Question about regulation

I have a question. Regulation means that the regulator adjust the voltage between such a voltage range and the brightness will be the same within that range. But how does this work when it comes to Maglite 2 and 3D?
The TLE-6EXB TerraLUX MiniStar5 provides around 100 lumens with 2D and 140 lumens with 3D. How is that possible? I mean the regulator cannot know how many cells are used in the flashlight. Or? After a while when the voltage of 3 cells will drop to the level of 2 fresh cells the brightness ought to drop to around 100 lumens. Does the regulator have 2 levels so it provides 140 lumens above 3 volts and 100 lumens below that? Or does the regulation work only for 2cells?

Regards, Patric

It depends on the circuit. I don't know about that board exactly, but if it's a boost (necessary for 2-cell operation), it'll increase the battery voltage until it's high enough for the LED to use. Some boost circuits allow you to use a battery of higher voltage than the LED needs and just direct drive (DD), which feeds current straight from the battery (at whatever voltage it's at) to the LED. When battery voltage falls too low, it'll start boosting. Other boost circuits will fry if battery voltage exceeds LED voltage.

And yes, they can know how many batteries you're using, or rather, the voltage of the battery, either through a sense resistor, or simply different behavior on various voltages.