文档介绍：July 1996 ?? TOPSwitch ? Flyback Transformer Construction Guide Application Note AN-18 Introduction This application note is a design and construction guide for margin wound or triple insulated wire wound flyback transformers suitable for use with TOPSwitch . Margin wound and triple insulated wire transformer designs are derived in Appendix B for a 12 V, 15 W universal input power supply with secondary regulation, using the step-by-step procedure developed in application note AN-16. It is assumed that the reader is already familiar with TOPSwitch and the fundamental principles of flyback power supplies. This information can be found in the TOPSwitch data sheets, and application notes AN-14 and AN-16. More details on flyback transformer theory and design can be found in AN-17. Required Reference Materials: This application note, AN-16, and AN-17 provide the necessary techniques for design and construction of flyback transformers for TOPSwitch applications. In addition, the following reference materials are required to provide dimensional and electrical data for cores, bobbins, and wire. Sources for these reference materials are listed in Appendix A. Ferrite Core Manufacturer’s Catalogs Ferrite core manufacturers publish catalogs supplying core dimensions and electrical characteristics used in transformer design. Some manufacturers also provide additional engineering information for the more popular core sizes, such as A L vs. gap and core loss curves. The catalogs for the manufacturers listed in Appendix A supply basic electrical data mon US, Asian, and European core types. For core mon to several manufacturers, the electrical characteristics given by one core manufacturer can be used for a core of the same physical dimensions from another manufacturer. Bobbin Manufacturer’s Catalogs Bobbin manufacturer's catalogs are used to provide mechanical dimensions for transformer design. The bobbin manufacturers in Appendix A offer a wide variety of bo