PLANAR TRANSFORMER AND RESONANT CONVERTER

摘要

In the present invention, a planar transformer comprises: a flat primary coil in which a spiral-shaped conductive first coil pattern is formed on an insulative substrate; and a pair of flat secondary coils in which a spiral-shaped conductive second coil pattern is formed on the substrate. The flat primary coil is disposed between the pair of flat secondary coils, and the flat primary coil and the pair of flat secondary coils are electromagnetically coupled to each other. Electrostatic-connection shield members, formed of a thin-plate conductive material, are disposed between the flat primary coil and the flat secondary coils. According to this transformer, while reducing electrostatic coupling capacitance and keeping size down, voltage conversion efficiency can be improved and the coils and a core can be effectively cooled.