Very Wide Input, low outpu non-isolated power supply?

PLS check the link: http://www.powerint.com/sites/default/files/PDFFiles/di152.pdf
The design idea talks about a 3W output,18V-265Vac input.

Thanks a lot for using PI part.

Thank you very much, is it possible to eliminate transformer here?

I guess your input return and output return must be connected together, so buck boost is not a choice. If the input and output return are not same, you can use buck boost, and thus the transformer is not necessary.

I don't need that output and input returns connected together but i don't know how can it be? I'll use buck only by the way.

Your input range is too high for buck to handle that. buck boost is doable if the input return and output return can be separated.

Ok thanks, i'll go the way the appnote describes. Do you know any place that i can obtain the transformer readily or else i'll wind it myself.

For the RDK board and DER board, PI may order some trnasformers from vendors. But for design idea, technician build the transformers at PI.

Thanks again for using Pi part.

Thanks for your help.

thanks a lot!