Patent ID: 7190598

Claim:
A three-phase charge pump circuit for producing a low noise output voltage on an output conductor, the three-phase charge pump comprising: (a) a first flying capacitor; (b) a first amplifier circuit having an output coupled to control a first current source to produce a first controlled current in a first conductor in response to the output voltage, a first input coupled to a first supply voltage, and a second input coupled to the output conductor; (c) a second amplifier circuit having an output coupled to control a second current source to produce a second controlled current in a second conductor in response to a precharge voltage, a first input coupled to the first supply voltage, and a second input coupled to receive the precharge voltage; (d) a first switching circuit for selectively coupling a first terminal of the first flying capacitor to the first supply voltage during a first recharging phase and to the output voltage during a first discharging phase; (e) a second switching circuit for selectively coupling a second terminal of the first flying capacitor to a second supply voltage during the first recharging phase and to the first conductor during the first discharging phase; and (f) the second switching circuit coupling the second terminal of the first flying capacitor to the second conductor during a first parasitic capacitance precharging phase that occurs between the first recharging phase and the first discharging phase so as to cause the voltage of the first terminal of the first flying capacitor to have a value that avoids noise spikes on the output conductor due to charge redistribution when the first terminal of the first flying capacitor is coupled to the output conductor.