Patent ID: 9576717
Date: 2017-02-21
CPC Classifications: H01F,Y10T

Claim:
1. A multi-layered printed circuit board, PCB, for providing coplanar first windings for a first side of a planar magnetic transformer and coplanar second windings for a second side of the planar magnetic transformer, the multi-layered PCB comprising: a plurality of coplanar conductive layers configured to provide the coplanar first windings; a plurality of coplanar conductive layers configured to provide the coplanar second windings; and a plurality of layers of an isolation material; wherein: each layer of the isolation material is arranged between an adjacent pair of the coplanar conductive layers to provide electrical isolation between said adjacent pair of the coplanar conductive layers, a group of two or more adjacent coplanar conductive layers are all coplanar conductive layers of the coplanar first windings and are all arranged between coplanar conductive layers of the coplanar second windings, wherein the thickness of the isolation material between at least one of the adjacent pairs of the coplanar conductive layers in the group of layers of the coplanar first windings is less than the thickness of the isolation material between a conductive layer of the coplanar second windings and a conductive layer of the coplanar first windings, the isolation material comprises a substrate that is between an adjacent pair of the coplanar conductive layers of the coplanar second windings, the isolation material between a conductive layer of the coplanar first windings and a conductive layer of the coplanar second windings comprises pre-preg, and the thickness of the substrate has a value in the range of 90 μm to 110 μm and the thickness of the pre-preg has a value in the range of 157.5 μm to 192.5 μm.