AnalogicTech 公司的AAT2862是背景光LED驱动和多个LDO照明管理单元，集成了基于电荷泵的照明管理电路和4个LDO线性稳压器.电荷泵为所有的LED输出提供电源，并可配置多个LED，每个LED的输出可编程至30mA，两个LED输出，每个可编程至60mA.而每个LDO可提供高达200mA的负载电流. AAT2862输入电压从2.7V到5.5V，可用在有照相功能的移动设备，数码相机和多媒体手机.本文介绍了AAT2862的主要特性，功能方框图，典型应用电路以及评估板电路图， 评估板MCU电路图和元件列表.

      AAT2862: Backlight LED Driver and Multiple LDO Lighting Management Unit The AAT2862 is a highly integrated charge pump-based lighting management unit with four linear regulators optimized for single-cell lithium-ion/polymer systems.

      The charge pump provides power for all LED outputs and multiple LED configurations are available. The LED outputs can be programmed up to 30mA each and two LED outputs can be programmed up to 60mA each. An I2C serial digital interface is used to enable， disable， and set the current to one of 32 levels. Current matching is better than 3% for uniform display brightness， and high current matching is better than 5% for uniform power dissipation.

      The AAT2862 also offers four high-performance lownoise MicroPower low dropout (LDO) linear regulators. The regulators are enabled and their output voltages are set through the I2C serial interface. Each LDO can supply up to 200mA load current and ground-pin current is only 80μA making the AAT2862 ideal for battery-operated applications.

      The AAT2862 is available in a Pb-free， space saving TQFN34-24 package and operates over the -40℃ to +85℃ ambient temperature range.

AAT2862主要特性:

Input Voltage Range: 2.7V to 5.5V

Tri-Mode Charge Pump

Drives up to Eight LEDs

32 Programmable Backlight Current with Auto-fade

Settings Ranging From 500μA to 30mA

Drives up to Two Auxiliary LEDs

1MHz Switching Frequency

Automatic Soft Start

I2C Selectable Drivers

Four Linear Regulators

200mA Output Current

200mV Dropout

I2C Programmable Output Voltage from 1.2V to 3.3V

Output Auto-Discharge for Fast Shutdown

Built-In Thermal Protection

Automatic Soft Start

-40℃ to +85℃ Temperature Range

TQFN34-24 Package

AAT2862应用:

Camera Enabled Mobile Devices

Digital Still Cameras

Multimedia Mobile Phones

图1.AAT2862方框图

图2.AAT2862典型应用电路

图3.AAT2862评估板电路图

图4.AAT2862评估板微控制器电路图

表1.AAT2862评估板元件列表

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