I am looking to add overvoltage protection to a circuit of mine.
A standard way of doing this is with a crowbar circuit with a fuse to blow when tripped, thus disconnecting the circuit. However, I don't want to have to deal with replacing blown fuses. This leads to looking at resettable polyfuses.
However, I'm concerned about the condition where the overvoltage is maintained for a period of time - this would lead to the intended effect immediately, followed by a period of no current through the polyfuse, allowing it to cool, at which point we eventually get to a point where enough current flows to raise the voltage past my tripping point and the process repeats until the overvoltage is removed - this seems like unnecessary stress on the components.
Is there a better way of managing this situation? I've not really used polyfuses before - how long do they take to "reset"? The datasheet of the one I'm looking at doesn't mention this at all, but perhaps the period is long enough that it wouldn't really matter.