I’m currently working on a solution to power some SK6812 LED strips using a WT32-ETH01 Board which has an ethernet port I intend to use to improve reliability of my lighting.
I am using 2x 470 uF Capacitors with a 8A Fuse (which matches max output for my currently used PSU) for shared power to the strip/ESP32 and a 68R for the data line. PSU is Meanwell LPV-60-5. This seems to be in line with the recommendations and I expected it to work. It does, kind of, until the PSU loses power from a switch or outage or whatever and you want the ESP32 to come back to life.
As soon as my mains power line to the PSU is cut, the ESP32 on my board refuses to boot up after mains power is restored unless 5V line is also cut and restored after PSU power up. I suspected an issue I had read about GPIO12 and flash memory set into low power mode causing a brownout on boot but this does not seem to be the issue.
This also happens when the ESP32 is directly connected to the PSU, though not all the time as oppsosed to my full wiring, I assume capacitors are responsible for that.
ESP32 NodeMCU as well as any ESP8266 I tried show no issues at all using the same PSU.
I now suspect the voltage ramp up to be too slow, causing the ESP32 to brownout on boot. I’m not much of an electronics guy so I would not be able to make accurate measurements, I just used a cheap multimeter seeing 5V output at 4.6V before going to 5.15V. From what I have read, ESP32 might be a bit sensitive to low voltage on boot and this board in particular has to power not only the wifi module but also the ethernet module. For me this would be more of a timing problem than an actual problem with the voltage but this behaviour does counter my goal to improve reliability using ethernet.
Question is, do you think this issue could be resolved with another and hopefully more quality PSU? I haven’t tried disabling the brownout protection entirely which doesn’t seem to be a good idea anyway. As long as I can make the ESP32 boot, it works flawlessly.
I already have another PSU on the way but you guys might have another idea I haven’t thought about yet?