In the DCDC circuit, there will occasionally be abnormal noise on the board

zhangdaoyu

In the DCDC circuit, there will occasionally be abnormal noise on the board [Copy link]

 

The circuit boards on the product occasionally make unusual noises near the power chip. After analyzing one of the boards, we found that it was caused by a capacitor in the later stage, but this capacitor is indispensable. Most boards have no problems. How to solve or avoid this individual phenomenon? I have encountered it once before and it was normal when in use. Will this be a hidden danger?

吾妻思萌

I have encountered two types: 1. The circuit board is installed in the chassis and vibrates. You can see if there is a gap between the capacitor welding and the board contact. 2. The inductor vibrates and howls.

zhangdaoyu

This problem seems to be difficult to check. I remember encountering it when I was making a power charging board 10 years ago. A colleague spent a lot of time to check it.

zhangdaoyu

Even if the current board is good after adjusting the parameters, you will still encounter noise when using this parameter in batches.

chunyang

You can consider choosing a suitable capacitor to solve the problem, and sometimes changing the PCB design can also improve the problem.

zhangdaoyu

chunyang posted on 2023-4-12 15:23 You can consider choosing a suitable capacitor to solve the problem. Sometimes changing the PCB design can also improve the problem.

Thank you Teacher Chunyang. To be honest, I am looking forward to your reply!

zhangdaoyu

Today I encountered a board with an unusual noise. I removed all the power supply related tubes, cleaned them, re-welded them, and replaced some with new ones. Then it was fixed. This solution is for your reference only.

led2015

Since it is fixed by re-soldering, it may be a soldering problem, or it may be due to a problem with the power chip itself, or it may be caused by the resonance of components such as capacitors and inductors.