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Showing posts from June, 2018

Current limiting for battery protection

Having figured out how to add under voltage shutdown, and reverse voltage protection for lithium battery powered modules, I obviously also need to look at over-current protection: I don't want a motor stall to set a battery on fire. Current limiting with discrete components isn't that hard, but it involves lots of components and lots of testing. The result is probably just too big. I wanted to see if there was a reasonably priced integrated solution. Anyway, it's worth observing that accuracy of a simple transistor pair is ±30%, just to set expectations on accuracy. These turn out to be called smart switches, or current limit switches. It's not easy to do parametric search on these: they have different features, as well as basics like current, voltage handling and Rds(on). Some searches: Farnell Some of these have current feedback. I.e. they have a pin which is a current source that's some fraction of the output current. They all have thermal shutdown to