Hi,
I checked all LLC synchronous rectifiers and none of them was for non-center tapped secondaries.
Center tapped secondaries have poor transformer utilization (because you basically use half of the turns in every half cycle).
I now a current doubler could be used to increase the power rating but then you are basically storing energy which implies decreasing the power density due to the size of the passives. (My frequency is rather low and thus the inductor becomes pretty large)
If I’m missing something, please let me know.
Best regards
The synchronous rectifiers that MPS has that are designed for LLC resonant converters rely on center tapped secondary windings for the following reasons:
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The center tapped design enables two FETs to conduct alternately during every half-cycle of the AC waveform, which simplifies the rectification process overall. Non-center tapped designs would require a full bridge or dual SR FET for each phase, increasing both complexity and cost.
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Non-center tapped solutions require isolated or floating gate drivers whereas center-tapped designs share a common source for the FETs, making the gate driving process simpler and avoids the need for level shifting. This is critical for common high frequency LLC designs and applications.
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Having a center tapped LLC resonant converter operating at high frequencies would minimize the effects of any patristic inductance, which increases overall efficiency.
I suppose I can see why you are asking such questions as you are correct that these designs have relatively poor transformer utilization when compared to a full bridge topology. Given that your application involves a low frequency due to your inductor size, have you considered the Full-Bridge Synchronous Rectifiers MPS offers for your application?
Best,
Krishan
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