Lighting Management Unit Reduces System Cost for Smartphones

Advanced Analogic Technologies Inc. (AnalogicTech) has launched the AAT2870, a highly configurable lighting management unit (LMU)capable of driving eight independently programmed LEDs for backlighting and four low-dropout (LDO) regulators for powering camera modules. The LMU supports the drive for cost efficiency in the smartphone market with built-in support for low-cost photo diodes as ambient light sensors. Automation of all backlight functions, including fading and ambient light brightness adjustments greatly extends battery runtime.

Offering complete ambient light sensor management, the AAT2870 provides automatic sensor bias, calibration and control of analog ambient light sensors and low-cost photo diodes. The implementation of these functions provides seamless ambient-light-controlled backlight brightness, reduces calibration effort in production and processor overhead during operation.

The AAT2870's tri-mode negative charge pump is capable of independent current control of eight white LEDs up to 27.9mA and offers direct LED connection to the battery, further enhancing efficiency and making it comparable to inductor-based conversion. Independent load switches selectively connect LEDs with high forward voltage (VF) to the charge pump for better management of VF variations. The device also drives four I(2)C programmable LDO outputs at up to 300mA that are designed to provide power to camera modules and other accessories.

The AAT2870 is packaged in a 3.1x2.6mm 30-pin WLCSP.

AnalogicTech