Hi,
I have been using UC3845 for a flyback converter, primary side feedback. I have some problems about the voltage in the current sense pin. According to the datasheet, the voltage can be 1V for maximum. However, voltage of the current sense pin of my prototype can only be 0.4V for maxmum! Some ringing happens in the pin. I don't konw if this is the reason.
Here is the detailed information
I started from a light load. The voltage in the current sense pin is very low, and the converter worked very well. Then I increased the load, the peak voltage in the current sense pin increased as well. Before the peak voltage of the current sense pin reached 0.4V, the converter worked well all the time. After that, when I increased the load. The voltage pin in the "comp" pin achieved it's maxmum, about 7V. The control loop broke down!
Thanks!