Patent ID: 7142047

Claim:
A switching circuit, comprising: an input stage having an input referred offset voltage associated therewith; an output stage having an output offset voltage associated therewith which is due at least in part to the input referred offset associated with the input stage; and offset cancellation circuitry for temporarily canceling a portion of the output offset voltage, the offset cancellation circuitry being operable to cancel a portion of the input referred offset voltage associated with the input stage before switching of the output stage is enabled thereby resulting in cancellation of the portion of the output offset voltage after switching of the output stage begins, the offset cancellation circuitry further being operable to release the input referred offset voltage after switching of the output stage begins thereby allowing the output offset voltage to drift, wherein the offset cancellation circuitry comprises an offset calibration capacitor operable to be temporarily coupled to an input terminal of the input stage to effect cancellation of the portion of the input referred offset voltage, control circuitry operable to facilitate charging and discharging of the offset calibration capacitor, and a constant current source for facilitating discharging of the offset calibration capacitor.