# How do I analyse a SEPIC circuit?

## Main Question or Discussion Point

Very simple question. The following circuit (I want to build one with my specs): https://en.wikipedia.org/wiki/Single-ended_primary-inductor_converter

How do I analyse it?

What I mean is that if a circuit has only capacitors, I use this. If it has only resistors, I use Ohm s Law, or Kirchhoff Laws. If it has capacitors and resistors I use the RC model.

Now, this one has capacitors, resistors, diodes, and inductors.... what set of equations can I use to analyse it and design one to my needs?

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analogdesign
And inductor isn't that much different from a capacitor in circuit analysis equations, it just has a different impedance, sL instead of 1/sC like a capacitor.

This is a switched circuit so it doesn't have a useful DC solution. You'll have to write out the equations for the two phases (when S1 is closed and when it is open). Use the solution of S1 closed as the initial condition of the case when S1 is open.

It looks like Maxim has an app note that explains it:
http://www.maximintegrated.com/app-notes/index.mvp/id/1051

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meBigGuy
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Thanks guys.