High Efficienct White LED Drivers for LCD Backlighting Applications

Advanced Analogic Technologies, Inc. (AnalogicTech™) (Nasdaq: AATI), an analog semiconductor company focused on powering innovative solutions in consumer, industrial, and communications markets, today 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 innovative 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 percent 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.
• 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 percent 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 percent accuracy with +/- 1.5 percent 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. For other quantities, contact AnalogicTech or its distributors. The AAT1451 is currently shipping.

Key Features:

• Input Voltage Range: 2.7 to 26V
  • Integrated 50V Boost Converter
• 32 kHz PWM frequency
• Fully adjustable switching frequency of 600kHz to 1MHz.
• Maximum IOUT: 120mA
• Integrated Fault Protection for:
  • Over-voltage
  • Over-temperature
• Soft-Start
• Low Profile TDFN34-16 Package
• -40 C to + 85oC Temperature Range