公开(公告)号：US10720888B2

公开(公告)日：2020-07-21

申请号：US15336995

申请日：2016-10-28

Applicant: Cirrus Logic, Inc.

Inventor： Ramin Zanbaghi ,  Aaron J. Brennan ,  John L. Melanson ,  Mikel Ash

IPC: H03F3/185 ,  H03F3/217 ,  H03K7/08 ,  H03F1/02 ,  H03F1/30

Abstract: An integrated circuit may have two signal paths: an open-loop modulator (which may comprise a digital-input Class-D amplifier) and a closed-loop modulator (which may comprise an analog-input Class-D amplifier). A control subsystem may be capable of selecting either of the open-loop modulator or the closed-loop modulator as a selected path based on one or more characteristics (e.g., signal magnitude) of an input audio signal. For example, for higher-magnitude signals, the closed-loop modulator may be selected while the open-loop modulator may be selected for lower-magnitude signals. In some instances, when the open-loop modulator is selected as the selected path, the closed-loop modulator may power off, which may reduce power consumption. In addition, one or more techniques may be applied to reduce or eliminate user-perceptible audio artifacts caused by switching between the open-loop modulator and the closed-loop modulator, and vice versa.