Hi team,
Posting for a colleague:
Currently working on a bias supply using the UCC2889 controller running from 600-1200Vdc. I’ve run into some issues regarding the Line Voltage Detection and unexpectedly long on times.
The supply as currently designed was expected to have a maximum line voltage fault threshold of 545V, with a typical threshold of 436V. The part appears to be staying in the line voltage detection fault state until nearly 600V. Ron is 1.8Meg.
The supply also has longer than expected on times. Measured on time is 4.36µs at 600V and 2.61µs at 1200V. Expected on times are 3.77µs and 1.878µs. Ron is 1.8Meg, Ct is a 270pF NP0 ceramic, Rs is 1Meg.
Any idea what could be causing this?
Thanks,
Nate