AAT1271 1.5A Step-Up Current Regulator for Flash LEDs

The AAT1271 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 AAT1271 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 AAT1271 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 AAT1271. 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 AAT1271 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 AAT1271, where in the case of two LEDs the output current is matched between each diode. The AAT1271 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 AAT1271 is available in a Pb-free, thermally-enhanced 14-pin 3x3mm TDFN package.

技术特性

Input Voltage Range: 2.7V to 5.5V
Dual Channel Output
Up to 1A Regulated Output Current (0.5A per Channel)
Up to 85% Efficiency with Small Magnetics
2 MHz Switching Frequency
Separate Flash Enable Input
Separate Flash Inhibit Input
Single Resistor Sets Flash and Movie Mode Current
Fixed Flash-to-Movie Mode Current Ratio
16-Level Movie Mode Current via S2Cwire™
User-Programmable Safety Timer
True Load Disconnect
Input Current Limit
Over-Voltage (Open LED, Open Circuit), Short-Circuit, and Over-Temperature Protection
Shutdown Current: < 1.0μA
Small Inductor Solution: 1μH (0.9mm in height)
14-pin STDFN 3x3 Package
-40 to +85°C Temperature Range

订购信息 Ordering Information

AAT1271

应用领域 APPLICATION

Camcorder Video Light (Torch Light)
Cellphones/Smartphones
Digital Still Cameras (DSCs)
LED Photo Flash/Torch
Mobile Handsets

AAT1271 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
AAT1271 数据资料DataSheet下载:pdf	Rev.V2	2 页