocoupler G2 is output at the end connected by R21 and R25 and connected to the gate (G) of Q2. The low-potential signal HB is output at the end connected by R22 and R26 and connected to the gate (G) of Q3.

[0015] In the dual-path drive signal forming circuit, diodes D4, D5, D10, D11 and NPN transistors Q7, Q8, Q9, Q10 together form the anti-straight-through interlock protection circuit of the dual-path drive signal forming circuit.

[0016] Preferably, the motor forward rotation control signal circuit and the motor reverse rotation control signal circuit are further connected to a control signal undervoltage protection circuit, which includes a Zener diode WD1, resistors R1 and R2, and a PNP transistor Q0.

[0017] Specifically, Zener diode WD1 is connected between resistor R6 and PNP transistor Q0. The anode of Zener diode WD1 is connected to resistor R6, and the cathode of Zener diode WD1 is connected to the base of PNP transistor Q0. Resistor R1 is connected between Zener diode WD1 and the base of PNP transistor Q0. One end of resistor R2 is connected to the cathode of diode D3, and the other end of resistor R2 is connected to the base of PNP transistor Q0.

[0018] Preferably, a circuit power supply undervoltage protection circuit is connected between the motor direction control signal input circuit and the dual-path drive signal forming circuit. The circuit power supply undervoltage protection circuit includes a positive feedback hysteresis voltage comparator composed of a voltage comparator U1A, a Zener diode WD7, and resistors R19, R23, and R27 to provide undervoltage protection when the motor rotates in the forward direction, and a positive feedback hysteresis voltage comparator composed of a voltage comparator U2A, a Zener diode WD8, and resistors R24, R20, and R28 to provide undervoltage protection when the motor rotates in the reverse direction.

[0019] Specifically, the signal output from the emitter of the optocoupler G1 is directly connected to the non-inverting input of U1A. Simultaneously, the signal output from the emitter of the optocoupler G1 is grounded after passing through resistor R19. The output of U1A is grounded after passing through resistors R27 and R19 in sequence. The emitter of the output of the optocoupler G1 is simultaneously connected to one end of the connection between R19 and R27. The inverting input of U1A is grounded after passing through resistor R17. The anode of the Zener diode WD7 is grounded, and its cathode is connected to the circuit power supply after passing through resistor R23. The end of the Zener diode WD7 connected to R23 is simultaneously connected to the inverting input of U1A, providing a reference voltage Vref1 to U1A. After the voltage comparator U1A compares the reference voltage Vref1 with the voltage signal O_G1 output by the optocoupler G1, it outputs a voltage signal DYBH1, which is connected to the cathodes of diodes D4 and D5 to convert it into a high-potential signal LB and a low-potential signal HA in the dual-channel drive signal forming circuit.

[0020] The signal output from the emitter of the optocoupler G2 is directly connected to the non-inverting input of U2A. Simultaneously, the signal output from the emitter of the optocoupler G2 is grounded after passing through resistor R20. The output of U2A is grounded after passing through resistors R28 and R20 in sequence. The emitter of the output of the optocoupler G2 is simultaneously connected to one end of the connection between R20 and R28. The inverting input of U2A is grounded after passing through resistor R18. The anode of the Zener diode WD8 is grounded, and its cathode is connected to the circuit power supply after passing through resistor R24. The end of the Zener diode WD8 connected to resistor R24 ​​is simultaneously connected to the inverting input of U2A, providing a reference voltage Vref 2 to U2A. After the voltage comparator U2A compares the reference voltage Vref 2 with the voltage signal O_G2 output from the optocoupler G2, it outputs a voltage signal DYBH2, which is connected to the cathodes of diodes D10 and D11. This is converted into a high-potential signal LA and a low-potential signal HB in the dual-channel drive signal forming circuit.

[0021] Preferably, the motor forward rotation control signal circuit and the motor reverse rotation control signal circuit are further equipped with a control signal input range adjustment circuit. The control signal input range adjustment circuit includes a TV pin with one end empty and a TI pin with one end empty. The terminal of the TV pin is connected to the cathode of the Zener diode WD1. The terminal of the TI pin is connected to the collector of the PNP transistor Q6 after passing through a resistor R3. The collectors of the PNP transistor Q6 and the PNP transistor Q5 are interconnected. The input voltage of the control signal is changed by connecting the Zener diode WD0 between the TV pin and the common terminal COM, and connecting a matching resistor R0 between the TI pin and the common terminal COM. The Zener diodes WD0 and WD1 are reverse biased and connected in parallel. In addition, when the required control signal voltage is less than 8V, the TV pin and the common terminal COM are shorted.

[0022] Preferably, a 6.8V~8.2V Zener diode WD0 is connected between the TV pin and the common terminal COM, and a 4.7k current-limiting resistor R0 is connected between the TI pin and the common terminal COM. The circuit is adjusted to a 12V control signal input circuit.

[0023] Preferably, the TV pin and the common terminal COM are shorted, and a 1k current-limiting resistor R0 is connected between the TI pin and the common terminal COM, and the circuit is adjusted to a 5V control signal input circuit.

[0024] The beneficial effects of this invention are:

[0025] 1. This invention replaces relays containing mechanical contacts with an electronic DC motor rotation direction controller constructed using contactless power electronic devices. When changing the rotation direction of the DC motor, the forward or reverse rotation of the DC motor can be achieved by connecting a high-potential signal to one of the pins In_F or In_R. This avoids the problem of arcing and burning that easily occurs in mechanical metal contact motor direction controllers, which increases the on-resistance.

[0026] 2. This invention achieves interlocking of the forward and reverse rotation direction control signals of the input isolation optocouplers G1 and G2 through the functions of diodes D2 and D3 and PNP transistors Q5 and Q6, so that the rotation direction of the motor is determined and unique, ensuring that the same bridge arm switching devices do not simultaneously conduct drive signals, and reliably preventing the occurrence of shoot-through short circuit fault conditions.

[0027] 3. This invention uses diodes D4, D5, D10, D11 and NPN transistors Q7, Q8, Q9, Q10 to form a dual-path drive signal forming circuit with a shoot-through interlock protection circuit. This allows the controller to interlock the forward and reverse rotation drive signals under any malfunction, preventing a full-bridge shoot-through short circuit fault caused by the simultaneous conduction of two MOS transistors (Q1, Q2 or Q3, Q4) on the same bridge arm of the full-bridge circuit, thus improving the reliability of the full-bridge circuit.

[0028] 4. By setting the Zener diode WD1 and resistors R1 and R2, this invention avoids the transistor Q0 from conducting under low voltage conditions, ensuring that the signal through the PNP transistor Q0 is within a stable range.

[0029] 5. This invention uses positive feedback hysteresis voltage comparators U1A and U2A to form a circuit power supply undervoltage protection circuit. In the case of low power supply voltage, it can prevent power electronic devices from being damaged due to unsaturated conduction, realize undervoltage protection of load voltage, eliminate circuit oscillation, and improve the anti-interference capability of the product.

[0030] 6. This invention uses a single optocoupler to form dual-channel non-bridge arm switching transistor drive signals, thus halving the number of optocouplers used.

[0031] 7. This invention allows for the independent setting of the control signal input voltage value by connecting external components between the TI pin and the common terminal COM and between the TV pin and the common terminal COM, making the optocoupler input control signal voltage applicable in ranges such as 5V, 12V, and 24V. Attached Figure Description

[0032] Figure 1 This is the overall circuit diagram of the DC motor rotation direction controller of the present invention;

[0033] Figure 2 This is a circuit diagram of the motor forward rotation control signal of the present invention;

[0034] Figure 3 This is a circuit diagram of the motor reverse rotation control signal of the present invention;

[0035] Figure 4 This is a circuit diagram showing the connection between the motor forward rotation control signal circuit and the motor reverse rotation control signal circuit of the present invention.

[0036] Figure 5(a) is a schematic diagram of the H-bridge drive circuit and the forward flow of load current of the present invention;

[0037] Figure 5(b) is a schematic diagram of the H-bridge drive circuit and the reverse flow of load current of the present invention;

[0038] Figure 6 This is a circuit diagram of the dual-channel drive signal forming circuit of the present invention;

[0039] Figure 7 This invention relates to a circuit power supply undervoltage protection circuit.

[0040] Figure 8 This invention relates to a circuit power supply undervoltage protection circuit.

[0041] Figure 9 This is the 12V control signal input circuit of the present invention;

[0042] Figure 10 This is the 5V control signal input circuit of the present invention;

[0043] Figure 11 This is a table showing the relationship between the motor rotation direction control signal and the motor operating state according to the present invention;

[0044] Figure 12 This is a table showing the relationship between the output signal of the voltage comparator of the present invention and the motor operating state. Detailed Implementation

[0045] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention. Example

[0046] See Figure 1 A DC motor rotation direction controller includes a PCB board with a motor direction control signal input circuit disposed within the controller. The input terminal of the controller is connected to an AC / DC converter, allowing the PCB board to receive a 24V voltage and a stable DC power supply. The output terminal of the controller is connected to the motor. The PCB board of the motor direction control signal input circuit is provided with a motor forward rotation control signal pin In_F and a motor reverse rotation control signal pin In_R for adjusting the motor rotation direction. The motor direction control signal input circuit includes a motor forward rotation control signal circuit, a motor reverse rotation control signal circuit, a dual-path drive signal forming circuit, and an H-bridge drive circuit. The PCB board is also provided with a control signal input range adjustment circuit, a control signal undervoltage protection circuit, a circuit power supply undervoltage protection circuit, a shoot-through interlock protection circuit for the motor forward rotation control signal circuit and the motor reverse rotation control signal circuit, and a shoot-through interlock protection circuit for the dual-path drive signal forming circuit.

[0047] The circuit of the DC motor rotation direction controller consists of a motor direction control signal input circuit, a control signal input range adjustment circuit, a control signal undervoltage protection circuit, and a circuit power supply undervoltage protection circuit.

[0048] See Figure 2 , Figure 3 , Figure 4 The forward rotation control signal circuit of the motor includes diode D3, PNP transistor Q0, isolation optocoupler G1, PNP transistor Q5, voltage divider and current limiting resistors R4, R6, and R7.

[0049] Specifically, the anode of the diode at the input terminal of the isolation optocoupler G1 is connected to the collector (c) of the PNP transistor Q0, and the cathode of the diode at the input terminal of the isolation optocoupler G1 is connected to the emitter (e) of the PNP transistor Q5. The base (b) of the PNP transistor Q5 is connected to the common terminal pin COM via resistors R7 and R4. The collector (c) of the PNP transistor Q5 is connected to the common terminal COM via resistor R6. The forward rotation control signal pin In_F of the motor is connected to the anode of diode D3, and the cathode of diode D3 is connected to the emitter (e) of the PNP transistor Q0. One end of resistor R6 connected to the common terminal COM is also connected to the base (b) of the PNP transistor Q0.

[0050] The motor reverse rotation control signal circuit includes diode D2, PNP transistor Q0, isolation optocoupler G2, PNP transistor Q6, voltage divider and current limiting resistors R5, R6, and R8;

[0051] Specifically, the anode of the diode at the input terminal of the isolation optocoupler G2 is connected to the collector (c) of the PNP transistor Q0, the cathode of the diode at the input terminal of the isolation optocoupler G2 is connected to the emitter (e) of the PNP transistor Q6, the base (b) of the PNP transistor Q6 is connected to the common terminal pin COM via R8 and R5, and the collector (c) of the PNP transistor Q6 is connected to the common terminal COM via R6. The collectors of the PNP transistor Q6 and the PNP transistor Q5 are connected to the same end of R6. The motor reverse rotation control signal pin In_R is connected to the anode of D2, and the cathode of D2 is connected to the emitter (e) of the PNP transistor Q0.

[0052] In addition, In_R is connected between R7 and R4 so that the voltage signal is divided by R7 and then connected to the base of PNP transistor Q5. In_F is connected between R8 and R5 so that the voltage signal is divided by R8 and then connected to the base of PNP transistor Q6. The collector of the output terminal of isolation optocoupler G1 is connected to a voltage divider resistor R11 and then connected to the circuit power supply. The collector of the output terminal of isolation optocoupler G2 is connected to a voltage divider resistor R12 and then connected to the circuit power supply.

[0053] Among them, diodes D2 and D3, resistors R4, R7, R5, and R8, and PNP transistors Q5 and Q6 together form the anti-straight-through interlock protection circuit for the motor forward rotation control signal circuit and the motor reverse rotation control signal circuit.

[0054] Meanwhile, the control signal undervoltage protection circuit is directly connected to the motor direction control signal input circuit. The control signal undervoltage protection circuit includes a Zener diode WD1, a PNP transistor Q0, and resistors R1 and R2.

[0055] Specifically, Zener diode WD1 is connected between resistor R6 and PNP transistor Q0. The anode of Zener diode WD1 is connected to resistor R6, and the cathode of Zener diode WD1 is connected to the base of PNP transistor Q0. Resistor R1 is connected between Zener diode WD1 and the base of PNP transistor Q0. One end of resistor R2 is connected to the cathode of diode D3, and the other end of resistor R2 is connected to the base of PNP transistor Q0.

[0056] The specific working process of the above circuit is as follows:

[0057] See Figure 11 The table shows the signal V when the motor rotates in the forward direction. In_F The signal V indicates that the motor is rotating in reverse and is set to "1" (+24V). In_RWhen the voltage is "0" (set to 0V~15V), diode D2 is reverse-biased and cut off, while diode D3 is turned on. The forward rotation signal VIn_F of the motor is directly applied to the emitter of PNP transistor Q0 after passing through diode D3. Simultaneously, the voltage is divided by a voltage divider circuit consisting of resistors R1 and R2 and Zener diode WD1. In_F After voltage division, a DC bias voltage is applied to the base (b) of transistor Q0, providing a DC bias voltage to Q0. At this time, the voltage between the emitter (e) and base (b) of transistor Q0 is:

[0058] V Q0eb =V R2 =(V In_F - V D3 -V wD1 )×R2 / (R2+R1)

[0059] When the voltage V Q0e-b When the voltage exceeds the turn-on threshold voltage, transistor Q0 turns on; the control signal amplified by Q0 is simultaneously applied to the input terminals of optocouplers G1 and G2. Due to the reverse rotation control signal V... In_R When the value is "0", transistor Q5 is turned on, and V In_F When the value is "1", transistor Q6 is cut off; the control signal is output as signal VO_G1 after being isolated by the optocoupler G1.

[0060] Similarly, the motor reverse rotation control signal V In_R The motor's forward rotation control signal V is "1" (+24V). In_F When the voltage is "0" (0~15V), diode D2 is on and diode D3 is reverse-biased and off, and the motor reverse rotation control signal V is received. In_R The voltage is applied to the emitter of transistor Q0 after passing through diode D2, and simultaneously to V through a voltage divider circuit consisting of resistors R1 and R2 and Zener diode WD1. In_R After voltage division, a DC bias voltage is applied to the base (b) of transistor Q0, providing a DC bias voltage to Q0. At this time, as long as the voltage V between the emitter (e) and base (b) of transistor Q0 is... Q0eb When the voltage exceeds the turn-on threshold voltage of Q0, transistor Q0 turns on, and the amplified control signal is simultaneously applied to the inputs of isolation optocouplers G1 and G2. Since the motor reverse rotation control signal VIn_R is "1", transistor Q5 is cut off, and the motor forward rotation control signal V... In_F When the value is "0", transistor Q6 is turned on, and the control signal is output as signal VO_G2 after being isolated by the optocoupler G2.

[0061] In the above circuit, the isolation optocouplers G1 and G2 respectively realize the isolation function of the motor forward and reverse rotation control signals. The Zener diode WD1 can maintain the base voltage of transistor Q0 at a certain threshold, preventing transistor Q0 from conducting under low voltage conditions and ensuring the stability of the transistor Q0 conduction signal. Resistor R6 is the current limiting resistor at the input of optocouplers G1 and G2. Pull-down resistors R4 and R5 respectively ensure the smooth conduction of transistors Q5 and Q6. Transistors Q5 and Q6, along with resistors R4, R7, R5, and R8, form an interlock protection circuit for the forward and reverse rotation control signals of the motor, interlocking the outputs VO_G1 and VO_G2 of the two control signals to ensure that only one direction of the drive circuit works under any circumstances. Thus, the hardware circuit protection method ensures that the H-bridge drive circuit will not experience a same-arm conduction failure. Even if the control signals for both the forward and reverse directions of the motor are mistakenly connected at the same time, the voltage at the base (b) of transistors Q5 and Q6 will be cut off because it is higher than the voltage at their emitter (e). The control signals VO_G1 and VO_G2 for both the forward and reverse directions will be completely disconnected, thus avoiding the phenomenon of conduction in the same bridge arm.

[0062] Referring to Figures 5(a) and 5(b), the H-bridge drive circuit includes P-MOS transistors Q1 and Q2 in the same bridge arm, as well as P-MOS transistors Q3 and Q4 in the same bridge arm. The source (S) of P-MOS transistor Q1 and the source (S) of P-MOS transistor Q3 are connected to the circuit power supply. The drain (D) of P-MOS transistor Q1 is connected to the drain (D) of N-MOS transistor Q2. The drain (D) of P-MOS transistor Q3 is connected to the drain (D) of N-MOS transistor Q4. The source (S) of N-MOS transistor Q2 and the source (S) of N-MOS transistor Q4 are grounded together. One end of the motor DCM is connected to the drains of Q1 and Q2. The low-potential signal HA of the isolation optocoupler G1, converted by the dual-path drive signal forming circuit, is connected to Q1, and the high-potential signal LB is connected to Q4. The low-potential signal HB of the isolation optocoupler G2, converted by the dual-path drive signal forming circuit, is connected to Q3, and the high-potential signal LA is connected to Q2.

[0063] The H-bridge drive circuit also includes freewheeling diodes Dx1, Dx2, Dx3, and Dx4 to protect other components in the circuit. Specifically, the anode of Dx1 is connected to the end where the motor DCM connects to the drain (D) terminals of Q1 and Q2, and the cathode of Dx1 is connected to the source (S) terminal of Q1. The anode of Dx2 is connected to the source (S) terminal of Q4, and the cathode of Dx2 is connected to the end where the motor DCM connects to the drain (D) terminals of Q1 and Q2. The anode of Dx3 is connected to the end where Q3 and Q4 connect to the motor DCM, and the cathode of Dx3 is connected to the source (S) terminal of Q3. The cathode of Dx4 is connected to the end where the drain (D) terminals of Q3 and Q4 connect to the motor DCM, and the anode of Dx4 is connected to the source (S) terminal of Q4.

[0064] See Figure 6 The dual-channel drive signal forming circuit includes diodes D4, D5, D10, and D11; transistors Q7, Q8, Q9, and Q10; and voltage divider resistors R13, R14, R15, R16, R21, R22, R25, and R26. Specifically, the cathodes of diodes D4 and D5 are interconnected. The anode of diode D4 is connected to the circuit power supply through resistor R9, and the anode of diode D5 is connected to the power supply through resistor R10. The end of diode D4 connected to resistor R9 is also connected to the base (b) of Q7, and the end of diode D5 connected to resistor R10 is also connected to the base (b) of Q8. The cathodes of diodes D10 and D11 are interconnected. The anode of diode D10 is connected to the circuit power supply through resistor R29, and the anode of diode D11 is connected to the power supply through resistor R30. The end of diode D10 connected to resistor R29 is also connected to the base (b) of Q9. One end of diode D11 connected to R30 is simultaneously connected to the base (b) of Q10; the emitter (e) of Q7 is grounded after passing through voltage divider resistors R13 and R15 in sequence, and the emitter of Q9 is grounded after passing through R25 and R21 in sequence. The collectors (c) of Q7 and Q9 are simultaneously connected to the circuit power supply. The emitters of Q8 and Q10 are simultaneously grounded. The collector of Q8 is connected to the power supply after passing through R14 and R16 in sequence, and the collector of Q10 is connected to the circuit power supply after passing through R26 and R22 in sequence. A shoot-through interlock protection diode D6 is connected to the end of Q8's collector connected to R21 and R25. The anode of D6 is connected to R21, and the cathode of D6 is connected to the collector of Q8. A shoot-through interlock protection diode D9 is connected between Q10's collector and R13 and R15. The anode of D9 is connected to R15, and the cathode of D9 is connected to the collector of Q10.

[0065] Specifically, the signal VO_G1 output by the isolation optocoupler G1 is connected to the cathodes of D4 and D5. The high-potential signal LB converted from the signal VO_G1 output by the isolation optocoupler G1 is output at the end connected by R13 and R15 and connected to the gate (G) of Q4. The low-potential signal HA is output at the end connected by R14 and R16 and connected to the gate (G) of Q1. The signal VO_G2 output by the isolation optocoupler G2 is connected to the cathodes of D10 and D11. The high-potential signal LA converted from the signal VO_G2 output by the isolation optocoupler G2 is output at the end connected by R21 and R25 and connected to the gate (G) of Q2. The low-potential signal HB is output at the end connected by R22 and R26 and connected to the gate (G) of Q3.

[0066] In the dual-path drive signal forming circuit, diodes D4, D5, D10, D11 and NPN transistors Q7, Q8, Q9, Q10 together form the anti-straight-through interlock protection circuit of the dual-path drive signal forming circuit.

[0067] The specific working process of the above circuit is as follows:

[0068] This circuit converts the single-channel optocoupler output control signal into two separate bridge arm switching transistor drive signals. It also features a shoot-through short-circuit interlock protection function for the bridge arm switching transistor drive signals. This allows the controller to interlock the forward and reverse rotation drive signals under any malfunction, preventing a full-bridge shoot-through short-circuit fault caused by the simultaneous conduction of the two MOS transistors (Q1, Q2 or Q3, Q4) on the same bridge arm of the full-bridge circuit. This improves the reliability of the full-bridge circuit.

[0069] participate Figure 1 , Figure 7 , Figure 8 The circuit power supply undervoltage protection circuit includes a positive feedback hysteresis voltage comparator composed of voltage comparator U1A, Zener diode WD7, and resistors R19, R23, and R27 to provide undervoltage protection for the motor when it rotates in the forward direction, and a positive feedback hysteresis voltage comparator composed of voltage comparator U2A, Zener diode WD8, and resistors R24, R20, and R28 to provide undervoltage protection for the motor when it rotates in the reverse direction.

[0070] For details, please refer to Figure 7 The signal output from the emitter of the optocoupler G1 is directly connected to the non-inverting input of U1A. Simultaneously, the signal output from the emitter of the optocoupler G1 is grounded after passing through resistor R19. The output of U1A is grounded after passing through resistors R27 and R19. The emitter of the output of the optocoupler G1 is simultaneously connected to the end of the connection between R19 and R27. The inverting input of U1A is grounded after passing through resistor R17. The anode of the Zener diode WD7 is grounded, and its cathode is connected to the circuit power supply after passing through resistor R23. The end of the Zener diode WD7 connected to R23 is simultaneously connected to the inverting input of U1A, providing a reference voltage Vref1 to U1A. After the voltage comparator U1A compares the reference voltage Vref1 with the voltage signal O_G1 output by the optocoupler G1, it outputs a voltage signal DYBH1, which is connected to the cathodes of diodes D4 and D5. This is converted into a high-potential signal LB and a low-potential signal HA in the dual-path drive signal forming circuit.

[0071] See Figure 8The signal output from the emitter of the optocoupler G2 is directly connected to the non-inverting input of U2A. Simultaneously, the signal output from the emitter of the optocoupler G2 is grounded after passing through resistor R20. The output of U2A is grounded after passing through resistors R28 and R20 in sequence. The emitter of the output of the optocoupler G2 is simultaneously connected to one end of the connection between R20 and R28. The inverting input of U2A is grounded after passing through resistor R18. The anode of the Zener diode WD8 is grounded, and its cathode is connected to the circuit power supply after passing through resistor R24. The end of the Zener diode WD8 connected to resistor R24 ​​is simultaneously connected to the inverting input of U2A, providing a reference voltage Vref 2 to U2A. After the voltage comparator U2A compares the reference voltage Vref 2 with the voltage signal O_G2 output by the optocoupler G2, it outputs a voltage signal DYBH2, which is connected to the cathodes of diodes D10 and D11. This is converted into a high-potential signal LA and a low-potential signal HB in the dual-path drive signal forming circuit.

[0072] The specific working process of the above circuit is as follows:

[0073] See Figure 12 Motor forward rotation signal V In_F The output signal VO_G1, isolated by the optocoupler G1, is sent to the non-inverting input of the voltage comparator U1A. If VO_G1 is less than the reference voltage Vref, the voltage VDYBH1 at the output of the voltage comparator U1A is low, the base (b) voltage of the NPN transistors Q7 and Q8 in the circuit is low, and the transistors Q7 and Q8 are reverse-biased and cut off. If VO_G1 is greater than the reference voltage Vref, the voltage VDYBH1 at the output of the voltage comparator is high, the diodes D4 and D5 are cut off, and the NPN transistors Q7 and Q8 in the circuit are forward-biased and conducted.

[0074] Similarly, the reverse rotation signal V of the motor In_R The output signal VO_G2, isolated by optocoupler G2, is sent to the positive input of voltage comparator U2A. If VO_G2 is less than the reference voltage Vref, the voltage VDYBH2 at the output of voltage comparator U2A is low, and NPN transistors Q9 and Q10 in the circuit will be cut off. If VO_G2 is greater than the reference voltage Vref, the voltage at the output of voltage comparator DYBH2 is high, and NPN transistors Q9 and Q10 in the circuit will be turned on.

[0075] When the power supply voltage is too low (the low voltage threshold can be set, such as 19.1V for a 24V power supply, and the Zener diodes WD7 and WD8 are set to provide a reference voltage Vref of 9.1V for the inverting inputs of the two positive feedback hysteresis voltage comparators U1A and U2A respectively), the optocoupler output voltage VO_G1 (or VO_G2) is forced low. As long as VO_G1 (or VO_G2) is lower than 9.1V, the voltage VDYBH1 (or VDYBH2) at the output of the comparator is low, and the transistors Q7, Q8 or (Q9, Q10) are cut off.

[0076] The undervoltage protection circuit, which uses a positive feedback hysteresis voltage comparator, can prevent power electronic devices from being damaged due to unsaturated conduction when the power supply voltage is too low. It achieves undervoltage protection for the load voltage, eliminates circuit oscillation, and improves the product's anti-interference capability.

[0077] The working principle of this part of the circuit can be derived by combining the undervoltage protection circuit, the dual-channel drive signal forming circuit, and the H-bridge drive circuit:

[0078] See Figure 12 The table shows that when the voltage comparator output voltage VDYBH1 is high and VDYBH2 is low, diodes D4 and D5 are cut off, transistors Q7 and Q8 are forward-biased and conducting simultaneously, diodes D10 and D11 are conducting, and transistors Q9 and Q10 are reverse-biased and cut off. The control signal VO_G1 output from optocoupler G1 is then split into two paths: HA and LB, driving the P-MOS transistor Q1 and N-MOS transistor Q4 of the bridge power circuit to conduct simultaneously. Specifically, HA is low, driving P-MOS transistor Q1 to conduct; LB is high, driving N-MOS transistor Q4 to conduct. At this time, the voltage across the full-bridge output or load is A positive and B negative, and the DC motor rotates in the positive direction.

[0079] Similarly, when the voltage comparator output VDYBH1 is low and VDYBH2 is high, diodes D4 and D5 conduct, transistors Q7 and Q8 are reverse-biased and cut off, while diodes D10 and D11 are cut off, and transistors Q9 and Q10 are forward-biased and conduct. The control signal VO_G2 output from optocoupler G2 is then split into two paths: LA and HB, which can simultaneously drive the N-MOS transistor Q2 and P-MOS transistor Q3 of the bridge power circuit. Specifically, LA is high, driving N-MOS transistor Q2 to conduct; HB is low, driving P-MOS transistor Q3 to conduct. At this time, the voltage across the load changes direction, with B positive and A negative, causing the DC motor to rotate in the opposite direction.

[0080] When the output voltages VDYBH1 and VDYBH2 of the voltage comparator are both at low potentials, diodes D4, D5, D10, and D11 are turned on, transistors Q7 to Q10 are all turned off, HA and HB are at high potentials, and LA and LB are at low potentials. Q1 to Q4 of the power drive circuit do not meet the conduction conditions and are turned off, and the motor stops rotating.

[0081] When the voltage comparator output voltages VDYBH1 and VDYBH2 are both at high potentials, diodes D4, D5, D10, and D11 are all reverse biased and cut off, and transistors Q7 to Q10 are all turned on. Due to the effect of diodes D6 and D9, LA and LB are pulled down, and Q2 and Q4 are forcibly turned off and locked. Even if VDYBH1 and VDYBH2 are at high potentials, the DC motor cannot achieve rotational commutation.

[0082] By controlling the turn-on and turn-off sequence of MOSFETs Q1-Q4, the polarity of the voltage applied across the DC motor (DCM) can be changed, thereby altering the motor's rotation direction. When the forward and reverse rotation control signal of the DC motor is output as control signal VO_G1 or VO_G2 from the control signal input circuit, it then passes through a voltage comparator and a drive control protection circuit composed of transistors Q7-Q10, forming MOSFET drive control signals HA, LA, HB, and LB with anti-shoot-through interlock function. Changes in these signals alter the polarity of the DC supply voltage across the DC motor, thus changing the motor's rotation direction.

[0083] The design of the anti-shoot-through interlock function of the drive control circuit can prevent the bridge power drive circuit from experiencing shoot-through in any situation by using hardware circuit protection, thereby greatly improving the reliability and stability of forward and reverse rotation commutation of the DC brushed motor and reducing the system failure rate.

[0084] In addition, see Figure 1 The motor forward rotation control signal circuit and the motor reverse rotation control signal circuit also include a control signal input range adjustment circuit. The control signal input range adjustment circuit includes a TV pin with one end empty and a TI pin with one end empty. The terminal of the TV pin is connected to the cathode of the Zener diode WD1, and the terminal of the TI pin is connected to the collector of the PNP transistor Q6 after passing through a resistor R3. The input voltage of the control signal is changed by connecting appropriate components between the TV pin and the common terminal COM, and between the TI pin and the common terminal COM.

[0085] For example, see Figure 9By connecting a 6.8V~8.2V Zener diode WD0 between the TV pin and the common terminal COM, and a 4.7k current-limiting resistor R0 between the TI pin and the common terminal COM, the 24V control signal input circuit can be adjusted to a 12V control signal input circuit; see reference. Figure 10 By shorting the TV pin and the common terminal COM, and connecting a 1k current-limiting resistor R0 between the TI pin and the common terminal COM, the 24V control signal input circuit can be adjusted to a 5V control signal input circuit. In this circuit segment, the voltage node of the control signal is set to 8V (of course, it can also be 5V, 6V, or other values). When the voltage required by the control signal is between 8V and 24V, by connecting an appropriate Zener diode WD0 between the TV pin and the common terminal COM, and an appropriate resistor R0 between the TI pin and the common terminal COM, the P value can be changed. The clamping voltage at the base of the NP transistor R0 is used to meet the conduction conditions of the PNP transistor. When the voltage required by the control signal is 8V or below, the TV pin and the common terminal COM need to be shorted. The clamping voltage at the base of the PNP transistor R0 can be adjusted by selecting R0 with different parameters. It should be noted that the 8V node is determined by the parameters of WD1. Since WD1 and WD0 are reverse biased in parallel, the current of each Zener diode should be as equal as possible. Otherwise, it will lead to excessive load on one Zener diode, thus affecting the stability of the entire circuit.

[0086] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A DC motor rotation direction controller, characterized in that: The system includes a PCB board with a motor direction control signal input circuit installed in the controller. The input terminal of the controller is connected to an AC / DC converter so that the PCB board is connected to a 24V voltage and a stable DC power supply. The output terminal of the controller is connected to the motor. The PCB board of the motor direction control signal input circuit is provided with a motor forward rotation control signal pin In_F and a motor reverse rotation control signal pin In_R for adjusting the motor rotation direction. The motor direction control signal input circuit includes a motor forward rotation control signal circuit, a motor reverse rotation control signal circuit, a dual-path drive signal forming circuit, and an H-bridge drive circuit; the motor forward rotation control signal circuit includes a diode D3, a PNP transistor Q0, an isolation optocoupler G1, a PNP transistor Q5, and voltage divider and current limiting resistors R4, R6, and R7. Specifically, the anode of the diode at the input terminal of the isolation optocoupler G1 is connected to the collector (c) of the PNP transistor Q0, and the cathode of the diode at the input terminal of the isolation optocoupler G1 is connected to the emitter (e) of the PNP transistor Q5. The base (b) of the PNP transistor Q5 is connected to the common terminal pin COM via resistors R7 and R4. The collector (c) of the PNP transistor Q5 is connected to the common terminal COM via resistor R6. The forward rotation control signal pin In_F of the motor is connected to the anode of diode D3, and the cathode of diode D3 is connected to the emitter (e) of the PNP transistor Q0. One end of resistor R6 connected to the common terminal COM is also connected to the base (b) of the PNP transistor Q0. The motor reverse rotation control signal circuit includes diode D2, PNP transistor Q0, isolation optocoupler G2, PNP transistor Q6, voltage divider and current limiting resistors R5, R6, and R8. Specifically, the anode of the diode at the input terminal of the isolation optocoupler G2 is connected to the collector (c) of the PNP transistor Q0, the cathode of the diode at the input terminal of the isolation optocoupler G2 is connected to the emitter (e) of the PNP transistor Q6, the base (b) of the PNP transistor Q6 is connected to the common terminal pin COM via R8 and R5, and the collector (c) of the PNP transistor Q6 is connected to the common terminal COM via R6. The collectors of the PNP transistor Q6 and the PNP transistor Q5 are connected to the same end of R6. The motor reverse rotation control signal pin In_R is connected to the anode of D2, and the cathode of D2 is connected to the emitter (e) of the PNP transistor Q0. In addition, In_R is connected between R7 and R4 so that the voltage signal is divided by R7 and then connected to the base of PNP transistor Q5. In_F is connected between R8 and R5 so that the voltage signal is divided by R8 and then connected to the base of PNP transistor Q6. The collector of the output terminal of the isolation optocoupler G1 is connected to a voltage divider resistor R11 and then connected to the circuit power supply. The collector of the output terminal of the isolation optocoupler G2 is connected to a voltage divider resistor R12 and then connected to the circuit power supply. Among them, diodes D2 and D3, resistors R4, R7, R5 and R8, and PNP transistors Q5 and Q6 together form the anti-short-through interlock protection circuit for the motor forward rotation control signal circuit and the motor reverse rotation control signal circuit. The dual-path drive signal forming circuit is used to convert the signal O_G1 emitted from the emitter of the transistor at the output terminal of the isolation optocoupler G1 into a high-potential signal LB and a low-potential signal HA, and to convert the signal O_G2 emitted from the emitter of the transistor at the output terminal of the isolation optocoupler G2 into a high-potential signal LA and a low-potential signal HB. The H-bridge drive circuit includes P-MOS transistors Q1 and Q2, and P-MOS transistors Q3 and Q4, on the same bridge arm. The source (S) of P-MOS transistors Q1 and Q3 are connected to the circuit power supply. The drain (D) of P-MOS transistor Q1 is connected to the drain of N-MOS transistor Q2, and the drain of P-MOS transistor Q3 is connected to the drain of N-MOS transistor Q4. The source (S) of N-MOS transistors Q2 and Q4 are grounded together. One end of the motor DCM is connected to the drains of Q1 and Q2. The low-potential signal HA of the isolation optocoupler G1, converted by the dual-path drive signal forming circuit, is connected to Q1, and the high-potential signal LB is connected to Q4. The low-potential signal HB of the isolation optocoupler G2, converted by the dual-path drive signal forming circuit, is connected to Q3, and the high-potential signal LA is connected to Q2.

2. The DC motor rotation direction controller according to claim 1, characterized in that: The dual-path drive signal forming circuit includes diodes D4, D5, D10, and D11; transistors Q7, Q8, Q9, and Q10; and voltage divider resistors R13, R14, R15, R16, R21, R22, R25, and R26. Specifically, the cathodes of diodes D4 and D5 are interconnected. The anode of diode D4 is connected to the circuit power supply via resistor R9, and the anode of diode D5 is connected to the power supply via resistor R10. The end of diode D4 connected to resistor R9 is also connected to the base (b) of Q7, and the end of diode D5 connected to resistor R10 is also connected to the base (b) of Q8. The cathodes of diodes D10 and D11 are interconnected. The anode of diode D10 is connected to the circuit power supply via resistor R29, and the anode of diode D11 is connected to the power supply via resistor R30. The end of diode D10 connected to resistor R29 is also connected to the base (b) of Q9. One end of diode D11 connected to R30 is simultaneously connected to the base (b) of Q10; the emitter (e) of Q7 is grounded after passing through voltage divider resistors R13 and R15 in sequence, and the emitter of Q9 is grounded after passing through R25 and R21 in sequence. The collectors (c) of Q7 and Q9 are simultaneously connected to the circuit power supply. The emitters of Q8 and Q10 are simultaneously grounded. The collector of Q8 is connected to the power supply after passing through R14 and R16 in sequence, and the collector of Q10 is connected to the circuit power supply after passing through R26 and R22 in sequence. A shoot-through interlock protection diode D6 is connected to the end of Q8's collector connected to R21 and R25. The anode of D6 is connected to R21, and the cathode of D6 is connected to the collector of Q8. A shoot-through interlock protection diode D9 is connected between Q10's collector and R13 and R15. The anode of D9 is connected to R15, and the cathode of D9 is connected to the collector of Q10. Specifically, the signal O_G1 output by the isolation optocoupler G1 is connected to the cathodes of D4 and D5. The high-potential signal LB converted from the signal O_G1 output by the isolation optocoupler G1 is output at the end connected by R13 and R15 and connected to the gate (G) of Q4. The low-potential signal HA is output at the end connected by R14 and R16 and connected to the gate (G) of Q1. The signal O_G2 output by the isolation optocoupler G2 is connected to the cathodes of D10 and D11. The high-potential signal LA converted from the signal O_G2 output by the isolation optocoupler G2 is output at the end connected by R21 and R25 and connected to the gate (G) of Q2. The low-potential signal HB is output at the end connected by R22 and R26 and connected to the gate (G) of Q3. In the dual-path drive signal forming circuit, diodes D4, D5, D10, D11 and NPN transistors Q7, Q8, Q9, Q10 together form the anti-straight-through interlock protection circuit of the dual-path drive signal forming circuit.

3. A DC motor rotation direction controller according to claim 1, characterized in that: The motor forward rotation control signal circuit and the motor reverse rotation control signal circuit are also connected to a control signal undervoltage protection circuit, which includes a Zener diode WD1, resistors R1 and R2, and a PNP transistor Q0. Specifically, Zener diode WD1 is connected between resistor R6 and PNP transistor Q0. The anode of Zener diode WD1 is connected to resistor R6, and the cathode of Zener diode WD1 is connected to the base of PNP transistor Q0. Resistor R1 is connected between Zener diode WD1 and the base of PNP transistor Q0. One end of resistor R2 is connected to the cathode of diode D3, and the other end of resistor R2 is connected to the base of PNP transistor Q0.

4. A DC motor rotation direction controller according to claim 2, characterized in that: A circuit power supply undervoltage protection circuit is connected between the motor direction control signal input circuit and the dual-path drive signal forming circuit. The circuit power supply undervoltage protection circuit includes a positive feedback hysteresis voltage comparator composed of voltage comparator U1A, Zener diode WD7, and resistors R19, R23, and R27 to provide undervoltage protection when the motor rotates in the forward direction; and a positive feedback hysteresis voltage comparator composed of voltage comparator U2A, Zener diode WD8, and resistors R24, R20, and R28 to provide undervoltage protection when the motor rotates in the reverse direction. Specifically, the signal output from the emitter of the optocoupler G1 is directly connected to the non-inverting input of U1A. Simultaneously, the signal output from the emitter of the optocoupler G1 is grounded after passing through resistor R19. The output of U1A is grounded after passing through resistors R27 and R19 in sequence. The emitter of the output of the optocoupler G1 is simultaneously connected to one end of the connection between R19 and R27. The inverting input of U1A is grounded after passing through resistor R17. The anode of the Zener diode WD7 is grounded, and its cathode is connected to the circuit power supply after passing through resistor R23. The end of the Zener diode WD7 connected to R23 is simultaneously connected to the inverting input of U1A, providing a reference voltage Vref1 to U1A. After the voltage comparator U1A compares the reference voltage Vref1 with the voltage signal O_G1 output by the optocoupler G1, it outputs a voltage signal DYBH1, which is connected to the cathodes of diodes D4 and D5 to convert it into a high-potential signal LB and a low-potential signal HA in the dual-channel drive signal forming circuit. The signal output from the emitter of the optocoupler G2 is directly connected to the non-inverting input of U2A. Simultaneously, the signal output from the emitter of the optocoupler G2 is grounded after passing through resistor R20. The output of U2A is grounded after passing through resistors R28 and R20 in sequence. The emitter of the output of the optocoupler G2 is simultaneously connected to one end of the connection between R20 and R28. The inverting input of U2A is grounded after passing through resistor R18. The anode of the Zener diode WD8 is grounded, and its cathode is connected to the circuit power supply after passing through resistor R24. The end of the Zener diode WD8 connected to resistor R24 ​​is simultaneously connected to the inverting input of U2A, providing a reference voltage Vref 2 to U2A. After the voltage comparator U2A compares the reference voltage Vref 2 with the voltage signal O_G2 output from the optocoupler G2, it outputs a voltage signal DYBH2, which is connected to the cathodes of diodes D10 and D11. This is converted into a high-potential signal LA and a low-potential signal HB in the dual-channel drive signal forming circuit.

5. A DC motor rotation direction controller according to claim 3, characterized in that: The motor forward rotation control signal circuit and the motor reverse rotation control signal circuit are also equipped with a control signal input range adjustment circuit. The control signal input range adjustment circuit includes a TV pin with one end empty and a TI pin with one end empty. The terminal of the TV pin is connected to the cathode of the Zener diode WD1. The terminal of the TI pin is connected to the collector of the PNP transistor Q6 through a resistor R3. The input voltage of the control signal is changed by connecting a Zener diode WD0 between the TV pin and the common terminal COM, and connecting a matching resistor R0 between the TI pin and the common terminal COM. The Zener diodes WD0 and WD1 are reverse biased and connected in parallel. In addition, when the required control signal voltage is less than 8V, the TV pin and the common terminal COM are shorted.

6. A DC motor rotation direction controller according to claim 5, characterized in that: A 6.8V~8.2V Zener diode WD0 is connected between the TV pin and the common terminal COM, and a 4.7k current-limiting resistor R0 is connected between the TI pin and the common terminal COM. The circuit is adjusted to a 12V control signal input circuit.

7. A DC motor rotation direction controller according to claim 5, characterized in that: The TV pin and the common terminal COM are shorted, and a 1k current-limiting resistor R0 is connected between the TI pin and the common terminal COM. The circuit is adjusted to a 5V control signal input circuit.

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