Abstract: A converter for converting AC to DC or DC to DC comprises a first transformer (10) having a secondary winding connected to a DC-load side of the converter, semiconductor switches connected to a primary winding of the transformer, a drive circuit configured to control the semiconductor switches to switch so as to deliver a voltage to the primary winding with a frequency exceeding 1 MHz and electronic components. The drive circuit comprises a second transformer (12) for voltage level shifting of said semiconductor switches with respect to a logic drive circuit unit of said drive circuit. The transformers are arranged inside or at the surface of a first printed circuit board (30), and the electronic components of the converter including said semiconductor switches are arranged inside or at the surface of a second printed circuit board (31). The two circuit boards are separated by a shielding ferrite layer (32) sandwiched therebetween.

Abstract: A printed circuit board transformer comprises at least one primary winding and one secondary winding, each in the form of at least one layer of turns inside or at the surface of a printed circuit board. The transformer is designed for a step-up/down-operation. Each of the two layers (10, 11) has an elongated winding element (12, 13, 13?) substantially following an elongated winding element of the other layer while being in an overlapping relationship therewith as seen perpendicularly to said printed circuit board over substantially the entire extension of said winding elements. A second (11) of the layers belonging to the secondary winding has a fewer number of turns than the first (10) of said layers belonging to said primary winding.

Abstract: A printed circuit board transformer comprises at least one primary winding and one secondary winding, each in the form of at least one layer of turns inside or at the surface of a printed circuit board. The transformer is designed for a step-up/down-operation. Each of the two layers (10, 11) has an elongated winding element (12, 13, 13?) substantially following an elongated winding element of the other layer while being in an overlapping relationship therewith as seen perpendicularly to said printed circuit board over substantially the entire extension of said winding elements. A second (11) of the layers belonging to the secondary winding has a fewer number of turns than the first (10) of said layers belonging to said primary winding.