Patent ID: 7332993
Filing Date: 2008-02-19
Classification: H01F

Abstract:
1. A planar transformer comprising: a multilayer printed circuit board comprising more than two layers; a magnetic core coupled to the multilayer printed circuit board comprising a common leg and at least a first and a second return leg, the common leg and the first return leg forming a first core window and the common leg and the second return leg forming a second core window; a first coil comprising a first coil winding formed on one or more layers of the multilayer printed circuit board, the first coil winding passing through each of the first and second core windows; and a second coil comprising a plurality of coil windings formed on one or more layers of the multilayer printed circuit board, at least two of the plurality of coil windings comprising fractional turn windings, each of the plurality of coil windings passing through at least one of the first and the second core windows and being interconnected such that the sum of ampere turn products from all of the coil windings passing through each of the first and the second core windows is substantially equal to zero.