High-frequency large current handling transformer

A high-frequency large current handling transformer comprising:

• a higher-voltage side coil comprising a plurality of stacked planar coil members formed of metal, each having a window in a center portion thereof and a slit extending outward from said window through said planar coil member, said planar coil members each having first and second terminals disposed thereon on opposite sides of the slit in that planar coil member, and a plurality of insulating sheets each having a window in a center portion thereof and being interposed between and in direct contact with adjacent ones of said stacked planar coil members, the second terminal of each planar coil member being connected to the first terminal of adjacent planar coil member so that said stacked planar coil members can be connected in series, wherein the second terminal of each planar coil member is disposed over the first terminal of adjacent planar coil member;
• a lower voltage side coil comprising at least one planar coil member formed of metal, said planar coil member having a window in a center portion thereof and a slit extending outward from said window through said planar coil member, said lower voltage-side coil being placed on said high-voltage side coil;
• and
• a core extending through said windows in said high-voltage side and lower voltage side coils.