Patent ID: 8040701

Claim:
A control circuit for a charge pump circuit having at least one flying capacitor and at least one output capacitor, comprising: a first switch group including at least one switch provided on a path for charging the flying capacitor using an input voltage; a second switch group including at least one switch provided on a path for charging the output capacitor using charge stored in the flying capacitor; a pulse modulator which generates a pulse signal having a duty ratio adjusted so that a feedback voltage corresponding to an output voltage of the charge pump circuit matches a given reference voltage; and a driver which receives the pulse signal from the pulse modulator, turns on one of the first switch group and the second switch group during a period corresponding to a high-time of the pulse signal and turns on the other switch group during a period corresponding to a low-time thereof, wherein the pulse modulator limits the duty ratio of the pulse signal within a given range.