When you look at today’s smartphones, or phablets and you see that the screens are getting bigger and bigger, do you realize that the display is what is taking up most of the power in the system?  

Take a look at this screen shot of a Galaxy Tablet running the Android operating system…  

Clearly you can see that the screen is what takes up the most power. Minimizing the power required for that part of the system directly impacts the battery life. Now, if you have kids, they have probably showed you that dimming your screen will make it last longer. But what if you are in the bright sun all day and need the brightness?

Choosing the right backlight device and the right configuration can make all the difference. TI’s LM3697 allows the designer to use 1, 2, or 3 strings to configure the LEDs for the backlight of the display. The more strings you can use, the lower the boost voltage, and the better the efficiency. In this simple example, you can see the impact of using 2 strings to drive 8 LEDs instead on 1.

On average, you can save up to 4% of the power used in the display, just by changing the configuration of the LED strings. Using the LM3697’s flexibility of having up to 3 strings for backlight connections, allows designers to choose the right configuration to maximize their efficiency.

-John Woodward, Technical Marketing Engineer at Texas Instruments