公开(公告)号：US20200036352A1

公开(公告)日：2020-01-30

申请号：US16181762

申请日：2018-11-06

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： Lei ZHU ,  Tejasvi DAS ,  John L. MELANSON ,  Wai-shun Wilson SHUM ,  Jing BAI ,  Xin ZHAO ,  Xiaofan FEI

IPC: H03G3/30 ,  H03F3/217 ,  H03F3/187 ,  H03F3/387

Abstract: A system may include a digital modulator configured to modulate an input signal received at an input of the digital modulator to generate a modulated input signal at an output of the digital modulator, a digital gain element having a digital gain and coupled to the digital modulator, an open-loop Class-D amplifier coupled to an output of the digital modulator and configured to amplify the modulated input signal, wherein the open-loop Class-D amplifier is powered from a variable power supply having a variable supply voltage which is variable in response to one or more characteristics of the input signal, and a control circuit configured to control the digital gain to approximately cancel changes in an analog gain of the open-loop Class-D amplifier due to variation in the variable supply voltage in response to the one or more characteristics of the input signal.