Patent ID: 7902905
Filing Date: 2011-03-08
Classification: H02M

Abstract:
1. A voltage supply circuit comprising: a booster circuit; and a ripple filter circuit that has if an output voltage at the first output terminal is equal to a first voltage, the first switch circuit is turned on, and the second switch circuit is turned off, if the output voltage at the first output terminal is equal to a second voltage higher than the first voltage, the first switch circuit is turned on, and the second switch circuit is turned on, and the booster circuit has the pump controlling circuit controls the pump circuit to reduce a number of active charge pump circuits according to one of output signals of the first comparator and the second comparator, controls the pump circuit to reduce a frequency of a second clock signal for operating the active charge pump circuits by reducing a frequency of the first clock signal according to the other of the output signals of the first comparator and the second comparator, and brings the pump circuit into an inactive state according to an output signal of the third comparator.