Patent ID: 8310184

Claim:
A PWM control circuit that generates PWM signals based on an analog sensor output from a sensor provided in a device to be controlled, comprising: a polarity determination unit that judges positive polarity sections and negative polarity sections of the analog sensor output to generate a polarity signal; a full wave rectification unit that generates a full wave rectification signal by doing full rectification of the analog sensor output; an adjustment unit that generates an adjusted waveform signal by adjusting waveform of the full wave rectification signal; and a PWM waveform shaping unit that generates a first PWM signal for the positive polarity section and a second PWM signal for the negative polarity section, based on the polarity signal and the adjusted waveform signal, wherein the adjustment unit includes a validity signal interval setting unit that sets only part of the full wave rectification signal as valid and the other part as invalid.