UCC 28070 Aging-damaged Mosfet problem: UCC28070 is PFC, input voltage 180-265VAC, output 390 V 7A, MOS damage occurs in aging test, both MOS will be damaged. UCC 28070 Aging.docxPCB FILE.pdf
Hi user1932012
The component values in your schematic are not right.
For example the resistor setting the switching frequency is the same value as the resistor setting the max duty cycle.
This will give you a Dmax = 1
This will cause the current transformer and possible the boost inductor to saturate.
Allso I notice that the divider ration on VINAC and VSENSE are very different.
There may be other component values that need to change.
My suggestion is that you read the data sheet for the UCC28070 and use the Excel calculator tool for your application.
The calculator is located here:
http://www.ti.com/product/UCC28070/toolssoftware
Also I suggest you disable the dithering feature while you troubleshoot your design.
This will make it easier to view your switching waveforms.
Regards
John
