MosFet Selection and protection

[pikstart]

Hi!

I am searching for the appropriate MosFet to build an H-Bridge for 40Volts at 15Amps max current. Will drive a coil of about 18mH (a very big 60cm coil of 2mm wire). The frequency that will feed the coil is from 1 to 50Hz.

Unfortunately all MosFets I found have not the SOA that is needed for such a slow signal and such a high current.

Also what is the best protection of the MosFets from the coil kick? TVS, diode or zeners? And how is this calculated? Have not found calculations anywhere, just the need to add such protection. For a small project any power schotky might be OK, but at 40Volts/15Amps?

Thank you,
Ioannis

 

[danadak]

Not sure if this might be of interest -

https://www.st.com/resource/en/application_note/an4892-vipower-m05-hbridges--hardware-design-guide-stmicroelectronics.pdf

Regards, Dana.

 

[pikstart]

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