[rescue] Netra 1100/1400 => 1105/1405?

[Gregory Leblanc]

On Thu, 2001-08-23 at 09:34, Greg A. Woods wrote:
> [ On , August 22, 2001 at 22:00:26 (-0700), Gregory Leblanc wrote: ]
> > Subject: Re: [rescue] Netra 1100/1400 => 1105/1405?
> >
> > No, you misunderstood.  I have no problem with the -48vdc input to the
> > power supply...  I just don't like the fact that it relies on the power
> > supply to create the correct voltages for the CPU.
> 
> "So, where do you you expect it to generate the correct voltages for the
> CPU?  In the RAM or something?"  :-)

Erm, no, nice VRMs external to the power supply.  They're trivial
devices...

> >  I like -48V dc, I
> > just don't have that coming out of the power supply on my workbench...
> 
> Ah, I see.  Well this is more common on workstations than it was on PCs,
> though even on PCs we now have ATX supplies generating 3.3vdc for the
> CPU, which is much closer to what most CPUs need now.  Of course Intel's
> constantly tuning little things so you still need a custom VRM on the
> motherboard (nobody in their right mind want's to also change their PS
> when they change their CPU! :-).  In the workstation world though it's
> probaby common enough to generate exactly the right voltages for the CPU
> from right in the power supply with no intervening VRM.

Ahh, interesting.  I suppose I can see why you'd want that circutry
inside of the PSU, but you still need some way to tell the PSU what
voltage you want.  Clearly the U60 needs different voltages for
different CPUs, as it has leads going back to the PSU to change that
voltage.  Hmm, the mainboard still has to figure out what signal to send
back to the PSU to change the voltage, which may be a bit easier than
regulating the voltage, but probably not that much.  
	Greg