# How can design a transformer for an LCC resonant converter.

#### HRN88

Joined Jul 21, 2020
24
Hi guys!!

I need to design a transformer for a LCC resonant converter. I've calculated the values for the Ls, Cs and Cp to work at the desired resonant frequency and to work on a wide range of output load.

Now the challenge is that I don't know how calculate the transformer and I don't find something info about that. What would be calculated the inductance and from there use the well known formula Vp/Vs = Np/Ns

#### HRN88

Joined Jul 21, 2020
24
Hi lan0, the first one yes, I have read it. But both application notes are for a LLC resonant converter, in my case is an LCC.
For the LLC the magnetizing inductance of the transformer is part of the resonance frequency, so including that relation in the equations is easy to solve for Lm and then for the transformer.

But not for the LCC that its frequency depends on Ls, Cs and Cp.

#### Ian0

Joined Aug 7, 2020
8,947
Hi lan0, the first one yes, I have read it. But both application notes are for a LLC resonant converter, in my case is an LCC.
For the LLC the magnetizing inductance of the transformer is part of the resonance frequency, so including that relation in the equations is easy to solve for Lm and then for the transformer.

But not for the LCC that its frequency depends on Ls, Cs and Cp.
That's not such a popular design. Could you post your circuit?

#### HRN88

Joined Jul 21, 2020
24
Of course. And yes it isn't a popular design, so it was hard get documentation. In this simulation I put the calculated values for Ls, Cs, and Lp.

The transformer value was selected by guesswork and run the simulation jajaja. But I need to feel confident with the result because all the design and that transformer will be manufactured.

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#### Irving

Joined Jan 30, 2016
3,548