LM3533 Overview
The LM3533 is a plete power source for backlight, keypad, 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 to LVLED5).
LM3533 Key Features
- 1 Drives Two Parallel High-Voltage LED Strings for Display and Keypad Lighting
- High-Voltage Strings Capable of up to 40-V Output Voltage and up to 90% Efficiency
- Up to 30 mA 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
- Five Low-Voltage Current Sinks for Indicator LEDs
- Integrated Charge Pump for Improved Efficiency
- Internal Pattern Generation Engine
- Fully Configurable LED Grouping and Control