[nSLUG] Low Power system

Jason Kenney jdkenney at gmail.com
Mon Aug 25 15:02:14 ADT 2008


> What's most important is the efficiency curves. Most PSUs
> (older/current ones not covered by 80plus) are quite inefficient at
> the low end of output, and relatively inefficient at the high end,
> with a sweet spot somewhere in the middle. I'm not an EE, not sure why
> that is... anyone?

I don't know anything about power supply design, but a guess about the
inefficiencies is:

low-end:
------------
Maybe you need some kind of minimum current level in the circuitry,
and so even if your output would not require that much, the circuit
itself does to maintain operation

high-end:
-------------
Might be hysterisis effects in the transformer(s) if they're chosen to
be efficient at the most common load levels, and meh for anything
higher (ie, cheaper than to be hysterisis free for all)


I'm sure there are details of the circuitry operation beyond this that
probably contain the real answers though.


Jason



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