Embodiments of the invention provide an off line DC-DC converter comprising a transformer (180) coupled to a monolithic integrated circuit (400). The transformer applies an input supply DC voltage (Vin) applied to a primary winding (181) of the transformer to produce an output supply DC voltage provided from a secondary winding (182). The monolithic integrated circuit (400) comprises a switching regulator including a switch (151) and a switch controller (100) on a first portion of the monolithic integrated circuit. A capacitive isolator (201) is provided on a second portion of the monolithic integrated circuit. The monolithic integrated circuit regulates the output supply DC voltage and isolates the output supply DC voltage from the input supply DC voltage with respect to electrical shock hazard.