Patent ID: 9036836
Filing Date: 2015-05-19
Classification: H03F

Abstract:
1. An amplifier apparatus comprising: a power amplification unit for amplifying a power of an input audio signal by switching a power supply voltage using a pulse width modulation signal appropriate for a level of the input audio signal; a power-supply voltage control unit for detecting an amplitude level of the input audio signal and applying a target set voltage appropriate for the detected amplitude level of the input signal to the power amplification unit as the power supply voltage; means for monitoring output of the power amplification unit; a pulse width conversion unit for converting the input audio signal to a pulse width modulation signal with a pulse width appropriate for the level; and a pulse width correction unit for correcting the pulse width of the pulse width modulation signal generated by the pulse width conversion unit based on the target set voltage and the monitored output of the power amplification unit to cancel out a change in amplification gain of the power amplification unit, and applying the corrected pulse width modulation signal to the power amplification unit.