Patent ID: 7509032

Claim:
A motor drive control circuit comprising: a rotation control amplifier arranged to input a peak voltage of a voltage generated in an impedance element to detect a drive current of a motor, a voltage limiting reference voltage, and a rotation speed control voltage arranged to control a rotation speed of the motor and compare the lower of the voltage limiting reference voltage and rotation speed control voltage with the peak voltage; a rotation limiting comparator arranged to input and compare a voltage that is substantially equal to said voltage limiting reference voltage with said peak voltage; a synthesis circuit arranged to amplify a rotation position detection signal of the motor according to an output voltage of the rotation control amplifier; a PWM output comparator arranged to compare an output of the synthesis circuit with a triangular wave voltage of a triangular wave generator and outputs a PWM signal; and a motor-driver control circuit arranged to input the PWM signal and an output signal of the rotation limiting comparator, remove an output period of the rotation limiting comparator from an ON period of the PWM signal, and control a motor driver that drives the motor.