A Capacitance-To-Digital Converter for MEMS Sensors for Smart Applications
AbstractThe use of MEMS sensors has been increasing in recent years. To cover all the applications, many different readout circuits are needed. To reduce the cost and time to market, a generic capacitance-to-digital converter (CDC) seems to be the logical next step. This work presents a configurable CDC designed for capacitive MEMS sensors. The sensor is built with a bridge of MEMS, where some of them function with pressure. Then, the capacitive to digital conversion is realized using two steps. First, a switched-capacitor (SC) preamplifier is used to make the capacitive to voltage (C-V) conversion. Second, a self-oscillated noise-shaping integrating dual-slope (DS) converter is used to digitize this magnitude. The proposed converter uses time instead of amplitude resolution to generate a multibit digital output stream. In addition it performs noise shaping of the quantization error to reduce measurement time. This article shows the effectiveness of this method by measurements performed on a prototype, designed and fabricated using standard 0.13 µm CMOS technology. Experimental measurements show that the CDC achieves a resolution of 17 bits, with an effective area of 0.317 mm2, which means a pressure resolution of 1 Pa, while consuming 146 µA from a 1.5 V power supply. View Full-Text
Share & Cite This Article
Pérez Sanjurjo, J.; Prefasi, E.; Buffa, C.; Gaggl, R. A Capacitance-To-Digital Converter for MEMS Sensors for Smart Applications. Sensors 2017, 17, 1312.
Pérez Sanjurjo J, Prefasi E, Buffa C, Gaggl R. A Capacitance-To-Digital Converter for MEMS Sensors for Smart Applications. Sensors. 2017; 17(6):1312.Chicago/Turabian Style
Pérez Sanjurjo, Javier; Prefasi, Enrique; Buffa, Cesare; Gaggl, Richard. 2017. "A Capacitance-To-Digital Converter for MEMS Sensors for Smart Applications." Sensors 17, no. 6: 1312.
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.