| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an audio signal amplification apparatus and an audio signal amplification method that can improve a sound quality degradation of a class D amplifier irrespective of the location of a distortion or noise. <P>SOLUTION: An output filter 14a demodulates a positive phase PWM signal amplified by an output stage transistor 13p to generate a positive phase output audio signal. The output filter 14a also demodulates a negative phase PWM signal amplified by an output stage transistor 13n to generate a negative phase output audio signal. An output detection circuit 20 computes a voltage difference between the positive phase output audio signal and the negative phase output audio signal to generate an output audio signal. A variable output power supply device 17 controls a voltage applied to the output stage transistor 13p according to a difference signal indicating a difference between the output audio signal and an input audio signal. <P>COPYRIGHT: (C)2012,JPO&INPIT |
