How to implement dc-dc 12v for wide input voltage 3..40v

[Terminator3]

I need some design idea. I thought about implementing two circuits for step up and step down and switch between them somehow, any better ideas?

 

[umesh49]

You may need to look for some sepic converter based topology. It first does a boost operation then a buck operation.

 

[goldsmith]

Hi all
Yes i agree with umesh49
A sepic converter will suit the aim as well . but how much is your maximum required current ? can you tell more about what you need ?
Best Wishes
Goldsmith