Wireless Multimodality Sensing System-on-a-Chip With Time-Based Resolution Scaling Technique and Analog Waveform Generator in 0.18 µm CMOS for Chronic Wound Care.

ABSTRACT

Multimodal sensing can provide a comprehensive and accurate diagnosis of biological information. This paper presents a fully integrated wireless multimodal sensing chip with voltammetric electrochemical sensing at a scanning rate range of 0.08-400 V/s, temperature monitoring, and bi-phasic electrical stimulation for wound healing progress monitoring. The time-based readout circuitry can achieve a 1-20X scalable resolution through dynamic threshold voltage adjustment. A low-noise analog waveform generator is designed using current reducer techniques to eliminate the large passive components. The chip is fabricated via a 0.18 µm CMOS process. The design achieves R2 linearity of 0.995 over a wide current detection range (2 pA-12 µA) while consuming 49 µW at 1.2 V supply. The temperature sensing circuit achieves a 43 mK resolution from 20 to 80 degrees. The current stimulator provides an output current ranging from 8 µA to 1 mA in an impedance range of up to 3 kΩ. A wakeup receiver with data correlators is used to control the operation modes. The sensing data are wirelessly transmitted to the external readers. The proposed sensing IC is verified for measuring critical biomarkers, including C-reactive protein, uric acid, and temperature.