| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress a degradation in power efficiency resulting from a variation in use environment. <P>SOLUTION: An amplifier comprises: an envelope detection section; a comparison section; a selection section; a voltage control section; a current measurement section; and a reference voltage control section. The envelope detection section detects an envelope of a transmission signal. The comparison section compares a voltage of the envelope with a reference voltage. The selection section selects an amplifying element to amplify the transmission signal from a plurality of amplifying elements different in operating power on the basis of the result of comparison in the comparison section. The voltage control section controls a voltage used to amplify the transmission signal in the amplifying element selected by the selection section on the basis of the envelope. The current measurement section measures a current of a power supply supplying the voltage controlled by the voltage control section. The reference voltage control section controls the reference voltage such that the current measured by the current measurement section decreases. <P>COPYRIGHT: (C)2013,JPO&INPIT |
