The problem starts with my 3D printer which is powered by a 12V SMPS. When it drives a heavy load such as heated base and hot end, it causes a ripple on the 12V rail. Also it affects the 5V rail with the same ripple as the image shows.
Note: My printer uses Ramp 1.4 with Arduino Mega2560
Chanel A is 5V from Arduino Mega, Chanel B is 12V from PSU.
What I want to know is:
- How does this happen? As I know, voltage regulator should regulate all above 5V+(dropout voltage), so it should be a flat 5V line.
- How to fix or prevent this? (Do I need to add some component filter or change regulator ICs?)