DC DC converter 105V to 12V at 500mA

what is your input voltage range? is this going to run only at 105 VDC +/- ?

I am sorry for my previous answer. I did not realized your input voltage range is from 60 to 105VDC.

You can use the DPA family. There are so design examples in the reference design section

http://www.powerint.com/en/design-support/reference-designs/design-examples

Your input voltage is little to the high side. Is ok as long as you maintain your drain voltage below 220V under any condition.

In looking through the design examples I'm having a hard time finding somethign that meets my input criteria, I find inputs of Vmin=85Vac but that translates to 120Vdc which my min is 60Vdc.... any suggestions? I think mhy input voltage range is making this design difficult

You need to look the DPA controller examples design. I know there is not any one that meet your specs. You need to take as a base any DPD design.

You need to download PI expert program.

http://www.powerint.com/en/design-support/pi-expert-design-software

This program will help you to design your transformer and key components for your design.

you need to spent some short time in getting familiar with the program. Once you enter your needed specs, the software performs some calculations and gives you suggestions, tips, transformer design for you to implement your power supply

I'm having some trouble understanding how the voltage at the Line Sense Pin is determined, looking at the DPA422-426 family datasheet the max voltage limit for this pin is 9Vdc, now this pin connects to the input DC voltage through a resistor which can go between 16-75Vdc How do I calculate what the voltage at the pin is? I'm trying to figure out how to make this work for my 60Vdc-105Vdc range.

thanks

Datasheet
http://www.powerint.com/sites/default/files/product-docs/dpa_family_datasheet.pdf

Did you see pages 22 and 23 of the data sheet? the voltage is about 2.3 to 2.5 volts