Boost converter LED drive systems for emergency backup lighting
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.
For an introduction to switched-mode power converters, see LEDs Magazine July/August 2007 p9 or www.ledsmagazine.com/features/4/8/4.
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.
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