General Description
●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 provides 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.
●Features
● Drives Two Parallel High-Voltage LED Strings for Display and Keypad Lighting
● 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
● PWM Input for Content Adjustable Brightness Control(CABC)
● Five Low-Voltage Current Sinks for Indicator LEDs
● Integrated Charge Pump for Improved Efficiency and VIN Operating Range
● Internal Pattern Generation Engine
● 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
●Applications
● Power Source for Smart Phone Illumination
● Display, Keypad and Indicator Illumination
● RGB Indicator Driver
