For isolated DC/DC converters, a number of topologies is available. To start with you may consider the following page: http://www.ti.com/lsds/ti/power-management/offline-and-isolated-dc-dc-controllers-and-converters-products.page

What might make "things" a bit challenging is your input voltage range. Considering these figures: is this voltage from some PV panel? If so, searching for PV DC/DC applications might help to speed-up your task.

Hope this helps

Infact, I'm looking for DC/DC converter module as a package. It's for BMS application wherein battery cells at min number should also be working. 

I know about some BMS DC/DC converters, but all are customer-specific and with different voltage levels (nom. 48 V resp. nom 200 or 400 V). And your output voltage is quite 'special' as well.

Ad hoc I could recommend a german company ( http://www.syko-power.de/Englisch.htm ). I currently could n9t come up with a perfect fit, but you are free to ijvestigate on your own. If you need more tzan a single piece, these guys are up to modify one of their standard units according to your specific needs.

I worked with some of their products before and recommend them as being feasible, robust and long-living.

Regards

I has good experience with murata dcdc converters ttp://power.murata.com/en/products/dc-dc-converters/isolated.html.

you can used CUK converter with isolation circuit it is good in contains current or you used the current mode converter circuit.