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I am struggling to tune in the RG_on and RG_off values of gate resistors for SiC MOSFET. I have tried a lot to tune in the values but at turn off transition there is persistence high frequency ringing which at low switching currents are not causing any huge impact but as soon as I switch high power, it causes false turn on as magnitude of that ringing is very close to threshold voltage of SiC MOSFET. Anyone can recommend any good literature? I read few papers but the strategy they have written either I am unable to understand or its not applicable on my case. Thank you Attached is the schematic of my design.

Attached here is the oscillogram when I switch 800V and 10A. You can see persistent high frequency ringing which is roughly 5 to 6V which is more then threshold voltage of this sic mosfet

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  • \$\begingroup\$ What is your gate driver? Are you driving the gate negative to turn it off, as is usually recommended for SiC parts? \$\endgroup\$
    – Hearth
    Commented Dec 5, 2023 at 16:31
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    \$\begingroup\$ I would probably design a snubber circuit to address the ringing and help you filter out that behavior. What is your design here? Perhaps you should probably resort to the datasheet of your FET and look at the frequency responses as you set parameters for RG. \$\endgroup\$
    – user319168
    Commented Dec 5, 2023 at 17:06
  • \$\begingroup\$ It sounds like your issue is something beyond a mere gate resistor. What have you determined about the switching loop, particularly stray inductance? \$\endgroup\$
    – Tim Williams
    Commented Dec 5, 2023 at 17:24
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    \$\begingroup\$ Please provide you PCB layout \$\endgroup\$
    – John Birckhead
    Commented Dec 6, 2023 at 3:13
  • \$\begingroup\$ @Hearth I have added my schematic and result for your reference. I am noy using negative turn off voltage infact i am turning off at 0V \$\endgroup\$
    – Alison
    Commented Dec 6, 2023 at 7:47

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