Patent ID: 8258857

Claim:
A circuit comprising: a first functional circuit, the first functional circuit having a first power supply voltage requirement and a first power supply current requirement; a second functional circuit, the second functional circuit having a second power supply voltage requirement and a second power supply current requirement, wherein the first power supply voltage requirement is less than the second power supply voltage requirement and the first power supply current requirement is greater than the second power supply current requirement; a first charge pump having an input coupled to a first power supply to receive a first power supply voltage, the first charge pump having a first output coupled to a first power supply input of the first functional circuit to provide a first charge pump output voltage and a first charge pump output current, wherein the first charge pump output voltage is greater than the first power supply voltage, and wherein the first charge pump output voltage meets the first power supply voltage requirement of the first functional circuit and the first charge pump output current meets the first power supply current requirement of the first functional circuit; and a second charge pump having an input coupled to at least one output of the first charge pump, the second charge pump having a second output coupled to a second power supply input of the second functional circuit to provide a second charge pump output voltage and a second charge pump output current, wherein the second charge pump output voltage is greater than the first charge pump output voltage, and wherein the second charge pump output current is less than the first charge pump output current, and wherein the second charge pump output voltage meets the second power supply voltage requirement of the second functional circuit and the second charge pump output current meets the second power supply current requirement of the second functional circuit; wherein the first functional circuit, the second functional circuit, the first charge pump, and the second charge pump are on a single integrated circuit; and wherein the first charge pump comprises a plurality of first capacitors and the second charge pump comprises a plurality of second capacitors, and wherein the first capacitors are external to the integrated circuit and the second capacitors are internal to the integrated circuit.