MAX1555 Schematic

Community PCB Design
1

I just got back a MAX1555 board, and it seemed drop-dead simple to me (1 LED, three caps and a resistor), but when I plug the battery in it and add power with the DC Barrel it doesn’t charge and the LED doesn’t light up (yes I have the anode and cathode in the right direction). Is there something I’m just not understanding on the schematic side? Given that this is such a simple IC, I’m definately feeling pretty dim-witted about this:

http://img397.imageshack.us/img397/3235 … ematic.png

If anyone has a second to look at the schematic, I’d appreciate it.

2

Looks right to me. Please don’t take it as a stupid question, but is it possible your battery is already fully charged? Otherwise, I’m not sure why it wouldn’t work.

3

I intentionally discharged the battery, leaving it hooked up to a GPS all night, and of course measured the voltage on it during the whole process. It discharges fine, but when I hook it up to the board … nothing. Could just be bad soldering on my part, though it looked OK under the microscope. I’ll have to see if I can remove the MAX1555 from the current board and try on another PCB.

Thanks for taking the time to reply, though. I can’t imagine a simpler schematic, so I was really wondering what I could have gotten wrong?

4

Hello. Did you ever get your board to work by any chance? I just bought a few MAX1555’s and plan on putting together a similar design soon.

5

ktownsend:
I intentionally discharged the battery, leaving it hooked up to a GPS all night, and of course measured the voltage on it during the whole process.

This is all well and good, but did you cut it off after it dropped to a certain level or just let it go until completely dead? If you did the latter, there is a good chance the cell entered LVC and it just about toast now.

I have a couple of chargers that I designed around the MAX1555 (http://www.rpc-eheli.com/) and my most common complaint from customers is the charger is “not charging”. 99% of the time, I find out they ran the cell down so low that the charger will not even see the cell to start a charge cycle.

Just my $0.02