Demonstration circuit 1228A is an isolated flyback converter featuring the LT3573. This demo circuit is designed for a 5.0V output from a 10V to 30V input. The maximum output current is 1A when the input voltage is higher than 20V. No third winding or opto-isolator is required for regulation. The part senses the isolated output voltage directly from the primary-side flyback waveform. The LT3573 operates with input supply voltages from 3V to 40V, and can deliver an output power up to 7W with no external power devices. The LT3573 utilizes boundary mode operation to provide a small magnetic solution with improved load regulation.