16 W flyback with an 800 V avalanche-rugged MOSFET
The STMicroelectronics VIPER28HD is a monolithic flyback PWM controller integrating an 800 V avalanche-rugged power MOSFET and a current-mode control circuit in a single 16-SOIC package. It delivers up to 16 W in an isolated flyback topology — a common power stage for auxiliary supplies in appliances, industrial control boards, and three-phase meter power feeds. The 115 kHz switching frequency lets the designer shrink the transformer core and output filter compared to 60–70 kHz designs, saving board area without pushing into the conducted-EMI trouble zone of 150 kHz+.
Fault protection set reduces external supervision
On-chip fault protection covers current limiting, over-temperature, over-voltage, and short-circuit events — four protection domains that would otherwise require a supervisor IC or discrete comparator network. The 80% maximum duty cycle is typical for a flyback running in continuous-conduction mode, giving the transformer reset margin. The 14 V start-up voltage and 8.5 V to 23.5 V Vcc range suit the wide rail swings seen in bulk-capacitor-fed offline supplies.