Patent ID: 7161510

Claim:
A switching amplifier comprising: a delta-sigma modulation circuit that is a circuit for performing delta-sigma modulation of an input signal and outputting a quantized signal, the delta-sigma modulation circuit including a group of integrators that consists of a plurality of integrators connected in a cascade arrangement and receives the input signal at a first-stage integrator, and a quantizer that quantizes a signal based on an output signal of the group of integrators and outputs a quantized signal, the delta-sigma modulation circuit that feeds back a signal based on the quantized signal to the first-stage integrator; a pulse amplifier that has a switching element and performs pulse amplification of the quantized signal by switching the switching element according to the quantized signal; an amplitude level detector that detects an amplitude level of the input signal; and a sampling frequency adjuster that varies a sampling frequency of the quantizer according to a detection result of the amplitude level detector.