US Patent 6914509 Transformer former between two layout layers

A printed circuit transformer includes a first wiring layer, a second wiring layer, a primary conductive coil including a first conductive trace, a second conductive trace, a third conductive trace, and a fourth conductive trace, which are on the first wiring layer or the second wiring layer, a first via plug, a second via plug, and a third via plug for connecting the ends of the conductive traces in the primary conductive coil, and a secondary conductive coil including a fifth conductive trace, a sixth conductive trace, a seventh conductive trace, and a eighth conductive trace, which are on the first wiring layer or the second wiring layer, a fourth via plug, a fifth via plug, and a sixth via plug for connecting the ends of the conductive traces in the secondary conductive coil.