I think the limitation is my own knowledge of this LEDC library. When I run it with the frequency value of 25,000 it doesn’t output anything on my GPIO pin that I can detect with my multimeter.
Thanks for typing this up! This helps me understand a lot more about what is going on.
I may have purchased too large of cap for the first try: 470uF. I bought it online so still waiting for arrival. I’ll get some in the 40uF to 200uF range for more testing
Interesting suggestions, I would not have tried such low frequencies except based on your suggestion and it turns out that going very low, below 1000Hz and even down to 100Hz causes the power supply whine to almost entirely go away. I also have a 470uF capacitor in between the power rails now too.
This range is a usable - there is no visible flickering even at very low duty cycles.
From what I understand in the reference guides the LEDC library attaches directly to the 80mhz or 40mhz esp32 hardware clock for PWM. Intuitively I’d have guessed that higher frequency would always mean less discernable audible feedback, but seems not in this case.
Ok, good thinking. I settled on 1000Hz and also made it something in remotely reconfigure should the need arise. That combined with the other suggestions, and getting a better power supply has made the system whisper quiet now.
How to solve power supply whine with continuous dimming LED? (imgur.com)
My project is a “breathing” white 12v LED strip controlled by an esp32 on a dev board, and switched with an IFLZ44N mosfet....
I made a website that tells you, based on the year you graduated high school, what your school (probably) got wrong! (yourschoolgotwrong.com)
This is an Octobass (sh.itjust.works)