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 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 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.