[HN Gopher] Intel's changing the future of power supplies with i...
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Intel's changing the future of power supplies with its ATX12VO spec
Author : wyldfire
Score : 32 points
Date : 2020-03-09 13:18 UTC (9 hours ago)
(HTM) web link (www.pcworld.com)
(TXT) w3m dump (www.pcworld.com)
| superkuh wrote:
| This makes sense for specific use case computers, specialty ones,
| etc. So it'll be adopted. And because of economies of scale it'll
| push into actual desktop computers and their mobos. Having to
| dissipate all that heat on/in the mobo will be terrible for
| actual desktop computers. But it'll happen anyway because it's
| better for corporations and the desktop market doesn't drive
| their decisions.
| [deleted]
| baybal2 wrote:
| You already dissipate quite a lot in CPU VRMs. For everything
| 3.3V on mobo, a linear reg on board will still be more
| efficient than one in the PSU.
| jleahy wrote:
| A typical CPU (or SSD even) uses a voltage of 0.9V currently,
| surely it doesn't matter whether the motherboard is converting
| 12V to 0.9V or 5V to 0.9V.
|
| Back when this stuff was originally designed 12V, 5V and 3.3V
| was all you needed (actually with the AT standard it was just
| 12V for motors and 5V for logic, that was pre-CMOS). Now every
| component requires a different voltage (if there's any standard
| it might be 1.8V or 1.2V), and to get several hundreds watts of
| power at 0.9V would require cables about an inch thick.
|
| 12V is the defacto standard for powering pretty much anything
| these days. Converting 12V into whatever you want is utterly
| trivial and incredibly efficient.
| raverbashing wrote:
| It's an interesting development. Things like -12V made sense on
| the 80s (sigh), while high-powered 3.3v/5v needs made sense on
| the 90s (it still makes some sense today, for example for USB)
|
| Though one thing they might have considered but maybe rejected
| was going for a higher voltage single rail power supply
| (something like 24v)
|
| Your board might still need those voltages but will have to DC-DC
| convert it themselves (as opposed to a multi-tap transformer as
| the article was implying)
| throwaway2048 wrote:
| pretty much all modern boards use DC/DC power stages from 12v,
| even for 5v and 3.3v stuff.
| baybal2 wrote:
| Indeed, found that for myself when got into mobo design.
|
| ATX 5V is really unsuitable for USB power, and can play
| tricks on you.
|
| Similarly, 3.3V from PSU is useless at powering 3.3V logic.
|
| You have to do power staging on board to guarantee that PCI
| and i2c stuff turns on after the bridge/soc.
|
| Some PSUs don't follow reset timings, or don't do them at all
| on standby rail.
|
| So if you do ATX power by the book, you may end up with
| improperly inited board, and 3.3V ICs booting up before the
| CPU.
|
| So, yes, most of ATX power supply functionality is already
| duplicated by most mobos
| mmastrac wrote:
| > ATX 5V is really unsuitable for USB power, and can play
| tricks on you.
|
| Would you mind elaborating on this?
| baybal2 wrote:
| Poor transient response.
|
| Ringing on some PSUs.
|
| Out of spec ripple on most PSUs.
| garaetjjte wrote:
| >ATX 5V is really unsuitable for USB power, and can play
| tricks on you.
|
| Why? I don't think current motherboard duplicate 5V
| converter.
|
| >you may end up with improperly inited board, and 3.3V ICs
| booting up before the CPU.
|
| Why it cannot just hold reset line for these chips high
| until CPU started?
| londons_explore wrote:
| Why does this still have 10 pins?
|
| 2 pins would be plenty. 12v Power, Ground, and an overlaid
| capacitively coupled 2 way data comms running at a few hundred
| khz to send and receive status messages, fan speeds, model/serial
| numbers, firmware/ temperatures, on/off commands, etc.
| kbumsik wrote:
| > 2 pins would be plenty
|
| No. You are gonna burn wires.
| mackal wrote:
| 1 pin is called PS_ON, this shorting to ground turns it on. 1
| called PWR_OK which says everything is working in some way I
| don't want to research. 1 +12V for stand by. 1 +12V sense for
| detecting voltage drop or something. And then 2 normal +12V and
| 3 ground. There is 1 reserved pin as well (rectangle connector
| so needs even pin count)
| jleahy wrote:
| > +12V sense for detecting voltage drop or something
|
| This is actually the best bit, incredibly smart idea. It's a
| kelvin connection to ensure that you get 12V at the
| motherboard, regardless of power dissipation in the wire.
| [deleted]
| generatorguy wrote:
| to deliver 1500 watts at 12v through one pin would be 125 amps.
| 5 pins each with 25A I would think you'd want at least 14 gauge
| per pin and even then I think they would be rather warm.
| baybal2 wrote:
| > Why does this still have 10 pins? 2 pins would be plenty.
|
| No, modern desktop can easily use up to 30A constant load. No
| way to provide so much over 1mm wires at 12V
| Melkman wrote:
| I wonder how easy this would make server local UPS systems. A
| battery with a single buck/boost converter should be enough as a
| power supply. Just need to add a mains fed charge circuit.
| mmastrac wrote:
| Probably would allow _very_ cheap power supplies w /built-in
| UPSes. 12V+-5% voltage is the allowed range.
| baybal2 wrote:
| +-5% would not be that easy with current spikes from CPU and
| GPU.
|
| It's 300W-400W load going to near zero and back within
| microseconds.
| chmod775 wrote:
| It's not black magic to handle that with a capacitor.
| ars wrote:
| It would be awesome if they speced an external 12V connector on
| the power supply that just goes to a battery - no electronics.
|
| Then every power supply could be its own UPS, and handle
| charging the battery.
|
| It would need to be a pretty fat wire, but that's handleable.
| [deleted]
| mmastrac wrote:
| 12V makes so much more sense to be sending around - the losses at
| lower voltages are rough. It would be nice to replace legacy
| molex connectors with a more modern standard, however.
| kbumsik wrote:
| > It would be nice to replace legacy molex connectors with a
| more modern standard
|
| Any example of the modern one? I personally have no issues with
| the current one. I am not sure if those molex connectors should
| be called as legacy.
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