Current controlled motor drive circuit

摘要

A switching regulator causes a supply voltage to be intermittently chopped to provide energy pulses in a lowpass filter circuit. The lowpass filter circuit includes a capacitor which is being charged by the chopped energy pulses and whose output is used to drive a low voltage stepper motor. The duty cycle of the energy pulses is a function of the average value of the stepper motor coil current. By correlating the duty cycle of the energy pulses with the average current in the motor coil a relatively high torque is provided to drive the motor during a startup phase and is automatically adjusted to meet the running requirements of the particular stepper motor.