I am building a 16x11 LED matrix which has 176 cells.
- The power supply unit must be placed 20~25 meters away from the LED matrix.
- The size of each cell is 30cm x 30cm. Each cell contains 2~4 WS2812 units.(datasheet)
- A micro-controller which is placed near the matrix to send signals to the WS2812 LEDs
The challenge is to come up with a proper power distribution design and how to provide a stable ground reference for the LED matrix and the micro-controller.
Here is what I am planning to do, a diagram is attached:
- Assign one PCB to each cell. The PCB contains a bulk converter(step down to 5V), 2 x WS2812 LED, and two RJ45 connectors to connect each PCB together (see attachment for a schematic of the PCB). The reason to use a buck converter is to eliminate the voltage drop caused by the long power cable as well as to make sure each LED has enough power for full brightness.
- Each led at full brightness consumes about 0.5W, one row has 16 cells, each row consumes about 0.5w x 2leds/cell x 16 cells = 16W. Adding other factors such as wires and bulk converter. I can assume each row consume about 24V x 1A = 24W
- At the location of the PSU, which I choose a 24V, 350W unit, split the power into 12 channels: 11 channels to 11 rows and 1 channel to MCU. Each channel is protected by a 2A PTC resettable fuse. I try to avoid high current power wires. This is probably a bad design. It would mess up the ground reference since each row doesn’t consume the same power when the matrix is doing its thing. How should I distribute the power?