Electronics > Beginners
Recommend overcurrent protection circuit
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tm:
Hi all - I have been following EEVBLOG for a while and glad to post my first question here.

I am trying to add overcurrent protection (and nice to have voltage protection) circuit to one of my design to limit them to 12V and 1.5A. I did some research on using fuse, PTC and protection circuit and wondering if I can have a guidance. I think PTC is too slow and prefer not to use one time use fuse (though, it is ok for my application).

So, I am looking into find a protection IC that I can use. I find many of them and don't know which to choose from so I am wondering if there is such a jelly bean part for this?

spec:
Hi tm

One of the simplest over-current protection devices is a resettable fuse. The data sheet for a popular range of resettable fuses is here: https://www.bourns.com/docs/Product-Datasheets/mfmsmf.pdf

If you then put a power zener diode across the voltage rail after the fuse you will have over-voltage protection too. An alternative to a power zener diode, is a low power zener diode (normal) and a power transistor.

T3sl4co1l:
What's the power source?  Load?  Allowable peak current?  Response time?

Example, a small SMPS source probably won't deliver enough fault current to clear a fuse.  But it's current limited anyway, so it doesn't matter.

If you don't know the answers to these questions, then to what end are you looking?  If it's protecting wiring, any fuse will do.  if it's protecting transistors, an active current limiter (or voltage crowbar, as the case may be) is needed.  There's an answer for everything, but finding the correct one requires more information. ;)

Tim
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