Switching Power Supplies A - Z

DC-DC Converter Design and Magnetics

and a peak flux density of

B

PK

=

r + 2

2 × r

× ∆B =

0.438 + 2

2 × 0.438

× 1174 = 3267 gauss (any topology)

In our application this will give us a swing of

∆B =

Et

Et

100

× 200 =

38

10.12

× 200 = 751 gauss (any topology)

and a peak of

B

PK

=

r + 2

2 × r

× ∆B =

0.277 + 2

2 × 0.277

× 751 = 3087 gauss (any topology)

We see that the peak field in our application is within the design limits of the inductor, as

expected, so we need not worry about core saturation. This is a basic qualification the

inductor must pass before we can proceed with the rest of the analysis.

Note that the proportionality constant connecting B and I is

L

NA

=

B

PK

I

PK

=

3087

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