I am looking for an autoranging front-end circuit to convert a
universal AC input ( 90-265VAC ) to an unregulated DC voltage ( in the
range of 220-400VDC ) to power some DC supplies at 90 Watts.

It seems that such a front-end should operate as a doubler/rectifier in
the lower AC input voltage ranges and as a simple rectifier in the
higher AC input ranges.

I have not found anything like this on the market except for Vicor's
FARM which is 1000 Watts and overkill ( both power and pricewise ).

Any ideas will be appreciated.

Best Regards

Oguz