A time-based technique for a resistive detector
24 May 2015-pp 361-364
TL;DR: Differently from existing time-based technique, the proposed approach allows increasing the sensitivity of the detection by increasing the time of the measurement, thus extending the dynamic range of the Measurement.
Abstract: The present paper describes a time-based technique for resistive detector. Thanks to the comparison with a reference resistance, the circuit easily compensate the baseline contribution, thus extending the dynamic range of the measurement. The implemented circuit is based on a resistance to time converter followed by a time comparator for signal comparison. Differently from existing time-based technique, the proposed approach allows increasing the sensitivity of the detection by increasing the time of the measurement. The circuit exhibits a measured resolution in the order of 20ppm with a nominal value of resistance of about 3MΩ while the maximum dynamic range is of about 40dB.
Citations
More filters
TL;DR: This article proposes simple relaxation-oscillator-based digital interfacing schemes for resistive sensors in single-element and quarter-bridge forms, equipped with novel compensation techniques, that render a direct-digital output proportional to sensor resistance.
Abstract: This article proposes simple relaxation-oscillator-based digital interfacing schemes for resistive sensors in single-element and quarter-bridge forms. The proposed interfaces, equipped with novel compensation techniques, render a direct-digital output proportional to sensor resistance. These interfaces offer many meritorious features, such as simplicity of design, nonrequirement of the reference voltage, lower execution time, and negligible influences from circuit nonidealities. The methodology of the interfaces and their design criteria and error analysis are described in this article. The first two interfaces are suitable for nonremote resistive sensors, while the third interface has been developed for remotely located resistive sensors. The functionality of the proposed interfaces has been verified using simulation as well as detailed experimental studies. The developed interfaces provide a linear direct-digital output, and the maximum experimental nonlinearity is merely 0.08%. Later, a representative sensor based on the giant magnetoresistance (GMR) phenomenon is selected, characterized, and tested with the developed interfaces. The complete instrumentation system is shown to act as a linear digital magnetometer. Finally, the performance of the developed interfaces is compared and shown to be better/comparable with respect to the existing works.
14 citations
Cites background from "A time-based technique for a resist..."
...A number of digital techniques, such as pulsewidth conversion [7]–[9], dual slope [10], [11], direct microcontroller interfacing [12]–[15], sigma-delta [16], and relaxation oscillator [17]–[21], are prevalent for resistive sensors....
[...]
...A digitizer employing dual-resistance-to-frequency converter and a reference resistor has been proposed for resistive sensors in [7]....
[...]
References
More filters
TL;DR: In this paper, the authors review the emerging field of CMOS gas sensors and focus upon the integration of two main gas-sensing principles, namely, resistive and electrochemical and associated circuitry by CMOS technology.
Abstract: Modern gas sensor technology is becoming an important part of our lives. It has been applied within the home (monitoring CO levels from boilers), the workplace (e.g., checking levels of toxic gases) to healthcare (monitoring gases in hospitals). However, historically the high price of gas sensors has limited market penetration to niche applications, such as safety in mines or petrochemical plants. The high price may be attributed to several different components: (1) cost of a predominantly manual manufacturing process; (2) need for interface circuitry in the form of discrete components on a PCB; and (3) fireproof packaging, making the cost of gas detection instruments typically many hundreds of dollars. Consequently, there has been a considerable effort over the past 20 years, towards the goal of low-cost ($1-$5) gas sensors, employing modern microelectronics technology to manufacture both the sensing element and the signal conditioning circuitry on a single silicon chip. In this paper, we review the emerging field of CMOS gas sensors and focus upon the integration of two main gas-sensing principles, namely, resistive and electrochemical and associated circuitry by CMOS technology. We believe that the combination of CMOS technology with more recent MEMS processing is now mature enough to deliver the exacting demands required to make low-power, low-cost smart gas sensors in high volume and this should result in a new generation of CMOS gas sensors. These new integrated, mass-produced gas sensors could open up mass markets and affect our everyday lives through application in cars, cell phones, watches, etc.
186 citations
TL;DR: A time-to-digital converter with ~1.2 ps resolution and ~327 mus dynamic range suitable for laser range-finding application for example and an external integral nonlinearity look-up table (INL-LUT) for the interpolators is described.
Abstract: This paper describes a time-to-digital converter (TDC) with ~1.2 ps resolution and ~327 mus dynamic range suitable for laser range-finding application for example. The resolution of ~1.2 ps is achieved with interpolation based on a cyclic time domain successive approximation (CTDSA) method that resolves the time difference between two non-repetitive signals using binary search. The method utilizes a pair of digital-to-time converters (DTC), the propagation delay difference between which is implemented by digitally controlling the unit load capacitors of their delay cells, thus enabling sub-gate delay timing resolution. The rms single-shot precision, i.e., standard deviation sigma-value of the TDC is 3.2 ps, which is achieved by using an external integral nonlinearity look-up table (INL-LUT) for the interpolators. The power consumption is 33 mW at 100 MHz with a 3.3 V operating voltage. The prototypes were fabricated in a 0.35 mum CMOS process.
158 citations
20 May 2003
TL;DR: In this article, a low-cost interface for high-value resistive sensors varying over a wide range, from k/spl Omega/ to G/spl O(spl Omega), is presented.
Abstract: This paper presents a low-cost interface for high-value resistive sensors varying over a wide range, from k/spl Omega/ to G/spl Omega/. The proposed circuit that acts as a "resistance to period converter" is suitable to be interfaced to a microcontroller or a counting device. The behavior of real electronic components that produce estimation errors, is taken into account. Experimental results obtained by the realized prototype show a good resolution and repeatability.
98 citations
TL;DR: An integrated wide-dynamic-range interface circuit for resistive gas-sensors arrays that achieves a measurement accuracy almost always better than 0.1 % over a sensor resistance range of more than 5 decades is presented.
Abstract: In this paper an integrated wide-dynamic-range interface circuit for resistive gas-sensors arrays is presented. The proposed device consists of a multiscale transresistance continuous time amplifier followed by a 13-bit incremental A/D converter. The circuit selects automatically the scale to use for each measurement and includes two digital-to-analog converters for the calibration of offset and gain of each scale. The proposed interface circuit achieves a measurement accuracy almost always better than 0.1 % over a sensor resistance range of more than 5 decades [100 Omega-20 MOmega], leading to an equivalent dynamic range of about 160 dB. The chip has been realized with a 0.35 mum CMOS technology and occupies an area of 3.1 mm2 consuming 6 mW from a 3.3 V power supply.
81 citations
07 Apr 2011
TL;DR: A 21b ROIC that meets the challenge of maintaining system accuracy over temperature in precision thermocouples and bridge transducers by exhibiting very low offset and gain drift.
Abstract: Precision thermocouples and bridge transducers such as strain gauges and thermistors require read-out ICs with low noise, high accuracy and low drift. In such applications, the sensor and the read-out IC (ROIC) are usually calibrated as a single system, and so in addition to low thermal and 1/f noise, the ROIC should exhibit very low offset and gain drift (a few ppm/°C) to maintain system accuracy over temperature. This paper describes a 21b ROIC that meets this challenge.
29 citations