Patent ID: 8848476

Claim:
A charge pump circuit, comprising: a first booster set for receiving a supply voltage and generating a first output voltage, wherein the first booster set comprises a plurality of charge pump stages connected in series; a detecting circuit for generating a detecting signal depending on the voltage level of the first output voltage; and a second booster group for receiving the supply voltage and generating the first output voltage or a second output voltage according to the detecting signal, wherein the second booster group comprises a plurality of booster sets connected in parallel, and each booster set comprises a plurality of charge pump stages and a plurality of switch units; wherein the stable voltage level of the first output voltage is greater than the second output voltage; the number of charge pump stages in the first booster set is the same as the number of charge pump stages of each booster set in the second booster group; and the number of serially-connected charge pump stages of each booster set in the second booster group is controlled by the plurality of switch units according to the stable voltage levels of the first and second output voltages.