500mA High Efficiency Charge Pump
for White LED Flash Applications
General Description
The AAT3112 is a member of AnalogicTech's Total
Power Management IC™ (TPMIC™) family. It is a
dual voltage doubling charge pump that provides a
regulated output voltage. It operates with an input
voltage range of 2.7 to 5.0 volts. The device can
deliver a constant 200mA output load current and up
to 500mA of pulsed current. The 500mA peak cur-
rent capability of the AAT3112 makes it ideal for
white LED flash applications. A low external parts
count (two 1μF flying capacitors and two small
capacitors at V
IN
and V
OUT
) makes the AAT3112 ide-
ally suited for small battery-powered applications.
The AAT3112 has a thermal management system
to protect the device in the event of a short-circuit
condition at the output pin. Built-in soft-start circuit-
ry prevents excessive inrush current during start-
up. A high charge pump switching frequency
enables the use of very small external capacitors.
A low current shutdown feature disconnects the
load from V
IN
and reduces quiescent current to less
than 1μA. The AAT3112 is available in a Pb-free
16-pin 3x3mm QFN package and is rated over the
-40°C to +85°C temperature range.
AAT3112
Features
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ChargePump
™
Input Voltage Range:
— AAT3112-5.0: 2.7V to 5.0V
— AAT3112-4.5: 2.7V to 4.5V
Up to 500mA Peak Output Current
200mA Continuous Output Current
I
Q
<1μA in Shutdown
Regulated 4.5V or 5.0V Output
26μA of Quiescent Current
Small Application Circuit
Automatic Soft Start
No Inductors
Short-Circuit/Over-Temperature Protection
16-Pin 3x3mm QFN Package
Temperature Range: -40°C to +85°C
Applications
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General-Purpose High-Current Boost Supply
White LED Backlighting
White LED Photo Flash
Typical Application
C1 = 1μF
C2 = 1μF
C1
+
C1
-
C2
+
C2
-
VOUT1
V
IN
C
IN
VIN
VOUT2
C
OUT
AAT3112
D1
Enable Light
EN1
D2
D3
D4
Enable Flash
EN2
GND
R
B
3112.2007.01.1.5
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ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
