DIY Self Oscillating Class-D
I have for a long time worked on
different class-d amplifiers on a breadboard, and have now settled for a
solution based on self oscillation, and using a HIP4080A as MosFet bridge
driver. The MosFets I'm using are the well known IRF640. These seems to work
well and are dirt cheap. This article is divided into parts or stages, to give
you an idea of the design evolution. Starting from the very first bread board
tryout to finalized double sided PCB based on SMD components.
This amp is intended as an amp for my
subwoofer project, where I'm using a 12" Peerless XLS driver. I want in the
region of 400 W to drive it fully, and I hope this design will be able to
This article is meant as an inspiration
for others working on similar projects, and not a description on how you can or
should do yourself. I think class-d amplifiers are a real challenge, this
project has taken countless hours in research and development. It requires real
good insight in electronics and the art of PCB layout.
A word of advise: don't do a full
bridge (H-bridge) as the first project! Though this kind of design offers a lot
of benefits over a half bridge design (no PSU pumping, single sided PSU), it
tends to get quite a lot more complex and hard to get to work properly.
Another advise: Do start with a
breadboard ..... it will save you hundreds of hours. You should definitely use
simulation programs like spice, but these models are not reality, and especially
not in the case of class-d amplifiers. Breadboards will enable you to change
components almost on the fly, at will help identify the most critical parts of
Enjoy reading the next pages:
how it all started
first PCB. It ended up quite good, but I had some troubles with noise, which
requires some changes.
Prototype has been implemented. All the important circuits work, and the
sound is excellent. This will be the final version, which will go into the