DC-DC boost converter where Vout = Vin + dV, tracking input with offset possible?

Hi!

Will really appreciate if you could point me to the following DC-DC boost converter:
I need that Vout=Vin+dV, i.e that Vout will follow Vin with a certain delta V.
Is there such thing?
If not, how can I make it?

Thanks!

Assuming you don't need an isolated boost converter it is relatively simple. Take the output of the divider network in the voltage feedback loop and instead of directly connecting it to the feedback pin on the controller, run it through a summing amplifier and run the dV control voltage into the second input of the summing amplifier.

http://www.electronics-tutorials.ws/opamp/opamp_4.html

Note that the dV will be scaled by the same divider ratio as the feedback resistor divider, so if your boost converted has a Vfb threshold of 1.8V (they vary) and the nominal output of the converter is 18V, then you have a 10:1 resistor divider network. Your output voltage will be 18V + 10 * dV. If you need 18V + dV, then use another pair of resistors with the same values as the divider in the output feedback loop.