Sensor Circuit Research Articles

MICROELECTRONIC AUTOGENERATOR TEMPERATURE SENSORS

Microelectronic autogenerator temperature sensors based on transistor structures with differential negative resistance with primary parametric thermosensitive elements based on bipolar and field-effect transistors are proposed, moreover, primary parametric thermosensitive elements are active components of the circuits of parametric autogenerator temperature sensors, which greatly simplifies the design of the device. Based on the consideration of physical processes in primary parametric temperature-sensitive components and autogenerators of temperature sensors, mathematical models of autogenerator temperature sensors were developed, on the basis of which analytical expressions were obtained to determine the parametric dependences of sensitivity functions and transformation functions. It is shown that the main contribution to the conversion and sensitivity functions is made by a change in the ambient temperature, which causes a change in the equivalent capacitance and negative differential resistance of parametric autogenerator temperature sensors, which, accordingly, changes the output frequency of the device. The sensitivity of the sensor with a thermally sensitive bipolar transistor is from 11.25 kHz/°C to 21.5 kHz/°C, and the sensor with a thermally sensitive field-effect transistor is from 2.77 kHz /°C to 4.25 kHz/°C in the range of ambient temperature change 0 оС up to 100 оС. The obtained parametric dependences of the sensitivity and conversion functions show the possibility of easier calculation of the main characteristics of parametric autogenerator sensors, and also clearly demonstrate the influence of each component of parametric transducers and elements of parametric self-oscillating sensors on the output frequency of devices in comparison with the calculations of sensitivity and conversion functions from nonlinear equivalent circuits basis for solving the Kirchhoff equations.

Automated system for performing pH-based titrations

Liquid delivery and endpoint determination during titrations may be problematic if an analyst does not have adequate training or formal education. This can lead to issues with method accuracy and precision. This work is focused on the development of a simple, low-cost, automated system capable of performing potentiometric titrations with a push of a button. A single-board computer (Raspberry Pi), a stepper motor-based syringe pump, and a commercially available pH sensor circuit board were the primary components used to construct the auto-titrator system. Open-source Python programming language was used to control and coordinate components and provide a simple-to-use graphical user interface. A standard alkalinity method for drinking and raw water was evaluated and yielded an accuracy (recovery) between 92% and 104% for concentrations above 10 mg L−1. The precision of the method was less than 5% regardless of concentration. The developed titrator was tested at Lebanon, TN, and Woodruff, SC water treatment plants. The system was also certified by LabtronX to perform alkalinity measurements in Lebanon, TN, and served the plant operators for the past two years.

Simulation and implementation of a harmonics suppression technique for a single-phase full-bridge converters

ABSTRACT This paper presents a harmonic suppression technique for a single-phase full-bridge converter, and the mathematical principles underlying a modified PWM technique are discussed. To verify the effectiveness of the proposed technique, voltage and current sensor circuits in a single-phase full-bridge converter connected to a digital signal processor controller with an analog-to-digital converter were analyzed experimentally. The output voltage harmonics of the converter were examined, and the frequency spectra of the output voltage were analyzed. Furthermore, a digital control system with a TMS320F2808 digital signal microcontroller was realized. The experimental results verified the effectiveness of the proposed technique in suppressing low-frequency harmonic in a prototype of a converter.

Bandgap reference, temperature sensor and low drop-out regulator circuits monolithic sensors in TPSCo 65 nm ISC technology

With Inner Tracking System v3 (ITS3), the ALICE experiment is pursuing a wafer-scale Monolithic Active Pixel Sensor (MAPS). The chip is being developed in TPSCo 65 nm ISC technology which is under study in the framework of CERN EP R&D on monolithic sensors for High Energy Physics (HEP) applications. This contribution presents designs and measurement results of building blocks needed for this chip, in particular bandgap references and temperature sensors. In addition, simulation results of the design of Low Drop-out Regulator (LDO) to be submitted for the next prototyping run will be discussed.

An 11.6aF/kPa Mechanical Stress Sensor With 0.808% Temperature-Drift Oscillator for Flip-Chip Packaging

During the package processes, including chip attachment and encapsulation, the stress caused by the thermal and mechanical load is usually generated in integrated circuit chips. This brief developed a mechanical stress sensor in a standard 180nm CMOS process for runtime stress measurement. The contributions done in this brief are summarized as follows: 1) A temperature-compensation RC oscillator circuit converts the warpage of the die induced by the mechanical stress into the frequency output. It even can measure the thermally induced stresses with a wide temperature range. The oscillator has a frequency variation of −0.808% from temperature stability measurements from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- 40^{\circ }\text{C}$ </tex-math></inline-formula> to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$120^{\circ }\text{C}$ </tex-math></inline-formula> . 2) Rather than the complicated calibrations and advanced measurement equipment, the frequency can be easily measured with the chip area less than 0.569 mm2 and the power consumption less than 22.9 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> . 3) As for the sensing array, the sensitivity and stability of the metal-insulator-metal (MIM) and metal–oxide–metal (MOM) capacitors are verified. The measured average sensitivity of the test chip using a MIM capacitor with 0.1736 Hz/kPa is more sensitive than that using a MOM capacitor with 0.102 Hz/kPa. The linear fit curves of the output frequency have the coefficient of determination ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{R}^{2}$ </tex-math></inline-formula> ) of 0.9983 for MIM and 0.9959 for MOM, indicating an excellent linear response of the sensor circuit.

Resistive sensor array readout circuit: nodal array approach

In this paper, Nodal Array Approach (NAA) will be chosen in implementing readout circuit for pressurize touch sensor in hand grip application sensor array. We proposed a comparison methods of readout topology for resistive sensor array in terms of the circuit complexity, measurement error, and sensor capacity.

Workshop Perakitan Audio Amplifier Guna Meningkatkan Keterampilan Bidang Elektronika Werga Desa Serdang Kulon, Kec. Panongan, Kab. Tangerang

Changes and developments in the times of society are required to be able to keep abreast of technological advances. The development in the field of electronics technology certainly requires human resources who have competence in accordance with the needs of society and industry., the results of observations carried out on the Serdang Kulon village, there are still many community members who do not understand the field of electronics so it is very necessary to carry out community service activities the community in that location. In this community service activity, several things were carried out which were expected to be a solution to problems in the village of Serdang Kulon, namely the Audio Amplifier Assembly Workshop to Improve the Electronics Skills of the Residents of Serdang Kulon Village, Panongan District, Tangerang Regency. With activity material: basic electronics theory (basic electronic components, basic electrical science, electronic circuits) , soldering practice, assembling series and parallel LED circuits, assembling LED blinking circuits, assembling automatic light sensor circuits and assembling audio amplifiers. The implementation of PKM activities involves Lecturers and Cadets and stakeholders as a form of Higher Education Dharma. In addition, this activity is also a field experience and direct learning media for students/cadets.

Mathematical models of magnetic circuits of high currents induction sensors for electric power supply systems devices of electric transport

The magnetic circuits of the developed high currents induction sensors for the electric power supply systems devices of electric transport are researched, analytical expressions of the magnetic flux in ferromagnetic connecting elements and magnetic voltage, the replacement circuit of the magnetic circuit elementary section, as well as mathematical models of the magnetic circuit of the developed sensors, are obtained.

An Improved Digitizing Interface Circuit for Wide-Range Current-Output Sensors

A current digitizer, suitable for interfacing with a wide-range current-output sensor (COS) is proposed. The circuit features a transimpedance amplifier with a programmable-gain attenuating amplifier in its feedback which mimics the high-valued resistance required for a wide-range low-current to voltage conversion. The proposed scheme offers a fast response and is immune to switch resistances in the feedback circuit. This low-cost circuit uses a unipolar analog to digital converter (ADC) to sense bidirectional currents with reduced ADC quantization noise and offset error. A mathematical model of the scheme with error analysis is presented. The performance of the digitizing interface was established using simulations as well as experiments on a hardware prototype. The results show that the developed interface works well over the current range of 500 pA to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5 ~\mu \text{A}$ </tex-math></inline-formula> (dynamic range of 104) with nonlinearity (N. L.) less than 1.2%.

Model of field robot manipulators and sensor for measuring angular displacement of its rotating parts

This research aims to measure and control the angular change of rotation mechanisms of (energy-saving) robotic manipulators used in agriculture to develop digital farming, energy saving, and quality product harvesting. The novelty of this research is that different processes and images are placed in a special processor for processing, and this robot processes the image according to the size of the tomato plant and tomato and tries to harvest the crop. This study presents the electromagnetic angular displacement sensor and its technical characteristics. The existing electromagnetic angular displacement sensors have been thoroughly analyzed and compared with other types of sensors. The reason for the low sensitivity of the electromagnetic angular displacement sensor has been investigated, and some technical modification to the existing sensor has been made. The magnetic circuits of the electromagnetic sensors have been analyzed. A method is proposed for expanding the range of angular measurements up to 180 degrees and increasing the sensitivity of the electromagnetic sensor without compromising the measurement accuracy. This, in turn, allows high-precision control and measurement of rotating mechanisms of all types of mechatronic systems and agricultural robots.

Simple Digitizing Circuit for Resistive Sensors in π-Network Form

This paper presents a detailed discussion on the design and performance verification of a digitizing circuit for a special type of resistive sensor - the resistive π-network model. The proposed circuit digitizes the output without requiring an additional ADC and boasts several positive features, such as a simple architecture with a single reference voltage, wide-range measurements, and good linearity. Moreover, the circuit can measure the input quantity independently of sensor elements and few other error sources. The paper clearly explains the working mechanism of the circuit and examines the impact of dominant error sources. Furthermore, it details the circuit’s performance through simulation and experimental studies. The maximum measured nonlinearity is lower than 0.14 % for a range of 40 dB. This demonstrates the linearizing-capability of the circuit for a wide range of inputs.

Ion Sensors for Pulsed and Continuous Detonation Combustors

Presented in the article are the design and operation principles of ion sensors intended for detecting the propagating reaction fronts, the deflagration/detonation mode, apparent subsonic/supersonic propagation velocity of the reaction front, and duration of heat release by measuring the ion current in the reactive medium. The electrical circuits for ion sensors without and with intermediate amplifiers, with short response time and high sensitivity, as well as with the very wide dynamic range of operation in the reactive media with highly variable temperature and pressure, are provided and discussed. The main advantages of ion sensors are their very short response time of about 1 ms, versatility of design, and capability of detecting and monitoring reaction fronts of different intensities directly in combustion chambers. Several examples of ion sensor applications in sensing deflagration-to-detonation transition in pulsed detonation engines and developed detonations in rotating detonation engines operating on different fuel–air and fuel–oxygen mixtures are presented and discussed.

Direct Interface Circuit for Capacitive Sensors Affected by Parasitic Series Resistances

This article presents a novel circuit to directly interface a capacitive sensor affected by parasitic series resistances to a digital processor (DP). The presence of such resistances distorts the estimation of the capacitance to be measured. Current measurement procedures for these sensors, such as impedance-frequency characteristics, are complex and require significant hardware resources, power consumption, and time. To eliminate these drawbacks, a new circuit based on the so-called direct interface circuits (DICs) is introduced, which performs the digital reading of the sensors taking advantage of the presence of DPs in many applications. The hardware requirements in the new design are minimal: just two resistors and an operational amplifier in addition to the DP. The circuit requires only two time measurements to estimate sensor capacitance. These are obtained during a single capacitor charging-discharging process, simultaneously reducing power consumption and measurement time. The circuit has been implemented using a field-programmable gate array (FPGA), as the DP, in a general-purpose board to evaluate its performance. Although it is not an application-specific design, the circuit shows a maximum systematic error of 0.37% for capacitances in the 100 pF–96 nF range with parasitic series resistances up to 1200 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> . The maximum measurement time for this range is just 4.5 ms.

Smart angular displacement sensor for agricultural field robot manipulators

This study presents the electromagnetic angular displacement sensor and its technical characteristics. The existing electromagnetic angular displacement sensors have been thoroughly analyzed and compared with other types of sensors. The reason for the low sensitivity of the electromagnetic angular displacement sensor has been investigated and some technical modification to the existing sensor has been made. The magnetic circuits of the electromagnetic sensors have been analyzed. A method is proposed for expanding the range of angular measurements up to 180 degrees and increasing the sensitivity of the electromagnetic sensor without compromising the measurement accuracy. This, in turn, allows high-precision control and measurement of rotating mechanisms of all types of mechatronic systems and agricultural robots.

VSFPWM Based on Circulating Current Ripple Prediction for ZVS in Two Paralleled Grid-Tied Inverters With Coupled Inductors

Zero voltage switching (ZVS) control is an effective and promising way to further improve the power density, efficiency and electromagnetic interference for the two paralleled silicon carbide inverters with coupled inductors. In this article, focusing on the popular 180 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sup> interleaved pulsewidth modulation (PWM), the circulating current ripple prediction model is first derived as a function of operating conditions in the time-domain. With the assistance of this model, the actual trajectory of phase-leg currents can be reconstructed by superposition of sampling fundamental current and predicted circulating current ripple, without adding any high-frequency current sensor or auxiliary circuit. By carefully considering the ZVS requirement of all switches, a variable switching frequency PWM (VSFPWM) for full range ZVS control is proposed in this article. The proposed VSFPWM shows a good performance of ZVS realization in various load situations, as well as a good dynamic response of the inverter during current step change. In addition, due to the real-time variation of switching frequency, the proposed VSFPWM demonstrates the obvious advantage in conductive EMI reduction. Both the simulation and experimental results are presented to verify the effectiveness of the analysis and proposed method.

Development and Implementation of Portable Ultrasonic Sensor Circuit with USB Interface and Signal Processing to Detect Damages in the Mild Steel Structure

Mild steel is one of the widely used structures for commercial use. In this paper, we present a PZT-based portable ultrasonic wave interfacing circuit with a USB interface to detect the damages in the mild steel structure. The designed circuit amplifies and shifts the level of the ultrasonic waves. The wave is then digitized by the microcontroller with a sampling rate of 2 MHz. The digitized wave is then transferred to the PC via USB communication. The CDC class was used in USB communication to generate a virtual com port and capture the data in real-time. The wave was then filtered and processed in the PC to detect damage to the structure. The dimension and weight of the used mild steel are 570mm x 205mm x 10mm and 10 kg respectively. To detect the damage to the structure, the 200 kHz tone-burst signal was induced in it through the PZT actuator. The ultrasonic wave was then captured in both intact and damaged conditions of the structure. The induced damage was of dimension 1mm x 10mm x 5mm. The RMS value of the captured wave in intact condition and the undamaged condition was calculated. This run-in of the RMS values in the intact and damaged condition of the structure solidifies the capability of the device to gather the ultrasonic wave correctly.

A simplified approach to the signal modulation circuit of magnetoelectric speed sensors

A simplified approach to the signal modulation circuit of magnetoelectric speed sensors

Design of Precision-Aware Subthreshold-Based MOSFET Voltage Reference

A new precision-aware subthreshold-based MOSFET voltage reference is presented in this paper. The circuit was implemented TSMC-40 nm process technology. It consumed 9.6 μW at the supply voltage of 1.2 V. In this proposed work, by utilizing subthreshold-based MOSFET instead of bipolar junction transistor (BJT), relatively lower power consumption was obtained in the design while offering comparable precision to that offered by its BJT counterpart. Through the proposed second-order compensation, it achieved the temperature coefficient (T.C.) of 3.0 ppm/°C in the TT corner case and a 200-sample Monte-Carlo T.C. of 12.51 ppm/°C from -40 °C to 90 °C. This shows robust temperature insensitivity. The process sensitivity of Vref without and with trimming was 2.85% and 0.75%, respectively. The power supply rejection (PSR) was 71.65 dB at 100 Hz and 52.54 dB at 10 MHz. The Figure-of-Merit (FOM) for the total variation in output voltage was comparable with representative BJT circuits and better than subthreshold-based MOSFET circuits. Due to low T.C., low process sensitivity, and simplicity of the circuit architecture, the proposed work will be useful for sensor circuits with stringent requirements or other analog circuits that require high precision applications.

Macroscopic analysis and design of Si HFGFET gas sensor for sensitive gas detection

In this study, we investigate gas sensing performance of horizontal floating-gate field-effect transistor (HFGFET) gas sensors having different FET channel width and length, and the number and length of FG fingers using both technology computer-aided design (TCAD) device simulation and actual gas sensing measurement. The HFGFET gas sensors have a control-gate (CG) and a FG, which are horizontally interdigitated. An indium oxide (In2O3) film is locally deposited between the CG and FG to be used as a sensing layer. Utilizing a simplified equivalent circuit and electrical characteristics of the HFGFET gas sensors, we define a new parameter G, which represents a magnitude of gas sensitivity. The effect of channel width and length, and the number and length of FG fingers of the HFGFET gas sensors on gas sensitivity is first investigated by TCAD device simulation, and then verified by NO2 and H2S gas sensing measurement.

A Paper‐Based Triboelectric Touch Interface: Toward Fully Green and Recyclable Internet of Things

AbstractThe transition to a sustainable society is driving the development of green electronic solutions designed to have a minimal environmental impact. One promising route to achieve this goal is to construct electronics from biobased materials like cellulose, which is carbon neutral, non‐toxic, and recyclable. This is especially true for internet‐of‐things devices, which are rapidly growing in number and are becoming embedded in every aspect of our lives. Here, paper‐based sensor circuits are demonstrated, which use triboelectric pressure sensors to help elderly people communicate with the digital world using an interface in the form of an electronic “book”, which is more intuitive to them. The sensors are manufactured by screen printing onto flexible paper substrates, using in‐house developed cellulose‐based inks with non‐hazardous solvents. The triboelectric sensor signal, generated by the contact between a finger and chemically modified cellulose, can reach several volts, which can be registered by a portable microcontroller card and transmitted by Bluetooth to any device with an internet connection. Apart from the microcontroller (which can be easily removed), the whole system can be recycled at the end of life.