SPEED CONTROL SYSTEM FOR SMALL MEDICAL MOTORS

A speed control system for small medical motors. The system comprises a drive voltage regulation circuit, a current detection circuit which generates a detection signal in accordance with motor current, a voltage detection circuit which generates a detection signal in accordance with motor voltage, and a speed control circuit which controls the drive voltage regulation circuit in accordance with the detection signals of both detection circuits. With this system, the detection signal of the current detection circuit is positive-fed back, and the detection signal of the voltage detection circuit is negative-fed back to the speed control circuit to keep motor speed constant by effectively coping with abrupt load fluctuation.