800 V breakdown, 10 W output — the parametric anchor
The VIPER16HN is an offline switching regulator from STMicroelectronics' VIPer™ plus series, integrating a power MOSFET with a current-mode PWM controller in a single 7-DIP package. Its 800 V breakdown rating means the internal switch survives the rectified DC bus from a universal AC input (85–265 VAC) with margin for line transients — no external clamping needed for most flyback designs up to 10 W.
Topology flexibility and switching behaviour
The part supports buck, buck-boost, and flyback topologies with either isolated or non-isolated output configurations. The 115 kHz fixed switching frequency keeps the transformer or inductor physically small while staying below the AM radio band — a practical choice for auxiliary supplies in appliance and industrial control boards. Maximum duty cycle is 70%, which limits the off-time and sets the volt-second product the transformer must handle. The 11.5 V to 23.5 V Vcc range and 13 V start-up threshold mean the IC powers up cleanly from the rectified line through an external resistor, then self-supplies from an auxiliary winding once switching begins.
Junction temperature and protection envelope
On-chip fault protection includes cycle-by-cycle current limiting and thermal shutdown. The current limit responds within each switching cycle, preventing transformer saturation on start-up or overload; the overtemperature sensor latches the output off until the junction cools, protecting the IC and the load from sustained fault conditions.