Patent ID: 8860498

Claim:
A charge pump circuit, comprising: a first stage and an at least second stage, each having a capacitor and a current source, wherein the first stage and the at least second stage each comprise: a first switch arranged between the current source of the respective stage and a first electrode of the capacitor of the respective stage and set in a closed state in a first phase of operation and in an open state in a second phase of operation; a second switch arranged between the first electrode of the capacitor of the respective stage and an output of the respective stage and set in an open state in the first phase of operation and in a closed state in the second phase of operation; and a third switch that couples the first electrode of the capacitor of the respective stage to a reference potential terminal and is set in a closed state in a first sub-phase of the first phase of operation and in an open state in a second sub-phase of the first phase of operation and in the second phase of operation; and a comparator having: a first input which is coupled to an electrode of one of the capacitors of the first and the at least second stage, a second input for receiving a reference voltage, and an output for generating a comparator signal, wherein the charge pump circuit is configured such that, in the first phase of operation, the capacitor of the first stage is switched in series to the current source of the first stage for charging the capacitor of the first stage and the capacitor of the second stage is switched in series to the current source of the second stage for charging the capacitor of the second stage and that, in the second phase of operation, the capacitor of the first stage and the capacitor of the second stage are switched in series for providing a supply voltage at an output of the charge pump circuit, and wherein the first and the second phase are set depending on the comparator signal.