Hello,
I have a power supply designed following the guidelines of the LM5116 datasheet.
This power supply is generating EMI and interfering on radio devices.
I got the waves of the gate driving and inductor:
As we can see above, when the HS gate is driven, the LS gate (that was off) is also driven.
I suspect that this is the problem, because this is apparently a shoot-through. We can see that in
this moment the inductor have a spike of 15V greather than the Vin voltage (24V), reaching 40V.
I tried several things like:
1) Increase the gate resistor
2) Change the FET to a FET with a different gate charge
3) Minimize the distance between LM5116 and the gates
4) Use the VCCx with 5V, to supply the gate driver
5) And others....
None of these attempts has solved the issue.
The requirements that I used in the project was:
Input: 13V - 28V
Output: 3V
Max Output Current: 10A
The layout of my entire power supply is attached, and a ppt with a test done with different transistors and several
load currents.
I accept any suggestion.
Thanks a lot.
