Patent ID: 7623896

Claim:
A wireless communication circuit, provided with an amplifier for amplifying an inputted signal so as to output thus amplified signal to an antenna, said wireless communication circuit comprising: a switch configured to be supplied predetermined plural constant voltages and to select one of the predetermined plural constant voltages as a constant voltage supplied to the amplifier, the predetermined plural constant voltages also being supplied to at least one of a plurality of circuits, other than the amplifier, either contained in the wireless communication circuit or electrically connected to the wireless communication circuit; control means for controlling the switch to select said one of the predetermined plural voltages as the constant voltage supplied to the amplifier in accordance with a power which should be outputted by the amplifier; and a detector to detect an output of the amplifier; and a controller to adjust transmission power of the antenna to be constant in response to the detected output of the amplifier, wherein the constant voltages of the predetermined plural constant voltages are different from one another.