stand alone 12v supplies

[Elrast]

FWIW, I found some 12v supplies while hunting parts for my next system.

www.mpja.com:
"SKSP500"- 12v 40A (need 10% derating @ 25 deg C?!), 84% eff, $120US
"PS1-150W-12"- 12v 12.5A, 82% eff, $40.75
No MTBF data
2nd one not so interesting. the 40A one could be, for a few niche applications.

www.powerstream.com:
http://www.powerstream.com/DC-PC-12V-400.htm
PST-APS15- 12v 15A 80-86%eff (not clear), $132
PST-APS30- 12v, 30A, ditto eff, $208

They look like some variants of the supplies made by Advanced Power Solutions (www.advpower.com).
The powerstream ones look like they pull a fair bit of reactive current. 432VA required for 200Wdc output. So no PFC for the powerstream if that's a gripe.

The mpja ones claim PFC but have a massive cold start surge. Probably passive PFC... (I just like the idea of the SMPS being nice to my house wiring)

I think I'm now more or less over the idea of using the pico. The system efficiencies for a (relatively) high powered system just doesn't cut it, and it requires munging around with unsequenced supplies around the pico.

Although if someone finds a 95%+ eff ac/dc converter @ 250W, let me know

More efficiency might be had modding an existing ATX supply, by replacing the 12v diodes in the secondary rectification stage with smart mosfets (if that's not already done by the manufacturer).

Elrast

[suzyj]

I was thinking of doing this for my desktop machine, but eventually settled on a Sparkle SPI220LE. The power supply I was looking at was the EMA212PS12 from XP Power. It does 212W, has >0.9 power factor, and has 88% efficiency (80% at 20% load). They come in a pretty tiny package, too, in a standard 3" x 5" footprint, so you could mount one in a standard ATX case. They actually have three outputs, 12V 16.7A, 12V 1A, and 5V, 100mA standby. Farnell have them, but they're pretty pricey, at AU$225.

Also of interest are the TI non-isolated DC-DC converter modules. The PTH12010W is a good example - it does 5V or 3.3V out from 12V in at up to 12A, and is 94% efficient (5V out) or 93% efficient (3V3 out). They come as a little PCB with pins. All one needs to add is some filter caps and a resistor to set the output voltage. There's a PTH12030W too, with similar efficiencies, but at 20A output current.

To build a 200W ATX supply, all you'd need are a pair of the PTH12010W's, an EMA212PS12, a little DC-DC converter to do -5V. You could wire it all up on Veroboard. Only downside is that it's bloody expensive. Even with exorbitant shipping from the US, an SPI220LE was only AU$100.

[Elrast]

Yeah, it's pretty expensive compared with commercial products. I'm tempted to ebay one of those SPI220LE myself, I didn't know it was available in Aust (well, someone willing to ship it here anyway) till you mentioned it. Thanks

I got a feeling that whatever I end up with it'll perform within 5% of the next solution $400 up :S