AAT2807A
Dual High Efficiency Charge Pump
for White LED and Flash Applications
™
ChargePump
General Description
Features
The AAT2807A is a member of AnalogicTech's Total
Power Management IC™ product family. It is a dual
charge pump designed to support both white LED
backlight and flash applications for systems operat-
ing with Lithium-Ion batteries. The backlight charge
pump is capable of driving up to three LEDs at a
total of 60mA. The current sinks may be operated
individually or in parallel for driving higher current
LEDs. To maximize power efficiency, the charge
pump operates in 1X, 1.5X, or 2X mode, where the
mode of operation is automatically selected by
comparing the forward voltage of each LED with the
input voltage. AnalogicTech's S2Cwire™ (Simple
Serial Control™) serial digital input is used to
enable, disable, and set current for each LED with
eight settings. The charge pump consumes
extremely low current internally (80µA typical) at
light load for optimized efficiency.
•
•
VIN Range: 2.7V to 5.5V
Dual Charge Pump to Support Backlight and
Flash LEDs
•
Backlight Charge Pump:
•
•
•
•
•
Regulated Current
Three Current Sink Inputs
Brightness Control via Single GPIO
Tri-Mode Charge Pump
20mA of Current Per Input Current Sink
•
Flash Charge Pump:
•
•
Regulated Output Voltage
300mA of Pulsed Current
•
•
•
•
•
•
Independent Enable Pins
Low Noise Constant Frequency Operation
1MHz Switching Frequency
Automatic Soft Start
No Inductors
Available in DFN44-16 Package
The flash charge pump is a charge pump doubler
with a regulated output voltage. It is designed to
deliver 150mA of continuous current and up to
300mA of pulsed current. It has an independent
enable pin for improved power savings.
Applications
•
•
•
Color (RGB) Lighting
White LED Backlighting
White LED Photo Flash
Built-in soft-start circuitry prevents excessive inrush
current during start-up. In shutdown mode, the
device disconnects the load from VIN and con-
sumes less than 1µA.
The AAT2807A is available in a space-saving, ther-
mally-enhanced 16-pin 4x4mm DFN package and
is rated over the -40°C to +85°C temperature range.
Typical Application
C1
1µF
C2
1µF
C3
1µF
C1+ C1- C2+ C2- C3+ C3-
VOUT_FL
VOUT_FLASH
COUT
Flash
VIN
1µF
AAT2807A
CIN
1µF
VIN
Backlight
VOUT_BL
D1
D2
D3
EN/SET
EN/SET
EN_FLSH
COUT
D1
D2
1µF
EN_FLSH
D3
GND
2807A.2004.12.1.0
1