Patent ID: 7315155

Claim:
A load drive control system, comprising: a PWM control system comprising PWM fundamental wave generation section that forms a PWM fundamental wave by dividing a fundamental frequency signal; PWM cycle setting section that sets a PWM cycle on the basis of the PWM fundamental wave; duty ratio formation section that forms a duty ratio (N/M:N≦M where M is the maximum number of clocks) in the PWM cycle; and PWM control signal output section that outputs a PWM control signal with the duty ratio to a load drive circuit; load operational state detection means; load operational state command means; a PLL circuit for dividing the fundamental wave at a division ratio corresponding to the operating command state; and comparison section that compares the output from the PLL circuit with the load operational state detection value, wherein the comparison result is supplied to the duty ratio formation section of the PWM system; and the PWM control signal of the duty ratio formed in accordance with the comparison result is outputted to the load drive circuit by the PWM control signal output section.