Hi,

I am running a double-pulse test (DPT) using the DPT_Test_Stand_HB example from All SPICE Models\Modules\LTspice\Example Circuits\HalfBridge

I am comparing two cases: one using a SiC power module and another using a discrete SiC MOSFET.

When I zoom in on the switching transient, I can see some differences in the current and voltage waveforms. In the attached figure:

• Left: Shunt current, voltage across the lower switch, and gate signal for the SiC power module.
• Right: The same signals for the discrete SiC MOSFET.

In the literature and examples, the voltage and gate waveforms generally look more similar to the ones shown on the left. However, in the discrete MOSFET case (right), I observe a spike in the gate signal together with a dip in the switch voltage.

Could someone please clarify what is causing this behavior in the discrete SiC MOSFET case? In particular:

1. What causes the spike in the gate signal?
2. Why does the switch voltage show a corresponding voltage dip?
3. Is this behavior expected for a discrete SiC MOSFET, or is there an issue with my model or test setup?

For each case, I have adjusted the load inductance L and the gate resistors Rgon and Rgoff accordingly.

Any explanation of the differences would be much appreciated.

Thank you!