How to create self oscilating SMPS

[luka]

Using only capacitors, diode, transistors,resistors...

No active components like chips,...

 

[BWRX]

Here's something I came up with a little while back - http://www.diyaudio.com/forums/showthread.php?s=&threadid=85947&highlight=

If you make a discrete comparator that can current couple to the high side driver then you'd have a discrete self oscillating buck regulator, in theory and simulation. I haven't tried to build it yet.

 

[luka]

Nice design, but I do want it to be powered someday by 230Ac and I don't have a clue have to make a discrete comparator.

 

[BWRX]

So you're looking for an on-line design. I'd recommend against that unless you're well aware of what you're doing working with mains voltages.

 

[luka]

I have a lot of experience with halh-brdge by now and I have a broken smps, i thin it is a fly, mains power.It is/was 9v charger, bet fuse burned out, nothing other seems to be wrong. That fuse is in series with 230Ac. So in time fuse got smaller (not in size 😀) and blow at some point.

 

[cerrem]

You can try to use a "current-fed" Royer Converter with FETS...
Don't use the regular version it is prone to problems...

Chris

 

[luka]

The one I can find has FIN chip or something, so how would Royer Converter loke like with fets?

 

[Sambal Oelek]

try this:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=56948&highlight=

Gr. Sambal

 

[luka]

How did I missed this one

Thx for link

 

[N-Channel]

I barely rmemeber posting to to that thread and never saw it again until now. Hadn't set up preferences in my user profile yet, and never received notices of subsequent postings to the thread.

I will go to the ARRL website and re-download the 13.8V 40A SMPS article and shotgun it around as requested, starting with Luka.

Cheers everyone.

Steve

 

[N-Channel]

Here' the schematic........

And here's the link to the original author's website: http://www.qsl.net/xq2fod/Electron/PS40/PS40.html
enjoy!

Steve