800 V breakdown, 10 W flyback — the offline power stage
The STMicroelectronics VIPER15LDTR is a monolithic offline flyback converter from the VIPer™ plus series, integrating the PWM controller and an 800 V avalanche-rugged power MOSFET in a single SO-16 package. It delivers up to 10 W in isolated flyback topologies, switching at 136 kHz — a frequency that balances transformer size against switching losses for auxiliary and bias supplies in appliances, industrial power supplies, and AC-DC adapters.
Parametric profile for the flyback design
The 800 V breakdown voltage provides adequate derating margin for universal-input (85–265 VAC) offline flyback designs, including those with reflected voltage spikes from the transformer leakage inductance. The 10 W output power ceiling is a practical limit for auxiliary supplies in motor drives, home appliances, and industrial control boards. The 136 kHz switching frequency allows a smaller transformer core than a 60 kHz design, though the higher frequency demands careful layout to manage EMI and gate-drive losses. Integrated protection includes current limiting, over-temperature shutdown, and over-voltage protection — all on-chip, reducing external component count. The start-up voltage is 14 V, and the Vcc operating range is 8.5 V to 23.5 V, accommodating the auxiliary winding voltage variation across load and line.