| 摘要 |
A motor drive control circuit includes a rotation control amplifier that compares the lower of a voltage limiting reference voltage of a reference voltage source and a rotation speed control voltage, which controls the rotation speed of the motor, on a terminal with a peak voltage from an impedance element that detects a drive current of a motor. The motor drive control circuit further includes a rotation limiting comparator that compares a voltage that is substantially equal to the voltage limiting reference voltage with the peak voltage, a synthesis circuit that amplifies rotation position detection signals from the motor according to the output voltage of the rotation control amplifier, a PWM output comparator that compares the outputs of the synthesis circuit with a triangular wave voltage and outputs PWM signals, and a motor-driver control circuit that removes an output period of the rotation limiting comparator from the ON period of each PWM signal and controls a motor driver that drives the motor. The motor drive control circuit operates the elements defining the motor driver more in a safe operation region.
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