Driving Higher Power Motors

Driving the ‘small’ motors that may be used in robotics doesn’t usually pose much of a problem. Servo motors actually have their own drive electronics, stepper motors can be easily driven by conventional power transistors or by ULN2803 ICs as has been shown elsewhere in this issue, as they rarely draw more than a few hundreds of mA. For small DC motors, simple transistors will suffice, unless you prefer for example the LB1630 from Sanyo, though limited alas to a current of 400 mA and a voltage of 6 V.

On the other hand, as soon as the motor starts drawing 1 A or more, or its supply voltage exceeds 20 V or so, the situation gets more complicated all the more so because many of you don’t much care for power electronics. So, this article hopes to give you a few ideas or research paths for driving such motors.