阅读说明：本技术 一种电机驱动电路 (Motor driving circuit ) 是由 曾雄伟 方榆 陈树波 于 2018-08-20 设计创作，主要内容包括：本发明公开了一种电机驱动电路,包括H桥、第一控制电路和第二控制电路；所述H桥包括第一场效应管、第二场效应管、第三场效应管和第四场效应管,以及起到钳位作用的第一二极管、第二二极管、第三二极管和第四二极管。本发明电机驱动电路的H桥设有钳位二极管进行保护,防止场效应管短路时电流过大而烧毁场效应管或电机；驱动电路的主要元件为分立元件,能够通过大电流、承受大功率、散热效果好、电能转换效率高,尤其适合200W以上的大功率直流电机的连续驱动。本发明广泛应用于电子电路技术领域。(The invention discloses a motor driving circuit, which comprises an H bridge, a first control circuit and a second control circuit, wherein the H bridge is connected with the first control circuit; the H-bridge comprises a first field effect transistor, a second field effect transistor, a third field effect transistor, a fourth field effect transistor, a first diode, a second diode, a third diode and a fourth diode which play a clamping role. The H bridge of the motor driving circuit is provided with a clamping diode for protection, so that the field effect transistor or the motor is prevented from being burnt due to overlarge current when the field effect transistor is in short circuit; the main elements of the driving circuit are discrete elements, can bear high power through large current, have good heat dissipation effect and high electric energy conversion efficiency, and are particularly suitable for continuous driving of a high-power direct current motor with the power of more than 200W. The invention is widely applied to the technical field of electronic circuits.)

1. A motor driving circuit is characterized by comprising an H bridge, a first control circuit and a second control circuit;

the H bridge comprises a first field effect tube, a second field effect tube, a third field effect tube and a fourth field effect tube; the drain electrode of the first field effect tube and the drain electrode of the second field effect tube are both connected to a power supply, the source electrode of the third field effect tube is connected with the source electrode of the fourth field effect tube to serve as a grounding end, the source electrode of the first field effect tube is connected with the drain electrode of the third field effect tube, and the source electrode of the second field effect tube is connected with the drain electrode of the fourth field effect tube; the grid electrode of the first field effect transistor is used as a first control end of the H bridge, the grid electrode of the second field effect transistor is used as a second control end of the H bridge, the grid electrode of the third field effect transistor is used as a third control end of the H bridge, and the grid electrode of the fourth field effect transistor is used as a fourth control end of the H bridge;

the first control end and the third control end are both connected with a first control circuit, and the second control end and the fourth control end are both connected with a second control circuit;

the H bridge further comprises a first diode, a second diode, a third diode and a fourth diode, the first diode and the third diode are reversely connected between the drain electrode of the first field effect tube and the source electrode of the third field effect tube in series, the second diode and the fourth diode are reversely connected between the drain electrode of the second field effect tube and the source electrode of the fourth field effect tube in series, the connection point of the first diode and the third diode serves as a first power supply end for connecting the H bridge and the motor, and the connection point of the second diode and the fourth diode serves as a second power supply end for connecting the H bridge and the motor;

the first power supply end is connected with a source electrode of the first field effect transistor, and the second power supply end is connected with a source electrode of the second field effect transistor.

2. A motor driving circuit according to claim 1, wherein said first control circuit comprises a first chip and a first bootstrap circuit;

the first chip comprises an enabling end, a control signal receiving end, a high-end grid driving output end, a low-end grid driving output end, a high-end floating power end and a high-end floating power return end; the high-side floating power supply comprises an enable end, a control signal receiving end, a high-side grid driving output end, a low-side grid driving output end, a third control end and a high-side floating power supply return end, wherein the enable end is used for receiving an enable signal, the control signal receiving end is used for receiving a control signal, the high-side grid driving output end is connected with the first control end, the low-side grid driving output end is connected with the third control end, and the;

the first bootstrap circuit comprises a fifth diode and a first capacitor, the first capacitor is connected between a high-end floating power supply end and a high-end floating power supply return end, the cathode of the fifth diode is connected with the high-end floating power supply end, and the anode of the fifth diode is connected with a power supply.

3. A motor drive circuit according to claim 2, wherein the first control circuit further comprises a first high side limiter circuit and a first low side limiter circuit, the first high side limiter circuit comprising a first resistor and a sixth diode connected in parallel, the first low side limiter circuit comprising a second resistor and a seventh diode connected in parallel, the first high side limiter circuit being connected between the high side gate drive output and the first control terminal, and the first low side limiter circuit being connected between the low side gate drive output and the third control terminal.

4. The motor driving circuit according to claim 2, further comprising an undervoltage protection circuit, wherein the undervoltage protection circuit comprises a first voltage division circuit, a first not gate, a second not gate and a third not gate, the first voltage division circuit is configured to collect a voltage from a power supply to ground and input the voltage to an input terminal of the first not gate, an output terminal of the first not gate is connected to an input terminal of the third not gate through the second not gate, and an output terminal of the third not gate is connected to an enable terminal of the first chip.

5. The motor driving circuit according to claim 2, further comprising an overvoltage protection circuit, wherein the overvoltage protection circuit comprises a second voltage division circuit and a fourth not gate, the second voltage division circuit is used for collecting a power supply to ground voltage and inputting the power supply to an input terminal of the fourth not gate, and an output terminal of the fourth not gate is connected to the enable terminal of the first chip.

6. The motor driving circuit according to claim 2, further comprising a current limiting protection circuit, wherein the current limiting protection circuit comprises a current sampling resistor, a non-inverting proportional amplifier and a fifth not gate, the current sampling resistor is connected between a ground terminal of the H-bridge and a ground line, an input terminal of the non-inverting proportional amplifier is connected to the ground terminal of the H-bridge, and an output terminal of the non-inverting proportional amplifier is connected to the enable terminal of the first chip through the fifth not gate.

7. The motor driving circuit according to claim 2, further comprising an overheat protection circuit, wherein the overheat protection circuit comprises a thermistor and a voltage comparator, the thermistor is used for measuring the temperature of the H-bridge, the thermistor is connected between an inverting input terminal of the voltage comparator and a ground line, a non-inverting input terminal of the voltage comparator is connected to a comparison voltage, and an output terminal of the voltage comparator is connected to an enable terminal of the first chip.

Technical Field

The invention relates to the technical field of electronic circuits, in particular to a motor driving circuit.

Background

Interpretation of terms

A direct current motor: a rotating electrical machine capable of converting direct-current electric energy into mechanical energy (a direct-current motor) or converting mechanical energy into direct-current electric energy (a direct-current generator).

Gate circuit: the unit circuit for implementing basic logic operation and complex logic operation is called a gate circuit, and the commonly used gate circuits have several logic functions, such as an and gate, an or gate, a not gate, a nand gate, a nor gate, an and nor gate, and an xor gate. Discrete gates have the advantage of nanosecond fast response compared to integrated circuits.

Dc motors are widely used in various fields, and an H-bridge is generally used to drive the dc motor. A conventional H-bridge is shown in fig. 1 and comprises four fets Q1-Q4 for driving a motor M, wherein two fets Q1, Q2 are located at two sides of the upper end of the H-bridge, two fets Q3, Q4 are located at two sides of the lower end of the H-bridge, and the motor M is located on the middle cross-bridge. To rotate the motor M, a pair of fets at two sides of the upper end of the H-bridge and the lower end of the H-bridge opposite to the upper end of the H-bridge need to be turned on. According to the difference of the conduction states of the field effect transistors on the two diagonal sides, the current passing through the motor M can be from left to right or from right to left, so that the forward rotation or the reverse rotation of the motor M is realized. In the process of realizing forward and reverse alternation, the field effect transistors on the same side of the H-bridge driving circuit are ensured not to be conducted simultaneously, if the driving transistors on the same side are conducted simultaneously, the current can directly flow from the anode to the power ground, and the field effect transistors are burnt because other loads except the two field effect transistors do not exist in the circuit.

In order to make the four field effect transistors Q1-Q4 turn on or off as required, the H-bridge is also provided with corresponding control circuits. The existing chips such as LMD18200, L6203 and L298 integrate the H bridge and the control circuit on the same chip. The integrated circuit has the advantages that the circuit structure is simple, the integrated circuit can work only by matching a small number of peripheral circuit elements, but compared with a discrete element circuit, the integrated circuit has the natural defect that the bearable current is small, so that the driving power of an H bridge of the integrated circuit is limited, the integrated circuit is seriously disturbed by the problem of heating, and meanwhile, the integrated circuit is easily interfered by external electromagnetic waves and even breaks down. In summary, in the prior art, both the H-bridge formed by discrete components and the H-bridge formed by integrated circuits have the defect that the field effect transistor is easy to burn out.

Disclosure of Invention

In order to solve the above technical problems, an object of the present invention is to provide a motor driving circuit.

The technical scheme adopted by the invention is as follows:

a motor driving circuit comprises an H bridge, a first control circuit and a second control circuit;

the H bridge comprises a first field effect tube, a second field effect tube, a third field effect tube and a fourth field effect tube; the drain electrode of the first field effect tube and the drain electrode of the second field effect tube are both connected to a power supply, the source electrode of the third field effect tube is connected with the source electrode of the fourth field effect tube to serve as a grounding end, the source electrode of the first field effect tube is connected with the drain electrode of the third field effect tube, and the source electrode of the second field effect tube is connected with the drain electrode of the fourth field effect tube; the grid electrode of the first field effect transistor is used as a first control end of the H bridge, the grid electrode of the second field effect transistor is used as a second control end of the H bridge, the grid electrode of the third field effect transistor is used as a third control end of the H bridge, and the grid electrode of the fourth field effect transistor is used as a fourth control end of the H bridge;

the first control end and the third control end are both connected with a first control circuit, and the second control end and the fourth control end are both connected with a second control circuit;

the H bridge further comprises a first diode, a second diode, a third diode and a fourth diode, the first diode and the third diode are reversely connected between the drain electrode of the first field effect tube and the source electrode of the third field effect tube in series, the second diode and the fourth diode are reversely connected between the drain electrode of the second field effect tube and the source electrode of the fourth field effect tube in series, the connection point of the first diode and the third diode serves as a first power supply end for connecting the H bridge and the motor, and the connection point of the second diode and the fourth diode serves as a second power supply end for connecting the H bridge and the motor;

the first power supply end is connected with a source electrode of the first field effect transistor, and the second power supply end is connected with a source electrode of the second field effect transistor.

Further, the first control circuit comprises a first chip and a first bootstrap circuit;

the first chip comprises an enabling end, a control signal receiving end, a high-end grid driving output end, a low-end grid driving output end, a high-end floating power end and a high-end floating power return end; the high-side floating power supply comprises an enable end, a control signal receiving end, a high-side grid driving output end, a low-side grid driving output end, a third control end and a high-side floating power supply return end, wherein the enable end is used for receiving an enable signal, the control signal receiving end is used for receiving a control signal, the high-side grid driving output end is connected with the first control end, the low-side grid driving output end is connected with the third control end, and the;

the first bootstrap circuit comprises a fifth diode and a first capacitor, the first capacitor is connected between a high-end floating power supply end and a high-end floating power supply return end, the cathode of the fifth diode is connected with the high-end floating power supply end, and the anode of the fifth diode is connected with a power supply.

Further, the first control circuit further comprises a first high-end amplitude limiting circuit and a first low-end amplitude limiting circuit, the first high-end amplitude limiting circuit is formed by connecting a first resistor and a sixth diode in parallel, the first low-end amplitude limiting circuit is formed by connecting a second resistor and a seventh diode in parallel, the first high-end amplitude limiting circuit is connected between the high-end gate driving output end and the first control end, and the first low-end amplitude limiting circuit is connected between the low-end gate driving output end and the third control end.

Further, the motor driving circuit further comprises an undervoltage protection circuit, the undervoltage protection circuit comprises a first voltage division circuit, a first not gate, a second not gate and a third not gate, the first voltage division circuit is used for collecting a power supply to ground voltage and inputting the ground voltage to an input end of the first not gate, an output end of the first not gate is connected with an input end of the third not gate through the second not gate, and an output end of the third not gate is connected with an enable end of the first chip.

Further, the motor driving circuit further comprises an overvoltage protection circuit, the overvoltage protection circuit comprises a second voltage division circuit and a fourth not gate, the second voltage division circuit is used for collecting a power supply to ground voltage and inputting the ground voltage to an input end of the fourth not gate, and an output end of the fourth not gate is connected with an enabling end of the first chip.

Further, the motor driving circuit further comprises a current-limiting protection circuit, the current-limiting protection circuit comprises a current sampling resistor, an in-phase proportional amplifier and a fifth not gate, the current sampling resistor is connected between a grounding end of the H bridge and a ground wire, an input end of the in-phase proportional amplifier is connected with the grounding end of the H bridge, and an output end of the in-phase proportional amplifier is connected with an enabling end of the first chip through the fifth not gate.

Further, the motor driving circuit further comprises an overheating protection circuit, the overheating protection circuit comprises a thermistor and a voltage comparator, the thermistor is used for measuring the temperature of the H bridge, the thermistor is connected between the inverting input end of the voltage comparator and the ground wire, the non-inverting input end of the voltage comparator is connected to a comparison voltage, and the output end of the voltage comparator is connected with the enabling end of the first chip.

The invention has the beneficial effects that: the H bridge is provided with a clamping diode for protection, so that the field effect tube or the motor is prevented from being burnt due to overlarge current when the field effect tube is in short circuit; the main elements of the driving circuit are discrete elements, can bear high power through large current, have good heat dissipation effect and high electric energy conversion efficiency, and are particularly suitable for continuous driving of a high-power direct current motor with the power of more than 200W. Furthermore, a simple and reliable undervoltage, overvoltage, current-limiting and overheating protection circuit is arranged to prevent adverse effects caused by undervoltage, overvoltage, current-limiting and overheating; compared with an integrated circuit, the integrated circuit has the advantages of high response speed and insensitivity to electromagnetic wave interference due to the integral use of a discrete circuit design.

Drawings

FIG. 1 is a circuit diagram of a prior art H-bridge;

FIG. 2 is a circuit diagram of an H bridge in embodiment 1;

FIG. 3 is a circuit diagram of a first control circuit in embodiment 2;

FIG. 4 is a circuit diagram of an under-voltage protection circuit according to embodiment 3;

FIG. 5 is a circuit diagram of an overvoltage protection circuit in embodiment 4;

FIG. 6 is a circuit diagram of a current limiting protection circuit according to embodiment 5;

FIG. 7 is a circuit diagram of an overheat protection circuit according to embodiment 6;

fig. 8 is a wiring circuit diagram of each circuit and the first chip in embodiments 3-6.

Detailed Description