Hello,
UCC28911 is used as follows:
VIN: 270V ~ 370VDC
VOUT: 14V/100mA x3 secondary outputs
Lp = 3.3mH
Lk = 31uH
NPA = 5.51
NPS = 6.96
Schematic is attached.
An Intermittent Operation is observed where the chip will work for a minute before it restarts. The following waveform shows a sudden increase in the primary current (blue trace) and an extended demagnetization period. I was wondering if that due to Lp = 3.5mH.
What is Lp max UCC28911 can tolerate?
I wasn't able to probe VS or IPK pins. The chip will act up when connecting a probe to those pins. What is the best way to probe VS? I tried a 5K series resistor with the probe but didn't make a huge difference.
Thanks
WB