公开(公告)号：US11228289B1

公开(公告)日：2022-01-18

申请号：US17000852

申请日：2020-08-24

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： Angus Black ,  Hemant Shukla

IPC: H03F3/217 ,  H03G3/30 ,  H04R3/00

Abstract: This application describes an amplifier circuit (200) with a forward signal path with a class-D output stage (102) for generating a driving signal (Sout) based on a digital input signal (Sin). The amplifier has a first feedback path for providing a first digital feedback signal (Sfb1) based on the driving signal and a second feedback path for providing a second digital feedback signal (Sfb2) from a digital part of the forward signal path. The digital input signal (Sin) is combined with a selected feedback signal (Sfbs). The amplifier circuit is selectively operable in a first mode, in which the first feedback signal is used as the selected feedback signal, and in a second mode, in which the second feedback signal is used as the selected feedback signal. A calibration module (204) is operable to calibrate the first feedback path to reduce any DC offset when the amplifier circuit is operating in the second mode.