Product category:
Power Supply ICs and Controllers
News Release from: Advanced Analogic Technologies | Subject: AAT2847
Edited by the Electronicstalk Editorial
Team on 14 December 2007
Power chip combines four LED drivers
with two LDOs
Charge pump-based white LED driver integrates two 200mA LDO linear regulators, each with its own independent enable pin, to power ancillary system functions.
New from AnalogicTech, the AAT2847 is a highly integrated four-channel white LED (WLED) driver for portable systems operating off a single-cell Li-ion/polymer battery The charge pump-based device also integrates two 200mA low dropout (LDO) linear regulators, each with its own independent enable pin, to power ancillary system functions
This article was originally published on Electronicstalk on 16 Jun 2004 at 8.00am (UK)
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The AAT3239 is a new 500mA low-dropout (LDO) linear regulator for battery-operated portable applications.
The key to success for any portable device is the designer's ability to configure the end product to meet customer needs in a cost-effective way.
By combining four independently controlled WLED channels adjustable across 52 different current settings, with two independently enabled LDOs, the AAT2847 gives designers maximum flexibility to add new features, such as additional lighting or camera functions, while minimising cost.
The AAT2847 is built around a low-noise triple-mode DC/DC charge pump convertor that delivers up to 120mA of output current.
Each of the device's four channels supplies up to 30mA of bias current for WLEDs.
To ensure uniform display brightness, WLED backlight bias current matching is typically 0.5%.
The device uses AnalogicTech's Advanced Simple Serial Control (AS2Cwire) digital interface to enable, disable and set the current for each backlight LED channel.
Current level can be set across 52 levels including 16 current settings in three separate current scales - 30, 20 and 15mA - as well as four low level current settings which go as low as 50uA.
Each LED channel features embedded short circuit protection and auto disable functionality.
A low shutdown current feature disconnects the load from the input and reduces quiescent current to less than 1uA.
The AAT2847 also integrates two LDOs.
Each LDO is controlled by its own independent enable input and supplies up to 200mA output current.
Fixed or adjustable output versions are available.
The AAT2847 is qualified across the -40 to +85 C temperature range.
It is available in a 20-pin, 3 x 4 x 0.75mm TQFN package.
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