Kickback diode heat

Thread Starter


Joined May 19, 2008
This is the second generation board I have built for a project. The first board had a simple MOSFET, part number FDD20AN06A0. It is now obsolete. I thought this would be a good chance to try another type of MOSFET that has current sensing functionality built into it part number, BUK7108-40AIE.

It works great and I am still working out the current sense side of the MOSFET. The one thing I have noticed is the kickback diode/rectifier runs alot hotter with this MOSFET. Part number BYV32EB-200118

The MOSFETS are literally the only thing I have changed on the board besides adding components for the current sensing. The current sensing is independent of the true Gate, Source, and Drain of the MOSFET on this type of MOSFET. I switch the MOSFETS at 1000hz now. I have tried different frequencies and that didn't seem to help.

Is the BYV32EB-200118 not suitable for this deal and I just got away with it on the old board?

The MOSFETS are overkill for the application but I have the room on the board and don't mind being overcenter on the MOSFETS. The MOSFETS power DC brushed 12 motors consuming around 2.5amps.

Any input/advice is appreciated.