Simplified transformer design for a switching power supply

摘要

A transformer has a primary winding made from a first conducting trace formed on a first multilayer printed circuit board, and a secondary winding made from a second conducting trace formed on a second multilayer printed circuit board. The primary winding is magnetically coupled to the secondary winding. The windings are etched as traces in copper layers of the PC boards as spirals. The spiral of one copper layer is connected to the spiral of a different copper layer by a via, or vias, formed through the insulating layer of the PC board. The vias are drilled, cleaned, and plated with conducting material, for example copper. By using multiple layers, and by connecting spiral windings of each layer to the windings of the next layer by use of vias, any number of turns can be built into a primary winding, or into a secondary winding.