Ubergeek63
Well-Known Member
The chip is meant for current sourcing power LEDs so it is a natural for driving current into a joint.bmachining said:Ubergeek63,
a PWM power supply? I like the sound of it! More info please!
The problem with "Just the old transformer for stepdown" is that at 1200W it will be huge. You need the "high" frequencies to get the size of the inductor down. It is imperative that you use switchmode since even a 50VA transformer will run $30 and up in that power range $200 plus shipping on something 8" diameter by 4" high at 25lbs.
https://www.electro-tech-online.com/custompdfs/2008/04/AN-H50.pdf is a good appnote on it, though what I suggest is going a bit further than that. And http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=M8374-ND would be a suitable inductor if a bit weak on the current.
It would run buck mode and I believe will reliably deliver 27A into 20V from a rectified mains. The formulas are all in the sheet. The other irritating detail is that this will NOT be isolated, which means that the entire circuit is tied to the mains. On the other hand, it IS the least expensive.
I would add that at the high levels in this discussion I would add an FET driver.
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