Compare Soft Saturation vs. Regular Inductor - Switching

Mike DonnellyDesigner19

Mike Donnelly

Member for

8 years

1,122

designs

groups

Original member of the PartQuest Explore development team. Modeling and Applications Specialist

269 views total

177 views today

Description

<p>This design shows the importance of choosing the right inductor size and type, to avoid saturation-induced current spikes during operating transients. In this case, the start-up transient in two nearly identical open-loop buck power stages (12V -&gt; 3V) is examined. The only difference is that the top circuit is using an inductor calibrated to a Coilcraft XAL6060-223 (22uH), which has "soft saturation" behavior. The bottom circuit is using a similarly sized inductor, but with a more typical "hard saturation" characteristic.</p><p>Both inductors work well for the steady-state load condition of 3 Amp. But during the turn-on transient, that current can go significantly above that nominal level. At that time, the instantaneous inductance of the hard-saturating device collapses, resulting in even larger current spikes in each switching interval. Note in the waveforms on the left: The soft-saturation inductance drops to 14uH minimum during the transient, whereas the hard-saturation inductance crashes to near 2uH, or only 10% of its nominal value!</p>

About text formats

What's this?

Please login or register to post comments

You must be a registered user to add a comment.

Design Notification Block

Thanks for trying out PartQuest Explore

Mike DonnellyDesigner19

Mike Donnelly

Member for

Please login or register to post comments

Design Notification Block

Thanks for trying out PartQuest Explore

Mike DonnellyDesigner19

Mike Donnelly

Member for

Please login or register to post comments

Design Titleby Mike Donnelly

Embed Design

Copy Embed Code

Embed Live Design

Copy Embed Code

Share a Link

Copy URL