DC/DC converter with efuse

You are looking for integrated solution with 48V input, 12V output and up to 3A output current with programmable OVP?

Yes, But I would like to see the practical size with current technology.

I am not aware of anything that we have with programmable OVP (maybe a PMBus feature?). Why are you interested in programmable OVP? Can you elaborate on your application and why it is needed?

It would be something like Smart FET with integrated converter. You can call it Smart converter, maybe. It would have some many applications in car distribution systmes

Searching for "Smart FET" does not return any results. If you are looking for a solution similar TIDU533, that application uses several different ICs to implement the voltage scaling and changing the OVP. You probably do not need to change the OVP. The OVP for most converters operates internally as a percentage of the fed back voltage, so it automatically "scales" as you change the output current. You could start by looking at TPS54360 or TPS54361. You can scale the output voltage using the techniques in TIDU533. Let me know if that helps answer your question.

Check it
www.onsemi.com/.../TND394-D.PDF

If you wanted to use a controller I suppose you could design with those FETs...