Low power lighting system with LED illumination

摘要

A DC-DC converter is configured as a constant current source to drive an LED load. This circuit configuration draws constant power from the input supply and delivers a constant current to the light source. A wide range of output voltages can be supported due to the implementation of current feedback for closed loop control. This allows for a selectable number of LED's to be powered simultaneously in a series configuration. Exceptional battery life is achieved due to the constant power discharge mode achieved with constant current feedback control. LED's powered at a constant current maintain a constant brightness level throughout the life of the battery.