Patent ID: 8188794
Filing Date: 2012-05-29
Classification: H03F

Abstract:
1. An RF amplifier circuit comprising: FET for receiving a RF input signal and generating an amplified RF output signal, the FET having a gate, drain, and source; control circuit, connected to the gate and drain of the FET, for controlling the current at the drain; bias circuit comprising a means for biasing and variably compensating drift in the gate threshold voltage required to set the quiescent drain current, the bias circuit being connected to the control circuit and controlling operation of the control circuit to maintain an essentially constant drain current; compensation means adapted to effect a change in drain current based at least in part on temperature variation to maintain essentially constant output power; whereby the control circuit maintains essentially constant drain current with respect to time, input drive, frequency, and device-to-device variations, while allowing the compensation means to alter drain current with respect to temperature variations.