On Thu, May 11, 2000 at 12:02:17PM -0400, [EMAIL PROTECTED] wrote:
> Ok. Here's another random thought.
>
> What if I use, say, a Linear LT1300 Step-up 3.3V DC/DC converter (almost
> exactly the same one the palm uses to regulate the 2 AAA cells to make its
> 3.3 V supply, I think) and connect it to the VCC pin in the hotsync port?
> Might this work?
Actually there may be a way that doesn't actually violate a Palm spec.
The RS-232 lines have minimum voltage and current outputs, so turning
on the Serial port (even if you don't communicate) will provide power
(though it will drain the battery a bit faster; I am assuming the RS232
lines themselves only pull the 5uA). Since you have to open them anyway,
you might be able to charge a cap or something and use the power from
the periodic acquisitions when the RS232 is on to run your device.
Two things to be careful with in using a Step-up chip. First,
component selection is critical - some diodes will change the
efficiency by a suprising amount, same with inductors - the
small surface mount stuff tends to be inefficient. And some have
problems at low currents. It would probably work well, but I
am just pointing out that there are a lot of subtle things to
make it work properly, i.e. you can't just copy the circuit from
the app note.
--
For information on using the Palm Developer Forums, or to unsubscribe, please see
http://www.palmos.com/dev/tech/support/forums/
