Patent attributes
A planar transformer is fabricated on a multilayer printed circuit board having more than two layers. A magnetic core includes a common leg and a first and a second return leg that form a first and second core window, respectively. A first coil includes a first coil winding formed on the circuit board. The first coil winding passes through each of the first and second core windows. A second coil includes a plurality of coil windings formed on the circuit board. Two or more of the plurality of coil windings include fractional turn windings. Each of the plurality of coil windings passes through at least one of the first and the second core windows and is 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.
