8.1 Overview

The LP503x device is a 30- or 36-channel constant-current-sink LED driver. The LP503x device includes all necessary power rails, an on-chip oscillator, and a two-wire serial I²C interface. The maximum constant-current value of all channels is set by a single external resistor. Two hardware address pins allow up to four devices on the same bus. An automatic power-saving mode is implemented to keep the total current consumption under 10 µA, which makes the LP503x device a potential choice for battery-powered end-equipment.

The LP503x device is optimized for RGB LEDs regarding both live effects and software efforts. The LP503x device controls each LED output with 12-bit PWM resolution at 29-kHz switching frequency, which helps achieve a smooth dimming effect and eliminates audible noise. The independent color-mixing and intensity-control registers make the software coding straightforward. When targeting a fade-in, fade-out type breathing effect, the global RGB bank control reduces the microcontroller loading significantly. The LP503x device also implements a PWM phase-shifting function to help reduce the input power budget when LEDs turn on simultaneously.