MosFet Selection and protection

Not sure if this might be of interest -



Regards, Dana.

Hi Dana.
Thanks for the link. Lots of good info but not on the protection of discrete MosFets. Rather a presentation of the ICs that ST carries as a compete chip solution.

Ioannis

Some snubber design info, attached.

TVS you can google that as well.

At the bottom end of the 1 - 50 Hz frequency range, 15 A will be achieved with a much smaller voltage than 40 V.

At the top end of the frequency range, 40 V won't give as much as 15 A into an 18 mH coil.

How are you intending to control the current?

Hi Diver300,

you are right about that. The current cannot be the same in every voltage set (1-40volts) or any frequency (1-50Hz). Also I do know that the coil will be saturated in many combinations, but this is what the requirements need.

To protect from overcurrent I will add a shunt resistor to shut off the MosFet drivers.

My concern is if there is a fullproof way to select the proper components for such working conditions.

In a smaller projects I just selected the diodes in the H-Bridge as Vf> V/R and Vrev-blocking>2*Vsupply. And power dissipated to the diode (Vf*i) < diodes rated power.

But here I have a beast coil! Want to be sure.

Ioannis