I have a symmetrical voltage input I need to protect agains reverse polarity, and over-voltage.

Here is the reverse polarity protection I designed. Is it correct ? I can't find much information about symmetrical voltages circuitry…

reverse polarity protection

For the over-voltage protection, I'm thinking about that: (with two 16V zener)

over voltage protection

What do you think about that ? Did I miss something ?


When you apply a positive voltage to Vin-, the body diode of Q2 will conduct and you will get the positive voltage minus one diode drop on your -12V signal.


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