AIC1841 Datasheet, PDF (1/17 Pages) Analog Intergrations Corporation – High Efficiency 1.5X charge Pump For White LEDs Backlighting

AIC1841/2
High Efficiency 1.5X charge Pump
For White LEDs Backlighting
FEATURES
1MHz Switching Frequency
2.7V to 5.5V Input Voltage Range
Low Shutdown Current: ≦1µA
Regulated 20mA Full-Scale Output Current
32-Position Linear Scale with Digital Control
High Accuracy Brightness Matching
33% Less Input Current Than Doubler Charge
Pump
No Inductors Required
Build-in Soft-Start
Current Limit and Over Temperature Protection
12-Pin (AIC1841) and 16-Pin (AIC1842) QFN
Package
APPLICATIONS
Cellular Phones
PDAs
Digital Still Cameras
Handheld Devices
White LED Backlighting
GENERAL DESCRIPTION
The AIC1841 and AIC1842 provide 4 and 6 LED
current source outputs with regulated constant
current for uniform intensity. The AIC1841/2 is the
low noise, constant frequency charge pump
DC/DC converter that uses 1.5X conversion to
increase efficiency in white LED applications. The
devices can be used to produce current levels up
to 20mA for each output from a 2.7V to 5.5V input.
Low external parts counts (two 1 μ F flying
capacitors and two small bypass capacitors at V_IN,
and OUT) make the AIC1841/2 ideal for small,
battery-powered applications.
EN/SET interface is used to enable, disable and
set the LED current for a 32 level logic scale LED
brightness control. Built-in current limiting, with
thermal shutdown provide protection to the
AIC1841/2 against fault conditions. Automatic soft-
start circuitry prevents excessive inrush current
during start-up. 1MHz high switching frequency is
enable to use tiny external components.
The AIC1841 is available in a 12-pin thin QFN
package, and the AIC1842 is available in a space-
saving 16-pin QFN package.
Analog Integrations Corporation 3A1, No.1 Li-Hsin Rd. I, Science Park, Hsinchu 300, Taiwan
TEL: [phone]
FAX: [phone] www.analog.com.tw
DS-1842P-02 041707
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