DESAT SiC MOSFET protection

[abhishek.2138]

Hello,
For the DESAT protection in below schematic -

The Vdd = 20V & ICHG = 500uA current source.

As zener diode require some reverse current more than 1 mA, If zener value = 3.9V, will this zener is regulated with such low current value.
Also if Rlim resistor is added it will further reduce the current below 500uA.

Can anybody suggest will this DESAT protection work effectively.

 

[FvM]

Protection resistor Rlim is standard in desaturation protection, Dz makes no sense, I think.

Generally, it's difficult to achieve effective desaturation protection for MOSFET because they don't show (other than IGBT) clear current limiting behaviour. Check the SOA of your MOSFET if desaturation protection can work.