Part Number:UCC28070
Hi,
We are using UCC28070 IC for power factor correction in our on board charger design whose rating is 1kW. while evaluating PFC circuit we observed that for a very low load current also IC is firing mosfets with more than 50% duty cycle and also the output of PFC (420V) is droping from 420V to 330V. Seams its duty is getiing saturated. We have selected all the components as per the excel calculator except for current transformer (we have used shunt resistor of 120mohm). Please suggest what could be the reason.
I am attaching our calculation with this post as well as plots captured on GDA and GDB.(Please visit the site to view this file)
