DM Choke Saturating

But what is the peak current This is the term that is usually completely underestimated by most designers, and that is why they often don t realize that their DM choke is ineffective because it is saturating. 

The temptation to wind a few more turns on the DM choke (if present of course) in an effort to raise its inductance may just produce enough ampere-turns to saturate it. What happens 

So in DM chokes, the major concern is core saturation. But in CM chokes, underestimating the current will make it run excessively hot, due to higher copper losses. 

Knowledge of the input RMS current is necessary to correctly estimate the copper losses in both the CM and DM chokes, whereas knowledge of the peak current is necessary to correctly estimate the DM core volume (its energy handling capability). In a CM choke, the input ac line current effectively cancels out, so its saturation is usually not considered either a possibility or a concern. That means it is chopped out of a vertically offset sine wave of that time period. 

The RMS and average values of the current waveform (calculated only over the diode conduction time) are, respectively, 

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