Overview

Controller board for a lighting fixture with 960 RGBWW LEDs. This controller drives a chain of 30 LedBoard's, each with 32 LED packages. Each package contains four LED dies (reg, green, blue and warm white), which makes for a grand total of 3840 LED dies, across the 30 boards. Each LedBoard also has two DM633 constant-current LED drivers, which each have 16 channels. Each channel has an individual 12-bit PWM. The 30 LedBoard's contain a total of 60 drivers, for a total of 960 individually controllable channels. The LEDs are arranged in groups of four, so every driver channel controls a single color of four LED packages.

LedBoard: https://workspace.circuitmaker.com/Projects/Details/Wouter-Devinck/LedBoard

The controller board is packed with functionality:

• Espressif ESP32 dual core microcontroller with WiFi and Bluetooth, on a certified ESP-WROOM-32 module
• Lattice ice40 UltraPlus FPGA responsible for sending the serial data to the LED drivers (12 bit brightness value for all 960 channels @ 120 fps)
  • With a configuration SPI flash, also writable by the ESP32 during OTA firmware upgrade
  • With an EEPROM to store animation sequence to be shown during microcontroller boot
• RGB status LED (WiFi connection etc.)
• Crypto chip for secure connections to IoT frameworks
• Sensors:
  • Current sensor measuring total current on 15V DC rail (limited to 8A for total fixture = 120W)
  • Digital microphone
  • IR receiver
  • Light sensor
• Power supply:
  • Passthrough 15V DC input to LedBoard chain (for current measurement)
  • Generates 5V DC rail from 15V for LED drivers logic supply (output to LedBoard chain)
  • Generates 3.3V DC rail for all controller logic and for the ESP32
  • Generates 1.2V DC rail for FPGA core supply

Block diagram

Layer stackup

This is a four layer board.

• Top: components & signal
• Internal 1: ground plane
• Internal 2: signal
• Bottom: power & signal

Bill of materials

Revision history

v1 - May 2018 - Boards ordered and to be assembled and tested (order here)