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| AAT3142_07 Datasheet, PDF (1/16 Pages) Advanced Analogic Technologies – High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications | |||
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AAT3142
High Efficiency 1X/1.5X/2X Charge Pump
for White LED Applications
General Description
Features
ChargePumpâ¢
The AAT3142 is a low noise, constant frequency
charge pump DC/DC converter that uses a tri-
mode load switch (1X), fractional (1.5X), and dou-
bling (2X) conversion to maximize efficiency for
white LED applications. The device produces cur-
rent levels up to 30mA on each of its three current
source outputs to drive various arrangements of
LEDs from a 2.7V to 5.5V input. Outputs may be
operated individually or in parallel for driving high-
er-current LEDs. A low external parts count (two
1µF flying capacitors and two small 1µF capacitors
at VIN and CP) make the AAT3142 ideally suited for
small battery-powered applications.
AnalogicTech's Simple Serial Control⢠(S2Cwireâ¢)
digital input is used to enable, disable, and set the
LED drive current with a 32-level logarithmic scale
LED brightness control. The AAT3142 has a thermal
management system to protect the device in the
event of a short-circuit condition at an output pin.
Built-in soft-start circuitry prevents excessive inrush
current during start-up. A high charge pump switch-
ing frequency enables the use of very small external
capacitors. In shutdown mode, the device discon-
nects the load from VIN and reduces quiescent cur-
rent to less than 1µA. The AAT3142 is available in
the very small, Pb-free 12-pin TSOPJW package.
⢠VIN Range: 2.7V to 5.5V
⢠Tri-Mode 1X, 1.5X, and 2X Charge Pump for
Maximum Efficiency and VF Coverage
⢠Drives Low-VF and High-VF Type LEDs
⢠Up to Three 30mA Outputs
⢠32-Position Logarithmic Scale with Digital
Control
⢠Low Noise Constant Frequency Operation
⢠1MHz Switching Frequency
⢠Small Application Circuit
⢠Regulated Output Current
⢠Automatic Soft Start
⢠No Inductors
⢠IQ < 1µA in Shutdown
⢠12-Pin TSOPJW Package
Applications
⢠Color (RGB) Lighting
⢠Programmable Current Sources
⢠White LED Backlighting
⢠White Photo Flash for Digital Still Cameras
Typical Application
VBATTERY
CIN
CCP
1μF
1μF
EN/SET
VIN
C1+
CP
C1-
C2+
AAT3142
C2-
D1
D2
D3
EN/SET
GND
C1
1μF
C2
1μF
D3
D2
D1
3142.2007.03.1.2
1
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