A Holistic Approach To Reducing Backlight Power Consumption

Focus:

Long battery life is a key metric in the portable electronics market. The LED backlight driver for LCD displays account for 25% to 40% of the total active system power. In the past, the tools a designer had to minimize backlight display power consumption were limited to decreasing the LED driver current and increasing the converter efficiency. Today, power savings of up to 50% are possible by using LED drivers with an optimized converter in combination with ambient light sensors, and content adjusted backlight control (CABC) methods. These techniques can enhance driver efficiency without severely degrading the visual quality of the information on the display. The article begins by discussing the two common choices for LED backlight driver architecture—inductive boost or switched-capacitor boost—explaining where each is used and the issues that arise when trying to optimize their efficiency. Then, article explains ambient light sensing and dynamic backlight control (a.k.a. content adjusted backlight control) and discussed their benefits. A design example using the LM3530 inductive boost driver.

What you’ll learn:

• How to reduce the power consumption of LED backlights in portable device designs

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Author & Publication:

Greg Lubarsky, Texas Instruments, Santa Clara, Calif., How2Power Today, Oct 27 2011

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