| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve the power conversion efficiency of a power amplifier. <P>SOLUTION: In the power amplifier for amplifying an input signal by means of a differential amplifier 3 and push-pull amplifiers (8, 9), an output from the differential amplifier is amplified by the push-pull amplifiers and an output from the push-pull amplifiers are fed back as an input to the differential amplifier. As a supply voltage generation circuit for each of a plurality of amplifying elements 8, 9 constituting the push-pull amplifiers, a plurality of blocks each comprising a closed circuit in which a DC voltage sources 12-19, switches 20-27 and diodes 28-35 are connected in series are connected such that an anode terminal of the diode of one of adjacent different blocks is connected to a cathode terminal of the diode of the other. Supply voltage control means 38 controls the switches on/off in response to a signal level of the input signal to the power amplifier or a signal level of the output signal from the power amplifier. <P>COPYRIGHT: (C)2012,JPO&INPIT |
