Forums

SATA power for embedded widgets

Started by Theo Markettos February 18, 2013
Been doing a lot of stuff recently that requires 3.3V and 12V at moderate
currents.  The simplest commodity way to do this seems to be a PC power
supply.  The 24 way ATX connector is a bit clumsy and you only get one per
PSU, so it seems simpler to use SATA connectors as a handy ecosystem of
3.3/5/12v power at up to 4.5A per rail.  A scattering of these provides the
necessary few hundred watts.

We've been doing this for a while and it works nicely (though with a custom
loom).  However, I've failed to find any male SATA power connectors  without
accompanying data part.  Do they exist?  Having a spurious SATA data
connector is a waste of space, and confusing in a system which does have
real SATA cabling around too.

Anyone use any other methods for commodity multi-voltage power supplies? 

Thanks
Theo
On 18 Feb 2013 15:50:26 +0000 (GMT), Theo Markettos <theom+news@chiark.greenend.org.uk> wrote:
> Been doing a lot of stuff recently that requires 3.3V and 12V at > moderate currents. The simplest commodity way to do this seems to > be a PC power supply. The 24 way ATX connector is a bit clumsy and > you only get one per PSU, so it seems simpler to use SATA connectors > as a handy ecosystem of 3.3/5/12v power at up to 4.5A per rail. A > scattering of these provides the necessary few hundred watts.
[...]
> Anyone use any other methods for commodity multi-voltage power > supplies?
Theo, I'm not completely clear on what you need in the way of connections to the power supply (how is "only get one per PSU" a problem?), but an ATX supply plus this item: http://www.seeedstudio.com/depot/atx-breakout-board-bench-power-supply-p-1222.html?cPath=155 will give you -12V, 3.3V, 5V and 12V via binding posts. Hope it helps... Frank -- We enjoy the foibles of the great, their follies, and their self-proclamations, as it titillates both our own grandiose folly and our feeling of self-importance -- as we feel ourselves, rightly, superior to them. But this thrill is cheap and it is as nothing compared to our enjoyment of real heroism. Why? Because when we see real heroism, the heroism of the ordinary person forced by circumstances to act bravely, we identify with that man or woman and we say, "If they can do it, then perhaps I could. too." -- David Mamet / True and False -- Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney aatt mindspring ddoott com
On 18 Feb 2013 15:50:26 +0000 (GMT), Theo Markettos
<theom+news@chiark.greenend.org.uk> wrote:

>Been doing a lot of stuff recently that requires 3.3V and 12V at moderate >currents. The simplest commodity way to do this seems to be a PC power >supply. The 24 way ATX connector is a bit clumsy and you only get one per >PSU, so it seems simpler to use SATA connectors as a handy ecosystem of >3.3/5/12v power at up to 4.5A per rail. A scattering of these provides the >necessary few hundred watts. > >We've been doing this for a while and it works nicely (though with a custom >loom). However, I've failed to find any male SATA power connectors without >accompanying data part. Do they exist? Having a spurious SATA data >connector is a waste of space, and confusing in a system which does have >real SATA cabling around too. > >Anyone use any other methods for commodity multi-voltage power supplies?
You mean like a Molex 67926-0021? Or am I misunderstanding you?
 Theo Markettos wrote:
> I've failed to find any male SATA power connectors without >accompanying data part. Do they exist?
Yes , see links below. (Not in the UK though) http://www.monoprice.com/products/subdepartment.asp?c_id=102&cp_id=10226&cs_id=1022604 http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10226&cs_id=1022604&p_id=8794&seq=1&format=2 http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100016766&IsNodeId=1&srchInDesc=power&page=1&bop=And&ActiveSearchResult=True&Order=PRICE&PageSize=100
>Anyone use any other methods for commodity multi-voltage power supplies?
If you are willing to cut the connectors that came with the PS, you have endless choices. -- Roberto Waltman [ Please reply to the group, return address is invalid ]
Robert Wessel <robertwessel2@yahoo.com> wrote:
> >We've been doing this for a while and it works nicely (though with a > >custom loom). However, I've failed to find any male SATA power > >connectors without accompanying data part. Do they exist? > > You mean like a Molex 67926-0021? Or am I misunderstanding you?
That's a female connector (the bit that goes on the cable). I'm looking for the bit that goes on the PCB. Theo
Roberto Waltman <usenet@rwaltman.com> wrote:
> Theo Markettos wrote: > > I've failed to find any male SATA power connectors without > >accompanying data part. Do they exist? > > Yes , see links below. (Not in the UK though)
Those aren't quite right, but it reminds me there are such things as SATA power splitters which have male power connectors on the 'input' side. Trouble is, they tend to be in-line rather than PCB mount. For example: http://www.newegg.com/Product/Product.aspx?Item=N82E16812198015
> >Anyone use any other methods for commodity multi-voltage power supplies? > If you are willing to cut the connectors that came with the PS, you > have endless choices.
Indeed, but that's not that useful if you want to give your widget to somebody else. Theo
Frnak McKenney <frnak@far.from.the.madding.crowd.com> wrote:
> I'm not completely clear on what you need in the way of connections to > the power supply (how is "only get one per PSU" a problem?), but an > ATX supply plus this item:
Let's say you want to power multiple boards. They might be clones of the same board, or all different (think rackmount card cage). Imagine the boards take 3.3V @ 4A, 5V @ 1.5A, 12V @ 3A (made up numbers). That's about 60W, which is well into SMPSU territory, and you don't really want to add a 60W PSU to every board so they can run off a single voltage, or a separate power brick for each board. 600W ATX PSUs are cheap, and even allowing for lies in the specs you can still power 5 or more of these boards. They come with strings of SATA connectors so that you can plug several boards into a string (assuming it isn't overloaded). Also, you can easily test, develop and distribute these boards to others - all they need is a simple PC PSU and they're good to go. You can mount these boards in PC cases - if you get the board layout right you can even use existing drive bays/backplanes/etc. So SATA is a really nice ecosystem for getting multi-voltages out of a commodity power supply. However it turns out that it's also lumbered with SATA signalling connectors, which isn't always what you want.
> http://www.seeedstudio.com/depot/atx-breakout-board-bench-power-supply-p-1222.html?cPath=155 > > will give you -12V, 3.3V, 5V and 12V via binding posts.
At 1.25A, which is a bit of a waste of a 600W PSU. Theo
On 19 Feb 2013 01:19:53 +0000 (GMT), Theo Markettos <theom+news@chiark.greenend.org.uk> wrote:
> Frnak McKenney <frnak@far.from.the.madding.crowd.com> wrote: >> I'm not completely clear on what you need in the way of connections >> to the power supply (how is "only get one per PSU" a problem?), but >> an ATX supply plus this item: > > Let's say you want to power multiple boards. They might be clones > of the same board, or all different (think rackmount card cage). > Imagine the boards take 3.3V @ 4A, 5V @ 1.5A, 12V @ 3A (made up > numbers). That's about 60W, which is well into SMPSU territory, and > you don't really want to add a 60W PSU to every board so they can > run off a single voltage, or a separate power brick for each board. > > 600W ATX PSUs are cheap, and even allowing for lies in the specs you > can still power 5 or more of these boards. They come with strings > of SATA connectors so that you can plug several boards into a string > (assuming it isn't overloaded). Also, you can easily test, develop > and distribute these boards to others - all they need is a simple PC > PSU and they're good to go. You can mount these boards in PC cases > - if you get the board layout right you can even use existing drive > bays/backplanes/etc. > > So SATA is a really nice ecosystem for getting multi-voltages out of > a commodity power supply. However it turns out that it's also > lumbered with SATA signalling connectors, which isn't always what > you want.
Ooooo-kay. So your concern is connector standardization both for the PSU _and_ for your "widget" boards. Got it.
>> http://www.seeedstudio.com/depot/atx-breakout-board-bench-power-supply-p-1222.html?cPath=155 >> >> will give you -12V, 3.3V, 5V and 12V via binding posts. > > At 1.25A, which is a bit of a waste of a 600W PSU.
Yabbut... the limitation is due to polyfuses, which could be bypassed. If that were the only problem, you could download the schematic and Gerber files and cut some new almost-alike PCBs sans polyfuses. However, based on your comments above, that still leaves the board with binding posts which you'd then need to connect to your boards. Given that, I see why putting SATA connectors on your "widget" boards is a better solution. As to the SATA "signalling connectors": If you don't like the standard ones coming off the PSU, what would you prefer to have on your PCBs? I suppose you could put a 24-pin ATX connector on each instead, but I suspect that those would be a bit large. <grin!> Ah, well. Frank -- "Many people think that science is logical, rigid, and cold, while art is intuitive, flexible, and touchy-feely. In fact, both processes are simply two faces of the same coin. Intuition feeds logic and vice versa. Science without imagination is useless; art without structure is pointless. Both Science and Art ultimately rest on the same foundation: the ability to draw patterns out of chaos. It's just that when you do science, you observe the chaos; when you do art, you get to define it." -- Diana Gabaldon, "The Outlandish Companion" -- Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney aatt mindspring ddoott com
On 19 Feb 2013 00:54:46 +0000 (GMT), Theo Markettos
<theom+news@chiark.greenend.org.uk> wrote:

>Robert Wessel <robertwessel2@yahoo.com> wrote: >> >We've been doing this for a while and it works nicely (though with a >> >custom loom). However, I've failed to find any male SATA power >> >connectors without accompanying data part. Do they exist? >> >> You mean like a Molex 67926-0021? Or am I misunderstanding you? > >That's a female connector (the bit that goes on the cable). I'm looking for >the bit that goes on the PCB.
This? http://www.eckind.com/product_976302_sata-connector-15p-plug.htm You'd probably have to find a local distributor.
Robert Wessel <robertwessel2@yahoo.com> wrote:
> This? > > http://www.eckind.com/product_976302_sata-connector-15p-plug.htm > > You'd probably have to find a local distributor.
That's just the ticket, thanks. Theo