[mjevans]

There's a push for '12vo' or 12 volt only PSUs for PCs... but with the major power consumers mostly the GPU, CPU, RAM (?), and possibly spinning drives, would a similar to telecom gear 48V make more sense?

For GPUs and any USB PD connections ('standard' is up to 20V 5A while 'extended' is 48V 5A) a system power level of ~48v might be very useful. It would also give a chance to replace the recent higher density connectors that aren't designed with a sufficiently robust user experience with improved versions that more clearly lock into solid connection.

[crote]

Not really.

Pretty much the only PC part which wants native 12V would be the fans. All the other parts drop it down to 5V / 3V3 for auxiliary components, or 1-2V for the CPU and GPU cores - which use the vast majority of power.

Dropping 12V DC to 1.5V is reasonably doable, but dropping 48V DC to 1.5V is a bit of a pain. In general you do not want to go beyond a 1:10 ratio for efficiency reasons, so 48V doesn't really gain you anything, while at the same time resulting in a massive compatibility break.

The push to 12VO is driven by a desire to get rid of technical debt. The 3V3 / 5V wires can't handle the current you need on those rails, so those are converted from 12V anyways. And literally nobody is using the -12V and -5V wires, so keeping those around is pointless.

[namibj]

Open compute platform switched to 48V years ago, to afford having multiple PSUs feeding multiple servers, with (those days) a fixed 4:1 switched capacitor down converter right next to the existing 12V-to-0.5~1.5V DrMOS VRM power stages.

There are iirc GaN devices from epc-co these days that make it feasible to go directly from 48V with the VRMs to the 0.5~1.5V for the core.

[mkj]

Why does the ratio affect efficiency? Naively it seems like it should just be able to use differently sized inductors.

[myself248]

Yes, I thought 48vo was already on the drawing board.