| 摘要 |
<p>Provided is a highly efficient power amplification device provided with a function of varying a power supply voltage in accordance with the magnitude of the amplitude of an input modulation signal. A control signal generating section (2) determines whether an amplitude component of the input modulation signal is larger or smaller than that of a reference signal, outputs a High control signal (11) when the amplitude component is smaller, and outputs a Low control signal (11) when the amplitude component is larger. A switching element is subject to on/off control in the interior of a power combining section (3) by using the control signals (11), thereby controlling the conduction/non-conduction of the current supplied from a second power supply (Vcc2). The pulse-shaped power, at the time when the second power supply (Vcc2) is brought into conduction, is transmitted to the direction of a first power supply (Vcc1) by using a transformer or the like. The difference power obtained, as viewed as a voltage, achieves a voltage waveform modulated so as to subtract a constant value from a first power supply voltage when the amplitude of the input modulation signal is smaller than that of the reference signal. A modulated voltage (12) is used as the power supply of an amplifier (1) to amplify the input modulation signal, thereby providing an output modulation signal (16) amplified with high efficiency.</p> |
