System and method for transferring duty cycle information in an isolated dc/dc converter or other circuit

Abstract

A signal processing methodology and circuit for supplying bias power and duty cycle information across an isolation barrier, wherein, at an input side of the isolation barrier at least one input signal carrying input duty cycle information, together with DC bias power, is received and encoded on a constant repetition rate, constant duty cycle carrier waveform. Encoding is carried out by an encoder implemented to encode the carrier waveform with a marker, such as a waveform discontinuity, at a timing corresponding to the input duty cycle information, and wherein the presence of the marker leaves the average value of the carrier waveform unaffected. At the output side of the isolation barrier, the duty cycle information may be received by a decoder, the input duty cycle information detected to reconstruct the at least one input signal, and optionally DC bias power extracted from the carrier waveform. An exemplary embodiment is based on PWM encoding and decoding of a bipolar square wave carrier waveform of constant repetition rate and duty cycle. Duty cycle information in the form of short pulse discontinuities may be superimposed on successive half cycles of the carrier waveform, to enable two independent PWM signals to be processed per cycle.