Designed specifically to be used with an open-loop flyback technology are ASIC reference designs that enable telecom power designers to design and implement 2W and 4W sinewave ring generators. Schematics and bills of material are provided with these designs along with transformer calculations and layout recommendations to meet UL, CSA, and VDE requirements. The controller drives a minimal component count for the final design and operates from a single 5V supply. The package is a 16-pin DIP that generates a PWM signal to drive FETs switching the primary flyback transformer. An additional control signal synchronizes a four-output transistor bridge that converts the half sinewave to a full sinewave.