12 V Computers

| On Mar 14, 3:58 pm, snipped-for-privacy@ipal.net wrote: |> So what about standardizing on a 360VDC delivery voltage and cut the PC |> power supply in half? | | The point is that the objective and what is done do not coexist. | The article claims many tiny supplies will be more efficient than one | main supply. That just does not make sense. Standardizing to one | inputs voltage on blade servers makes sense for other and different | reasons. I suspect the author has confused the solution with what | that solution is trying to solve.

Smaller supplies = less stuff to get impede power and get hot. The big issue is whether we just end up with smaller hotter supplies. I doubt it.

One advantage I see is that you can have UPS protection and skip the DC -> AC step and the subsequent additional AC -> DC step.

Google probably is doing some kind of commodity blade-like setup that is not based on proprietary blades. You can get single voltage boards, but they tend to be low power consuming low CPU power devices, typically for the embedded market. They just want big full power boards based on the single voltage concept.

As I noted in a first post, we built a computer with the UPS (battery) embedded inside the power supply.

Meanwhile, how does one create the multiple voltages from a common

12 VDC and do it efficiently? AC mains to DC 12 volts to AC to DCx5 and DCx8. Using a common supply does not eliminate DC to AC steps. What do those little 'on-board' converters or 'DC to DC' converter bricks do? DC to AC to DC.

But again, a single voltage means a computer is more easily designed to be hot-popped. Feeding multiple voltages makes that design far more complex.

On 15 Mar 2007 14:19:43 -0700 w_tom wrote: | On Mar 15, 9:46 am, snipped-for-privacy@ipal.net wrote: |> The single DC voltage also allows integrating the UPS with the supply. |> Rather than AC -> DC -> AC -> DCx5 -> DCx8 we get AC -> DC -> DCx8 |> I don't believe the removed steps are cold. So the efficiency is very |> likely to be increased at least somewhat. | | As I noted in a first post, we built a computer with the UPS | (battery) embedded inside the power supply. | | Meanwhile, how does one create the multiple voltages from a common | 12 VDC and do it efficiently? AC mains to DC 12 volts to AC to DCx5 | and DCx8. Using a common supply does not eliminate DC to AC steps. | What do those little 'on-board' converters or 'DC to DC' converter | bricks do? DC to AC to DC.

That's not the only way to convert DC to DC. If converting down, it can be done quite simple. Pulse width modulation gating into a capacitor can regulate it to a lower voltage level and filter the pulses out. The reverse polarity can be a bit trickier, but a pair of capacitors in cascade could potentially do it, though some would argue that doing alternating DC pulses is a kind of AC. But in any case, you don't need nice neat sine waves here, and so you can do things with clean on/off gating.

| But again, a single voltage means a computer is more easily designed | to be hot-popped. Feeding multiple voltages makes that design far | more complex.

Indeed.