[MinnowBoard] TurboT DualE board power by LSE header

Thu Apr 12 21:55:08 UTC 2018

Mark, Michael,

    Thank you for your reply. I agree that the trace width between LSE
header and Q103 could be a problem. And actually it is. There is one place
with trace width approx 0.68 mm. I don't really know if there is 0.5 oz or
1 oz copper on L06. I think that this is ok for 1Amp on 0.5 oz because the
rest of the trace width is about 1.4 mm.

[image: изображение.png]

>From this board we need CPU, 2xGigE, RAM. mSATA for booting and probably
USB for a flash drive.
To test the reliability - I ran dual cpuburn (burnK6 x 2 for 2 cores) for
about 8 hours - and everything was fine. Unfortunatelly we don't have a
thermal imager to check the PCB temperature at this point.

RIght now I'm not sure that this is a good idea to power this board by the
LSE header. But I really don't have any other ideas.

Michael. Also today we accidentally applied the +12V on PS_5VSB on LSE
header on one board:-( I'm pretty sure that U35 was failed. We'll replace
it (spare NCT3012S would be delivered by our supplier at the end of next
week) and check - if this was the only failed part - we are lucky:-)

чт, 12 апр. 2018 г. в 22:31, Krau, Michael P <michael.p.krau at intel.com>:

> One historical piece of information:  The Original (non-Turbot)
> MinnowBoard MAX had a different implementation, where the LSE Header was
> not populate with the +PS_5VSB but with the (post regulator) 5VSB trace.
>  This ties back to Mark’s trace comments, as the +P5_5VSB traces should be
> more robust than the 5VSB, as the 3 volt rail is drawn from the +PS_5VSB.
> In fact, I would doubt this solution would work on the non-Turbot
> MinnowBoard MAX, as the 3 volt rail would not be powered if the only source
> of power were 5 volts on the LSE.
>
>
>
> During the board design, the 3 Amp rule was discussed, but I can’t
> remember if 3 Amps was the target (meaning there should be some additional
> margin) or the upper limit (including the margin).
>
>
>
> I would like to think that the Turbot design change (5VSB to +PS_5VSB on
> the LSE) was done to accommodate projects like yours, where the LSE can be
> used as an alternate power supply source for the platform.  In which case
> they would have kept 3 AMPs as the standard…  However, since the 5 volt
> rail does not go through the on board regulator, it also means that the
> system is not protected by the 5 volt regulator.  Accidentally putting 12
> volts on the LSE 5volt pin could fry the board (instead of simply frying
> the regulator), and providing more amperage than the traces of the board
> can handle could have detrimental impact on the board under high load.
>
>
>
> The question that comes up is how much current does your application draw
> when fully operational?  If the draw is low enough, then it should be
> within the design rules applied.
>
>
>
> The photo does look great!
>
>
>
> Michael Krau
>
>
>
> *While I am an Intel employee, I do not represent Intel and am not
> authorized to speak for Intel. *
>
>
>
> *From:* elinux-MinnowBoard [mailto:
> elinux-minnowboard-bounces at lists.elinux.org] *On Behalf Of *Van Der Pol,
> MarkX
> *Sent:* Thursday, April 12, 2018 11:23 AM
> *To:* alex.bakhtin at gmail.com
> *Cc:* MinnowBoard Community Email List <
> elinux-minnowboard at lists.elinux.org>
>
>
> *Subject:* Re: [MinnowBoard] TurboT DualE board power by LSE header
>
>
>
> It is under investigation – while the circuit works, there is a concern if
> the PCB traces from the LSE header to the regulator are sized big enough to
> handle the current demands of the board and modules. It is supposed to be
> able to handle 3Amp, and I don’t know if that was actually implemented, and
> if that design rule was enforced into the board layout. And I don’t know
> what safety margin exists on the design rule, if it was applied.
>
>
>
> So – as you discovered, it works fine. And, until the analysis is done on
> the trace current capacity, we don’t know if it is reliable. There is risk
> of it failing under load.
>
>
>
> Thanks for sharing the update and photo! It looks great!
>
>
>
> |\/|ark.
>
>
>
> Mark van der Pol
>
> Firmware Engineer,
>
> Open Hardware Team,
>
> Open Source Technology Center
>
> Intel
>
> Markx.van.der.pol at intel.com
>
>
>
> The MinnowBoard.org Foundation: a US-based non-profit providing education
> and promotion of the design and use of open-source software and hardware in
> embedded computing on Intel® Architecture.
>
>
>
>
>
>
>
> *From:* elinux-MinnowBoard [
> mailto:elinux-minnowboard-bounces at lists.elinux.org
> <elinux-minnowboard-bounces at lists.elinux.org>] *On Behalf Of *Alex Bakhtin
> *Sent:* Thursday, April 12, 2018 12:38 AM
> *To:* elinux-minnowboard at lists.elinux.org
> *Subject:* Re: [MinnowBoard] TurboT DualE board power by LSE header
>
>
>
> Nobody sent a reply.
>
> We made some testing and designed a simple PSU to check this idea.
> Everything is working fine.
>
>
>
> [image: image001.jpg]
>
> вс, 1 апр. 2018 г. в 1:31, Alex Bakhtin <alex.bakhtin at gmail.com>:
>
> Hello.
>
>     Is it possible to power the TurboT Dual-Ethernet - Dual Core board
> from LSE header?
>
>     Right not we are testing how TurboT fits out project. TurboT could be
> one of the core components, but the whole device should be dual-powered
> (220V AC and 10-36VDC). From my point of view - this is a good idea to
> desing a PCB on which we would install our PSU, and also provide a mounting
> space for TurboT - holes and connection to the LSE header (I think we would
> also use one uart from LSE header).
>
>     I checked the turbot schematics and I see that DC_IN_1 (power supply
> connector) is filtered by an LC filter, connected to protection curcuit and
> after that is connected to +PS_5VSB.
>     +PS_5VSB is connected to pin 3 of LSE header and supply 5V power to
> the rest of the board. So, according to turbot schematics - we can supply
> +5V to the PS_5VSB directly and everything should be fine.
>
>     In the turbot gerber files I can see that this pin is connected to
> polygon on Layer 06, and it seems that this polygon is directly connected
> to Q103 and FB1->U13 (3V power supply).
>
>     Is it ok to supply 5VDC it from LSE header? Thank you.
>
> Alex Bakhtin
>
> --
>
> Alex Bakhtin
>
> --
>
> Alex Bakhtin
>
-- 

Alex Bakhtin
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.elinux.org/pipermail/elinux-minnowboard/attachments/20180412/728d25e6/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.jpg
Type: image/jpeg
Size: 212733 bytes
Desc: not available
URL: <http://lists.elinux.org/pipermail/elinux-minnowboard/attachments/20180412/728d25e6/attachment-0001.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: ???????????.png
Type: image/png
Size: 14896 bytes
Desc: not available
URL: <http://lists.elinux.org/pipermail/elinux-minnowboard/attachments/20180412/728d25e6/attachment-0001.png>