LM3533
Complete Lighting Power Solution for Smartphone Handsets
General Description
Features
The LM3533 is a complete power source for backlight, key-
pad, and indicator LEDs in smartphone handsets. The high-
voltage inductive boost converter provides the power for two
series LED strings for display backlight and keypad functions
(HVLED1 and HVLED2). The integrated charge pump pro-
vides the bias for the five low-voltage indicator LED current
sinks (LVLED1-LVLED5). All low-voltage current sinks can
have a programmable pattern modulated onto their output
current for a wide variety of blinking patterns.
Drives Two Parallel High-Voltage LED Strings for Display
and Keypad Lighting
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High-Voltage Strings Capable of up to 40V Output Voltage
and up to 90% Efficiency
Up to 30mA per Current Sink (Both Backlight and
Indicator)
14-Bit Equivalent Exponential Dimming with 8-Bit
Programmable Backlight Code
Selectable Analog ALS Input with 128 Programmable Gain
Setting Resistors or PWM ALS Input with Internal Low
Pass Filter
Additional features include a Pulse Width Modulation (PWM)
control input for content adjustable backlight control, and an
Ambient Light Sensor interface (ALS) with an internal 8-bit
ADC to provide automatic current adjustment based upon
ambient light conditions. Both the PWM and ALS inputs can
be used to control any high- or low-voltage current sink.
The LM3533 is fully programmable via an I2C-compatible in-
terface. The device is available in a 20-bump (1.755mm x
2.015mm x 0.6mm) micro SMD and operates over a 2.7V to
5.5V input voltage range and a −40°C to +85°C temperature
range.
PWM Input for Content Adjustable Brightness Control
(CABC)
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Five Low-Voltage Current Sinks for Indicator LEDs
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Integrated Charge Pump for Improved Efficiency and VIN
Operating Range
Internal Pattern Generation Engine
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Fully Configurable LED Grouping and Control
Four Programmable Over-voltage Protection Thresholds
(16V, 24V, 32V, and 40V)
Programmable 500kHz and 1MHz Switching Frequency
27mm2 Total Solution Size
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Applications
Power Source for Smart Phone Illumination
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Display, Keypad and Indicator Illumination
RGB Indicator Driver
TYPICAL APPLICATION CIRCUIT
30135701
PRODUCTION DATA information is current as of
publication date. Products conform to specifications per
the terms of the Texas Instruments standard warranty.
Production processing does not necessarily include
testing of all parameters.
301357 SNOSC68A
Copyright © 1999-2012, Texas Instruments Incorporated