DESIGN IDEAS Boost Converter Drives 1A White LEDs
by Keith Szolusha
White LEDs are brighter and more
powerful than ever. High-power white
LEDs, because of their extreme luminous density and ultra-compact size,
are replacing conventional bulbs in
flashlights, headlamps, streetlights,
and many automotive applications—
anywhere a conventional bulb might
be found. Some new white LEDs,
such as Lumileds’ Luxeon™ series,
improve on conventional bulbs in several characteristics, including greater
luminescence, improved response
time, and increased durability with
decreased size and cost.
The challenge in using white LEDs
in portable applications is powering
them with the wide input voltage range
that batteries present, such as 3.3V to
4.2V from a lithium-ion. LEDs require
constant current to maintain constant
luminosity. The battery-LED DC/DC
converter must both step up and step …