Patent ID: 7173492
Filing Date: 2007-02-06
Classification: H03F,H03G

Abstract:
1. A power amplifier circuit for use in a wireless communication system, the power amplifier circuit comprising: a power amplifier coupled to receive an input signal and amplifying the input signal to provide an output signal; a first converter coupled to receive the output signal of the power amplifier and providing a first signal which follows a power of the output signal; a non-linear converter coupled to receive the first signal and providing a second signal; a second converter coupled to receive the second signal and providing a voltage based on the second signal; an error amplifier coupled to both the voltage and an output level designation signal and providing a third signal corresponding to a difference therebetween; and a bias circuit coupled to receive the third signal and providing to the power amplifier a bias in accordance with the third signal, wherein the non-linear converter is an nth root converter converting the first signal into the second signal obtained by extracting the nth (where n is a positive integer) root of the first signal.