Analog signal amplifier and audio signal amplifier

摘要

An input limiting circuit limits the maximum signal voltage value of input signal voltage supplied from a signal source through an input terminal. A power amplifying circuit converts the signal voltage from the input limiting circuit to a switching signal having the input signal included in a low frequency component using, for example, a PWM modulation, and then amplifies the output power of the modulated signal using a D-class amplification. A signal demodulating circuit selects the switching frequency signal received from the power amplifying circuit, and demodulates it into a signal similar to the signal generated by the original source. The demodulated signal from the signal demodulating circuit is then supplied to a reproducing device.