Other Parts Discussed in Thread: UCC21225A
Connection of the DT input to VCC_1 is supposed to disable dead time logic so that each output is simply related to each input of the dual channel part. However, simply connecting the pins in the simulation always hangs the modeling – the simulator modeling solver fails – and it appears as if the dead time logic remains enabled when the simulation is able to run long enough to tell.
However, connecting the DT to a voltage source just 5mV above VCC_1 allows the simulation to work properly and, importantly, without failing any more than other TI models I have worked with.
Modifying the model by inserting a 5mV voltage source to the DT input node of the model to increase the DT input node by 5mV fixes this behavior.
I would think it would not be very hard to repair the model. i would hope that TI would repair the model in a way that doesn't alter the DT input voltage which is may need to be done to accurately program the dead time when the part is used in a mode that implements the dead time logic.
The model for the UCC21225A also exhibits this same behavior and I was able to repair it the same way I did for the UCC21520.
Thank you very much,
David Fiori, Jr.
215-584-2214 (cell)
