High-efficiency low-distortion linear power amplifier circuit for signals having a high peak power to mean power ratio and method for driving it

摘要

This invention relates to a high-efficiency low-distortion linear power amplifier circuit for signals with a high peak power to mean power ratio, specifically a microwave amplifier circuit and further to a method for driving such a linear power amplifier. In the circuit according to the invention the radiofrequency input signal is detected by an envelope detector in order to obtain an envelope signal, and used to drive the bias voltage of an amplifier device contained therein; bias voltage between the main electrodes (drain, source, collector, emitter) of the power amplifier device is driven in such a way to be proportional to said envelope signal. A preferred embodiment of this invention has a control circuit located between said envelope detector and said power amplifier device, which circuit causes said bias voltage to change from a minimum value to a maximum value as a function of the amplitude of said envelope signal.