AAT2806 Datasheet, PDF (1/16 Pages) Advanced Analogic Technologies – Dual High Efficiency Charge Pump for White LED AND Flash Applications

AAT2806
Dual High Efficiency Charge Pump
for White LED and Flash Applications
General Description
Features
ChargePump^™
The AAT2806 is a dual charge pump designed to
support both the white LED backlight and flash appli-
cations for systems operating with lithium-ion/poly-
mer batteries. The backlight charge pump is capable
of driving up to four LEDs at a total of 80mA. The cur-
rent 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 automati-
cally 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 an eight-level logarithmic scale plus
four low-current settings down to 50µA for optimized
efficiency, with a typical operating quiescent current
of less than 50µA.
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 AAT2806 has thermal protection and built-in
soft-start circuitry. A low-current shutdown feature
disconnects the load from V_IN and reduces quiescent
current to less than 1µA.
The AAT2806 is available in a Pb-free, space-saving,
thermally-enhanced TDFN44-16 package and is
rated over the -40°C to +85°C temperature range.
• V_IN Range: 2.7V to 5.5V
• Dual Charge Pump to Support Backlight and
Flash LEDs
• Backlight Charge Pump:
— Regulated Current
— Four Current Sink Inputs
— S²Cwire Brightness Control
— Tri-Mode Charge Pump
— Maximum 20mA of Current Per Input
— Low I_Q (50µA) in Light Load Mode
• Flash Charge Pump:
— Regulated Output Voltage
— Up to 250mA of Pulsed Current
• Independent Backlight/Flash Control
• Low Noise 1MHz Constant Frequency
Operation
• Automatic Soft Start
• No Inductors
• Available in TDFN44-16 Package
Applications
• Color (RGB) Lighting
• White LED Backlighting
• White LED Photo Flash
Typical Application
V_IN
C_IN
1μF
EN/SET
EN_FLSH
C1
C2
C3
1μF
1μF
1μF
C1+ C1- C2+ C2- C3+ C3-
VOUT_FL
VIN
AAT2806
VOUT_BL
EN/SET
D1
EN_FLSH
D2
D3
GND
D4
V_{OUT_FLASH}
C_OUT
1μF
Flash
Backlight
D1
D2
D3
D4
C_OUT
1μF
2806.2006.04.1.8
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