Low Vout, high Iout SMPS like on motherboards

[741]

In "The Art of Electronics" III, p637 is a footnote (see attached) saying microprocessors can need 1V at 60A.

Wow! That does surprise me.

I'd be interested to see a datasheet for one of these things. I tried looking for part numbers of those chips, so far not found one.

[MagicSmoker]

The search phrase you want to use is "multiphase buck converter" (or polyphase). This can be done with regular controller ICs that have a way to sync the clock then syncing each one to a phase-shifted clock, but motherboards will invariably use a special purpose IC capable of 2-8 phase operation.

[TiN]

That is quite outdated already, modern CPUs/GPUs can eat up over 400-500 Amp already with voltages in range 0.7 - 1.1 VDC.
Typical high-end GPU have 10+ phases DC/DC, with integrated 80A rated power stages (contain low-side/high-side FET and driver in one package), digitally adjusted VRM controllers, etc.
One such example, next to last-year high-end GPU card.

[T3sl4co1l]

Figure basically the whole thing runs at ~1V.  Any time you see TDP (total dissipated power), figure about as many amperes!

Hm, are the IO pins ran from 1V as well or something else (1.5, 1.8, 2.5)?  Back in the day I know the SSTL stuff was higher voltages, but I don't think that applies anymore, either...

Tim

[ejeffrey]

I know there are already systems out there that deliver high voltage to the package and use SMPS in the package because delivering 300A at 1 volt through a BGA gets really annoying.

[TiN]

I/O usually runs at 3.3V, and 1.8V for more modern cards. There are other I/O voltages and termination voltages too for stuff like PCIe/SerDes XVRs, etc.