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16 pages, 3681 KiB

Open AccessArticle

A Time-Based Electronic Front-End for a Capacitive Particle Matter Detector

by Umberto Ferlito, Alfio Dario Grasso, Michele Vaiana and Giuseppe Bruno

Sensors 2021, 21(5), 1840; https://doi.org/10.3390/s21051840 - 06 Mar 2021

Cited by 9 | Viewed by 1965

This paper introduces the electronic interface for a capacitive airborne particle matter detector. The proposed circuit relies on two matched ring oscillators and a mixer to detect the frequency difference induced by the deposition of a particle onto an interdigitated capacitor, which constitutes [...] Read more.

This paper introduces the electronic interface for a capacitive airborne particle matter detector. The proposed circuit relies on two matched ring oscillators and a mixer to detect the frequency difference induced by the deposition of a particle onto an interdigitated capacitor, which constitutes the load of one of the oscillators. The output of the mixer is digitized through a simple counter. In order to compensate the oscillation frequency offset of the two ring oscillators due to process and mismatch variations, a capacitive trimming circuit has been implemented. The sensor is connected to host through an I2C interface for communication and configuration. The sensor has been implemented using a standard 130-nm CMOS technology by STMicroelectronics and occupies 0.12-mm² die area. Experimental measurements using talcum powder show a sensitivity of 60 kHz/fF and a 3σ resolution equal to 165 aF. Full article

(This article belongs to the Special Issue Advanced Interface Circuits and Systems for Smart Sensors)

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11 pages, 2758 KiB

Open AccessCommunication

A Capacitive Feedback Transimpedance Amplifier with a DC Feedback Loop Using a Transistor for High DC Dynamic Range

by Jung-hoon Noh

Sensors 2020, 20(17), 4716; https://doi.org/10.3390/s20174716 - 21 Aug 2020

Cited by 3 | Viewed by 4376

Abstract

This study proposes a capacitive feedback transimpedance amplifier (CF-TIA) using a transistor in the direct current (DC) feedback loop for high DC dynamic range. In some applications, the background DC input can vary widely from the minimum to the maximum, and TIA have [...] Read more.

This study proposes a capacitive feedback transimpedance amplifier (CF-TIA) using a transistor in the direct current (DC) feedback loop for high DC dynamic range. In some applications, the background DC input can vary widely from the minimum to the maximum, and TIA have to sense the target signal even on the top of the maximum DC input. In a conventional CF-TIA, however, the allowable DC input is constrained by the value of the resistor in the DC feedback loop. To allow a fairly high DC input, the resistor is set to a very low value. This causes the thermal noise current to increase significantly. The increased thermal noise is always present even in the minimum DC input, thus degrading the overall noise performance. The circuit proposed herein overcomes this shortcoming by using the transistor instead of the resistor. The adverse effect of the parasitic capacitance of the transistor on system stability is compensated for as well. Then, the analyses of the overall frequency response and design parameters, including the cut-off frequency and attenuation ratio associated with system stability, are presented for the proposed circuit. In addition, in order to cope with the problem that stability is dependent on the amount of DC input, a simple method for ensuring system stability regardless of DC component value is introduced. The presented analyses and the method are generalized for all CF-TIA applications. Full article

(This article belongs to the Special Issue Advanced Interface Circuits and Systems for Smart Sensors)

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13 pages, 3173 KiB

Open AccessArticle

Reducing Measurement Time in Direct Interface Circuits for Resistive Sensor Readout

by José A. Hidalgo-López, José A. Sánchez-Durán and Óscar Oballe-Peinado

Sensors 2020, 20(9), 2596; https://doi.org/10.3390/s20092596 - 02 May 2020

Cited by 3 | Viewed by 2118

Abstract

Direct Interface Circuits (DICs) carry out resistive sensor readings using a resistance-to-time-to-digital conversion without the need for analog-to-digital converters. The main advantage of this approach is the simplicity involved in designing a DIC, which only requires some additional resistors and a capacitor in [...] Read more.

Direct Interface Circuits (DICs) carry out resistive sensor readings using a resistance-to-time-to-digital conversion without the need for analog-to-digital converters. The main advantage of this approach is the simplicity involved in designing a DIC, which only requires some additional resistors and a capacitor in order to perform the conversion. The main drawback is the time needed for this conversion, which is given by the sum of up to three capacitor charge times and their associated discharge times. This article presents a modification of the most widely used estimation method in a resistive DIC, which is known as the Two-Point Calibration Method (TPCM), in which a single additional programmable digital device pin in the DIC and one extra measurement in each discharge cycle, made without slowing down the cycle, allow charge times to be reduced more than 20-fold to values around 2 µs. The new method designed to achieve this reduction only penalizes relative errors with a small increase of between 0.2% and 0.3% for most values in the tested resistance range. Full article

(This article belongs to the Special Issue Advanced Interface Circuits and Systems for Smart Sensors)

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12 pages, 4084 KiB

Open AccessArticle

A 28 nm Bulk-CMOS Analog Front-End for High-Rate ATLAS Muon Drift-Tube Detectors

by Alessandra Pipino, Federica Resta, Luca Mangiagalli, Marcello De Matteis, Hubert Kroha, Robert Richter, Oliver Kortner and Andrea Baschirotto

Sensors 2020, 20(1), 42; https://doi.org/10.3390/s20010042 - 19 Dec 2019

Cited by 2 | Viewed by 2816

Abstract

This paper presents the design and experimental characterization of a 28 nm Complementary Metal Oxide Semiconductor (CMOS) Analog Front-End (AFE) for fast-tracking small-diameter Muon Drift-Tube (sMDT) detectors. The device exploits an innovative analog signal processing that allows a strong increase in the detection [...] Read more.

This paper presents the design and experimental characterization of a 28 nm Complementary Metal Oxide Semiconductor (CMOS) Analog Front-End (AFE) for fast-tracking small-diameter Muon Drift-Tube (sMDT) detectors. The device exploits an innovative analog signal processing that allows a strong increase in the detection rate of events and significantly reduces the impact of fake/pile-up events, which often corrupt incident radiation energy events. The proposed device converts the input charge coming from incident radiations into voltage by a dedicated Charge-Sensitive Preamplifier (CSPreamp). Therefore, the fast-tracking concept relies on sampling the slope of the CSPreamp output voltage and using it for detecting both the incident event arrival instant and the amount of charge that has been effectively read out by MDT detectors. This avoids the long processing times intrinsically needed for baseline recovery transient, during which the detected signal can be severely corrupted by additional and unwanted extra-events, resulting in extra-charge (and thus in CSP output voltage extra-transient) during the signal roll-off. The proposed analog channel operates with a 5–100 fC input charge range and has a maximum dead-time of 200 ns (against the 545 ns of the state-of-the-art). It occupies 0.03 mm² and consumes 1.9 mW from 1 V of supply voltage. Full article

(This article belongs to the Special Issue Advanced Interface Circuits and Systems for Smart Sensors)

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19 pages, 19332 KiB

Open AccessArticle

Measurement System for Lossy Capacitive Sensors: Application to Edible Oils Quality Assessment

by Ahmed Fendri, Ahmed Yahia Kallel, Hanen Nouri, Hamadi Ghariani and Olfa Kanoun

Sensors 2019, 19(19), 4299; https://doi.org/10.3390/s19194299 - 04 Oct 2019

Cited by 13 | Viewed by 3737

Abstract

This paper aimed to develop a portable, low-cost, and easy-to-use measurement system for oil quality degradation assessment. The main two chemical parameters affected by frying are the total polar compounds (TPC) and free fatty acids. The system should characterize the change of chemical [...] Read more.

This paper aimed to develop a portable, low-cost, and easy-to-use measurement system for oil quality degradation assessment. The main two chemical parameters affected by frying are the total polar compounds (TPC) and free fatty acids. The system should characterize the change of chemical parameters by measuring the changes in its dielectric parameters. The dielectric parameters, relative permittivity, and conductivity are measured by measuring the capacitance and resistance of a capacitive sensor dipped in oil. The main challenges are that the corresponding changes of the capacitance and resistance are very small and the presence of stray effects. For this reason, the measurement system should be able to detect changes in capacitance and resistance with high resolution and with good immunity to stray effects. The proposed measurement system is based on the conversion of impedance to voltage and time and combining, therefore, having two measurement methods in one circuit. In this way, it is possible to measure the dielectric and resistive parameters and not only the relative permittivity as was done in previous works. The results showed a strong correlation between the chemical and electrical parameters with a coefficient of determination in the range of 0.9. Full article

(This article belongs to the Special Issue Advanced Interface Circuits and Systems for Smart Sensors)

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19 pages, 12298 KiB

Open AccessFeature PaperArticle

An Integrated Thermopile-Based Sensor with a Chopper-Stabilized Interface Circuit for Presence Detection

by Elisabetta Moisello, Michele Vaiana, Maria Eloisa Castagna, Giuseppe Bruno, Piero Malcovati and Edoardo Bonizzoni

Sensors 2019, 19(18), 3999; https://doi.org/10.3390/s19183999 - 16 Sep 2019

Cited by 8 | Viewed by 3845

Abstract

This paper presents a sensor-readout circuit system suitable for presence detection. The sensor consists of a miniaturized polysilicon thermopile, realized employing MEMS micromachining by STMicroelectronics, featuring a responsivity value equal to 180 V/W, with 13 ms response time. The readout circuit is implemented [...] Read more.

This paper presents a sensor-readout circuit system suitable for presence detection. The sensor consists of a miniaturized polysilicon thermopile, realized employing MEMS micromachining by STMicroelectronics, featuring a responsivity value equal to 180 V/W, with 13 ms response time. The readout circuit is implemented in a standard 130-nm CMOS process. As the sensor output signal behaves substantially as a DC, the interface circuit employs the chopper technique in order to minimize offset and noise contributions at low frequency, achieving a measured input referred offset standard deviation equal to 1.36

μ

V. Measurements show that the presented system allows successfully detecting the presence of a person in a room standing at 5.5 m from the sensor. Furthermore, the correct operation of the system with moving targets, considering people either walking or running, was also demonstrated. Full article

(This article belongs to the Special Issue Advanced Interface Circuits and Systems for Smart Sensors)

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16 pages, 3491 KiB

Open AccessArticle

An FPGA-Based Ultra-High-Speed Object Detection Algorithm with Multi-Frame Information Fusion

by Xianlei Long, Shenhua Hu, Yiming Hu, Qingyi Gu and Idaku Ishii

Sensors 2019, 19(17), 3707; https://doi.org/10.3390/s19173707 - 26 Aug 2019

Cited by 15 | Viewed by 4378

Abstract

An ultra-high-speed algorithm based on Histogram of Oriented Gradient (HOG) and Support Vector Machine (SVM) for hardware implementation at 10,000 frames per second (FPS) under complex backgrounds is proposed for object detection. The algorithm is implemented on the field-programmable gate array (FPGA) in [...] Read more.

An ultra-high-speed algorithm based on Histogram of Oriented Gradient (HOG) and Support Vector Machine (SVM) for hardware implementation at 10,000 frames per second (FPS) under complex backgrounds is proposed for object detection. The algorithm is implemented on the field-programmable gate array (FPGA) in the high-speed-vision platform, in which 64 pixels are input per clock cycle. The high pixel parallelism of the vision platform limits its performance, as it is difficult to reduce the strides between detection windows below 16 pixels, thus introduce non-negligible deviation of object detection. In addition, limited by the transmission bandwidth, only one frame in every four frames can be transmitted to PC for post-processing, that is, 75% image information is wasted. To overcome the mentioned problem, a multi-frame information fusion model is proposed in this paper. Image data and synchronization signals are first regenerated according to image frame numbers. The maximum HOG feature value and corresponding coordinates of each frame are stored in the bottom of the image with that of adjacent frames’. The compensated ones will be obtained through information fusion with the confidence of continuous frames. Several experiments are conducted to demonstrate the performance of the proposed algorithm. As the evaluation result shows, the deviation is reduced with our proposed method compared with the existing one. Full article

(This article belongs to the Special Issue Advanced Interface Circuits and Systems for Smart Sensors)

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22 pages, 11332 KiB

Open AccessArticle

A Fully-Differential Switched-Capacitor Dual-Slope Capacitance-To-Digital Converter (CDC) for a Capacitive Pressure Sensor

by Christopher Rogi, Cesare Buffa, Niccolo De Milleri, Richard Gaggl and Enrique Prefasi

Sensors 2019, 19(17), 3673; https://doi.org/10.3390/s19173673 - 23 Aug 2019

Cited by 5 | Viewed by 4799

Abstract

This article focuses on a proposed Switched-Capacitor Dual-Slope based CDC. Special attention is paid to the measurement setup using a real pressure sensor. Performance scaling potential as well as dead zones are pointed out and discussed. In depth knowledge of the physical sensor [...] Read more.

This article focuses on a proposed Switched-Capacitor Dual-Slope based CDC. Special attention is paid to the measurement setup using a real pressure sensor. Performance scaling potential as well as dead zones are pointed out and discussed. In depth knowledge of the physical sensor behavior is key to design an optimal readout circuit. While this is true for high-end applications, low-performance IoT (Internet of Things) sensors aim at moderate resolution with very low power consumption. This article also provides insights into basic MEMS (Micro-Electro-Mechanical-System) physics. Based on that, an ambient air pressure sensor model for SPICE (Simulation-Program-with-Integrated-Circuit-Emphasis) circuit simulators is presented. The converter concept was proven on silicon in a 0.13

μ

m process using both a real pressure sensor and an on-chip dummy MEMS bridge. A 3.2-ms measurement results in 13-bit resolution while consuming 35

μ

A from a 1.5-V supply occupying 0.148 mm². A state-of-the-art comparison identifies potential room for improvements towards hybrid solutions, which is proposed in subsequent publications already. Full article

(This article belongs to the Special Issue Advanced Interface Circuits and Systems for Smart Sensors)

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17 pages, 8784 KiB

Open AccessArticle

A GaN-Based Wireless Monitoring System for High-Temperature Applications

by Ahmad Hassan, Mohamed Ali, Aref Trigui, Yvon Savaria and Mohamad Sawan

Sensors 2019, 19(8), 1785; https://doi.org/10.3390/s19081785 - 14 Apr 2019

Cited by 15 | Viewed by 4267

Abstract

A fully-integrated data transmission system based on gallium nitride (GaN) high-electron-mobility transistor (HEMT) devices is proposed. This system targets high-temperature (HT) applications, especially those involving pressure and temperature sensors for aerospace in which the environmental temperature exceeds 350 °C. The presented system includes [...] Read more.

A fully-integrated data transmission system based on gallium nitride (GaN) high-electron-mobility transistor (HEMT) devices is proposed. This system targets high-temperature (HT) applications, especially those involving pressure and temperature sensors for aerospace in which the environmental temperature exceeds 350 °C. The presented system includes a front-end amplifying the sensed signal (gain of 50 V/V), followed by a novel analog-to-digital converter driving a modulator exploiting the load-shift keying technique. An oscillation frequency of 1.5 MHz is used to ensure a robust wireless transmission through metallic-based barriers. To retrieve the data, a new demodulator architecture based on digital circuits is proposed. A 1 V amplitude difference can be detected between a high-amplitude (data-on) and a low-amplitude (data-off) of the received modulated signal. Two high-voltage supply levels (+14 V and −14 V) are required to operate the circuits. The layout of the proposed system was completed in a chip occupying 10.8 mm². The HT characterization and modeling of integrated GaN devices and passive components are performed to ensure the reliability of simulation results. The performance of the various proposed building blocks, as well as the whole system, have been validated by simulation over the projected wide operating temperature range (25–350 °C). Full article

(This article belongs to the Special Issue Advanced Interface Circuits and Systems for Smart Sensors)

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