RE: How to power a PCI card from either 3.3V OR 5V..

[Dimiter Popoff <tgi_earth@yahoo.com>]

Rick,

>You will have already designed the board to handle the higher dissipation,
>so what will the lower power accomplish, longer battery life?  ;)

While your point is correct, longer battery life is indeed an
issue sometimes. If not, total system power capability may be.
Or price; or board space. I know inductors can be made very small
and I have used at least once an SO-8 LT1506 which is a fine chip,
but a simple switch would be smaller and cheaper - provided the
board can afford the power the linear regulator will dissipate
when no 3.3V are present. To be sure, switching the 3.3V if
a switched regulator is on board makes no sense at all.

Dimiter

Dimiter Popoff
Transgalactic Instruments, Gourko Str. 25 b, 1000 Sofia, Bulgaria
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