Auxiliary Power Supply and Wall-Plug Adaptor
Common auxiliary ower supply uses fly-back topology. However at very low power the buck topology is used. Typically these are low power solutions with very low cost and low stand-by consumption. The block diagram facilitates your selection among a wide selection of recommended applicable products.
AN4007: EVLVIP37LE5V3A: 15 W (5 V - 3 A) wide range single-output demonstration board
AN4116: STEVAL-ISA112V1: 12 V/4 W, 115 kHz non-isolated flyback
Publications and Collaterals
How to implement negative SMPS for AC switch control