Jpanhalt is absolutely correct on the MOSFET body diodes. There are, however, MOSFETs with enhanced body diodes, and for applications like this, I always prefer MOSFET with proper avalanche rating. This means the MOSFET can break down (avalanche), and survive, provided you designed the circuit in such a way that the integral of the current through the MOSFET, while in avalanche mode, is sufficiently small.

EDIT:Iforgot; zener diodes are completely useless for limiting large voltage spikes, because they are simply to slow to react to a high voltage condition. Transorb diodes are much better in this application, and are specificially designed for such duties.

I truely don't have a clue as to what Nyemi is trying to say. It is just me, or are his posts completely devoid of anything sensible to all of you?


As I already told bigboat on the dutch forum, such things tend to take a while, because I always have many concurrent projects.

I have a nearly complete design in text, and I think I have everything covered. It's just waiting to be implemented now, which shouldn't be to hard; the design is the important and difficult part, the implementation should be relatively easy, if the design is good and complete.

With a little luck, I'll receive some PIC development tools tomorrow, otherwise I'll probably get them on monday.