| 摘要 |
PROBLEM TO BE SOLVED: To provide a power amplifier circuit that can be easily designed to switch a source voltage in such a manner that a transistor in an output stage consumes power as little as possible and to switch the source voltage at an appropriate timing stably at all times. SOLUTION: A charge pump 1 selects and generates one kind of source voltage out of at least two kinds of source voltages and supply it to a load driving unit 2. When an output state detection signal DETO indicating that the level of an output signal AMPO of the load driving unit 2 comes close to the source voltages CPVDD and CPVSS to be supplied to the load driving unit 2 beyond a predetermined limit, is outputted from an output state detecting unit 3, the source voltages CPVDD and CPVSS to be supplied to the load driving unit 2 are switched to higher source voltages. COPYRIGHT: (C)2011,JPO&INPIT
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