gdylp2004
Member level 5
Hello,
I've a +28V DC output from a SPMS Buck converter with a ringing phenomenon of 2V peak (or 4V pk-pk) as could see in the attached.
I've tried using many methods like:
But all seems to be useless. Recently, I've read about EMI filtering blocks and I've bought one to use (Model: BNX002-01 **broken link removed**). See attached.
Unfortunately the results (as in the ringings) never change.
The ringing period I've measured is about 80ns (hence about 12.5MHz).
Also, I've already separate the Analog GND with the power GND to reduce cross talk, and have packed all components as closely as possible. If assuming the buck system could no longer be modified. There should be something I could utilise?
And I would like to know if that something is it a form of filter, ferrite bead, EMI filter block, customised 2nd-stage filter using 2*pi*f = 1/√(LC)?
Looking at the effective suppression frequency range (underlined in red), could anyone tell me why on the EMI filter block is not suppressing any of the transients at the very least?
Please note I've already seperate the control circuit GND with the power GND but to no avail.
I just need a direction so that I could start researching on that part! Please help!
What EMI block should I use? Anyone could help me?
I've a +28V DC output from a SPMS Buck converter with a ringing phenomenon of 2V peak (or 4V pk-pk) as could see in the attached.
I've tried using many methods like:
- RC snubber across switch node
- RC snubber across V(gs) or even V(ds)
But all seems to be useless. Recently, I've read about EMI filtering blocks and I've bought one to use (Model: BNX002-01 **broken link removed**). See attached.
Unfortunately the results (as in the ringings) never change.
The ringing period I've measured is about 80ns (hence about 12.5MHz).
Also, I've already separate the Analog GND with the power GND to reduce cross talk, and have packed all components as closely as possible. If assuming the buck system could no longer be modified. There should be something I could utilise?
And I would like to know if that something is it a form of filter, ferrite bead, EMI filter block, customised 2nd-stage filter using 2*pi*f = 1/√(LC)?
Looking at the effective suppression frequency range (underlined in red), could anyone tell me why on the EMI filter block is not suppressing any of the transients at the very least?
Please note I've already seperate the control circuit GND with the power GND but to no avail.
I just need a direction so that I could start researching on that part! Please help!
What EMI block should I use? Anyone could help me?