Part Number:UCC28634
The working region of UCC28634 is divided into five regions, in which the switching frequency and the voltage Vcs at both ends of the sampling resistance also have mutual restrictive relations.With the current board and transformer, as the load increases, it is clear that UCC28634 moves from the first workspace to the fourth, but the fifth workspace clock does not arrive.Our application very much needs the double power property of the fifth workspace because we have a lot of instantaneous power, but we don't work very long.
We refer to the official "reference design of 160W primary side stabilizer flyback using UCC28633", only the transformer and sampling resistance and the partial voltage resistance on VSENSE are adjusted.When the power is large enough, the chip can enter CCM mode；The turns of my transformer are main 36 auxiliary 4 secondary 9；