Lighting IC covers smartphones
01 July 2008
A single IC can act as a backlight or sub-display LED, a flash LED driver or LDO for embedded
cameras.
The AAT2860-1 I2C-based lighting management unit integrates up to seven LED drivers and three LDO (low dropout) linear regulators in a single IC. Seven LEDs would be used in a main display or four and three for a sub-display.
The IC can be used to minimise component count, board space and cost for single large displays, as in PDAs or two displays as in a clamshell phone and the LDOs in embedded camera phones. It is optimised for a single cell li-ion/polymer use and operates across the 2.7V to 5.5V input range. A tri-mode charge pump drives up to seven LEDs in multiple backlight and flash configurations.
The current level for each LED is enabled, disabled and set via an I2C-compatible serial interface. Backlight LEDs can be programmed across 32 discrete levels from 0.5mA to 31mA. Current matching is better than three per cent for uniform display brightness.
Flash LEDs are programmable across 16 levels up to 300mA. Current matching is better than five per cent. To protect the flash LEDs form thermal damage, the IC includes a programmable safety timer, which automatically terminates the flash pulse in the event of software failure.
The three low-noise, LDO linear regulators each deliver up to 300mA load and current with 150mV dropout. Ground pin current is 80µA. Each output is programmable from 1.5V to 3V.
There is also the AAT2860-2, which offers six LED drivers for a main display and a flash driver or four for a main display, two for a sub-display and one flash driver. Other configurations are available on request.
The IC is qualified to operate across the -40°C to 85°C and is available in a 24pin TQFN34 package.
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