UCC28950: Transformer volume vs Frequency

Hello,

There is no author listed on this paper.  I am going to find the engineer that wrote this paper and will get the equations for you.

Regards,

Here is the equation:

fs is the switching frequency.

fs0 is the reference frequency for the graph. 

alpha and beta are Steinmetz coefficients for the core material.

The equation is derived by using the core geometry coefficient method for predicting optimal core size. The Kg coefficient is then scaled by the appropriate exponents to get a ratio of transformer volume. After this is done, most of the variables drop out of the result.

I hope that helps.

Please see the attached. Beta is ~2.7 and alpha is ~1.9

Yes, the graph is normalized to 100kHz.

Kgfe Background.pdf

If you substitute in the relationships for the of the Kfge equation (including the Steinmentz equation) you will get 2 results one at the normalized frequency (fs0) and one at the new frequency fs. Take the ratio of those equations and it will simplify to this result.