When I am looking at a circuit diagram for a power supply, what characteristics will I see that will identify the PS as a switch mode or other type supply. Does a particular component or certain way of managing the voltage stand out and make me say "ah yes, thats switch mode". I am trying to expand my very basic knowledge and understanding and I constantly see SMPS but do not understand the proper way of identifying the circuit, and Wiki doesnt get that basic. A side by side schematic comparison with the difference highlighted would be a ton of help if you have one. Thanks in advance for the help.
Bob

 

Hello,

Here is a page from the EDUCYPEDIA on smps:
http://www.educypedia.be/electronics/powerelectronicssmps.htm

It contains a lot of links on the subject.

Bertus

 

Here's another very good site to learn about SMPS:
http://www.smps.us/

There is a LOT to learn about switch-mode power supplies.

One really great site to get you started quickly is Ronald Dekkers' "Flyback Converters for Dummies" page:
http://www.dos4ever.com/flyback/flyback.html

Caution: the supplies on Ronalds' page are designed to output voltages that can be lethal. In both supply schematics, replacing R4 (220k) with a 47k or lower resistor will keep the output voltages in a more safe range (<50v).

Ronalds' page is great because it gives you both some "book knowledge" and practical experiments for you to try with real-world components that are easy to obtain even at your local Radio Shack.

The BUZ41 MOSFET can be replaced with an IRF510 for the experimental supplies.
Radio Shack carries a 100uH 2A inductor that will work OK, too - but I suggest that you follow Ronald's suggestion and experiment with his inductor test bench; you'll learn a lot more that way.

You might enjoy Rod Elliott's project for an automotive sound system switch mode dual supply:
http://sound.westhost.com/project89.htm

It takes a good bit of studying various power supply topologies before things start "jumping out" at you. It's very difficult in the beginning because there are SO many varieties out there, and newbies feel buried under a tidal wave of information.

I should've mentioned Ronald Dekkers' page first, because it lays down some basics that apply to just about any SMPS, along with giving you hands-on experience. Hope you enjoy it.

 

Bertus and Sgt Wookie, thanks for the replies. I now have a ton of studying to do. I appreciate all of your help and the time you guys spend to help noobs like me.
Bob

 

Here is a VERY good video that will answer your question exactly:

http://e2e.ti.com/videos/m/power_management/180921.aspx

I recommend it! (That is meant to be funny)

 

Thanks for that link Retched. that splained it good lucy!!!!! Now between the two earlier links and this one I have a basic understanding and know enough to be dangerous at least. And I know where to look it up again when I get dumb and have a magic smoke moment.... Thanks for the effort and time guys, I appreciate all of your help.
Bob

 

Hey, no problem Ricky!