i'm ready

Discussion in 'The Projects Forum' started by newton, Feb 2, 2010.

  1. newton

    Thread Starter New Member

    Apr 19, 2007
    I have built lots of different types of regulators, bucks, boost, charge pump, flyback circuits, all dc in, dc out (aside from your little transformer->bridge->filter to get a few mA from the wall). I want to do a real ac/dc one now. Something I can use.

    I use up to 480VAC fairly often for work, and understand very well, the risks with AC voltages (well, 120 isn't so bad, about the same as a good cup of coffee)

    So, I want to build a universal (85-265VAC 50/60Hz to 12V 2-3A or so) offline flyback converter. I have been scouring for a simple, cheap design that I can order all the parts from mouser / digikey / newark, etc. I would like suggestions. I really hate the idea of having a custom wound transformer, or winding it myself, it just seems silly. So, I am thinking, some manufacturers have had to come up with an example circuit using a stand transformer right, i mean there are 1000's of different transformers from hundreds of manufacturers, one has to fit the offline supply 12V i would even settle for starting with 5V, 24V, i don't really care. If you know of such a design, please let me know.

    As for the ic, i have read so many datasheets my head hurts, all the design stuff seems to be blurring together, but i think i like the topswitch....any experience with this? Seems simple.

    Basically, if you know where i can pick up a matching ic / transformer, I think i can start from there.

    Also, what determines the output, is it just the weakest link, seems the transformer is probably the big one, but then maybe the ic, the output filter components, etc...seems if you had the right ic / transformer combo, you could easily fill in the others to match... maybe i'm off here though.

    Anyway, I'm going to start ordering some parts for some other stuff today, probably pick out some things to fry for this endeavor and go from there. If you have build one before, speak up, if not and are trying to, speak up...there isn't enough info out there in my opinion, so share it if you've got it.
  2. Bernard


    Aug 7, 2008
    You are talking abuot my US$ 1.00 bench supply, 120-240V 50-60 Hz, !2V @ 4A. It starts witlh rectifing line V, but remainder burried in well glued case. With about 340V DC it takes me out of assistance .