To all concerned
I would like some advice on the transformer design when using the UCC28780.
For high frequency switching (over 400kHz), we are thinking of using RM8 (corresponding to material N49) as the core.
In fact, the ON Semiconductor NCP1568 application note recommends N49 (or ML29D) and shape is RM8.
(I think the UCC28780 and NCP1568 are competing devices)
However, there is one question. Both your evaluation board (UCC28780) and NCP1568 evaluation board directly take out the wire on the secondary side without using a bobbin.
Why are you directly using the wire without using the bobbin?
Is it because it cannot be cleared from the viewpoint of safety standards?
Or is there another reason?
Due to the small size of the core, it makes sense to use triple insulated litz wire.
Please tell me any other useful tips for transformer design.
Also, I will get all the pins from the bobbin.
Do you need shielded wires?
Considering Lp = 40uH, I feel that Ls = 3uH has a slightly larger leakage inductance. Is sandwich winding recommended?
For now, I would like to use RM8 or EER25.
(200W / 32V / 85V to 276V, single output)
B.R. Tak
