I've read your message twice and I still don't get your point. Saturation is a disaster, EMI wise, (not to mention what it can do to the current in some semiconductor devices) so as a designer you have to make sure you never go there. If you have a 6 amp peak current then use a choke rated for 6 amps RMS. Using any device outside it's rated parameters is cruising for a bruising.
Fred Townsend DC to Light Consulting Services Derek Walton wrote: > Good day all, > > I'm refining the input filter of a 150 watt SMPS. Nothing flashy, just a > few caps and a common mode choke. > > The current is drawn by the supply in short bursts as the DC link cap is > charged. I've shown that peak current reaches 6 amps for up to 2 ms. > I've also demonstrated that the CM choke, while rated for the RMS > current ( a 2 amp device ), does saturate when the current exceeds about > 4 amps. > > I've been trying to find out from the vendors, what current it takes to > saturate the CM choke. I've had answers from CM chokes can't saturate to > "that's not an important parameter, use the rms figure".... > > My question is, with over 20 potential vendors of this type of > component, is there any way I can find out saturation performance > without buying one of each type and testing it. I've played with 3 so > far, the most expensive was NOT the best! I guess, I'm curious why more > folks don't know about this effect also..... > > Thanks, > > Derek Walton > Owner > L. F. Research EMC Design and Test Facility > 12790 Route 76, > Poplar Grove, > IL 61065. > www.lfresearch.com > > --------- > This message is coming from the emc-pstc discussion list. > To cancel your subscription, send mail to [email protected] > with the single line: "unsubscribe emc-pstc" (without the > quotes). For help, send mail to [email protected], > [email protected], [email protected], or > [email protected] (the list administrators). --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
