US Patent 7436277 Power transformer

A multi-phase transformer is provided that includes a first layer having at least a first planar wire and a second planar wire and a second layer formed on the first layer and having at least a third planar wire and a fourth planar wires. At least the first planar wire and the second planar wire of the first layer to form two transformers with at least two planar wires of the second layer. The multi-phase transformer may also include a coupling device to couple one end of the planar wires of the first layer with one of the planar wires of the second layer.