How to change the Vth of a SiC MOSFET Ltspice model

Musk

The technical article in wolfspeed knowledge center https://www.wolfspeed.com/knowledge-center/article/modeling-common-topologies-with-wolfspeed-silicon-carbide-mosfets/

simulates parallelling SiC MOSFETs with different Vth, that is Vth=2V and Vth=3V as figure below

I'm wondering how to change the Vth of a SiC Ltspice model, which parameter in the model should be changed or using other methods to simulate like that in Figure.6

Forum_Moderator

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ZMiller

Hi,

In this instance, the e3 behavioral voltage source (from NET3 to ground) demonstrates the temperature-dependent threshold voltage. You can alter the value assigned here to fix to the Vth to a desired value.

I hope this helps!

Thanks,

Zack

Musk

Thanks Zack,

I have tried but it dosen't work, where can I alternate, just in the lib file or change which value in e3 or use spice order, I'll appreciate if you could give me an example.

Musk

just change in .lib file on e3 or use spice line code?

ZMiller

Hi,

You'll need to adjust this value in the *.lib file. If you want to have access to adjusting it using the spice line you can declare a .param for the threshold voltage inside the *.lib file and access/modify it using the spice line editor. I updated the model for the C3M0016120D to reflect this change and put together a simple circuit that demonstrates how this works - please see the attached zip. You should be able to use the *.lib file in your designs without issue.

Thanks,

Zack

Variable Vth.zip

TBhatia

Hi, I hope that this answered your question. I will close this discussion for now but if you have a follow up question, please "Start a New Discussion" and we would be glad to support you further.