1
\$\begingroup\$

I used TI Webench to spec out this boost converter circuit:

enter image description here

The design calls for an inductor that is marked as end of life. Can I use this inductor instead?

My hypothesis is that they are interchangeable. I think that if I boost from 3V to 5V with 80% efficiency, I should be able to draw 1.5A output by pulling 3.125A from the source. The original inductor was rated at 7A and the new one is rated at 18A max. Am I on the right track in my thinking here?

Also, the original had a maximum DC resistance of 14.7 mOhms. I decided that the lower value was better here. The new inductor has a DCR of 4.7 mOhms. Which is better? A higher or lower number for DCR? Why?

Are there any considerations that I missed? Will the inductor I selected work in this circuit?

\$\endgroup\$
1
\$\begingroup\$

Higher current and lower DCR are both good. I note that the substitute one is cheaper as well.

The one parameter that may be an issue is the SRF, which neither data sheet specifies. As they are essentially the same construction, if your switching frequency is reasonable, it probably won't be a problem.

The replacement is larger, which is encouraging, those better performance specifications are going to cost you somewhere.

\$\endgroup\$
1
\$\begingroup\$

Looks ok. Current rating is ok, saturation level ok and inductance ok. Lower Rdc means lower losses (assuming there are not significantly higher AC losses due to skin- and proximity effect), and no kind of damping required in this operating mode. The new one is larger, just to consider.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.