Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It's 100% free.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have the following schematic powering my circuit. enter image description here

Is it required that I protect the USB power pin with some fuse?

share|improve this question
up vote 3 down vote accepted

It looks like your device is a target as opposed to a host controller. As such your device would be consuming power off the USB cable. So generally it is not necessary for you to put a fuse in the 5V path from your USB connector. You could add it but it would be more for protecting against faults inside your target device.

On the other hand if your device was to be a host controller where it is expected to source power from in internal power source out to the USB connector then you would want to provide some current limit protection. How you choose to do that will depend upon your application but choices could include fuse, resettable polyfuse or one of the various USB power switch/current overload detector chips. Any of these will protect your host device in case someone plugs in a bad cable / device that happens to have a short in it.

share|improve this answer
Yes my device will draw power off the USB of the PC. Thank you for the answer. – Demetris Mar 9 '14 at 12:43

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.