SATA power for embedded widgets

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
-- 
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-- 
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
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    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