Offline flyback converter with integrated 800 V MOSFET
The STMicroelectronics VIPER35HE is a monolithic offline flyback converter that integrates a 800 V avalanche-rugged power MOSFET with a PWM controller in a single through-hole package.
22 W output — sizing the supply rail
The 22 W power rating is the continuous output ceiling for an isolated flyback design at nominal input. The 800 V breakdown handles universal AC input plus reflected voltage and leakage inductance spikes.
Protection set and operating range
Built-in fault protections cover current limiting, over-temperature, over-voltage, and short circuit — no external comparator or supervisor needed. The 8.5 V to 23.5 V Vcc range and 14 V start-up threshold are standard for auxiliary windings in flyback converters.
The VIPER35HE is marked obsolete by STMicroelectronics. For new designs, consider current ST families, but verify pinout and compensation differences.