an18TOPSwitch 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. Ferrite Core Manufacturer’s C……