The REF-XDPL8219-U40W is a digitally configurable front-stage HPF flyback converter with a secondary-side regulated (SSR) constant-voltage (CV) output of 54V. An isolated UART reporting evaluation plug-in board is also included in this reference design packaging box. This plug-in board has an isolated uni-directional UART circuit, which can be evaluated optionally, by connecting it to the REF-XDPL8219-U40W. This reference design is featuring a high -power -factor flyback controller IC with constant -voltage flyback outputcontroller IC (XDPL8219) with secondary- side feedback (XDPL8219). The REF-XDPL8219-U40W It presents excellent power quality over a wide load range and. This design enables exchangeable feedback via pluggable extension boards: TheXDPL8219has configurable output power limitations. The design provides configurable protection modes for failure during operation.