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Can you place two MOSFETs in series to increase teverse breakdown voltage?

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satyamfifa:
Hey All,

I want to use P-channel MOSFET to provide reverse polarity protection up to 32V, so can I simply use two 20V breakdown MOSFETs in series?

Kind Regards,
Sparsh

inse:
I think it would be easier to use one MOSFET with appropriate D/S voltage as you would have to supply a separate independent drive circuit for the second MOSFET.

niconiconi:
Yes, you can. But you must add static and dynamic voltage balancing circuits. First, to force the leakage current of each transistor to be equal, each transistor must have a megaohm resistor connected in parallel. This is called static voltage balacing (inevitably, the drawback is the creation of a high leakage current, since the resistors are always on). Otherwise an uneven leakage current means the transistor with the lowest leakage would experience the highest voltage and explode, the cycle repeats until all transistors are destroyed. Next, each transistor must also have a resistor-capacitor snubber network connected in parallel to suppress transient overvoltage at switching. This is called dynamic voltage balacing.

This is usually a special technique for high voltage applications when suitable transistors are unavailable. It's not recommended for other uses.

JustMeHere:
Should act like diodes in a series:
https://www.daenotes.com/electronics/basic-electronics/diodes-in-series

Terry Bites:
You certanly can. Adding the second MOSFET here doubles the breakdown point from -20 to -40V. but, as pointed out, why not use a 50V device from the start.
The disadvantage of adding a seond device is that you double Ron.

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