EMC circuit protector

Hello,
I need to know how to protect my circuit from EMC test. My input voltage is 24V(3A) and after a pole diode( for preventing from reverse voltage) and TVS diode it goes to my regulator(MinMax dc-dc). How can I increse my protection?

Hi,

Sure you mean EMC?

Your description rather sounds like "ESD" or "Surge pulse" ....

EMC is high frequency. You may protect against EMC problems by using a low pass filter.

ESD is high voltage, with relatively low energy. You may protact against ESD problems by using a ESD protection diode.
Surge is not that high voltage as ESD but with much higher energy. To protect against surge pulse problems you need an (extra) device that is able to dissipate that high energy.

***
But there are more than enough documents around. Every protection_device_manufacturer provides detailed application notes. They are free to use, so take your chance ;-)

Klaus
Klaus

Dear KlausST,

Thank you for your comment and you useful info. I have heard that my PCB should be checked for EMI/EMC test which my board is not a high-frequency board it just has Ethernet Connection+Max485 communication.

Hi,

Independent whether your board includes HF or not: The EMI and EMC test is a HF test.

EMC test: your application (DUT) is placed in an HF test chamber. Within the chamber an antenna sends HF to your application. Somebody has to watch whether your application still works properly or fails.
EMI test: the DUT is placed in an HF test chamber. Within the chamber an antenna receives HF sent out of your application. And be sure: if your application includes Ethernet and RS485, then it will send out HF.
A whole band of frequency is scanned. There are limits for each frequency. Your application needs to be below each limit.

Usually such tests also include ESD tests and surge tests.
Values, levels, frequency area, test methods, limits ... and so on depend on your application.

--> Please contact your test house for further detailed informations.

Klaus

Ethernet interfaces can easily fail radiated EMI test if not properly designed.

Necessity and voltage level of supply surge test depends on the device type and how it's powered in the final application. Can't say much about it without detail information.