Electronics > Beginners
A niche chip (LT4320) for mains powered AC -> low volt DC "linear" based psu ?
digsys:
Up to ~15A, 6VAC is fine, and it also depends on the level of ripple on the DC caps ! If you look at the Gate drive waveform,
it is heavily "influenced" by it. I don't have an exact correlation because I'd be guessing on how the charge pumps work.
Now that I know there is a 3 way relationship, I'll want to find the min AC at max I (at lowest reasonable ripple for now).
That sudden temp rise is most likely a result of "leakage" current, but now I have to set up an accurate current sense and
plot all the waveforms. At least I know it's not an issue over 12-15VAC for 20-30A respectively.
All that (old) gear is going to be sold, once I find time to work out the heck some of it is ! I'm also getting rid of several boxes
of various circuit boards from a 15yr old installation that's just been de-commissioned. So much for holidays :-)
BravoV:
--- Quote from: digsys on December 25, 2013, 12:02:43 pm ---Now that I know there is a 3 way relationship, I'll want to find the min AC at max I (at lowest reasonable ripple for now).
That sudden temp rise is most likely a result of "leakage" current, but now I have to set up an accurate current sense and
plot all the waveforms. At least I know it's not an issue over 12-15VAC for 20-30A respectively.
--- End quote ---
That is almost half a kilowatt there. :o
Btw, what is the 3 way relationships you're talking about ?
Looking forward to see the result on min AC while at max current, should be interesting and will be useful info. :-+
--- Quote from: digsys on December 25, 2013, 12:02:43 pm ---All that (old) gear is going to be sold, once I find time to work out the heck some of it is ! I'm also getting rid of several boxes
of various circuit boards from a 15yr old installation that's just been de-commissioned. So much for holidays :-)
--- End quote ---
That are butt load of gears you have there, I guess that can not be done in one or two days job. ::)
tszaboo:
--- Quote from: digsys on December 24, 2013, 04:01:14 pm ---In Version 2 I used
--- End quote ---
There are two minor problems I saw with your layout. One is that you put the fuse (in parallel? dont do that) on the output of the bridge, and it should be on the input. If your something fails on the bridge because of the destructive test, nothing is protecting your input. The other problem I see is the lack of high frequency bypassing. Otherwise it is interesting.
digsys:
--- Quote from: NANDBlog --- ... One is that you put the fuse (in parallel? dont do that) ...
--- End quote ---
Thanks, but they're actually Polyfuses, and they work extremely well in parallel. We even heatshrink them together for
tighter thermal "coupling".
--- Quote from: NANDBlog --- on the output of the bridge, and it should be on the input ...
--- End quote ---
I don't intend to place them there, I just needed a "test point" and that artwork looked sort of relevant to an observer :-)
It's a current "pick-off" point and a thermal break (for my FLIR E8+ .. oops I meant E4) to test the 3+3oz Cu temperature.
Usually I ALWAYS use 4+4oz, but had a short cut-off time for delivery before xmas. I usually have all protection somewhere
where it's user-serviceable, NEVER on the main PCBs anyway.
--- Quote from: NANDBlog --- ... lack of high frequency bypassing. ...
--- End quote ---
There's enough HF filtering, just not shown on the pix. All done as per design notes, but I do like to see what goes "wrong"
under those circumstances. It's all part of proper design / testing.
Phaedrus:
What's your efficiency looking like?
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