Offline switcher for 12 W auxiliary supplies
The STMicroelectronics VIPER115LSTR integrates the power MOSFET and control logic into a single 10-SSOP package. It handles buck, buck-boost, and flyback topologies at a fixed 60 kHz switching frequency, with an 800 V breakdown MOSFET.
Built-in protection and soft start
Soft start limits inrush on the output cap during power-up, which saves you from oversizing the bulk capacitor or adding an NTC. Over-load and over-voltage fault protection are on-chip — no external comparator needed. The 16 V start-up threshold means the part wakes up cleanly once the Vcc rail crosses that level, then runs down to 4.5 V once the auxiliary winding takes over. That wide Vcc range (4.5 V to 30 V) gives flexibility for self-supplied designs where the bias winding voltage varies with load.
For volume BOM lines, this part is a stable fit for new production runs.