Patent ID: 9136799
Filing Date: 2015-09-15
Classification: H03F

Abstract:
1. An amplifier comprising: a supply voltage control part for detecting an amplitude level of an input audio signal and outputting power of a voltage level indicated by target set voltage level information corresponding to the detected amplitude level; a PWM conversion part for converting the input audio signal to a pulse width modulation signal; a power amplifier stage for performing power amplification on the pulse width modulation signal output from the PWM conversion part; a low-pass filter part for demodulating the amplified PWM signal output from the power amplifier stage into an acoustic signal; a negative feedback part for attenuating the acoustic signal demodulated in the low-pass filter part, converting the attenuated acoustic signal into a digital signal through an A/D converter, and negatively feeding the digital signal back to the PWM conversion part; and a voltage conversion part for outputting voltage proportional to the voltage level of power output by the supply voltage control part, wherein the voltage output by the voltage conversion part is used as a reference voltage level of the A/D converter.