Demonstration circuit 1517A is a monolithic high voltage isolated flyback converter featuring the LT3511. This demo circuit is designed for a 5V isolated output from an input voltage range of 36V to 75V. The maximum output current is up to 300mA. The circuit doesn’t require an opto-isolator, due to the output voltage being sensed directly from the primary side transformer winding. A third winding off the transistor is used to bias the LT3511 for highest efficiency.