Patent ID: 8229373
Filing Date: 2012-07-24
Classification: H03F,H03G

Abstract:
1. A high frequency power amplifier for use in a high frequency mobile communication terminal, comprising: at least one amplification stage that amplifies an input signal from a gain variable amplifier, wherein the at least one amplification stage includes an output amplification stage which comprises a transistor and constitutes a final stage of the at least one amplification stage; an output matching circuit that is connected to an output side of the final stage of the at least one amplification stage; a first detection unit that detects a voltage amplitude at a node between the transistor of the final stage of the at least one amplification stage and the output matching circuit, and outputs the voltage amplitude as a first signal of gain control information of the gain variable amplifier; and a supply voltage detector unit that detects a supply voltage being supplied to the final stage of the at least one amplification stage and outputs the supply voltage as a second signal of the gain control information of the gain variable amplifier, wherein the gain variable amplifier is controlled based on the gain control information so as to limit a gain of the gain variable amplifier upon the voltage amplitude exceeding a predetermined threshold voltage.