Researchers have developed a hybrid transformer that has the benefit of a full planar transformer design but uses a wire-wound secondary winding to keep the parasitic winding capacitances lower. Alone, planar transformers have the advantage of a lower profile and better reproducibility, but wire-wound transformers allow for less parasitic capacitances. By combining elements from traditional wire-wound transformers and planar transformers, the overall performance and reliability were improved.
The hybrid transformer consists of a split planar primary winding. Between two primary planar printed circuit boards (PCBs), the secondary winding is wound using a traditional wire-wound transformer technique instead of conventionally stacking PCBs, which can lead to high parasitic winding capacitances. In addition, the use of the wire-wound technique reduces the profile height of the transformer, which would benefit many industries seeking to reduce volume of their assemblies.
Separation between the primary and secondary wiring ensures the reliability of a high-voltage transformer instead of relying on manual taping processes. The lowered parasitic capacitances can be beneficial for high-voltage flyback transformers in which the parasitic secondary capacitance can significantly impact the output voltage performance.