AAT2801 Datasheet, PDF (1/20 Pages) Advanced Analogic Technologies – Multi-Mode Charge Pump for White LED Backlight and Flash Applications

AAT2801
Multi-Mode Charge Pump for
White LED Backlight and Flash Applications
General Description
Features
ChargePump^™
The AAT2801 is a member of AnalogicTech's Total
Power Management IC™ (TPMIC™) product family.
It has a dual charge pump architecture designed to
support both the white LED backlight and flash appli-
cations for systems operating with Lithium-Ion bat-
teries. The backlight charge pump provides power
required to drive up to four LEDs. To maximize
power efficiency, it automatically selects 1X, 1.5X, or
2X mode. The device produces current levels up to
30mA on each of its four current source outputs.
AnalogicTech's Simple Serial Control™ (S²Cwire™)
interface is used to enable, disable, and set the LED
drive current with a 32-level logarithmic scale LED
brightness control.
The flash charge pump is a charge pump doubler
with a regulated output voltage. It is designed to
deliver 120mA of continuous current and up to
250mA of pulsed current. It has an independent
enable pin for improved power savings.
The AAT2801 is equipped with AnalogicTech’s
AutoBias™ technology which allows individual LEDs
to be powered either by charge pump or battery
input, determined internally and automatically to
maximize the power efficiency even with a large dif-
ference in LED forward voltage.
The AAT2801 has thermal protection and built-in
soft-start circuitry. A high charge pump switching fre-
quency enables the use of very small external capac-
itors. The AAT2801 is available in the 16-pin
TDFN44 package.
• V_IN Range: 2.7V to 5.5V
• Dual Charge Pump
— Flash: Charge Pump Doubler
— Backlight: Tri-Mode Charge Pump
• Drives Low-V_F and High-V_F LEDs
• Up to Four 30mA Outputs
• 32-Position Logarithmic Scale with Digital
Control
• Low Noise Constant Frequency Operation
• 1MHz Switching Frequency
• AutoBias Technology
• Regulated 4.5/5.0 Volts V_{OUT_FLASH}
• Up to 250mA of Current for Flash
• Automatic Soft Start
• No Inductors
• I_Q <1µA in Shutdown
• Available in 16-pin TDFN44 Package
Applications
• Display Modules
• Mobile Phones
• PDAs
• Smart Phones
Typical Application
C1
C2
C3
1μF
1μF
1μF
C1⁺
IN
C1^- C2⁺
C2^- C3⁺ C3^-
OUT_FLSH
CP
VIN
CIN
C _CP
1μF
1μF
AAT2801
D1
D2
D3
EN/SET
EN/SET
D4
Flash Enable
EN_FLSH
GND
C_F
1μF
R_B
Flash LED
Backlight
D4
D3
D2
D1
2801.2006.04.1.3
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