Patent ID: 7629782
Filing Date: 2009-12-08
Classification: H02M

Abstract:
1. A switching power circuit, comprising: a determining unit which continuously determines a third value between a first value and a second value, based on a voltage difference between an output voltage and a reference voltage; a PWM control unit having a counter to periodically count a value between the first value and the second value and a driving unit which alternately switches a first switching element and a second switching element, the PWM control unit switching the first switching element and the second switching element in pulse width modulation mode, based on a small and large relation between a counting value of the counter and the third value; and a PFM control unit to switch the first switching element and the second switching element in pulse frequency modulation mode based on any one of the third value, a fourth value generated by averages of the third value, and a current value at the second switching element.