Patent ID: 8633780

Claim:
A pulse width modulation control circuit, comprising: a pulse width modulation control signal generator that generates a pulse width modulation period signal defining a period of a pulse width modulation signal and a pulse width modulation resolution signal specifying a resolution in one period of the pulse width modulation period signal; and a pulse width modulation unit that generates the pulse width modulation signal based on the pulse width modulation period signal and the pulse width modulation resolution signal, wherein the pulse width modulation control signal generator changes a frequency of the pulse width modulation resolution signal while keeping a frequency of the pulse width modulation period signal unchanged , and the pulse width modulation unit includes a counter that repeatedly decreases a count value in sync with the pulse width modulation resolution signal for each cycle of the pulse width modulation period signal, and that outputs a signal that indicates a H level when the count value is eater than 0 and outputs a signal that indicates a L level when the count value is 0.