Model and experimental characterization of dynamic behaviour of low power Carbon Monoxide MOX sensors with pulsed temperature profile

Bicelli, S.; Depari, A.; Faglia, Guido; Flammini, A.; Fort, Ada; Mugnaini, Marco; Ponzoni, Andrea

doi:10.1109/imtc.2008.4547264

Cited by 8 publications

(2 citation statements)

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“…For example, for the characterization of new experimental sensors, it could be important to analyze the sensor response even during the fast transients due to gas sensing, or thermal profiles, or the modification of the sensor excitation. In addition, new heating techniques, such as pulsed methods, can be investigated to obtain both a reduction of the power consumption and to extract more useful information from the sensor response [9]- [10].…”

Section: Introductionmentioning

confidence: 99%

A new interface for resistive chemical sensors with low measuring time

Depari

Flammini

Marioli

et al. 2009

2009 IEEE Intrumentation and Measurement Technology Conference

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The main issue concerning metal oxide (MOX) gas sensors is mostly related to the wide range of resistive values the sensors can show. In addition, some sensors could have baseline resistive value up to tens of gigohms. To avoid the use of expensive pico-amperometers, different solutions have been recently proposed, exploiting the resistance-to-time conversion (RTC) technique. They show good linearity and are suitable for the integration in a chip together with the elaboration unit, but they may require long measurement time (tens of seconds) if high resistance values need to be estimated. In this work, a new method is proposed to reduce the measuring time, keeping the advantages offered by the RTC approach. The applicability of the interface is therefore extended for solutions requiring detailed information of the sensor response, such as the characterization of new sensors (e.g. nanowires) or the behavior analysis during non-standard thermal profiles. Particularly, an effective architecture, based on moving thresholds, has been proposed, simulated and experimentally tested with commercial resistors (values between 1 MΩ and 100 GΩ).

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Section: Introductionmentioning

confidence: 99%

A new interface for resistive chemical sensors with low measuring time

Depari

Flammini

Marioli

et al. 2009

2009 IEEE Intrumentation and Measurement Technology Conference

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“…Therefore, this circuit seems unsuitable for applications in which the sensor response must be well characterized during fast transients, due to gas sensing or thermal profiles or the modification of the sensor excitation. In addition, new heating techniques, such as pulsed methods, can be investigated to obtain both a reduction of the power consumption and to extract more useful information from the sensor response [9,10]. The aim of this work is to investigate a new circuit exploiting the RTC technique to estimate both sensor resistive and capacitive components, but keeping the measuring time in the order of tens of milliseconds.…”

Section: Introductionmentioning

confidence: 99%

A New, Fast Readout, Interface For High-value Resistive Chemical Sensors

Depari¹,

Flammini²,

Marioli³

et al. 2009

AIP Conference Proceedings

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Metal oxide (MOX) gas sensors show a resistive value varying in a wide range, from hundreds of kilohms up to tens of gigohms. For this reason, oscillating circuits are often used to interface such sensors. Simple oscillating circuits allow a measuring time which is directly proportional to the resistive value; with large resistive values (gigohms), the output updating time is on the order of seconds. In addition, the sensor is excited with a square wave, but the variable frequency can affect the measurement accuracy. In this paper, a new oscillating circuit is proposed with a limited measuring time regardless the resistive value. This behavior is obtained by means of self-moving thresholds. The working principle is always based on the integration of a constant current flowing through the sensor and generating a ramp. Such ramp is compared with two threshold ramps with known slope and the maximum measuring time is limited by the slower threshold. The proposed circuit has been simulated and experimentally tested with commercial resistors (values between 1 M and 100 G ).

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