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UCC21750QDWEVM-025: About Soft turn off, Activer Miller Clamp operation

Part Number: UCC21750QDWEVM-025


I have measured soft turn off waveform during DESAT operation as below image.

I have few question about this waveform.

1) I wonder if the soft turn-off action means the entire GATE voltage from 15V to VEE with large fall time or the GATE voltage slowly drops as the slope changes around 300ns.
2) Can we check the active miller clamp movement here? Is it because of the active miller clamp motion that the slope changes at the GATE voltage - VEE voltage = 2V point?

I think there are a lot of questions due to lack of understanding of this part. I'd appreciate an answer.

  • Hi Yoonjin, 

    Soft turn-off means that OUTL is continuously sinking 400mA current when DESAT is detected. As of why the slope is changing at around 300ns, it is because the miller clamp is "activated" and more current goes into the miller clamp pin, causing the slope change.