| 摘要 |
A power amplifier in which a DC power supply is coupled to a load through a switching element, a smoothing circuit, and an output amplifying element. The output amplifying element receives an input signal voltage to be amplified. A voltage detecting circuit is provided which compares a feedback voltage proportional to an output volgage of the smoothing circuit with the input signal voltage to switch the switching element, thereby varying both the power supply voltage of output amplifying element and the load output voltage in accordance with the input signal voltage. As the output voltage of the smoothing circuit is compared with the input signal voltage, the delay of the change of the power supply voltage of the output amplifying element relative to the load output voltage can be reduced, and the generation of distortion and the lowering of efficiency can be suppressed. |
