Patent ID: 7522368

Claim:
A differential feedback control circuit, comprising: a sense amplifier for sensing a feedback parameter and for generating a differential feedback signal; summing circuitry for producing a differential error signal corresponding to a differential input signal and the differential feedback signal; a tunable differential gain stage, having inputs coupled to the summing circuitry for receiving the differential error signal, and having a pair of outputs presenting an intermediate differential signal responsive to the differential error signal, the intermediate differential signal having a gain adjustable in response to a tuning current; a differential power amplifier, for generating a differential output signal responsive to the intermediate differential signal; and a tuning current circuit for producing the tuning current; wherein the tunable differential gain stage comprises: a master circuit, coupled to receive the tuning current, for establishing a tail current; and a slave differential circuit, having first and second inputs receiving the differential error signal, for developing the intermediate differential signal responsive to the differential error signal and responsive to the tail current of the master circuit.