[sdiy] ot: class d audio amp

[Ishaan Dalal]

Class D audio amps are pure switchers, in that the "amplifier" is either on
or off, resulting in higher efficiency (no crossover) compared to Class A,
B, AB amps.

How an implementation might work is:

1. A high frequency (~400 KHz) triangle wave
2. Analog input with full-scale comparable to triangle full-scale
3. 1 & 2 are inputs to a comparator, that drives a MOSFET, giving you a high
frequency pulse-width-modulated square pulse train.
4. These are lowpassed to audio frequency with an LC config before going to
your speakers.

Of course, this is a very rudimentary version. An improvement would be to
use a h-bridge to drive your speakers, giving you full +ve/-ve swings.

There is definitely literature on the web about class D audio amps, but it
is geared more towards EEs. You would be better off asking this question on
sci.electronics.design or sci.electronics.basics .

Cheers,
Ishaan


----- Original Message -----
From: "Czech Martin" <Martin.Czech at micronas.com>
To: "Sdiy (E-mail)" <synth-diy at dropmix.xs4all.nl>
Sent: Monday, October 20, 2003 10:18 AM
Subject: [sdiy] ot: class d audio amp


> Could anyone point me to diy audio amp project switch class D?
> So far I only could find some theoretical paper or commercials.
>
> m.c.
>