Patent ID: 7511560

Claim:
A charge pump circuit, suitable for a display panel, comprising: a first and second capacitors, each of the first and second capacitors having a first and second ends; a first, second, third, and fourth switches, wherein each of the first, second, third, and fourth switches is switched from an off state to an on state being defined as an enable transition and is switched from the on state to the off state being defined as a disable transition, and each of the first, second, third, and fourth switches has a first and second ends, the first ends of the first and third switches being both coupled to an input voltage, the second ends of the first and third switches being respectively coupled to the first and second ends of the first capacitor, the first ends of the fourth and second switches being respectively coupled to the first ends of the first and third switches are both coupled to an input voltage, the second end of the fourth switch being coupled to an output voltage and the first end the second capacitor, the second end of the second switch being coupled to a low voltage and the second end the second capacitor; and a switch control circuit, coupled to the first, second, third, and fourth switches, for generating a first and second control signals, wherein the first control signal controls the on/off states of the first and second switches, the second signal controls the on/off states of the third and fourth switches, the switch control circuit prolongs time required for the enable transition of the first, second, third, and fourth switches to be longer than time required for the disable transition of the first, second, third, and fourth switches, and an equivalent impedance of each of the first, second, third, and fourth switches changes from a high value to a low value when it is at the enable transition.