CMOS based capacitance to digital converter circuit for MEMS sensor

International Conference on Advances in Materials and Manufacturing Applications 2017

Rotake, D.R.^1 ; Darji, A.D.^1

Electronics Engineering Department, Sardar Vallabhbhai National Institute of Technology, Surat

395007, India^1

关键词: Capacitance-to-digital converter;    Digitally controlled oscillators;    Interfacing circuits;    Mems cantilevers;    Microcantilever deflection;    Power Optimization;    Total power dissipation;    Transmission gate;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/310/1/012030/pdf
DOI  :  10.1088/1757-899X/310/1/012030

来源: IOP

【 摘 要 】

Most of the MEMS cantilever based system required costly instruments for characterization, processing and also has large experimental setups which led to non-portable device. So there is a need of low cost, highly sensitive, high speed and portable digital system. The proposed Capacitance to Digital Converter (CDC) interfacing circuit converts capacitance to digital domain which can be easily processed. Recent demand microcantilever deflection is part per trillion ranges which change the capacitance in 1-10 femto farad (fF) range. The entire CDC circuit is designed using CMOS 250nm technology. Design of CDC circuit consists of a D-latch and two oscillators, namely Sensor controlled oscillator (SCO) and digitally controlled oscillator (DCO). The D-latch is designed using transmission gate based MUX for power optimization. A CDC design of 7-stage, 9-stage and 11-stage tested for 1-18 fF and simulated using mentor graphics Eldo tool with parasitic. Since the proposed design does not use resistance component, the total power dissipation is reduced to 2.3621 mW for CDC designed using 9-stage SCO and DCO.