PRODUCT DATASHEET
AAT1271
SwitchReg
TM
General Description
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.
AnalogicTech’s proprietary AS
2
Cwire™ (Advanced Simple
Serial Control™) serial digital interface is used to enable,
disable, configure, and program the operation of the
AAT1271. Using the AS
2
Cwire 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 proto-
col 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 user-
programmed 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 Movie-mode
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.
1.5A Step-Up Current Regulator for Flash LEDs
Features
• V
IN
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
• Separate Flash Inhibit
• User-Programmable Safety Timer
• Single Resistor Sets Flash and Movie Mode Current
• AS
2
Cwire Single Wire Programming:
▪
Movie Mode Current
▪
Flash/Movie Mode Current Ratio
▪
Movie Mode Output Configuration
▪
Flash Safety Timer
• True Load Disconnect
• Input 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
Applications
•
•
•
•
•
Camcorder Video Light (Torch Light)
Cellphones/Smartphones
Digital Still Cameras (DSCs)
LED Photo Flash/Torch
Mobile Handsets
1271.2008.08.1.1
www.analogictech.com
1
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