ESP32 based controller for high-current PWM dimming and long-distance addressable LED driving
- 4x 12V fault-protected differential output digital channels for addressable LED strips
- 4x 30A 0-26V open-drain PWM channels for RGB(W) or single colour LED strips
- 4x isolated optocoupler inputs (0-50V) in two groups
- Onboard programmer using CP2102N USB-UART bridge
- Fused connections on all output power ports - ATO/ATC fuse holders
- Two pinheaders for analog inputs
- Small outline - 100x100mm
- Optional TVS diodes when assembled using cheaper transceivers
- Compatible with the WLED project
- You can find the gerbers, BOM, and PnP files in the Outputs folder if you want to manufacture your own!
The 4 independent PWM channels are open-drain outputs tested at 30A load. With adequate cooling, it can handle more. The FETs have TVS diodes, snubbers and flyback diodes protecting them.
The 4 digital channels use THVD2450 transceivers for reliable long-distance addressable LED control. You can solder the in-line receiver module to the LED strip at the first pixel.
The 12V input is routed to the digital channels, and the 24V input is for the PWM LED strips (voltage range 0-26V). The control works from both the 12V and 24V inputs, however it needs the 12V input for the PWM gate drivers. Without +12V connected, the PWM will not work.
The differential outputs need a receiver module on the LED side.
If using long and/or thin wire runs on the PWM channels, the inductive kickback energy generated might overwhelm the Schottky diodes. As their temperature increases from increased dissipation, so will their leakage current (from 50µA at 25°C to about 4mA at 100°C). This means:
- at a certain wire length and power they will start to overheat,
- even if the channels are turned off, high-efficiency LEDs might still be giving off a dim light.
For this reason, driving motors and other highly inductive loads is ill-advised for this revision. To reduce this effect as much as possible, use tightly coupled thick wires.
When using multiple channels at maximum current, the board probably needs cooling. I haven't got the time to test for exact numbers.
The USB-UART bridge IC needs to be configured to toggle the RX/TX leds - this is done with Silicon Labs' own tool. The whole USB-UART section could be replaced with a CH340 alternative for lower cost, but I wanted to use parts readily available from EU/NA distributors.