Patent ID: 8742832

Claim:
A multi-step charge pump, having a power input terminal and a power output terminal, the charge pump comprising: a plurality of capacitors, wherein each of the capacitors respectively has a capacitance, and one of the capacitors is changeably selected as a voltage-regulating capacitor; a plurality of switching devices, connected among the capacitors, the power input terminal and the power output terminal; and a switch-controlling unit for controlling on/off states of the switching devices, wherein a charging-phase circuit corresponding to a desired pumping level is formed for charging the capacitors, and the charging-phase circuit comprises: a first circuit, formed by all of the capacitors other than the voltage-regulating capacitor, wherein the capacitors to form the first circuit are connected by the switching devices, and the first circuit is between the power input terminal and a grounded terminal; and a second circuit, comprising the voltage-regulating capacitor and connected between the power output terminal and the grounded terminal; and an output-phase circuit is formed to output a voltage to the power output terminal, and the output-phase circuit comprises: a third circuit, formed by all of the capacitors other than the voltage-regulating capacitor, wherein the capacitors to form the third circuit are connected by the switching devices and the third circuit has a first connection terminal connected to the power input terminal and a second connection terminal connected to the power output terminal; and a fourth circuit, comprising the voltage-regulating capacitor and connected between the power output terminal and the grounded terminal.