POWER AMPLIFIER AND OPERATING METHOD FOR SAME

摘要

The objective of the present invention is to allow power amplification of a wide range from low power to high power and to improve power added efficiency when amplifying power of RF input signals of a plurality of frequency bands. A first amplifier (1) and a second amplifier (2) include a large size element and a small size element, respectively, and an RF input signal (RFIN) is amplified by the amplifiers (1 and 2). The output of the amplifier (1) is connected to the input of a first output matching circuit (3), the output of the amplifier (2) is connected to the input of a second output matching circuit (4), the output of the circuit (4) is connected to the input of the circuit (3), and the output of the circuit (3) is connected to an RF signal output terminal (102). In the case of a high power state, the signal (RFIN) is amplified at the amplifier (1), and in the case of a low power state, the signal (RFIN) is amplified at the amplifier (2). In the case of amplification of a high frequency fHB at low power, the reactances of the circuit (4) are set at predetermined values (L1 and C1), and in the case of amplification of a low frequency fLB at low power, a reactance of the circuit (4) is set at a larger value (C1 or C2).