This slide shows a typical LT3798 schematic for an offline flyback converter with a 24V constant output voltage. The LT3798 simplifies the design further by eliminating the need for an optocoupler and secondary-side reference voltage for output voltage feedback, all while maintaining isolation between primary and secondary with only one part (power transformer) having to cross the isolation barrier. During the switch off-period, the output diode delivers the current to the output, and the output voltage is reflected to the primary-side auxiliary flyback transformer winding which the LT3798 senses in order to regulate the output.