Paper Info
Title
A Low-Power Interface for Capacitive Sensors With PWM Output and Intrinsic Low Pass Characteristic
Abstract
A compact, low power interface for capacitive sensors, is described. The output signal is a pulse width modulated (PWM) signal, where the pulse duration is linearly proportional to the sensor differential capacitance. The original conversion approach consists in stimulating the sensor capacitor with a triangular-like voltage waveform in order to obtain a square-like current waveform, which is subsequently demodulated and integrated over a clock period. The charge obtained in this way is then converted into the output pulse duration by an approach that includes an intrinsic tunable low pass function. The main non idealities are thoroughly investigated in order to provide useful design indications and evaluate the actual potentialities of the proposed circuit. The theoretical predictions are compared with experimental results obtained with a prototype, designed and fabricated using 0.32 CMOS devices from the BCD6s process of STMicroelectroncs. The prototype occupies a total area of 1025 515 and is marked by a power consuption of 84 . The input capacitance range is 0–256 fF, with a resolution of 0.8 fF and a temperature sensitivity of 300 .
Year
DOI
Venue
2013
10.1109/TCSI.2012.2220461
IEEE Transactions on Circuits and Systems I-regular Papers
Keywords
Field
DocType
capacitive sensor interface,chopper modulation,current mode,low power,capacitors,capacitance,synchronization,capacitive sensors,impedance,noise,low power electronics,cmos integrated circuits
Capacitance,Capacitor,Waveform,Pulse-width modulation,Electronic engineering,Capacitive sensing,Capacitive power supply,Pulse duration,Electrical engineering,Mathematics,Low-power electronics
Journal
Volume
Issue
ISSN
60
6
1549-8328
Citations 
PageRank 
References 
5
0.56
0
Authors
4
Name
Order
Citations
PageRank
Nicolo Nizza1335.82
Michele Dei2328.18
Federico Butti3101.75
Paolo Bruschi46217.83