7V is about the limit for a linear regulator, so you would probably get away with using your Li-Po batteries with something like a LP3872EMP-5.0 to give you a clean 5V output that will handle up to 2A.
These regulators need external capacitors of about 10uF but that is it as far as external components are concerned.
You can get the devices and surface mount ceramic capacitors from Newark and breadboard a regulator very easily.
 
Ben


From: gumstix-users-bounces@lists.sourceforge.net [mailto:gumstix-users-bounces@lists.sourceforge.net] On Behalf Of Marc Nicholas
Sent: 02 July 2007 12:30
To: General mailing list for gumstix users.
Subject: Re: [Gumstix-users] Powering a Gumstix

I suppose if it does go into thermal shutdown, adding a diode would shave off the best part of 1vdc and might make things a little more predictable?

-marc

On 7/2/07, Dave Hylands <dhylands@gmail.com> wrote:
Hi Miguel,

> I have a gumstix with a robostix module (Basix 400 I think). With that,
> Im controlling a small biped robot. The robot , and the servos on it,
> are powered with a Li-Po battery of 7,5 volts , and 2200 mA.
> This battery is sending 7 volts aprox.  Is it safe to power the gumstix
> with that?? (7 volts). Or I should try to find a different power source?
> (AAA batteries, or something like that).
> The robot is very "weight" sensitive, so I would prefer to use the Li-Po
> battery, instead of adding extra batteries. Should I add some resistors
> to the 7 volts?? wich value?
> I hope anyone with more expertice on electronics can help me on this

It will probably work, although you really need to test it.

The worst that happens is that the voltage regulator goes into thermal
shutdown, which will cause the gumstix to get reset. If you experience
this, then you should try using an external regulator to get the
voltage down in the 5v to 5.5v range.

--
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/

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