A pseudo-differential transmitting circuit causing reduced common-mode current variations

Abstract

This paper introduces a new type of pseudo-differential transmitting circuit (TX circuit) such that signaling ideally produces no common-mode current variations in the terminals intended to be connected to the interconnection. These terminals are expected to behave as if the TX circuit was composed of a floating circuit and a two-terminal circuit element connected between the common terminal and ground. This is in contrast with conventional pseudo-differential TX circuits in which the generation of signals produces a variable return current flowing in the reference conductor. We present a detailed design and provide simulation results. We then consider the implementation of this TX circuit in a pseudo-differential link. This link is capable of low reflections and a reduced common-mode current. It consequently offers a good protection against external crosstalk.