Electrical Power Amplifier Circuit, and Transmission Device and Communication Device Using the Same

摘要

The power amplifier circuit includes: a constant envelope signal generation circuit (100) which outputs two constant envelope signals; transistors (11, 12) including sources and gates which are supplied with the output signals from the constant envelope signal generation circuit; a variable gain amplifier (21) which amplifies an output signal from the transistor (11); a gain control circuit (40) which controls so that a gain of the variable gain amplifier (21) is increased when an amplitude of an input signal is smaller than a predetermined value; a transistor (13) including a gate supplied with an output signal from the variable gain amplifier (21) and a source which is grounded; a low-pass filter (32) connected between a drain of the transistor (13) and a power supply potential; and an output matching circuit (37) connected between the drain of the transistor (13) and an output terminal (38).