High Current LED Flash Driver Charge Pump IC
General Description
The AAT3172 is a high output current, high effi-
ciency, low noise, low profile charge pump DC/DC
converter, ideal for multi-function LED photo-flash
applications where solution cost, size, and efficien-
cy are critical.
The dual charge pump in the AAT3172 is capable
of delivering 600mA output current. Two current-
controlled paths are available for users of dual
flash LEDs that prefer current matching. Each LED
channel can be easily programmed in 32 steps with
a single GPIO output through the AS
2
Cwire™
(Advanced Simple Serial Control™) interface. This
allows smooth transitions and flexible adjustment
of brightness in flash or other lighting modes.
The tri-mode (1X/1.5X/2X) operation of the internal
charge pump offers excellent power efficiency for
both flash and movie modes. Combined with a low
external parts count (two 1µF flying capacitors and
one small bypass capacitor at V
IN
and OUT), the
AAT3172 is ideally suited for small, battery-powered
applications.
The AAT3172 has a thermal management system to
protect the device in the event of a short-circuit con-
dition at the output pin. Built-in soft-start circuitry
prevents excessive inrush current during start-up.
The shutdown feature disconnects the load from V
IN
and reduces quiescent current to less than 1.0µA.
The AAT3172 is available in the Pb-free, thermally-
enhanced, 12-pin 3x3mm TDFN package.
AAT3172
Features
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ChargePump
™
V
IN
Range: 2.7V to 5.5V
600mA Output Current
Tri-Mode 1X/1.5X/2X in Current Mode
Voltage Mode Operation: 1.5X, 100mA
Dual Regulated Current Sinks
Current Match Between Current Sinks
32 Current Steps Set by AS
2
Cwire
1µF Input, Output, and Flying Capacitors
<1.0µA of Shutdown
Small Application Circuit
No Inductors
Automatic Soft Start
12-Pin TDFN 3x3mm Package
-40°C to +85°C Temperature Range
Applications
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Camera Phones
Digital Still Cameras (DSCs)
PDAs and Notebook PCs
Smart Phones
Typical Application
C1
1μF
C2
1μF
C1+
2.7V to 5.5V
C
IN
4.7μF
C1- C2+
C2-
V
OUT
V
IN
AAT3172
C
OUT
2.2μF
Flash
LED 1
Flash
LED 2
F1
EN/SET
EN/SET
GND
F2
3172.2006.05.1.5
1
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
