I have a question I’ve been meaning to ask, but before that I need to preface it with a statement that needs confirmation: the current corresponding to a particular forward voltage is the MAXIMUM current that the LED will take @ that voltage, right? In other words, at that forward voltage, the LED can be powered by anything equal to or less than that max current.
If so, is it possible to design a driver for 1x18650 and 3V LEDs, that instead of bucking the voltage, feeds the full cell voltage to the LED (minus any voltage losses), BUT varies the current to provide constant WATTAGE to the LED, thereby providing constant output? At any output level, as the cell voltage drops, the driver draws more current to keep wattage constant, until the cell can no longer supply the required forward voltage needed at that output level. Then the driver drops to the next lower output level, which requires a lower forward voltage, and the cycle continues.
Would this kind of driver be more efficient than a buck driver?
How would the current variation be achieved?
Would the means of varying the current introduce additional losses that would negate any gains, assuming there are any to begin with?