Boost converter LED drive systems for emergency backup lighting

Dec. 6, 2007
In the third in a series of articles on power converters, Iain Mosely describes how the Boost converter switching topology can be used to drive LED systems for emergency backup lighting.
The Boost converter switching topology can be used to drive a series string of LEDs with constant current when the available system input voltage is lower than the required combined forward voltage drop of the LEDs.

For an introduction to switched-mode power converters, see LEDs Magazine July/August 2007 p9 or

Many security or emergency lighting applications use a lead-acid battery to provide power during a mains power failure. In these applications, the battery terminal voltage could be 12Vdc or 24Vdc and series string of LEDs may require a combined forward voltage in excess of this value.

The design presented in this article runs from 12Vdc to 24Vdc input, driving ten series-connected Luxeon K2 LEDs at 1A with an electrical conversion efficiency of 95% and 35W total output power capability.


This article was published in the November/December 2007 issue of LEDs Magazine.

To read the full version of this article, please visit our Magazine page, where you can download FREE electronic PDF versions of all issues of LEDs Magazine.

You can also request a print copy of LEDs Magazine (available by paid subscription) and sign up for our free weekly email newsletter.