Inter-IC for Wearables (I²We): Power and Data Transfer Over Double-Sided Conductive Textile

We propose a power and data transfer network on a conductive fabric material based on an existing serial communication protocol, Inter-Integrated Circuit (I²C). We call the proposed network inter-IC for wearables. Continuous dc power and I²C-formatted data are simultaneously transferred to tiny sensor nodes distributed on a double-sided conductive textile. The textile comprises two conductive sides, isolated from each other, and is used as a single planar transmission line. I²C data are transferred along with dc power supply based on frequency division multiplexing. Two carriers are modulated with the clock and the data signals of I²C. A modulation and demodulation circuit is designed such that off-the-shelf I²C-interfaced sensor ICs can be used. The novelty of this paper is that a special filter to enable passive modulation is designed by locating its impedance poles and zeros at the appropriate frequencies. The term "passive modulation" herein implies that the sensor nodes do not generate carrier waves by themselves; instead, they reflect only the externally supplied careers for modulation. The proposed scheme enables the flexible implementation of wearable sensor systems in which multiple off-the-shelf tiny sensors are distributed throughout the system.