On Tuesday, February 19, 2013 2:54:07 PM UTC-6, Theo Markettos wrote:
> Frnak McKenney <frnak@far.from.the.madding.crowd.com> wrote:
>
> > 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.
>
>
>
> Part of this is I really dislike hand-crimping Mini Fit connectors, which is
>
> what I'd need to do to make a 'special' wiring loom (eg 24w ATX to umpteen
>
> arbitrary-Mini-Fit connectors). Obviously not a problem if you're making
>
> vast numbers and can order the looms in volume, but more of an issue for
>
> small volumes. And why crimp if you can use the existing connectors?
You didn't really say how many of these you need, but if it's more than a few I would consider doing a simple power distribution board taking in the ATX, fusing for your slave boards, and then breaking out to a connector that you like or a set of screw terminals. You can also do a low voltage power on switch and power indicator on there.
Reply by Theo Markettos●February 19, 20132013-02-19
> 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.
Part of this is I really dislike hand-crimping Mini Fit connectors, which is
what I'd need to do to make a 'special' wiring loom (eg 24w ATX to umpteen
arbitrary-Mini-Fit connectors). Obviously not a problem if you're making
vast numbers and can order the looms in volume, but more of an issue for
small volumes. And why crimp if you can use the existing connectors?
> 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.
Sorry, I should have been clearer. More SATA male connectors are 22 way: 15
way part for power (3 rails * 3 pins each, 5 grounds, 1 reserved) and 7 way
part for data (2 twisted pairs, 3 grounds).
The PSU has 15 way connectors in the wiring loom. These plug into the HDD,
and a separate cable from the motherboard goes to the 7 way data connector.
If they're in drive bays, the drive mates directly with a 22 way connector
on the backplane that provides both parts.
So this means that any male connector has the data part included. That
means there's a tempting SATA data socket that you just know users are going
to try to plug into their motherboard, even if you don't speak SATA
signalling at all. It also wastes footprint on the board which you could
use for something else.
Hence the idea to just have the 15 way power part on the PCB to receive a
cable from the PSU, and no need for the 7 way data part.
Theo
Reply by Theo Markettos●February 19, 20132013-02-19
Reply by Robert Wessel●February 19, 20132013-02-19
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.
Reply by Frnak McKenney●February 19, 20132013-02-19
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.
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
Reply by Theo Markettos●February 18, 20132013-02-18
> 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.
At 1.25A, which is a bit of a waste of a 600W PSU.
Theo
Reply by Theo Markettos●February 18, 20132013-02-18
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
Reply by Theo Markettos●February 18, 20132013-02-18
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
Reply by Roberto Waltman●February 18, 20132013-02-18
Theo Markettos wrote:
> I've failed to find any male SATA power connectors without
>accompanying data part. Do they exist?
>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 ]
Reply by Robert Wessel●February 18, 20132013-02-18
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?