Re: Maximum Power for add in card more than 25W

[Ted Firlit <firlit@utmc.aeroflex.com>]

Brad,

I have been successful using the 12V power supply from the disk drive
connectors to supply my entire board power (with the exception of V(I/O)
coming from the PCI connector into my PCI interface device).  I used a
fairly inexpensive VRM 8.3 power converter hanging off the edge of the
card (kinda ugly) supplied by VXI/Celestica.  I was expecting to use up
to 60W to power up 5 DIMM slots. 

By the way, I can't seem to find the max power spec in the compact PCI
spec (PICMG 2.0).  Para 3.2.8.3 states that the V(I/O) pins can provide
an additional 4A to each card (above the 3.3V and 5V pins), but does not
state the minimum power available from the 3.3V and 5V pins.  Does
anyone know where this is spec'ed for compact PCI (or is it the same as
standard PCI?)

regards,

Ted


Richard Walter wrote:
> 
> Brad,
> 
> I've seen AGP cards that added a disk-drive power connector so that after the card is installed in the system, it could pull power from both the gold fingers and from the drive power system.
> 
> It would cost you some power supply circuitry to your board, but then you could draw 25W from the gold fingers and xxxW from the drive connector (where xxx is whatever the max power for a disk drive is (which I don't know, off-hand)).
> 
> -Richard Walter
> Senior Hardware Engineer
> Brocade Communications Systems
> rwalter@brocade.com
> Note: I speak for myself, not for Brocade Communications.
> 
> -----Original Message-----
> From: brad yu [mailto:bradyu2001@yahoo.com]
> Sent: Tuesday, December 19, 2000 9:54 AM
> To: pci-sig@znyx.com
> Subject: Maximum Power for add in card more than 25W
> 
> Hi,
> 
> I'm designing a PCI add in card, from the PCI Spec
> (page 146), there are two pins that are used to
> indicate the power comsumption for an add in card.
> 
> My question is, how if an add in card consume more
> power than the maximum power that is shown by the
> PRST1# and PRST2# pin (i.e 25W)? What will happen and
> what are the workaround so that my add in board which
> consume more than 25W can works. Thanks.
> 
> Cheers,
> Brad
> 
> __________________________________________________
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-- 
Ted Firlit		      		(719) 594-8138
Senior Design Engineer
UTMC Microelectronics Systems
4350 Centennial Blvd., MS 1004
Colorado Springs, CO 80907