Patent ID: 8847677
Filing Date: 2014-09-30
Classification: H03F

Abstract:
1. An amplifier circuit comprising: an input switching unit which outputs a reference voltage signal as a differential input signal; a preamplifier unit which amplifies the differential input signal and generates a differential output signal; a PWM conversion unit which generates a differential PWM signal based on a comparison of the differential output signal with a reference signal of a sawtooth or triangular waveform; a calibration unit which generates an offset adjustment signal according to a phase difference of the differential PWM signal at a time of calibration; and an electric amplifier unit which carries out electric power amplification of the differential PWM signal, and generates a differential final output signal, wherein the calibration unit adjusts a voltage level of the differential output signal based on the offset adjustment signal so that the voltage difference of the differential output signal may become smaller at the time of calibration.