A second-order PWM-in/PWM-out class-D audio amplifier

Class-D audio amplifiers convert an audio signal into a high-frequency square wave whose switching times are modulated according to that audio signal. Thus, they operate using so-called pulse-width modulation. When the high-frequency components of the output square wave are removed by filtering, the...

Full description

Saved in:
Bibliographic Details
Main Authors: Cox, Stephen Michael, Lam, Chun Kit, Tan, Meng Tong
Other Authors: School of Electrical and Electronic Engineering
Format: Article
Language:English
Published: 2013
Subjects:
Online Access:https://hdl.handle.net/10356/107069
http://hdl.handle.net/10220/18048
http://dx.doi.org/10.1093/imamat/hxr042
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
Description
Summary:Class-D audio amplifiers convert an audio signal into a high-frequency square wave whose switching times are modulated according to that audio signal. Thus, they operate using so-called pulse-width modulation. When the high-frequency components of the output square wave are removed by filtering, the remaining lower frequency components can reproduce the audio signal with very little distortion. This low distortion, coupled to the high efficiency of class-D amplifiers, is responsible for the increasing use of these devices in a wide variety of applications. However, to date there has been very little predictive mathematical modelling of those class-D amplifiers that employ negative feedback, as is usually the case in practice. Here, we derive and investigate a mathematical model for a novel design of the output stage for a class-D audio amplifier, which employs negative feedback to remove the effects of power supply noise on the amplifier's performance.