Patent ID: 7741903

Claim:
A radio frequency (RF) power amplifier circuit comprising: a power amplifier coupled to receive and amplify an input signal to generate an output signal; a distortion measurement module receiving the output signal of the power amplifier and determining a measured distortion level of the output signal of the power amplifier; a comparator receiving the measured distortion level from the distortion measurement module and a target distortion level, and generating a power supply control signal indicative of a difference between the measured distortion level and the target distortion level; and a power supply coupled to receive the power supply control signal from the comparator and adjust a supply voltage to the power amplifier based on the power supply control signal, wherein the measured distortion level comprises a ratio of a first output power of a first portion of the output signal outside a desired frequency channel to a second output power of a second portion of the output signal within the desired frequency channel.