I have a question. I have designed a small non-isolated power supply before, and used two identical Buck power chips to make two power supplies +5V and +8V. When the two outputs are loaded at the same time, +5V The output ripple of the power supply has oscillated. Only when the +8V output terminal returns to no load, the +5V output ripple returns to normal. How did this phenomenon cause this phenomenon? Have you encountered this phenomenon and how to solve it? ? Thank you!
This is the waveform diagram:
Kennedy Posted on January 18, 2021
C24=224 try
Skylar Posted on January 18, 2021
Thank you for your hint, I tested it, but no effect
Kennedy Posted on January 18, 2021
That is the problem of the input side. The two inputs are separated and two power sources (batteries) are connected. If it is not correct, there is interference on the board.
Eleanor Posted on January 18, 2021
Test the SW pins of the two circuits and look at the waveforms of both.
