Patent ID: 7224228

Claim:
A semiconductor integrated circuit device for wireless communication system, comprising: an input terminal which receives an input signal to be amplified; an output terminal which outputs an output signal to be transmitted; a high frequency power amplifier which is coupled between the input terminal and the output terminal and which has a plurality of amplifying stages; a detector which receives a first signal from the high frequency power amplifier in connection with the output signal, and outputs a detection signal; a converter which receives the detection signal and converts the detection current into a second signal; a first amplifier which receives the second signal and an output power instruction signal and outputs a third signal; and a bias generator which receives the third signal and supplies bias to each of the amplifying stages, wherein the first amplifier having a differential amplifier which has an inverting input terminal, a non-inverting input terminal and a first terminal, and a low pass filter which is arranged between the first terminal and the inverting input terminal, and wherein the inverting input terminal receives the second signal, the non-inverting input terminal receives the an output power instruction signal and the first terminal outputs the third signal.