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vorobey
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How to understand MAX25431 datasheet on inductor selection?

I am trying to design a project featuring MAX25431 buck-boost converter. After examining the datasheet I started the part selection for my application, but I have troubles understanding few details:

  • In the first image the inductor value is calculated from the max/min duty cycle in boost/buck modes respectively. In their equations the converter efficiency is used, and further down in the example it is selected as 95% on much more than inductance value and other values, so why they just throw this value like this?
  • Second question is why LIR is chosen to be so high? According to what I read online it is supposed to be around 30%.
  • And the last question is why the 2nd example that they give on image 2 is really different from 1st image?

enter image description here

vorobey
  • 113
  • 8