DC/DC converters are 36-72V Input, 5V Output, Isolated and 20W. Could you
please give us any aplication note or solution to do it?
Our ADP1621 flyback controller can be used in such an application. Since you
are looking for a low cost solution and considering the output power a flyback
design would be applicable. Please see attached an example of a 20V to 56V
Input 5V output design. You will need to slightly modify for the higher Vin and
will need to increase the power on one of the 5V rails and take the second rail
off. The example does show a very similar solution however.