LP3936 Datasheet, PDF (1/20 Pages) National Semiconductor (TI) – Lighting Management System for Six White LEDs and One RGB or FLASH LED

June 2004
LP3936
Lighting Management System for Six White LEDs and
One RGB or FLASH LED
General Description
LP3936 is a complete lighting management system de-
signed 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 sub-LCD panel and
1 set of RGB LED drivers.
Both WLED groups have 8-bit programmable constant cur-
rent drivers that are separately adjustable and matched to
1% (typ.). For efficient backlighting the backlight intensity
can be adjusted using the 8-bit ADC with ambient light
detection circuit.
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 converter provides the required
bias operating from a single Li-Ion battery. The DC/DC con-
verter output voltage is user programmable for adapting to
different LED types and for efficiency optimization. All func-
tions are software controllable through an I²C and
MicroWire/SPI compatible interface and 16 internal regis-
ters.
Features
n High Efficiency 250 mA Magnetic Boost DC-DC
Converter with Programmable Output Voltage
n PWM controlled RGB LED drivers with programmable
color, brightness, turn on/off slopes and blinking
n FLASH function with 3 drivers, each up to 120 mA
current
n 4 constant current White LED drivers with
programmable 8-bit adjustment (0 … 25 mA/LED)
n 2 constant current White LED drivers with
programmable 8-bit adjustment (0 … 25 mA/LED)
n 8-bit ADC for ambient light sensor with averaging
n Combined MicroWire/SPI and I²C compatible serial
interface
n Low current Standby mode (software controlled)
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
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