High efficiency lighting management unit reduces system cost for smartphones, enhances battery life
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.
"The increased adoption of cameras in smartphones and other small, portable devices has placed new demands on LMUs for next-generation products," said Raymond Chan, Technical Marketing Manager of AnalogicTech. "Implementing effective power management is critical for maximizing battery runtimes and increasing user satisfaction. The AAT2870 builds on our LMU portfolio by adding support for photo diodes and truly autonomous backlight control while surpassing the efficiency, small footprint and ease of design-in of our existing LMU
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 27.9 mA 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 300 mA that are designed to provide power to camera modules and other accessories.
Visit Advanced Analogic Technologies at www.analogictech.com