RGB LED Strip Short / Over Current Protection

Please be gentle.

I am looking for information on how I might go about creating an over current / short protection circuit for and led project I'm playing with. I've looked at several different methods, but cant quite get my head around how to implement.

I am currently using an Arduino along with 3x N-Channel mostfets to dim a 5 meter piece of 24v RGB led. I've looked at several different method of protection, but I cant quite figure out how to do it.

Any information / pointers / links would be gratefully recieved!

I assume you're talking about the 24V to the LEDs, and you want to protect the MOSFETs?

A fuse will probably work. A fuse won't always protect a transistor or MOSFET, especially in "linear" applications.... There's an old joke about the transistor blowing in order to protect the fuse. :wink: But in switching circuits, a fuse will probably work, especially if there is some safety margin in the MOSFET rating.

I made a "foldback" current limiter a long time ago, but I don't remember how I did it... It may have had something to do with a series current-sensing resistor across a transistor's base-emitter junction. Then, I guess the collector-base would "short out" the B-E on another transistor, turning it off...

Of course, it all starts with some way of measuring current or "sensing" an over-current condition. And, any series resistance (usually needed to measure current) will cause a voltage-drop, affecting voltage-regulation.