Smallest DC Power Control Circuit Possible

[LongToes]

I am working on a solution for a model train control circuit. I need to create an extremely small circuit that will take 12V-18V A/C input and convert it reliably to 11V-12V DC. Since it is going in the body of a very small toy, the components and circuit must be as compact as possible. This circuit will be married to other control circuits that require a clean DC input.

I have made plenty of rectified circuits before, my issue is purely size. What components would be best to achieve the smallest possible design?

Thank you in advance!

[KMoffett]

Rather than going through several suggestions followed by "that's too big"... what's the maximum dimensions that you can use?

Ken

[LongToes]

The largest dimension would be 0.5" x 0.25' x 0.2". Even smaller would be better. it should be rated for a minimum of 1.0 Amp and 1.5 or 2 amp would be better.

[KMoffett]

So, 12-18VAC (50-60Hz?) in, rectified, filtered, regulated down to 11-12VDC at 1-2A out, in a 0.5" x 0.25' x 0.2" space! I doubt that's going to happen. The rectifier and filter capacitor will likely be bigger than that. The closest regulator I could find with a quick Google search ("tiny DC-DC regulators") was this: http://gglabs.us/node/19. You might have better luck. But, with 12-18V@1-2A in you're going to need a big filter cap.

"Ye cannae change the laws o' physics" (Scotty...Star Trek)

Ken