Open LED Protection Leads to a Bright Future for LEDs

Thanks to declining prices and global government mandates to reduce energy consumption, light-emitting diodes (LEDs) are about to shine even brighter. They're now being used in many different lighting applications for important purposes, such as traffic signals and airport runway lighting. 

There's just one problem.  LEDs are very fragile devices — they're notorious for it. Thankfully, there's a solution: open LED protection technology.

Image via ledgrowlightstesters.com.

Open LED protection technology   

Designed as an electronic shunt, which provides a current bypass in the case of an open circuit caused by a single LED failure, open LED protection technology works as an internal dual-centered device. The protector is a voltage-triggered switch with low leakage on the order of microamps that becomes a low-impedance switch when triggered on, which minimizes power consumption. These systems lie parallel to the initial LED circuits and jump in to replace a single LED when it drops more than 0.7 V.   

Applying open LED protection

Open LED protection is easy to employ into just about any design. A protection device is placed in parallel with each LED in a string. Because a single LED failing by an opening in a string of LEDs will most likely cause a partial or full loss of the entire string, open LED protection provides a shunt current bypass around the open LED, saving the string from partial or complete failure. 

Conclusion   

Even though open LED protection technology isn't guaranteed to be able to completely save a whole series every time an LED fails, the idea is that the current bypass around the LED will be protected, saving most of the series during an LED failure.

For more information, see Littelfuse's Open LED Protection for LED Strings Application Note.  

By Emily Bahr

Littelfuse has created an Exploration & Discovery Experience for the engineering community as part of its 2013 Speed2Design program. Winning design engineers will get the opportunity to spend time with NASA engineers at two NASA facilities and learn about the latest in space technology. For more information and to enter, visit speed2design.com.