Patent ID: 7746676

Claim:
A charge pump for converting a voltage at an input node into a regulated voltage and outputting the regulated voltage at an output node, the charge pump comprising: a first capacitor; a first switch with adjustable on-state resistance coupled between a first electrode of the first capacitor and the output node; a second switch coupled between a second electrode of the capacitor and ground; a third switch coupled between the input node and the second electrode of the capacitor, the third switch having an open state and a close state that match the open and close states of the first switch, respectively; a fourth switch with adjustable on-state resistance coupled between the input node and the first electrode of the capacitor, the fourth switch having an open state and a close state that match the open and close states of the second switch, respectively; a feedback loop configured for monitoring the regulated voltage of the output node; and an oscillator for generating a first and a second pulse signals to switch the open and close states of the first, third switches and the second, fourth switches, respectively; wherein the first and the fourth switches each comprises an inverter and a field effect transistor; an input port of the inverter is connected to the oscillator to receive the first or second pulse signal, an enable port of the inverter is connected to an output port of the comparator, an output port of the inverter is connected to a gate electrode of the field effect transistor; the field effect transistor of the first switch comprises a source electrode connected to the first electrode of the first capacitor, and a drain electrode connected to the output node; the fourth switch comprises a source electrode connected to the second electrode of the first capacitor; and a drain electrode connected to ground.