UCC21520: Setting Deadtime

Hi Art,

Can you double check if there is already deadtime created by your input device? It is possible that the input you are sending into the driver has deadtime that is stacked with the gate driver's dead time, so please ensure that there is no deadtime on the input signals. 

Another idea may be that the resistor you are using may not be 3k. Double check this resistor. You can try replacing the 3k with 10k and see if the dead time agrees with the calculation, we then can continue based on your feedback. 

Thanks,

Krystian

Hello Krystian,

The customers input device also creates a deadtime of 120 ns. Is there a problem with input deadtime?
Also he checked the resistor, it really is 3.3k.
They believe that it is a problem concerning the under voltage lockout but they are not sure yet.

Thanks!

Art

Hi Art,

What are the voltages supplied to VDD-VSS? The UVLO on the output side will trigger if the voltage falls below  8.7V(max). On the input side, UVLO will trigger if the supplies go below 2.65V(max). Check if the supplies are maintained above this threshold.

Another possibility would be that the dead time from their input device is combining with the dead time of the driver. See what changes if they lower or remove the input side dead time, but keep the gate driver dead time. 

Regards,

Krystian

Hello Krystian,

I am still waiting for the customer response on this. I will let you know as soon as they did.

Thanks!

Art

Thanks for the update. No worries Art.

Regards,

Krystian