阅读说明：本技术 一种双隔离功放电路 (Double-isolation power amplifier circuit ) 是由 凌健 王聪霞 杜荣富 于 2020-08-10 设计创作，主要内容包括：本发明公开了一种双隔离功放电路,包括光耦隔离电路、逻辑控制电路、H桥驱动电路、H桥电路、电源电路与过压过流保护电路；所述光耦隔离电路通过逻辑控制电路与H桥驱动电路输入端相连；所述H桥驱动电路输出端与H桥电路相连；所述电源电路分别与H桥驱动电路、H桥电路相连；所述H桥电路输出端与过压过流保护电路相连。本发明H桥电路电机正端和电机负端同时采用二极管向上续流和二极管向下续流两种续流方式,能够防止电机电压超过电源电压；在H桥电路中,采用电容电阻串联连接续流稳压,能够防止电源波动和外部磁场对电机运行指标的影响,提高了电路可靠性和电路稳定性。(The invention discloses a double-isolation power amplifier circuit, which comprises an optical coupling isolation circuit, a logic control circuit, an H bridge driving circuit, an H bridge circuit, a power circuit and an overvoltage and overcurrent protection circuit, wherein the optical coupling isolation circuit is connected with the logic control circuit; the optical coupling isolation circuit is connected with the input end of the H-bridge drive circuit through a logic control circuit; the output end of the H-bridge driving circuit is connected with the H-bridge circuit; the power circuit is respectively connected with the H-bridge drive circuit and the H-bridge circuit; and the output end of the H-bridge circuit is connected with the overvoltage and overcurrent protection circuit. According to the H-bridge circuit, the two follow current modes of diode upward follow current and diode downward follow current are adopted at the positive end and the negative end of the motor at the same time, so that the voltage of the motor can be prevented from exceeding the voltage of a power supply; in the H-bridge circuit, the capacitor resistor is connected in series to follow current and stabilize voltage, so that the influence of power supply fluctuation and an external magnetic field on the operation index of the motor can be prevented, and the reliability and the stability of the circuit are improved.)

1. A double-isolation power amplifier circuit is characterized by comprising an optical coupling isolation circuit, a logic control circuit, an H-bridge driving circuit, an H-bridge circuit, a power circuit and an overvoltage and overcurrent protection circuit; the optical coupling isolation circuit is connected with the input end of the H-bridge drive circuit through the logic control circuit and is used for; the output end of the H-bridge driving circuit is connected with the H-bridge circuit; the power circuit is respectively connected with the H-bridge drive circuit and the H-bridge circuit; and the output end of the H-bridge circuit is connected with the overvoltage and overcurrent protection circuit.

2. The dual-isolation power amplifier circuit according to claim 1, wherein the logic control circuit comprises a first current limiting resistor, a second current limiting resistor, a third current limiting resistor, a fourth current limiting resistor, a first triode, a second triode, a third triode, a fourth triode, a first reverse-filling prevention power circuit, a second reverse-filling prevention power circuit, a third reverse-filling prevention power circuit and a fourth reverse-filling prevention power circuit;

the first output end of the optical coupling isolation circuit is connected with the base electrode of the first triode through a first current limiting resistor; the second output end of the optical coupling isolation circuit is connected with the base electrode of the second triode through a second current limiting resistor; the collector of the second triode is connected with the base of the third diode through a third current-limiting resistor; the second output end of the optical coupling isolation circuit is connected with the base electrode of the fourth triode through a fourth current limiting resistor; the second output end of the optical coupling isolation circuit is connected with the third input end of the H-bridge drive circuit; a collector of the first triode is connected with a first output end of the first reverse-filling prevention power circuit, a first output end of the second reverse-filling prevention power circuit and one end, far away from a base electrode of the fourth diode, of the fourth current-limiting resistor; the collector of the second triode is connected with the second output end of the first reverse-filling prevention power circuit, the second output end of the second reverse-filling prevention power circuit and one end, far away from the base of the third triode, of the third resistor;

the third output end of the first reverse-filling prevention power circuit is connected with the first input end of the H-bridge drive circuit; the third output end of the second reverse-filling prevention power supply circuit is connected with the first input end of the H-bridge drive circuit; the third output end of the third reverse-filling prevention power supply circuit is connected with the third input end of the H-bridge drive circuit; and the third output end of the fourth reverse-flow prevention power supply circuit is connected with the fourth input end of the H-bridge drive circuit.

3. The dual-isolation power amplifier circuit according to claim 2, wherein the first reverse-filling prevention power circuit, the second reverse-filling prevention power circuit, the third reverse-filling prevention power circuit and the fourth reverse-filling prevention power circuit each comprise a +5V low-voltage direct-current power supply, a divider resistor and two diodes; the +5V low-voltage direct current power supply is connected with the anodes of the two diodes through a voltage-dividing resistor.

4. The dual-isolation power amplifier circuit according to claim 1, wherein the H-bridge driving circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first MOS transistor, a second MOS transistor, a third MOS transistor, and a fourth MOS transistor; the output end of the power supply circuit is connected with the grid electrode of the first MOS tube and the output end of the isolation amplifying circuit through a first resistor; the output end of the power supply circuit is connected with the grid electrode of the second MOS tube and the output end of the isolation amplifying circuit through a second resistor; the output end of the power supply circuit is connected with the grid electrode of the third MOS tube and the output end of the isolation amplifying circuit through a seventh resistor; the output end of the power supply circuit is connected with the grid electrode of the fourth MOS tube and the output end of the isolation amplifying circuit through an eighth resistor; the output end of the power supply circuit is connected with the source electrode of the first MOS transistor and the first input end of the H-bridge circuit through a third resistor; the output end of the power supply circuit is connected with the source electrode of the second MOS transistor and the second input end of the H-bridge circuit through a fourth resistor; the output end of the power supply circuit is connected with the source electrode of the third MOS tube and the third input end of the H-bridge circuit through a fifth resistor; the output end of the power supply circuit is connected with the grid electrode of the fourth MOS tube through a sixth resistor; the drain electrodes of the first MOS tube, the second MOS tube, the third MOS tube and the fourth MOS tube are grounded.

5. The dual-isolation power amplifier circuit according to claim 1, wherein the H-bridge circuit comprises a fifth MOS transistor, a sixth MOS transistor, a seventh MOS transistor, an eighth MOS transistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, a first capacitor, a second capacitor, a third capacitor, and a fourth capacitor; a first input end of the H-bridge circuit is connected with a grid electrode of the fifth MOS tube through a ninth resistor; a second input end of the H-bridge circuit is connected with a grid electrode of the sixth MOS tube through a tenth resistor; a third input end of the H-bridge circuit is connected with a grid electrode of the seventh MOS tube through an eleventh resistor; a fourth input end of the H-bridge circuit is connected with a grid electrode of the eighth MOS tube through a twelfth resistor; the output end of the power supply circuit is connected with the sources of the fifth MOS tube, the sixth MOS tube, the seventh MOS tube and the eighth MOS tube, the cathodes of the first diode, the second diode, the third diode and the fourth diode, the first end of the thirteenth resistor, the first end of the second capacitor, the first end of the fifteenth resistor and the first end of the fourth capacitor; a second end of the thirteenth resistor is connected with the drain electrode of the fifth MOS tube, the anode of the first diode, a first end of the seventeenth resistor and a first output end of the H-bridge circuit through the first capacitor; the second end of the second capacitor is connected with the drain electrode of the sixth MOS tube, the anode of the second diode, the first end of the eighteenth resistor and the first output end of the H-bridge circuit through the second capacitor; a second end of the fifteenth resistor is connected with the drain electrode of the seventh MOS tube, the anode of the third diode, the cathode of the fifth diode and a second output end of the H-bridge circuit through the third capacitor; a second end of the fourth capacitor is connected with a drain electrode of the seventh MOS tube, a positive electrode of the third diode, a positive electrode of the sixth diode and a second output end of the H-bridge circuit through the fourth capacitor; the anode of the fifth diode is connected with the second end of the seventeenth resistor; and the cathode of the sixth diode is connected with the second end of the eighteenth resistor.

6. The dual-isolation power amplifier circuit according to claim 1, wherein the over-voltage and over-current protection circuit comprises a ninth MOS transistor, a first operational amplifier, a second operational amplifier, a seventh diode of the third operational amplifier, an eighth diode, a ninth diode, a +5V dc power supply circuit, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor and a twenty-fourth resistor; the +5V direct-current power supply circuit comprises a +5V direct-current power supply, a nineteenth resistor and a twentieth resistor; the +5V direct-current power supply is connected with the first end of the nineteenth resistor; the second end of the nineteenth resistor is connected with the output end of the +5V direct-current power supply circuit and the first end of the twentieth resistor; a second end of the twentieth resistor is grounded; the output end of the H-bridge circuit is connected with the source electrode of the ninth MOS tube; the +5V direct-current power supply is connected with the grid electrode of the ninth MOS tube, the anode of the seventh diode, the anode of the eighth diode and the anode of the ninth diode through a thirteenth resistor; the drain electrode of the ninth MOS tube is connected with the reverse input end of the first operational amplifier; the homodromous input end of the first operational amplifier is connected with the output end of the +5V direct-current power supply circuit; the output end of the first operational amplifier is connected with the cathode of the seventh diode; the output end of the second operational amplifier is connected with the cathode of the eighth diode; the output end of the third operational amplifier is connected with the negative electrode of the ninth diode; the output end of the +5V direct-current power supply circuit is connected with the reverse input end of the second operational amplifier and the same-direction input end of the third operational amplifier; the +5V direct-current power supply is connected with the homodromous input end of the second operational amplifier and the first end of the twenty-first resistor through the twenty-fourth resistor; the second end of the twenty-first resistor is connected with the inverting input end of the third operational amplifier and the first end of the twenty-second resistor; the second end of the twenty-second resistor is grounded.

7. The dual-isolation power amplifier circuit according to claim 1, wherein the power circuit comprises an input power supply, a power reverse connection protection circuit, a surge voltage protection circuit and a power noise protection circuit; the power supply reverse connection protection circuit comprises a twelfth polar tube; the surge voltage protection circuit comprises a first direct current power supply, a fifth capacitor, a sixth capacitor, a voltage stabilizing diode and an inductor; the power supply noise protection circuit comprises a seventh capacitor, an eighth capacitor and a ninth capacitor; the input power supply is connected with the second end of the fifth capacitor, the first end of the sixth capacitor, the second end of the ninth capacitor, the first end of the voltage stabilizing diode and the first end of the inductor through the tenth diode; the second direct current power supply is connected with the second end of the inductor; the second end of the voltage stabilizing diode is grounded; the output end of the direct current power supply is connected with the first end of the fifth capacitor; the second end of the sixth capacitor, the first end of the seventh capacitor and the first end of the eighth capacitor are grounded; the second end of the seventh capacitor and the second end of the capacitor are connected with the first end of the ninth capacitor.

8. The dual-isolation power amplifier circuit according to claim 1, wherein the optical coupler isolation resistor comprises an optical coupler chip HCPL 2630.

Technical Field

The invention relates to the technical field of circuits, in particular to a double-isolation power amplifier circuit.

Background

At present, missile is motor drive circuit for first control system of traction, generally adopt the input opto-isolator to keep apart, and the pulse width modulation signal passes through resistance and a NOT gate circuit, becomes two complementary pulse width modulation signals, and these two complementary pulse signals go the control H bridge again, and the drawback of this circuit has:

(1) the working voltage range is narrow;

(2) the protection to surge voltage is very small;

(3) the anti-interference capability is low;

(4) the power supply voltage interference resistance is low;

(5) the adaptability to electromagnetic compatibility is low;

the technical requirements of modern military electric control systems cannot be met.

Disclosure of Invention

The invention aims to solve the problems and provides a double-isolation power amplifier circuit, which comprises an optical coupling isolation circuit, a logic control circuit, an H-bridge drive circuit, an H-bridge circuit, a power supply circuit and an overvoltage and overcurrent protection circuit; the optical coupling isolation circuit is connected with the input end of the H-bridge drive circuit through a logic control circuit; the output end of the H-bridge driving circuit is connected with the H-bridge circuit; the power circuit is respectively connected with the H-bridge drive circuit and the H-bridge circuit; and the output end of the H-bridge circuit is connected with the overvoltage and overcurrent protection circuit.

The invention has the beneficial effects that:

1) the input and the output are isolated by optical coupling, so that the anti-interference capability of the circuit is enhanced; (ii) a

2) The circuit is provided with an upward freewheeling diode and has the capability of eliminating the reverse voltage of the motor;

3) the circuit is provided with a downward freewheeling diode and has the capability of eliminating the reverse voltage of the motor;

4) the circuit has the functions of capacitor resistance follow current and voltage stabilization and has the capability of eliminating the reverse voltage and voltage surge of the motor;

5) the circuit has an overvoltage protection function;

6) the circuit has an overcurrent protection function;

7) the circuit has a surge voltage protection function;

8) the circuit has the function of preventing power supply interference;

9) the circuit has a power supply noise protection function;

10) the circuit has an enable protection function.

Drawings

FIG. 1 is a system diagram of the present invention;

FIG. 2 is a circuit diagram of a logic control circuit;

FIG. 3 is a circuit diagram of an H-bridge driver circuit;

FIG. 4 is a circuit diagram of an H-bridge circuit;

FIG. 5 is a circuit diagram of an over-voltage and over-current protection circuit;

fig. 6 is a circuit diagram of a power supply circuit.

In the figure: RT1 — first current limiting resistor; RT2 — second current limiting resistor; RT3 — third current limiting resistor; RT 4-fourth current limiting resistor; QT 1-first triode; QT 2-second triode; QT 3-third triode; QT 4-fourth triode; a U0-H bridge drive circuit; a U1-H bridge circuit; u2 — first operational amplifier; u3 — second operational amplifier; u4 — third operational amplifier; q1-first MOS tube; q2-second MOS tube; q3-third MOS tube; q4-fourth MOS tube; q5-fifth MOS tube; q6-sixth MOS tube; q7-seventh MOS tube; q8-eighth MOS pipe; r1 — first resistance; r2 — second resistance; r3 — third resistance; r4-fourth resistor; r5-fifth resistor; r6-sixth resistance; r7 — seventh resistor; r8 — eighth resistance; r9 — ninth resistor; r10 — tenth resistance; r11 — eleventh resistor; r12 — twelfth resistor; r13 — thirteenth resistor; r14-fourteenth resistance; r15-fifteenth resistance; r16 — sixteenth resistance; r17-seventeenth resistor; r18 — eighteenth resistor; r19 — nineteenth resistor; r20-twentieth resistance; r21-twenty-first resistance; r22 — twenty-second resistance; r23-twenty-third resistance; r24-twenty-fourth resistance; c1 — first capacitance; c2 — second capacitance; c3 — third capacitance; c4-fourth capacitance; c5 — fifth capacitance; c6 — sixth capacitance; c7 — seventh capacitance; c8 — eighth capacitance; c9 — ninth capacitance; d1 — first diode; d2 — second diode; d3 — third diode; d4 — fourth diode; d5-fifth diode; d6-sixth diode; d7-seventh diode; d8-eighth diode; d9-ninth diode; d10-the twelfth pole tube.

Detailed Description

The invention will be further described with reference to the accompanying drawings in which:

as shown in fig. 1, the dual-isolation power amplifier circuit of the present invention comprises an optical coupling isolation circuit, a logic control circuit, an H-bridge driving circuit, an H-bridge circuit, a power circuit and an overvoltage and overcurrent protection circuit; the optical coupling isolation circuit is connected with the input end of the H-bridge drive circuit through a logic control circuit; the output end of the H-bridge driving circuit is connected with the H-bridge circuit; the power circuit is respectively connected with the H-bridge drive circuit and the H-bridge circuit; and the output end of the H-bridge circuit is connected with the overvoltage and overcurrent protection circuit.

Specifically, the logic control circuit comprises a first current-limiting resistor, a second current-limiting resistor, a third current-limiting resistor, a fourth current-limiting resistor, a first triode, a second triode, a third triode, a fourth triode, a first reverse-filling prevention power circuit, a second reverse-filling prevention power circuit, a third reverse-filling prevention power circuit and a fourth reverse-filling prevention power circuit;

the first output end of the optical coupling isolation circuit is connected with the base electrode of the first triode through a first current limiting resistor; the second output end of the optical coupling isolation circuit is connected with the base electrode of the second triode through a second current limiting resistor; the collector of the second triode is connected with the base of the third diode through a third current-limiting resistor; the second output end of the optical coupling isolation circuit is connected with the base electrode of the fourth triode through a fourth current limiting resistor; the second output end of the optical coupling isolation circuit is connected with the third input end of the H-bridge drive circuit; a collector of the first triode is connected with a first output end of the first reverse-filling prevention power circuit, a first output end of the second reverse-filling prevention power circuit and one end, far away from a base electrode of the fourth diode, of the fourth current-limiting resistor; the collector of the second triode is connected with the second output end of the first reverse-filling prevention power circuit, the second output end of the second reverse-filling prevention power circuit and one end, far away from the base of the third triode, of the third resistor;

the third output end of the first reverse-filling prevention power circuit is connected with the first input end of the H-bridge drive circuit; the third output end of the second reverse-filling prevention power supply circuit is connected with the first input end of the H-bridge drive circuit; the third output end of the third reverse-filling prevention power supply circuit is connected with the third input end of the H-bridge drive circuit; and the third output end of the fourth reverse-flow prevention power supply circuit is connected with the fourth input end of the H-bridge drive circuit.

The first anti-reverse-filling power supply circuit, the second anti-reverse-filling power supply circuit, the third anti-reverse-filling power supply circuit and the fourth anti-reverse-filling power supply circuit respectively comprise a +5V low-voltage direct-current power supply, a divider resistor and two diodes; the +5V low-voltage direct current power supply is connected with the anodes of the two diodes through a voltage-dividing resistor.

Specifically, the H-bridge driving circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first MOS transistor, a second MOS transistor, a third MOS transistor, and a fourth MOS transistor; the output end of the power supply circuit is connected with the grid electrode of the first MOS tube and the output end of the isolation amplifying circuit through a first resistor; the output end of the power supply circuit is connected with the grid electrode of the second MOS tube and the output end of the isolation amplifying circuit through a second resistor; the output end of the power supply circuit is connected with the grid electrode of the third MOS tube and the output end of the isolation amplifying circuit through a seventh resistor; the output end of the power supply circuit is connected with the grid electrode of the fourth MOS tube and the output end of the isolation amplifying circuit through an eighth resistor; the output end of the power supply circuit is connected with the source electrode of the first MOS transistor and the first input end of the H-bridge circuit through a third resistor; the output end of the power supply circuit is connected with the source electrode of the second MOS transistor and the second input end of the H-bridge circuit through a fourth resistor; the output end of the power supply circuit is connected with the source electrode of the third MOS tube and the third input end of the H-bridge circuit through a fifth resistor; the output end of the power supply circuit is connected with the grid electrode of the fourth MOS tube through a sixth resistor; the drain electrodes of the first MOS tube, the second MOS tube, the third MOS tube and the fourth MOS tube are grounded.

Specifically, the H-bridge circuit includes a fifth MOS transistor, a sixth MOS transistor, a seventh MOS transistor, an eighth MOS transistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, a first capacitor, a second capacitor, a third capacitor, and a fourth capacitor; a first input end of the H-bridge circuit is connected with a grid electrode of the fifth MOS tube through a ninth resistor; a second input end of the H-bridge circuit is connected with a grid electrode of the sixth MOS tube through a tenth resistor; a third input end of the H-bridge circuit is connected with a grid electrode of the seventh MOS tube through an eleventh resistor; a fourth input end of the H-bridge circuit is connected with a grid electrode of the eighth MOS tube through a twelfth resistor; the output end of the power supply circuit is connected with the sources of the fifth MOS tube, the sixth MOS tube, the seventh MOS tube and the eighth MOS tube, the cathodes of the first diode, the second diode, the third diode and the fourth diode, the first end of the thirteenth resistor, the first end of the second capacitor, the first end of the fifteenth resistor and the first end of the fourth capacitor; a second end of the thirteenth resistor is connected with the drain electrode of the fifth MOS tube, the anode of the first diode, a first end of the seventeenth resistor and a first output end of the H-bridge circuit through the first capacitor; the second end of the second capacitor is connected with the drain electrode of the sixth MOS tube, the anode of the second diode, the first end of the eighteenth resistor and the first output end of the H-bridge circuit through the second capacitor; a second end of the fifteenth resistor is connected with the drain electrode of the seventh MOS tube, the anode of the third diode, the cathode of the fifth diode and a second output end of the H-bridge circuit through the third capacitor; a second end of the fourth capacitor is connected with a drain electrode of the seventh MOS tube, a positive electrode of the third diode, a positive electrode of the sixth diode and a second output end of the H-bridge circuit through the fourth capacitor; the anode of the fifth diode is connected with the second end of the seventeenth resistor; and the cathode of the sixth diode is connected with the second end of the eighteenth resistor.

In an H-bridge circuit, the function of the diode freewheeling upwards is to prevent the load voltage from being higher than the supply voltage, and the function of the diode freewheeling downwards is to prevent the load voltage from being lower than the supply earth voltage. The capacitor-resistor follow current voltage stabilizing circuit can prevent instant peak voltage from occurring in load voltage, and meanwhile, the load voltage is prevented from being higher than power supply voltage and lower than power supply earth voltage.

Specifically, the overvoltage and overcurrent protection circuit comprises a ninth MOS transistor, a first operational amplifier, a second operational amplifier, a seventh diode, an eighth diode, a ninth diode, a +5V dc power supply circuit, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, and a twenty-fourth resistor; the +5V direct-current power supply circuit comprises a +5V direct-current power supply, a nineteenth resistor and a twentieth resistor; the +5V direct-current power supply is connected with the first end of the nineteenth resistor; the second end of the nineteenth resistor is connected with the output end of the +5V direct-current power supply circuit and the first end of the twentieth resistor; a second end of the twentieth resistor is grounded; the output end of the H-bridge circuit is connected with the source electrode of the ninth MOS tube; the +5V direct-current power supply is connected with the grid electrode of the ninth MOS tube, the anode of the seventh diode, the anode of the eighth diode and the anode of the ninth diode through a thirteenth resistor; the drain electrode of the ninth MOS tube is connected with the reverse input end of the first operational amplifier; the homodromous input end of the first operational amplifier is connected with the output end of the +5V direct-current power supply circuit; the output end of the first operational amplifier is connected with the cathode of the seventh diode; the output end of the second operational amplifier is connected with the cathode of the eighth diode; the output end of the third operational amplifier is connected with the negative electrode of the ninth diode; the output end of the +5V direct-current power supply circuit is connected with the reverse input end of the second operational amplifier and the same-direction input end of the third operational amplifier; the +5V direct-current power supply is connected with the homodromous input end of the second operational amplifier and the first end of the twenty-first resistor through the twenty-fourth resistor; the second end of the twenty-first resistor is connected with the inverting input end of the third operational amplifier and the first end of the twenty-second resistor; the second end of the twenty-second resistor is grounded.

The overvoltage protection circuit can enable the load when the power supply voltage is greater than a predetermined voltage. The overvoltage protection circuit consists of two comparators and a plurality of resistors; the overcurrent protection circuit can enable the load when the load current is larger than the predetermined current. The overcurrent protection circuit is composed of a comparator and an AND gate.

Specifically, the power supply circuit comprises an input power supply, a power supply reverse connection protection circuit, a surge voltage protection circuit and a power supply noise protection circuit; the power supply reverse connection protection circuit comprises a twelfth polar tube; the surge voltage protection circuit comprises a first direct current power supply, a fifth capacitor, a sixth capacitor, a TVS (transient voltage suppressor) and an inductor; the power supply noise protection circuit comprises a seventh capacitor, an eighth capacitor and a ninth capacitor; the input power supply is connected with the second end of the fifth capacitor, the first end of the sixth capacitor, the second end of the ninth capacitor, the first end of the TVS tube and the first end of the inductor through the tenth diode; the second direct current power supply is connected with the second end of the inductor; the second end of the TVS tube is grounded; the output end of the direct current power supply is connected with the first end of the fifth capacitor; the second end of the sixth capacitor, the first end of the seventh capacitor and the first end of the eighth capacitor are grounded; the second end of the seventh capacitor and the second end of the capacitor are connected with the first end of the ninth capacitor.

The surge voltage protection circuit can guarantee that the H bridge driving voltage is stable when irregular waveform voltage and peak voltage appear in power supply voltage, and mainly comprises an inductor, a bidirectional TVS (transient voltage suppressor), a pull-up capacitor and a pull-down capacitor. The power reverse connection protection circuit can prevent the power reverse connection from damaging the circuit. The power supply noise protection circuit can prevent the damage of power supply noise and electromagnetic waves in the environmental space to the circuit.

Specifically, the optical coupler isolation resistor comprises an optical coupler chip HCPL 2630.

The working process of the invention is as follows: the external pulse width modulation signal is converted into an A1 signal through an input optical coupling isolation circuit, and the optical coupling isolation circuit is used for signal isolation and increasing the anti-interference capacity. The a1 signal is then passed through an and gate and a not gate circuit to convert the a1 signal to an a2 signal and a B1 signal. The A2 signal and the B1 signal are respectively sent to two MOS tube driving circuits, the A2 signal is changed into HH and HL signals, the B1 signal is changed into LH and LL signals, wherein the HH signal and the HL signal are opposite in phase, and the LH and LL signal are opposite in phase.

The working process is as follows: an external pulse width modulation signal is converted into an A1 signal through an input optical coupling circuit, and the optical coupling circuit is used for signal isolation and increasing the anti-interference capacity; the A1 signal passes through an AND gate and a NOT gate circuit to change the A1 signal into an A2 signal and a B1 signal; the A2 signal and the B1 signal are respectively sent to two MOS tube driving circuits, the A2 signal is changed into HH and HL signals, the B1 signal is changed into LH and LL signals, wherein the HH signal and the HL signal are opposite in phase, and the LH and LL signal are opposite in phase.

The motor has back pressure in the running process, the motor voltage exceeds the power supply voltage, and the positive end and the negative end of the H-bridge circuit motor adopt two follow current modes of diode upward follow current and diode downward follow current simultaneously, so that the motor voltage can be prevented from exceeding the power supply voltage; in the H-bridge circuit, a capacitor resistor is connected in series to follow current and stabilize voltage, so that the influence of power supply fluctuation and an external magnetic field on the operation index of the motor can be prevented.

The invention realizes the purpose through the following technical scheme:

the positive end and the negative end of the H-bridge circuit adopt two follow current modes of diode upward follow current and diode downward follow current simultaneously, so that the voltage of the motor can be prevented from exceeding the voltage of a power supply; in the H-bridge circuit, a capacitor resistor is connected in series to follow current and stabilize voltage, so that the influence of power supply fluctuation and an external magnetic field on the operation index of the motor can be prevented.

In the circuit, an overvoltage and overcurrent protection circuit and a surge voltage protection circuit are arranged in the circuit, so that the reliability and the stability of the circuit are improved; the power supply noise protection circuit improves the noise anti-interference capability of the power supply, and the power supply reverse connection circuit is arranged to prevent the reverse connection of the power supply; the motor enabling circuit is arranged, so that the abnormal working condition of the motor can be processed.

The invention has the advantages that:

1) the input and the output are isolated by optical coupling, so that the anti-interference capability of the circuit is enhanced; (ii) a

2) The circuit is provided with an upward freewheeling diode and has the capability of eliminating the reverse voltage of the motor;

3) the circuit is provided with a downward freewheeling diode and has the capability of eliminating the reverse voltage of the motor;

4) the circuit has the functions of capacitor resistance follow current and voltage stabilization and has the capability of eliminating the reverse voltage and voltage surge of the motor;

5) the circuit has an overvoltage protection function;

6) the circuit has an overcurrent protection function;

7) the circuit has a surge voltage protection function;

8) the circuit has the function of preventing power supply interference;

9) the circuit has a power supply noise protection function;

10) the circuit has an enable protection function.

The technical solution of the present invention is not limited to the limitations of the above specific embodiments, and all technical modifications made according to the technical solution of the present invention fall within the protection scope of the present invention.