PMP20127: How to modify this design PMP20127 to support 600V DC in ?

PY,

Unfortunately to change this design to 600V input would require significant changes. This includes the transformer, power MOSFET and clamp circuit. PMP7958 and PMP5067 can be referenced, though they are for higher power. You can also use TI's Power Stage Designer 4.0 tool to look at the changes needed for PMP20127 to support a higher voltage. http://www.ti.com/tool/POWERSTAGE-DESIGNER

Thanks,
Ryan