AN-1071 Datasheet, PDF (1/14 Pages) International Rectifier – Application Note

Application Note AN-1071
Class D Audio Amplifier Basics
By Jun Honda & Jonathan Adams
Table of Contents
Page
What is a Class D Audio Amplifier? – Theory of Operation ..................2
Topology Comparison – Linear vs. Class D .........................................4
Analogy to a Synchronous Buck Converter..........................................5
Power Losses in the MOSFETs ...........................................................6
Half Bridge vs. Full Bridge....................................................................7
Major Cause of Imperfection ................................................................8
THD and Dead Time ............................................................................9
Audio Performance Measurement........................................................10
Shoot Through and Dead Time ............................................................11
Power Supply Pumping ........................................................................12
EMI Consideration: Qrr in Body Diode .................................................13
Conclusion ...........................................................................................14
A Class D audio amplifier is basically a switching amplifier or PWM amplifier. There are a number
of different classes of amplifiers. This application note takes a look at the definitions for the main
classifications.
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AN-1071
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