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From: firstname.lastname@example.org (Gibbo)
Date: 18 Nov 2002 18:14:45 GMT
Organization: AOL, http://www.aol.co.uk
Subject: Re: Multi-voltage PC switchers -- how?
David Lesher email@example.com wrote:
>PC supplies are getting up there. I wonder how they are now
>The 150w ones [i.e. bottom of the line] regulated on the 5v line,
>and just let the 12v and others tag along. [Maybe it was the 12v;
>but in any case..]
>But a friend has a new one that's something like 20A at 3.3v, 40A
>at 5v, 15A at 12v, and a little -5/12 etc. (I expect twist-lock 30
>amp plugs al-la PDP-11's Real Soon...) The first three claim
>Pondering same, I was wonder how it's done. You can have one
>rectifier/filter; that's easy. But do you have 3 separate
>oscillators/three separate PWM regulators; or do you make
>high frequency (well, in THIS context..) AC and distribute
>and use that....or?
Mutual inductors can massively increase cross regulation. This usually takes
care of the +/- 12 volt rails.
For very high current supplies the usual solution would be to use a magnetic
amplifier post regulators or another buck regulator.
But I'm guessing. Just saying what seems practical. I don't know how they do it
in the PC supplies as I've never looked at them.
But I do know there's a real expert on PC supplies on this NG and I imagine
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