ELM - White LED Head Lamp

[wellington]

From: ELM

This is a practical white LED head mount lamp (flashlight). Recently many white LED flashlights appear on the market. However, most flashlights require three cells because they are regurating output current with only series resister. The odd number of cells except one is not good, and a margin between VLED and VBAT is too small, intensity of light is affected by variation of input voltage within the battery life. Thus I built a white LED head lamp which operates with two cells and controls output current.

[audioguru]

Wellington,
It not only controls the output current, but it also steps-up the voltage with a DC to DC converter.