Class D amps are simple – just take an input, and use that to modulate a square wave with PWM. Send this PWM signal to a MOSFET or something, and you have the simplest class D amp in existence.

In audio applications there is a trend towards Class D audio amplifiers as replacements for traditional Class AB electronics. The main driving forces are improved efficiency and space savings.

This article was originally published in the Dec 14, 1998 issue of Electronic Design. Class-D audio power amplifiers (APAs) were first introduced nearly 50 years ago. Since then, they have been used ...