I just have issues with the RGB LED flickering under low duty-cycle like 10% on time with 780 Hz. I tried changing the PWM frequency to lower and higher rate but I still see flickering at low duty-cycle (on time). This flickering only happens when I connect a bunch of MCU (PIC18F87J11 with 8 MHz oscillator) to a single voltage source (15 volts). I need some feedback so I can understand what's causing the problem since I don't know a lot about electronics. Here is a quick summary about the issue.
With 1 MCU connected to 12 volts , regardless of the PWM frequency or the duty-cycle, there is no flickering at all.
The more MCU I add, the more flickering I would see. In my case, I have 15 MCU connected to 15 volts power supply. At low duty-cylce I see flickering of the RGB lights. However, at high duty-cycle there is no flickering at all. Also lowering the PWM frequency a little bit helps with flickering on low duty-cycle but overall the flickering is visible and annoying.
Some questions ..
- What is the best-recommend PWM frequecny for RGB lights?
- Can I still avoid this flickering without any hardware changes just software?
- Can you help me understand how and what's causing the flickering?