The LT8315 is a high voltage flyback converter with integrated 630V/300mA switch. No opto-isolator is needed for regulation. The device samples the output voltage from the isolated flyback waveform appearing across a third winding on the transformer. Quasi-resonant boundary mode operation improves load regulation, reduces transformer size, and maintains high efficiency.At start-up, the LT8315 charges its INTVCCcapacitor via a current source attached to the DRAIN pin. During normal operation, the current source turns off and the device draws its power from a third winding on the transformer.The LT8315 operates from a wide range of input supply voltages and can deliver up to 15W of power. It is available in a thermally enhanced 20-pin TSSOP package with four pins removed for high-voltage spacing.ApplicationsIsolated Telecom, Automotive, Industrial, Medical Power SuppliesIsolated Off Line Housekeeping Power SuppliesElectric Vehicles and Battery Stacks