Advanced Analogic Technologies introduced the AAT14XX family of 31 mA, step-up, single-channel light-emitting diode (LED) drivers capable of driving up to 10 LEDs in a single string.
The drivers’ small size and quiet operation make them suitable as LED backlight solutions for single-cell Lithium-ion battery-based equipment.
The AAT14XX family enables larger displays, allows higher efficiencies and offers filtered pulse-width modulation (PWM) dimming to eliminate interference with the radios in cellphones and other handheld devices. With a 1,15 x 1,55 mm wafer-level chip scale package (WLCSP) size, the devices require only 0,7 cm² of space on a printed circuit board. LED brightness is controlled in one of three ways: 32 dimming steps using the S2Cwire interface and filtered or direct PWM control. PWM dimming frequency of 100 kHz eliminates audible noise and is compatible with content adaptive brightness control (CABC) to further reduce backlight power consumption by up to 50%.
The major source of power drain in portable systems with displays is the backlight in a liquid crystal display (LCD) screen. The AAT14XX family addresses this with three dimming controls and an integrated precision, high-voltage current sink that provides flexibility in adjusting LED current from 10 to 31 mA regardless of the number of series LEDs. This approach achieves a high efficiency of 88%, more than that offered by traditional LED drivers that use a ballast resistor.
The family consists of four parts: the AAT1410 drives up to four series LEDs at 31 mA, the AAT1401 up to six, the AAT1402 up to eight and the AAT1403 up to 10. The devices support a voltage input range of 2,7 to 5,5 V, include over-temperature protection, programmable over-voltage protection, open LED protection and automatic recovery when the fault conditions are removed.
For more information contact Marinus Rudman, Hi-Q Electronics, +27 (0)21 595 1307, [email protected], www.hi-q.co.za
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