AAT1277 1.5A Step-Up Current Regulator for Flash LEDs

The AAT1277 is a high-efficiency, high-current boost converter capable of 1.5A typical output current. It is an ideal power solution for LED photo flash applications in all single cell Li-ion powered products. The AAT1277 maintains output current regulation by switching the internal high-side and low-side switch transistors. The transistor switches are pulse-width modulated at a fixed frequency of 2MHz. The high switching frequency allows the use of a small inductor and output capacitor, making the AAT1277 ideally suited for small battery-powered applications. Skyworks' proprietary AS2Cwire™ (Advanced Simple Serial Control™) serial digital interface is used to enable, disable, configure, and program the operation of the AAT1277. Using the AS2Cwire interface, the movie-mode current level for each LED, the safety timer delay, and the flash-to-movie-mode current ratio can be programmed to one of 16 levels. In addition, the single-wire serial protocol sets output channel control. The AAT1277 also includes a separate Flash Enable input to initiate both the flash operation and the default timer which can be used either to terminate a flash event at the end of a userprogrammed delay or as a safety feature. Also included is a Flash Inhibit pin which reduces the flash current to movie-mode levels during high battery demand. The maximum flash and movie-mode current is set by one external resistor where the ratio of Flash to Moviemode current is set at approximately 7.3:1. One or two LEDs can be connected to the AAT1277, where in the case of two LEDs the output current is matched between each diode. The AAT1277 contains a thermal management system to protect the device in the event of an output short-circuit condition. Built-in circuitry prevents excessive inrush current during start-up. The shutdown feature reduces quiescent current to less than 1.0μA. The AAT1277 is available in a Pb-free, thermally-enhanced 14-pin 3x3mm TDFN package.

技术特性
  • VIN Range: 2.7V to 5.5V
  • Dual Channel Output
  • Up to 1.5A Regulated Output Current (750mA per
    channel)
  • Up to 85% Efficiency with Small Inductor (1μH)
  • 2 MHz Switching Frequency
  • Separate Flash Enable
  • User-Programmable Safety Timer
  • Single Resistor Sets Flash and Movie Mode Current
  • Two Wire, I2C Compliant Serial Interface
  • Fast, 400kHz Serial Transfer Rate
  • 16 Level Movie-mode Current
  • Flash/Movie-mode
  • Current Output Channel Control
  • Safety Timer
  • True Load Disconnect
  • nput Current Limit
  • Over-Voltage (Open LED, Open Circuit), Short Circuit,
    and Over-Temperature Protection
  • Shutdown Current < 1.0μA
  • 14-pin TDFN 3x3 mm Package
  • 40°C to +85°C Temperature Range
应用领域 APPLICATION
  • Camcorder Video Light (Torch Light)
  • Cellphones/Smartphones
  • Digital Still Cameras (DSCs)
  • LED Photo Flash/Torch
  • Mobile Handsets
订购信息 Ordering Information
  • AAT1277
AAT1277 典型应用

AAT1277 典型应用

应用技术支持与电子电路设计开发资源下载 版本信息 大小
AAT1277 数据资料DataSheet下载:pdf Rev.V2 2 页