Re: [Gumstix-users] change from socket-operation to battery-operation

[Will <nyp...@gm...>]

On Wed, Apr 8, 2009 at 7:29 AM, R. P. McMurphy <log...@gm...> wrote:
> Whichever PSU has the higher output will drive the system. The only
> things to check are:
>
> - That the battery pack has a reverse diode to stop any current going
> the wrong way, i.e. to stop the other PSU acting like a charger.
> - That the voltages are not too dissimilar. A large sudden rise or
> drop may cause the system to crash but smaller sudden changes less
> than around 0.25V are usually not a problem.
>
> On 4/8/09, Tobias Benscheidt <tb...@tz...> wrote:
>> Hello all,
>>
>> I use the following setup:
>> - gumstix connex 400xm-bt
>> - netMMC
>> - GPSstix - R1286
>>
>> I want to change from socket-operation to battery-operation during
>> runtime, without restarting the system. Both the gumstix as well as the
>> GPSstix have a connection for power supply. Is it possible to use both
>> power jacks at same time for a few seconds without destroying anything?
>> If not, what other possibilities do I have?
>>
>> Thanks in advance.
>> Toby

To further decrease the chance of failure due to sudden voltage
change, you could stick a capacitor between power and ground to buffer
the change and make it more gradual along with McMurphy's diode
suggestion.