Low profile surface mount transformer

Abstract

A transformer is provided that consists of a primary winding, a secondary winding and a magnetic core. The primary winding is wound directly around the magnetic core, thereby removing the need for a bobbin. By removing the need for the bobbin, the transformer has a large window utilization factor, and associated low profile. As a result, the transformer has a high power to form factor ratio. A method for making the transformer includes the steps of joining two halves of the core before winding the primary winding. Because the half-cores are joined prior to the wrapping of the primary winding, the core provides bobbin functionality. In addition, a header plate is provided for coupling a plurality of leads of a transformer to sources on an integrated circuit board, where the transformer consists of a magnetic core, a primary winding and a secondary winding. The header plate engages the magnetic core, providing a termination path for the wire of the secondary winding. In addition, the header plate assists in providing electrical insulation for the core while providing a mechanism for ensuring that electrical safety constraints between the primary winding and the core are satisfied.