New Industry Products

AnalogicTech Targets Tablets With Automatic Phase Shifting White LED Driver for LCD Backlighting

June 09, 2011 by Jeff Shepard

Advanced Analogic Technologies, Inc. (AnalogicTech™) introduced the AAT1451, a high-efficiency white LED driver for liquid crystal display (LCD) backlighting applications in portable electronic devices such as the fast-growing tablet and the established computer markets.

"Power management considerations for system designers vary depending on the size of the display and the use-case scenarios they are targeting," said Ray Chan, Technical Marketing Manager of AnalogicTech. "With the AAT1451 we bring to market the most comprehensive feature set available in an LED driver that makes it possible for batteries to last longer, a critical differentiator in the rapidly growing tablet market. As a company, we now have LED drivers to support the entire range of LCD screen sizes from cell phones to large form factor televisions, all of which offer a wide variety of features and options to enhance the end-user experience."

The new AnalogicTech AAT1451 LED driver offers many features that enable manufacturers to offer products with comprehensive feature sets that address consumer demands. For example, the AAT1451: drives up to four light emitting diode (LED) strings at up to 93% efficiency, and extends this efficiency to low LED brightness levels by automatic phase shifting, which further increases battery life; uses a 32 kHz pulse width modulation (PWM) operating frequency to ensure silent operation; has a high switching frequency (600kHz – 1MHz) to allow original equipment manufacturers (OEMs) to select small passive components resulting in lighter and smaller end products; offers a wide selection of dc input voltages so that devices can be powered from sources including cigarette lighter adapters and multi-cell Li-Ion batteries; and incorporates comprehensive safety features to alert system controller and take corrective action by disabling shorted and open LED strings to prevent thermal fault conditions.

The AAT1451’s proprietary PWM dimming reduces peak currents by as much as 75% and the 256 LED brightness levels support the Android operating system platform and Content Adaptive Brightness Control (CABC) to further increase battery life.

To ensure accurate backlight color temperature and uniform brightness across the entire display, the AAT1451 has four precision current sinks that are programmable up to 30mA per string at ±2% accuracy with ±1.5% matching between strings to drive up to 48 white LEDs at 120mA total output current.

The AAT1451 is priced at US$0.82 @10K units.