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Updated: July 8th, 2008 05:26 PM CDT

Multifunction LED Drivers Simplify Lighting Circuit Design by Combining Backlight, Flash and LDOs into Single Chip

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via PRNewswire

SUNNYVALE , Calif., Aug. 7 /PRNewswire-FirstCall/ -- Advanced Analogic Technologies Incorporated (AnalogicTech) (Nasdaq: AATI), a developer of power management semiconductors for mobile consumer electronic devices, announced today two new high-performance charge pump products which enable designers to build dramatically smaller, more feature-rich mobile handsets. The AAT2846 andAAT2856 combine backlight drivers, high-current flash drivers and two general purpose low-dropout (LDOs) linear regulators in a single 4x4 mm package. Designed to eliminate multiple ICs in space-constrained portable applications,these new devices also maximize design flexibility by offering independent control for backlight and flash current drive via separate single-wire digital interfaces.

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"As today's high performance handsets and other portable devices rapidlyevolve and add new features, their lighting functions are growing increasingly complex," says Adolfo Garcia , product line director for AnalogicTech. "Manynow require WLEDs for backlight of large and sophisticated main displays,WLEDs for backlight of smaller sub displays, and flash LEDs for camerafunctions. By combining six outputs for WLEDs, two for flash and two LDOs onthe same chip, and providing independent control for each function, theAAT2846 and AAT2856 Total Display Solutions offer portable system designers the opportunity to build dramatically smaller and more economical portable systems."

No Performance Compromise

The AAT2846 uses a high current, tri-mode charge pump capable of driving up to six backlight LEDs at 30 mA each and two flash LEDs at up to a total of600 mA. For applications that do not require flash functionality, the AAT2856 offers a high current tri-mode charge pump designed to drive six backlight LEDs at up to 30 mA each.

Both devices feature AnalogicTech's AS2Cwire(TM) single-wire interface to independently enable, disable and set drive current for backlight and flash LEDs. Current for backlight LEDs on the AAT2846 and AAT2856 can be programmedto any of 32 levels ranging from 95 ľA to 30 mA. The devices also provide a 20mA full-scale range and a special low-current address for optimal performanceat low LED current levels. The six backlight outputs can also be segmented into a 5 + 1 configuration to support dual-panel mobile handset applications. In addition, a special operating mode can be invoked to provide individual control of each of the (6) LED outputs. Thus, any custom arrangement formain/sub panel displays, keypad illumination, general-purpose status indication, or flash indication can be programmed. For maximum white LED brightness uniformity, channel-to-channel backlight current matching is 1%.

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