HIGH-FREQUENCY POWER AMPLIFIER, HIGH-FREQUENCY POWER AMPLIFIER MODULE, AND PORTABLE TELEPHONE

摘要

PROBLEM TO BE SOLVED: To provide a small-sized high-frequency power amplifier which prevents the oscillation with a small number of switch circuits and outputs high power and small power with high efficiency, and a high frequency power amplifier module, and a portable telephone.;SOLUTION: This high-frequency power amplifier is composed of an amplifying circuit A and an amplifying circuit B connected in series, and the size of the transistor at the output stage of the amplifying circuit B is made quarter or smaller than the transistor at the output stage of the amplifying circuit A, and further a switch circuit is connected between the signal line, before the output stage of the amplifying circuit A and a ground terminal. Then, when the transistor constituting the amplifying circuit B is in nonoperation state and also the switch circuit is OFF, a high frequency signal of high power is outputted from the amplifying circuit A, and when the transistor constituting the amplifying circuit A is in nonoperation state and besides the switch circuit is ON, a high-frequency signal of low power is outputted from the amplifying circuit B.;COPYRIGHT: (C)2003,JPO