I’m using the Pololu Pushbutton Power Switch LV on my reverse geo-caching puzzlebox project. I’ve designed a simple PCB that incorporates the power switch board. Unfortunately, my switch board isn’t acting as it should. The board looks like a dead short. I was remiss and failed to test the board before soldering it into my project. Another board that I ordered earlier works fine in my prototype. So, my guess is that either the board I got is defective or, more likely, I managed to expose it to static or took too long soldering it. What I’d like to know is if a dead short is an expected failure mode for this product. If not, I’ve got a lot of head scratching to do.
I’ve revised my board design so I’ll be able to socket the switch board in the future, but it would be nice if there were a standard 2 pin header for the switch as well as the site for the little push button that comes with the board. That way, it would be easy to use a remote switch, which is what I’m doing.
I’m sorry to hear about your switch; in general, if you contact us directly about this sort of thing, we can usually at least get you a discount on a replacement.
The main switch function is performed by a MOSFET (you can see it in the block diagram on the product page), which can indeed fail like a short circuit. I am not sure of the various things that can lead to that failure mode, but I think one of the common ones is excess voltage (when the switch was supposed to be off).
I’m pretty sure that if the switch is bad it’s because of mistreatment. Today I got the other three I ordered as backups and so I was able to compare measurements. That showed me that I had been measuring on the ground pins, doh, not the Vin and Vout pins. Across those I find the same half meg of resistance across the one installed in my board as I do on the ones I just got. So now I’m no longer convinced that the problem is the switch board at all.
Now I remember why I originally went into software. Mistakes are a lot cheaper.
