Patent ID: 7551012

Claim:
A charge pump circuit comprising: a capacitor connected in parallel to an output node; a reference current source generating a reference current; a primary current switching circuit for charging said capacitor with a source current and for discharging said capacitor with a sink current, said source current tracking the reference current and said sink current tracking the reference current; a supplemental source circuit including an offset generator for sourcing, in response to a bias voltage, a positive phase shift producing current having a range of magnitudes, the supplemental source circuit also including a programmable array of transistors for providing the bias voltage, the bias voltage being adjustable in response to at least one source selection signal, said positive phase shift producing current tracking the same current tracked by said source current; and a supplemental sink circuit for sourcing a negative phase shift producing current having a range of magnitudes, a magnitude of the negative phase shift producing current being determined by at least one sink selection signal, said negative phase shift producing current tracking the same current tracked by said sink current.