Amplifier circuit

摘要

According to one embodiment, an amplification circuit can be switched between amplifying and calibration modes. During calibration, a preamplifier amplifies a differential input signal and generates a differential output signal. The amplifier circuit includes an input switch unit which sets a differential input signal as the reference voltage signal of the same voltage level at the time of calibration, a PWM conversion unit which carries out Pulse-Width-Modulation of the differential output signal, and generates a differential PWM signal based on the result of comparing the differential output signal with the reference signal, a calibration unit which generates an offset adjustment signal according to the phase difference of differential PWM signals, and an electric amplifier which carries out electric power amplification of the differential PWM signal and generates the differential final output signal.

主权项

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.