Hi guys
I'm a EE student on placement and I've just taken over an existing power supply design that was never EMC tested. We are now wanting to put the design into a system that needs to be certified for EMC class A (EN 55032 CISPR 32). I took the system to the EMC test house the other day for some pre-compliance testing and it failed, miserably.
We determined that it was the AC/DC power supply that was the source because the system was still failing with just the power supply in the test rack.
We are using a PFE500SA-48 from TDK-Lambda as the main power module and have used the same supporting passives as they used for there in house verification. (See attached schematic).
Some notes from the pre-compliance:
- It failed both emission and immunity
- When we increased the size of the earthed chassis the results were worse
- It was failing at around 30MHz (Ive attached some results)
- It was broadband interference
Any experience would be appreciated.
Thanks