High Efficiency 1X/1.5X/2X Charge
Pump for White LED Applications
General Description
The AAT3169 is a low noise, constant frequency
charge pump DC/DC converter that uses a tri-mode
load switch (1X), fractional (1.5X), and doubling
(2X) conversion to maximize efficiency for white
LED applications. The AAT3169 is capable of driv-
ing six LEDs for a total of 180mA from a 2.7V to
5.5V input. The current sinks may be operated indi-
vidually or in parallel for driving higher current LEDs.
A low external parts count (two 1µF flying capacitors
and two small 1µF capacitors at VIN and VOUT)
make this part ideally suited for small, battery-pow-
ered applications.
AnalogicTech's AS
2
Cwire™ (Advanced Simple
Serial Control™) serial digital input is used to
enable, disable, and set current for each LED with
a 16-level logarithmic scale plus four low-current
settings down to 115µA. For optimized efficiency,
low-current settings require only 65µA of house-
keeping current.
Each output of the AAT3169 is equipped with built-
in protection for V
OUT
short-circuit and auto-disable
for load short-circuit conditions. Built-in soft-start
circuitry prevents excessive inrush current during
start-up. A low-current shutdown feature discon-
nects the load from V
IN
and reduces quiescent cur-
rent to less than 1µA.
The AAT3169 is available in a Pb-free, space-sav-
ing, thermally-enhanced 16-pin 3x4mm TDFN or
4x4mm QFN package.
AAT3169
Features
•
•
ChargePump
™
•
•
•
•
•
•
•
•
•
•
•
V
IN
Range: 2.7V to 5.5V
Fully Programmable Current with Single Wire
— 16-Step Logarithmic Scale
— 20/30/15mA Max Current
— Four Low-Current Settings Down to 115µA
— Low I
Q
(65µA) for Single-Channel, Low-
Current Mode
Tri-Mode 1X, 1.5X, and 2X Charge Pump for
Maximum Efficiency and V
F
Coverage
Drives Up to Six LEDs
Individual Main-Sub (5-1) Group Control
No Inductors, Low Noise Operation
1MHz Constant Switching Frequency
Small Application Circuit
Built-In Thermal Protection
Built-In Auto-Disable for Open Circuit
Automatic Soft Start
I
Q
<1µA in Shutdown
Thermally-Enhanced TDFN34-16 or
QFN44-16 Package
Applications
•
•
•
•
Color (RGB) Lighting
Programmable Current Sink
White LED Backlighting
White Photo Flash for Digital Still Cameras
Typical Application
C1+
C1
1μF
C2+
C2
1μF
C1-
2.7V to 5.5V
C
IN
1μF
C2-
VOUT
VIN
AAT3169
GND
D1
D2
D3
D4
D5
D6
D1
D2
D3
D4
D5
D6
C
OUT
1μF
EN/SET
EN/SET
3169.2006.04.1.0
1
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
