CL1B power distribution

[Reinder de Haan]

John Watlington wrote:
> On Apr 27, 2009, at 6:11 AM, Joel Stanley wrote:
> 
>> Hello Wad,
>>
>> On Sun, Apr 26, 2009 at 12:35, John Watlington <wad at laptop.org> wrote:
>>> On Apr 25, 2009, at 7:29 PM, pgf at laptop.org wrote:
>>>>     - will we have (approximate) numbers at some point for how
>>>>       much power any given subsystem takes?  (e.g., for the
>>>>       above case, how much would powering down the kbd/tpad
>>>>       save?  this will inform decisions like "how much effort
>>>>       is it worth?")
>>> I have estimates for the new sections, and we have numbers from
>>> Tinderbox for the portions that aren't changing (keyboard, touchpad,
>>> DCON, display).
>> Out of interest, will the new PCB layout be tinderbox-friendly?  Are
>> you planning to wire a 1.5 up?
> 
> Tinderbox friendly and production friendly are different goals.
> A-phase will be tinderbox friendly, but the resistors will be
> going away before C-phase.

I have a nice construction in a couple of pcbs:
* Add a big (>= 0805) SMD resistor footprint in any lines you want to
measure later on
* add a trace from pad 1 to pad 2
* if you wnat to measure scratch away the trace (or add the trace to the
next revision of the pcb)
* soldere a shunt resistor on the footprint

in the production phase just keep the shorted footprint.. i think that
will add no cost to the pcb (and saves a small bit of time->money for
the redesign)

if anyone want to measure on a production unit they just cut the trace
between the pads and adds a resitor (or the leads of an A meter)


Reinder de Haan

> 
> wad
> 
> _______________________________________________
> Devel mailing list
> Devel at lists.laptop.org
> http://lists.laptop.org/listinfo/devel
>