EMI AC/DC design

Benjamin Couture

Hi,

I'm trying to find some information on EMI for isolated AC/DC converter. There is plenty on DC/DC not so much for isolated AC/DC. It's for a high precision, high performance ADC (40Mhz, 625ksps). What I need is a 3.5V and 6V, about 5Watt each.

Could I have some guidance in which topology might be best for me? Should I consider AC/DC and then a couple DC/DC? What are the recommanded noise mitigation? Efficiency and cost is not as much of an issue. Also we would like to have the power supply in the same compartment than the converter, would a aluminum box be enough to block all EMI?

Any recommandation would be greatly appréciated, especially that there is not as much info on AC/DC converter that there is for DC/DC.

Thank You,

Benjamin Couture

over 6 years ago

0 Hong Huang over 6 years ago

TI__Guru 73215 points

Can you search on the web first? There are plenty of such materials from the beginner to the very sophisticated. If a particular TI device is involved in your design, please provide that device and associated EMI conderation so we can make help.

0 Benjamin Couture over 6 years ago in reply to Hong Huang

Prodigy 140 points

Hi Hong Huang,

Thanks for the reply. I do agree that their is a lot of information on mitigation for the circuit designing part (layout and some about filters). What I don't seem to find is if their is some preference for some topology over an other in the AC/DC. When it comes to DC/DC, such info is much more available.

Same thing could be said about the choice of the controller component. When it's a DC/DC I can easily find controllers which are designed specifically to minimise EMI. Minimal EMI doesn't seem to be a selling point for AC/DC controllers.

My guess for now is that topology and controllers has little to do in EMI, and that mostly in depends on layout. And I haven't found anything about making (2 x AC/DC) vs (1 x AC/DC+ 1 or 2 x DC/DC). Both design seems common.

But if anyone has a prefered topology or controller for EMI I would love to hear it.

Thanks,

Ben