Frequency modulation based resistive sensing for wearable galvanic skin response

© 2015 ICST. This paper presents a frequency modulation based readout circuit for the measurement of skin conductance or resistance. A charge pump based frequency-to-voltage converter circuit with adjustable sensitivity is used to convert the frequency shifts due to skin resistance changes into voltage variations. The readout circuit improves the measurement accuracy and artifact rejection in measurements of the galvanic skin response on the skin, and can be integrated with wearable physiological monitoring systems. The readout circuit is designed and fabricated using the UMC 0.18 μm CMOS technology. It occupies an area of 0.18 mm2 and consumes 11.7 mW.