Potential DSC Damage

[Matt Krass]

Originally Posted by EricVanWyk

I'm still mildly surprised it caused permanent damage. 5 Amps is a lot, but there is a solid connection to the power and ground planes to wick away the heat. I'm wondering if bonus current is being added to the circuit - maybe from the compressor?

Don't you mean Wyk away the heat?

Joking aside, 5A is a fair amount of current, if it was pulling that much for a long time (in the last few days of build our poor robot was pretty much on nonstop for 15 hour stretches), it seems feasible that the board would eventually start suffering damage. The impression I got from this post:

During testing we discovered that the DSC was bad. We replaced it and continued looking for our perceived short. After burning out DSC #2 we started looking at what was going on with that part of the system. A few changes later we mounted #3 and turned it on.

was that there was a fair amount of time between power up and the actual damage, which may have also been done incrementally?

The 5V regulator for the DSC is the TPS5431DDA, correct? As I see here:
http://www.ti.com/lit/ds/symlink/tps5431.pdf
That is a nifty buck converter, nice high speed switching frequency too
It also has a thermal shutdown, but that is at a (typical) value of 162C, which is pretty high, I don't have the figures on the PCB/resin material to estimate how hot it is getting, nor what temperatures it will tolerate, so could you tell me if that kind of failure is feasible with long term exposure to those temperatures?

If so, perhaps using the (currently disconnected) enable line on the converter with a temperature sensor on the board near the regulator and a comparator to provide a much lower thermal shutdown? I can't imagine our typical operations heat the system that much (but, again, I don't have all the numbers here). Just throwing ideas out there.

Matt