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Backlighting for Optimized Color RGB LED driver solution

by Man Lau, Senior Application Engineer, National Semiconductor, Hong Kong, Power Systems Design Europe, May 01 2009

Focus:
When using LED backlights in midsize TFT LCD displays, RGB LEDs can improve display quality versus white LEDs. That's because RGB LEDs make it possible to achieve a better NTSC color gamut and also perform color correction. This advantage can be particularly beneficial in applications such as electronic photo frames. However, the LED driver design is more complex than that required by white LED backlights. A reference design is presented here for an RGB LED driver for backlighting the LCD display in a medium-size (7-inch) photoframe. The design is based on the LP5520 driver IC and some additional components that allow it to drive 15 RGB LEDs. The article includes a calibration procedure that ensures the LEDs produce truly white light over temperature.

What you’ll learn:

How to build an RGB LED driver for backlighting medium-size LCD displays
How to calibrate an RGB LED driver to achieve uniform white light over temperature

Notes:
This article from the May 2009 issue is found in the Power Systems Design archive. To access the archive, you must log in as a member of the PSD Community at www.powersystemsdesign.com/signup.

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