High current reverse polarity protection

Thread Starter

electrovrbek

Joined Jun 20, 2023
7
Hello,

I am new to the field of power electronics and I have a question regarding reverse polarity protection for high current applications. Specifically, I am working on a system that controls working lights for heavy machinery, with a total current to the PCB of approximately 80A at 12V.

Currently, I am using the reverse polarity protection circuit shown in the image. It functions well up to a current of about 40A, but anything above that causes the MOSFET to become excessively hot. I have attempted to address this issue by using three MOSFETs in parallel, but unfortunately, it has not made significant improvement.

I would appreciate any guidance on whether there is a more effective method for implementing reverse polarity protection, or any suggestions on how I can enhance the current circuit to improve its performance.

Thank you,
Aleksander

Reverse_polarity_01.PNG
 

crutschow

Joined Mar 14, 2008
34,468
That shows four MOSFETs in parallel, so each should dissipate only about 1/4th that of one.
What is the MOSFET's on-resistance?
 

Thread Starter

electrovrbek

Joined Jun 20, 2023
7
I will try using a MOSFET with a lower Rdson resistance (the current one has Rdson = 3mΩ), and I will also mount a heatsink on it. This should likely improve the performance.

Thank you to everyone for your help and support!
 
Top