Looking for Critical Comments

[Perry Babin]

I've had quite a few requests for a page on switching power supplies. The following page (page 109 on the site if you want to get to it that way) is what I have so far. I'm looking for critical comments and suggestions to make it better/more useful (especially for those who are interested in building a supply but know nothing about them). About 20% of what's there will be edited out. I plan on tripling (approximately) the information that's already there. What I'd like is to know what other information is needed and where I need to expand upon the information already there. I plan to provide significantly more information on transformer and inductor design but that will be later.



Basic Switching Power Supply Design Tutorial

[jol50]

Come on you guys, a couple days and not one post?
I know the success rate of this is pretty low as you are very good at this, but I'll man up and post some first impressions at least.

My first impression is....I want to build one. You sure put a lot of features into it, it could run a lot of different projects.

I'm sure you have it already but snubber operation.

I'm always looking at material on mosfet/transistor specification/selection far as design and real use. For example the point about transistor saturation for Q101 is something the inexperienced would not think of automatically. Lot of good design/build it stuff there. But I come from repair so I've never done that much.

Too much for me to take in with one read, other general points might be durability/quality detail here and there with components (or what is better/worse or quality vs not needed) such as capacitors/transistors, I see the two leg rectifiers not three, the bank of caps, you have a handy socket for the 594, etc...though I'm more used to cheap amps that do not do those things or perhaps do not run as much power.

The detail about calculating various things is great exercise, another thing not very present in repair yet very important to be competent in for design and better circuit understanding. I recognize some is from the tutorial but better to have it all together. However I'm torn if some of the theory stuff might be better in another page or already is in another page. I get the impression if I were to use this page to build one I better know that first and then it would be in the way as I referenced the page while working on it, but I don't know if you have gotten that far yet or if it really matters that much. Having everything in one spot has advantages too unless it ends up being too massive to find what you want to find. On the other hand I have no idea what things other people will know or not know. But if you wanted to have everything in one stand alone page for someone who has not seen your other material, looks like you have a good start.

Not sure its useful, that was all I could come up with.

[1moreamp]

I think he has done a excellent job on his project, and should make it part of his tutorial for training. I see lots of people chime in on this forum that do not have the slightest clue what a power supply is or how to work on one.

My only suggestion is possibly adding a group of opto feedback circuitry for all the regulation and safety circuitry. Like PG, Clarion, Zapco and others use. That is the only item I see that is not covered presently...Great work Perry, I see a bunch of useful info and effort on your part, as usual for you...

[Perry Babin]

Thanks for the input.

I'm including links to other pages that already cover some of the basics (diodes, resistors, transistors...) and I'm also trying to include specific information for the various parts of this particular project.

For the regulation, I don't use opto-couplers for feedback. The feedback is taken directly from the rails. Normally, I wouldn't do this on supplies with an isolated secondary because a shift in the secondary (for whatever reason) could cause the regulation to fail. Here, the opto-coupler shuts the supply down if the secondary shifts up or down (due to a short from one of the supply outputs to chassis ground) so the regulation isn't likely to fail.

[Perry Babin]

One more time...

For those who have nothing to do and are interested in switching power supplies, please read through the page again. It's about 80% done (I hope). Please post or email me with any suggestions that you feel will make the page more useful.

Click HERE.

Thanks.

[chris661]

Had a quick read through, and it's informative enough for those just starting out, but no so long winded that someone with experience isn't bored.

[aptquark]

damn...im bookmarking this sucker. Thanks. It a great write-up to fill my brain.

Cheers

[john blackburn]

Agreed, lots of learning to be had.

Thanks

John

[1moreamp]

Excellent work!

I have it bookmarked myself..thx Perry

[FAA]

nice, alots of reading.. thanks very much..