A flashlight is provided. The flashlight includes a LED light source, a power circuit that provides power to the LED light source and a buck and boost power controller within the power circuit in series with the LED light source where the buck and boost circuit boosts a battery voltage to the light source...http://www.google.ca/patents/US7581848?utm_source=gb-gplus-sharePatent US7581848 - Flashlight with replaceable housing
