zim2dive

Ok, some added info...

AFAICT, the Axim A/C power pins are not driven out, so the reverse charge should not be occuring over those. Using the Dell AC -> Cradle connector, I measured 0V across the connector.

Next, I put the Axim in the cradle, and disconnected the USB from the computer so I could measure it. With the AC power connected to the cradle, I saw 3.86V on the USB power pins. With the AC disconnected, it dropped slightly to 3.77V.

So it would appear to me that any reversal must be happening on those pins...

From this I offer a hypothesis to be considered... if one were to take the USB sync/charge cable, and disconnect the USB power pins, then there should not be a battery reverse drain scenario. The only "problem" area would be if the connected source could deliver enough current on the AC power pins.... (what happens if it cannot, is it a problem, or just a slower charge?)

Somewhat unrelated, I found that the Axim would accept down to 4.5V on the AC power connection and still charge (using a variable power supply) and the AC -> Cradle connector. I did not test for a VINmax (being unsure what protection circuits might/not exist).

Edit: and/or if one were to disconnect the USB power on the cable (pin 21 according the the charts), and insert a 0.3V Schottky diode, that _should_ prevent the reverse problem too.

Thoughts?

Mike