A Floating Linear Voltage Regulator for Powering Large-Scale Differential Communication Networks

This paper deals with the central powering of very low power sensor networks deployed over wide areas. Although wireless communications are nowadays dominant in the majority of implementations, wired differential communications sometimes provide the only ultimately reliable solution. In a large-scale network, it is of interest to implement both communication and powering with a small number of thin conductors. The consequential problem of the serial resistance of the long powering lines appears as the limiting factor. Sensor nodes powered with linear supply support very low power consumption, but the current flow through ground loops creates common mode voltage on communication lines. An introduction of the galvanic isolation resolves the common mode issue, but the isolation usually consumes more power than a sensor node itself, which in total gives even worse results than linear regulation. Moreover, a galvanic isolation demands an additional reference conductor for signal return path. In this paper, a novel approach to the realization of a floating linear power supply is proposed, incorporating advantages of both linear and isolated solutions. The new power supply scheme retains linear regulation characteristics regarding low power consumption, at the same time eliminating common mode voltage issue, such as an isolated power supply.