Print Email Facebook Twitter A Phase-Domain Readout Circuit for a CMOS-Compatible Hot-Wire CO₂ Sensor Title A Phase-Domain Readout Circuit for a CMOS-Compatible Hot-Wire CO₂ Sensor Author Cai, Z. (TU Delft Electronic Instrumentation; NXP Semiconductors) van Veldhoven, Robert (NXP Semiconductors) Suy, Hilco (Ams AG) de Graaf, G. (TU Delft Electronic Instrumentation) Makinwa, K.A.A. (TU Delft Microelectronics) Pertijs, M.A.P. (TU Delft Electronic Instrumentation) Department Microelectronics Date 2018 Abstract This paper presents a readout circuit for a carbon dioxide (COࠢ) sensor that measures the CO₂-dependent thermal time constant of a hot-wire transducer. The readout circuit periodically heats up the transducer and uses a phase-domain Δ Σ modulator to digitize the phase shift of the resulting temperature transients. A single resistive transducer is used both as a heater and as a temperature sensor, thus greatly simplifying its fabrication. To extract the transducer's resistance, and hence its temperature, in the presence of large heating currents, a pair of transducers is configured as a differentially driven bridge. The transducers and the readout circuit have been implemented in a standard 0.16μm CMOS technology, with an active area of 0.3 and 3.14 mm², respectively. The sensor consumes 6.8 mW from a 1.8-V supply, of which 6.3 mW is dissipated in the transducers. A resolution of 94-ppm CO₂ is achieved in a 1.8-s measurement time, which corresponds to an energy consumption of 12 mJ per measurement, >10x less than prior CO₂ sensors in CMOS technology. Subject Carbon dioxide (CO₂) sensorCMOS compatibledelta-sigma modulatorphase-domain readoutEnergy measurementresistive sensorthermal conductivity (TC) To reference this document use: http://resolver.tudelft.nl/uuid:d78c827c-a98d-49f3-9171-b83eb288ae9c DOI https://doi.org/10.1109/JSSC.2018.2866374 Embargo date 2022-03-30 ISSN 0018-9200 Source IEEE Journal of Solid State Circuits, 53 (11), 3303-3313 Bibliographical note Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. Part of collection Institutional Repository Document type journal article Rights © 2018 Z. Cai, Robert van Veldhoven, Hilco Suy, G. de Graaf, K.A.A. Makinwa, M.A.P. Pertijs Files PDF A_Phase_Domain_Readout_Ci ... Sensor.pdf 5.23 MB Close viewer /islandora/object/uuid:d78c827c-a98d-49f3-9171-b83eb288ae9c/datastream/OBJ/view