Powerful Multi-String LED Drivers for LCD Screens

Advanced Analogic Technologies, Inc. (AnalogicTech™) (Nasdaq: AATI), an analog semiconductor company focused on powering innovative solutions in consumer, industrial, and communications markets, today introduced its AAT1409/7/5 family of multi-string LED backlight drivers.

Offering integrated boost converters and precision current sinks that can support up to 88 LEDs at 360mA total LED current, the AAT1409/7/5 drivers are among the most powerful in the marketplace.

These new drivers bring to market a fully featured solution that reduces the number of backlight PCBs, reducing costs, yet is capable of driving high brightness LEDs and ensuring uniformity across the display by precisely controlling the backlight intensity.

“As LCD displays continue to gain traction in the computing, consumer and industrial markets, features like power, efficiency, accuracy and flexibility of the backlight drivers are all critical differentiators,” said Ray Chan, technical marketing manager at AnalogicTech. “By offering a product family designed for a specific range of LCD panels – 10-inch to 22-inch in this case – we are able to offer a very powerful and effective approach to LCD power management.”

The AAT1409/7/5 drivers operate from DC inputs, cigarette lighter adapters or multi-cell Li-ion batteries over the 4.5V to 26V range. The family is available in 8, 6 and 4 channels making them ideal for driving white LED (WLED) edge backlighting for LCD panels ranging from 10 to 22 inches in size. The drivers also support up to 100 kHz PWM dimming frequency to ensure silent operation.

An additional consideration is that many portable LCD devices are battery-powered and operate under low ambient lighting conditions or in power saving modes, so require low level backlight dimming to extend battery run time. The AAT1409/7/5 addresses this with a design that maintains high efficiency during low PWM duty cycles to reduce wasted energy during light load conditions. The driver’s high resolution 1000:1 PWM dimming range delivers precise control of backlight brightness, equivalent to a 10-bit resolution.

Key Features and benefits:

• High-efficiency light load mode achieves up to 88 percent conversion efficiency at a 5 percent dimming duty cycle
• Step-up converter can deliver up to 360mA total LED current at a 45V operating voltage
• 100kHz PWM dimming frequency and optionally synchronized switching frequency to system clock reduces audible noise
• +/- 2 percent LED current accuracy and matching between strings
• Selectable switching frequency accommodates various inductor and capacitor sizes
• Up to 92 percent efficiency over wide input voltage (VIN) range of 4.5V to 26.0V
• LX rated to 50V
• Up to eight LED current sinks at 45mA each
• Flexible configurations with disable or parallel channels
• Open/shorted LEDs enable fault tolerance
• Current limit protection, over-voltage protection and over-temperature protection
• Soft-start to minimize inrush current
• TQFN34-24 low profile package
• -40 C to +85C operating temperature range