Four DC motor drive circuit diagrams and design ideas

Four DC motor drive circuit diagrams and design ideas

DC motor drive design needs attention, simple gate drive of low-voltage drive circuit, edge delay drive circuit diagram and its design ideas.

First, the design goal of DC motor drive circuit

In the design of the DC motor drive circuit, the main considerations are as follows:

1. Function: Is the motor unidirectional or bidirectional? Does it need speed regulation? For one-way motor drive, just use a high-power triode or FET or relay to directly drive the motor. When the motor needs to rotate in both directions, An H-bridge circuit consisting of 4 power components can be used or a double-pole double-throw relay can be used. If you do not need speed regulation, just use the relay; but if you need speed regulation, you can use PWM (pulse width modulation) speed regulation by using switching elements such as triode and FET.

2. Performance: For the PWM drive motor drive circuit, the main performance indicators are as follows.

1) Output current and voltage range, which determines how much power the circuit can drive.

2) Efficiency, high efficiency not only means saving power, but also reducing the heating of the drive circuit. To improve the efficiency of the circuit, it is possible to ensure the switching state of the power device and prevent common-state conduction (a problem that may occur in the H-bridge or push-pull circuit, that is, the two power devices are simultaneously turned on to short-circuit the power supply).

3) The effect on the control input. The power circuit should have good signal isolation at its input to prevent high voltage and high current from entering the main control circuit, which can be isolated with high input impedance or optocoupler.

4) The impact on the power supply. Common-state conduction can cause a transient drop in the supply voltage to cause high-frequency power supply contamination; large currents can cause the ground potential to float.

5) Reliability. The motor drive circuit should be as close as possible, no matter what kind of control signal, what kind of passive load, the circuit is safe.

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