LP3933 Datasheet, PDF (1/18 Pages) National Semiconductor (TI) – Lighting Management System for Six White LEDs and Two RGB or FLASH LEDs

March 2004
LP3933
Lighting Management System for Six White LEDs and
Two RGB or FLASH LEDs
General Description
The LP3933 is a complete lighting management system
designed for portable wireless applications. It contains a
boost DC/DC converter, 4 white-LED drivers to drive the
main LCD panel backlight, 2 white-LED drivers for the sub-
LCD panel and two sets of RGB/FLASH LED drivers.
Both backlight drivers have 8-bit constant current drivers that
are separately adjustable and matched to 0.5% (typ.). The
RGB LED drivers are PWM-driven with programmable color,
intensity and blinking patterns. In addition, they feature a
FLASH function to support picture taking with camera-
enabled cellular phones.
An efficient magnetic boost DC/DC converter provides the
required bias for LEDs, operating from a single Li-Ion bat-
tery. The DC/DC converter output voltage is user program-
mable from 4.1V to 5.3V for adapting to different LED types
and for efficiency optimization. All functions are software
controllable through a SPI interface and 19 internal registers.
Features
n High Efficiency Programmable 300 mA Magnetic Boost
DC-DC converter
n 2 separately controlled PWM RGB LED drivers with
programmable color, brightness, turn on/off slopes and
blinking patterns
n FLASH function with up to 6 outputs, each up to 120
mA
n 4 constant current LED drivers with programmable 8-bit
adjustment (0 … 25 mA/LED)
n 2 constant current LED drivers with programmable 8-bit
adjustment (0 … 25 mA/LED)
n Functions software controlled through SPI interface
n Additional LED on/off and dimming hardware control
n Programmable low current Standby mode
n Low voltage digital interface down to 1.8V
n Space efficient 32-pin thin CSP laminate package
Applications
n Cellular Phones
n PDAs
Typical Application
© 2004 National Semiconductor Corporation DS200805
20080505
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