描述 Description

The AAT1236 is a highly integrated, high efficiency power solution for white LED and keypad backlights in mobile/portable devices. It is based on a switching boost converter which steps up the single cell lithium-ion/polymer battery voltage to drive 5 strings of series-connected white LEDs with precision current regulation. The AAT1236 is capable of driving a total of four LEDs per channel.
The boost converter can produce an output drive of up to 24V at 100mA. The high switching frequency (up to 2MHz) provides fast response to load transients and allows the use of small external components. A fully integrated control circuit simplifies the design and reduces total solution size.
A two-wire I2C serial digital interface is used to individually turn each output sink on/off and adjust the LED current by group. Unlike conventional pulse width modulation (PWM) control of LED brightness, the AAT1236 drives the LEDs with constant, non-pulsating current. The interface is fully compliant to the Fast/Standard mode I2C specification, allowing a transfer rate of up to 400kHz.
A similar device is also available with a proprietary Advanced Simple Serial Control? (AS2Cwire?) single wire interface; please see the AAT1235 datasheet.
The AAT1236 is available in a Pb-free, thermally-enhanced 16-pin 3x4mm TDFN package and is specified for operation over the -40°C to +85°C temperature range.

特性 Features

·Input Supply Voltage Range: 2.7V to 5.5V
·Maximum Boost Output Drive: Up to 24V at 100mA
·Up to 85% Efficient Operation
·Up to 2MHz Switching Frequency with Small Inductor
·User-Programmable Full-Scale LED Current, Up to 30mA
·Two-Wire, I2C Compliant Serial Interface
·Two Addressable Registers
·Independent LED Current Control by Group
·Backlight Group B1-B2, 16 Settings
·Auxiliary Group A1-A3, 16 Settings
·Independent LED ON/OFF Control
·Fast, 400kHz Serial Transfer Rate
·Non-Pulsating, High-Performance LED Current Drive
·for Uniform Illumination
·10% Absolute Accuracy
·2% Channel-to-Channel Matching
·Over-Voltage and Over-Temperature Protection
·Automatic Soft-Start Minimizes Large Inrush Current at Startup
·Available in 3x4mm TDFN34-16 Package