A Multifunctional Integrated Circuit Router for Body Area Network Wearable Systems

A multifunctional router IC to be included in the nodes of a wearable body sensor network is described and evaluated. The router targets different application scenarios, especially those including tens of sensors, embedded into textile materials and with high data-rate communication demands. The router IC supports two different functionality sets, one for sensor nodes and another for the base node, both based on the same circuit module. The nodes are connected to each other by means of woven thick conductive yarns forming a mesh topology with the base node at the center. From the standpoint of the network, each sensor node is a four port router capable of handling packets from destination nodes to the base node, with sufficient redundant paths. The adopted hybrid circuit and packet switching scheme significantly improve network performance in terms of end-to-end delay, throughput and power consumption. The IC also implements a highly precise, sub-microsecond one-way time synchronization protocol which is used for time stamping the acquired data. The communication module was implemented in a 4-metal, 0.35 μm CMOS technology. The maximum data rate of the system is 35 Mbps while supporting up to 250 sensors, which exceeds current BAN applications scenarios.This work was supported in part by the Fundação para a Ciéncia e a Tecnologia (FCT) (Portuguese Foundation for Science and Technology) under Project PROLIMB PTDC/EEAELC/103683/2008 and through the Ph.D. Grant SFRH/BD/75324/2010, and in part by the CREaTION, FCT/MEC through national funds and co-funded by the FEDER-PT2020 partnership agreement under Project UIDB/EEA/50008/2020, Project CONQUEST (CMU/ECE/030/2017), Project COST CA15104, and ORCIP. (Corresponding author: Fardin Derogarian Miyandoab.)info:eu-repo/semantics/publishedVersio

A Single Inductor, Multiple Input Piezoelectric Interface Circuit Capable of Harvesting Energy from Asynchronously Vibrating Sources

The energy harvesting industry has seen steady growth in recent years. This growth has been driven by the increasing demand for remote sensing, implantable technologies, and increased battery life in mobile and hand held devices. Due to the limited amount of energy available from ambient sources, any system that attempts to harness energy from them should necessarily be highly efficient to make the net output power useful. A lot of work has been done on minimizing losses in piezoelectric energy harvesters. Most of this has however been limited to harvesters with single vibration sources or multiple sources vibrating synchronously. This work presents a multiple input piezoelectric energy harvester capable of harvesting from multiple piezoelectric energy sources vibrating asynchronously (at different frequencies, or at the same frequency but in different phases) using a single inductor. The use of a single inductor eliminates the extra quiescent power consumption, component count, printed circuit board real estate that would have been incurred by using a one inductor per input device. The inductor is time shared between three input devices using a digital control circuit which regulate access to the inductor while avoiding any destructive interaction between the input devices. The chip was designed in a 0.18µm technology and achieves a conversion efficiency of 60%. Testing with three asynchronously vibrating sources shows that the chip extracts maximum power from all inputs simultaneously, independent of vibration frequency or phase