Sensors, Vol. 19, Pages 3545: A VCII-Based Stray Insensitive Analog Interface for Differential Capacitance Sensors

Sensors, Vol. 19, Pages 3545: A VCII-Based Stray Insensitive Analog Interface for Differential Capacitance Sensors Sensors doi: 10.3390/s19163545 Authors: Gianluca Barile Leila Safari Giuseppe Ferri Vincenzo Stornelli In this paper, a novel approach to implement a stray insensitive CMOS interface for differential capacitive sensors is presented. The proposed circuit employs, for the first time, second-generation voltage conveyors (VCIIs) and produces an output voltage proportional to differential capacitor changes. Using VCIIs as active devices inherently allows the circuit to process the signal in the current domain, and hence, to benefit from its intrinsic advantages, such as high speed and simple implementation, while still being able to natively interface with voltage mode signal processing stages at necessity. The insensitiveness to the effects of parasitic capacitances is achieved through a simple feedback loop. In addition, the proposed circuit shows a very simple and switch-free structure (which can be used for both linear and hyperbolic sensors), improving its accuracy. The readout circuit was designed in a standard 0.35 μm CMOS technology under a supply voltage of ±1.65 V. Before the integrated circuit fabrication, to produce tangible proof of the effectiveness of the proposed architecture, a discrete version of the circuit was also prototyped using AD844 and LF411 to implement a discrete VCII. The achieved measurement results...
Source: Sensors - Category: Biotechnology Authors: Tags: Article Source Type: research