UCC21750: Is there a benefit to connecting the CLMPI pin to the Gate when using a bipolar supply

David,

Generally, bipolar supply on its own is considered sufficient to prevent false turn-on when driving IGBTs.

It can depend on the dv/dt, IGBT size, and VBUS voltage/ power level. If you expect these to cause some charge injection, or expect some ringing at the gate caused by that, better to connect it. By providing the device with extra low impedance path to VEE, it would only just help keep the gate even more stable to VEE during turn off. If youre driving an especially large IGBT the miller capacitance will be larger so it has more potential for charge injection to gate during switching off, which is increased when switching faster and at higher VBUS

There shouldn't be a drawback to using internal miller clamp (maybe in some cases a CLMPE (external clamp control offered on other UCC217xx devices would be preferred), and its designed to be used with conjuction with bipolar supply.

Since not knowing specifics of your design, we do have some info from one of our EVMS using Miller clamp with bipolar supply 15/-8V with and without miller clamp and comparing impact on gate voltage transient.

The comparison is at the link below. Should help to give some real-world data

https://www.ti.com/lit/ug/tidudg6/tidudg6.pdf#page=24

If this answered your questions please let me know by pressing the green button, let me know if you have any further questions!

Best

Dimitri

Thanks for the response