Differential Circuit Research Articles

Online Identification of Inductance and Flux Linkage for Inverter-Fed SPMSMs Using Switching State Functions

This article presents an online method to acquire the stator inductance and flux linkage for inverter-fed surface-mounted permanent magnet synchronous motors (SPMSMs) using switching state functions instead of average models. Given the switching state functions when different voltage vectors are applied to the motors, the information of inductance and flux linkage is revealed. Based on the dc bus voltage and current derivatives obtained from either hardware methods like Rogowski coil and differential circuit, or software methods such as tracking differentiator, stator inductance, and flux linkage are able to be figured out directly using the redundant or more practical methods with the help of recursive least square (RLS). Simulations and experiments are carried out to prove the effectiveness of the proposed methods, besides, dc voltage and operating speed variation as well as the impact of resistance are taken into account. Finally, compared with the conventional parameter identification based on the average models either in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">α</i> – <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">β</i> or <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> – <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</i> coordinate, the proposed methods with switching state functions have remarkable advantages especially when the rotor position error exists. What needs further effort is the challenging case at very low speed, e.g., it is hard to identify flux linkage due to the small back electromotive force (EMF).

Differential Negative Group Delay Circuit Topology with Reverse Nested Double U-shaped Defected Ground Structure

Differential Negative Group Delay Circuit Topology with Reverse Nested Double U-shaped Defected Ground Structure

IFFERENTIAL TRANSFORMER SENSORS WITH SIMPLE STRUCTURE OF MAGNETIC CIRCUITS METHODS FOR INCREASING THE DISTRIBUTION LINEARITY OF MAGNETIC CURRENTS

In the article differential transformer sensors measuring shifts the magnetic capacitance of the air gap between two long ferromagnetic cores, which allows the linear distribution of magnetic currents in ordinary structural scattered parameter differential magnetic circuits along the length of the chain, the expressions of the change of the magnetic circuit length of the compare values of the magnetic driving forces located longitudinal. Based on the analysis of differential magnetic chains with the proposed simple structure according to these analytical expressions, it was determined that the construction of a magnetic chain is technologically relatively simple and does not require an excess of non-ferrous metal (copper) due to the fact that the air gap between two long ferromagnetic cores changes the compare value of the magnetic.

An electronic dosimeter for diagnostic X-ray beams based on a differential amplifier circuit with MOSFETs

An electronic dosimeter for diagnostic X-ray beams based on a differential amplifier circuit with MOSFETs

An Analog SiPM Based Receiver With On-Chip Wideband Amplifier Module for Direct ToF LiDAR Applications

An analog silicon photomultiplier (SiPM) based receiver with wideband transimpedance amplifier (TIA) is proposed for direct ToF LiDAR applications. The analog SiPM comprises a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$16\times 32$ </tex-math></inline-formula> single photon avalanche diodes (SPADs) array with a 25% fill factor. A fully differential pixel readout circuit is proposed within the pixel cell to facilitate the monolithic integration with the subsequent TIA and reduce the output capacitance of the analog SiPM. The TIA with the multipath feedforward compensation technique is proposed to improve the stability and achieve a wider −3-dB bandwidth. The adder array is used in this design to output the intensity information for the walk error compensation and the target identification. The proposed receiver, which is fabricated in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.18~\mu \text{m}$ </tex-math></inline-formula> HV-CMOS technology, achieves a −3-dB bandwidth of 420 MHz. A maximum detection range of 65 m is obtained with 20 W laser peak power, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.8^{\circ }\times 1.8^{\circ }$ </tex-math></inline-formula> field of view, and 40 mm aperture. A ranging accuracy of ±0.4 cm and precision of 4.5 cm are attained under a condition of 5 klux ambient light based on 1000 measurement results.

A Generalization and Differentiation Circuit Implementation Based on Neural Mechanisms

A Generalization and Differentiation Circuit Implementation Based on Neural Mechanisms

Graphene Bridge Heterostructure Devices for Negative Differential Transconductance Circuit Applications

HighlightsGraphene (Gr)-bridge heterostructure, consisting of a laterally series-connected (cascade) ambipolar/Gr/n-type 2D van der Waals channel materials for ambipolar semiconductor-based high-end application devices was developed.Non-classical transfer characteristics (humped curve) in FET operation and negative differential transconductances were observed.Gr-bridge heterostructure device with PdSe2 (narrow bandgap) allows multi-value logic operation while WSe2 (wide bandgap) enables frequency tripler circuit operation.

4H-SiC integrated circuits for high-temperature applications

In order to take full advantage of the properties of SiC (silicon carbide) materials at high temperatures, the characteristics of common-source and differential amplifier circuits composed of NMOSFET and PMOSFT based on 4H-SiC have been presented at 25 °C and 300 °C. The characteristics of NMOSFET and PMOSFET based on 4H-SiC are presented from 25 °C to 500 °C. The common-source amplifier displayed gain of 37 dB and GBW (gain–bandwidth product) of 125 kHz at 25 °C. When the temperature increases to 300 °C, the gain decreases to 32 dB and the GBW increases to 600 kHz. The differential amplifier displayed gain of 30 dB and GBW of 25 kHz at 25 °C. When the temperature increases to 300 °C, the gain increases to 34.6 dB and the GBW increases to 130 kHz. Both circuits show good characteristics, indicating that SiC materials and related devices can be applied to high temperature environment.

A Time-Domain Three-Dimensional Numerical Method for Comprehensive Common-Mode Analysis of Electric Circuits in Inhomogeneous Media

This article presents a numerical method to treat comprehensive common-mode (CM) signals in the time domain, which are electromagnetic noise sources in electrical and electronic devices. Electromagnetic potentials are a better choice to quantify the CM signals because we can easily extend the full-wave analysis of a multiconductor system. We start with the Maxwell equations in inhomogeneous media, which include conductors and dielectrics, and express the wave equations of the electromagnetic potentials. We also introduce a numerical method for the wave equations with lumped-parameter circuits by using the leap-frog scheme based on the central difference method. We calculate normal-mode (NM) and CM voltages in differential circuits with discontinuity and nonuniformity and conduct experiments by using the time-domain reflectometry method. The numerical results of the proposed method are compared with results from the finite-difference time-domain method and experiments for validation, observing conversions and reflections of NM and CM at discontinuities and nonuniformity, and show good agreements among these results.

Integrase-mediated differentiation circuits improve evolutionary stability of burdensome and toxic functions in E. coli

Advances in synthetic biology, bioengineering, and computation allow us to rapidly and reliably program cells with increasingly complex and useful functions. However, because the functions we engineer cells to perform are typically burdensome to cell growth, they can be rapidly lost due to the processes of mutation and natural selection. Here, we show that a strategy of terminal differentiation improves the evolutionary stability of burdensome functions in a general manner by realizing a reproductive and metabolic division of labor. To implement this strategy, we develop a genetic differentiation circuit in Escherichia coli using unidirectional integrase-recombination. With terminal differentiation, differentiated cells uniquely express burdensome functions driven by the orthogonal T7 RNA polymerase, but their capacity to proliferate is limited to prevent the propagation of advantageous loss-of-function mutations that inevitably occur. We demonstrate computationally and experimentally that terminal differentiation increases duration and yield of high-burden expression and that its evolutionary stability can be improved with strategic redundancy. Further, we show this strategy can even be applied to toxic functions. Overall, this study provides an effective, generalizable approach for protecting burdensome engineered functions from evolutionary degradation.

A New Platform of Iron Oxide-Based Nanoparticles Assay Using GMR Chip-Based Sensor With Microcontroller

The low-cost, simple, and fast quantitative assay of magnetic nanoparticles (MNPs) is important for the development of magnetic-based immunoassay applications. However, the bulky sensing element and instruments of the recent iron oxide-based MNPs assays are still concerns that should be resolved. This article reports the new platform of an iron oxide-based MNPs label assay using the commercial giant magnetoresistance (GMR) chip AAL024, manufactured by Nonvolatile Electronics (NVE) Corporation, complemented with a basic differential amplifier circuit and Arduino microcontroller (AM) to acquire the digital output voltage. The as-prepared Fe3O4@Ag label possessed (15 ± 2.6) nm of average size and behaved as soft ferromagnetic with 52.1 emu/g of saturation magnetization, and 0.15 kOe of coercive field. Sensor performance for magnetic field detection, as well as Fe3O4@Ag nanoparticles label assay, was evaluated. The results show the implementation of a basic differential amplifier op-amp circuit succeed to magnify the sensor’s response to the magnetic field up to 23 times with the output voltage in the order of volt. The employment of the AM as a voltage supply of the GMR chip, an analog-to-digital converter, and a voltage gauge simplifies the data acquisition without the additional measuring instrument. Meanwhile, for the purpose of the Fe3O4@Ag nanoparticles label assay, the sensor revealed promising performance due to the high signal linearity and the rapid detection which is only 30 s with acceptable signal stabilities.

Precise Mathematical Model of PSCM Class-D Amplifiers

A mathematical analysis of four-level (three-phase) phase-shifted carrier modulation class-D amplifiers with analog feedback is proposed. The nonlinear difference equations are extracted and solved using the perturbation theorem. In this way, a closed-form function describes the low-frequency part of the output for an arbitrary input signal. The results are generalized for an arbitrary number of levels by analogy, well matched with the previous model of two-, three-, and the proposed four-level ones. The analytical results confirm that, apart from switching frequency, the multilevel class-D amplifiers converge to linear amplifiers as the number of output levels increases. An analytical equation expresses the harmonic distortion of practically interesting five-level amplifiers with bridge-tied load. The model is verified by system-level simulations and circuit-level implementation. In this way, a prototype fully differential five-level circuit is implemented on the printed circuit board to confirm the model.

Miniature and Symmetrical Transformer Based on Through-Silicon Vias

A high-density symmetrical transformer based on through-silicon via (TSV) is proposed in this article. The primary winding and secondary winding have strong symmetry, and the inductance mismatch is less than 0.1%, so the transformer structure is suitable for differential circuit. Compared with transformers in other literatures, the proposed transformer has advantages in area and efficiency, which is reflected in that the on-chip area is greatly reduced by 58% to 89%, and the coupling coefficient can reach more than 0.92.

A 3.95 ppm/°C 7.5 μW Second-Order Curvature Compensated Bandgap Reference in 0.11 μm CMOS

In order to meet the requirements of modern portable electronics for high accuracy and low power consumption of bandgap reference circuits, a new low-voltage bandgap reference with a second-order compensated circuit at 1.8 V is proposed. It features a new self-biased fully symmetric differential operational amplifier circuit with the help of split transistors for achieving low power consumption and high accuracy; by adding a new sub-threshold compensated circuit. The results of simulation show that the temperature coefficient of the second-order circuit is 3.95 ppm/°C in the temperature range of −40 to 125 °C, and the power consumption is only 7.5 μW; this meets both the requirements of high precision and low power consumption. At the same time, the output noise voltage of the design is less than 30 μV/sqrt (Hz) at a frequency of 100 Hz, and the low-frequency supply voltage rejection ratio is −103 dB@100 Hz; these are acceptable for bandgap reference circuits.

Leakage-Current-Canceling Current-Sampling Sense Amplifier for Deep Submicrometer STT-RAM

In the design of nonvolatile memory (NVM), the sense amplifier (SA) contributes a major part of the power consumption due to high-frequency read operations. This brief proposes a leakage-current-canceling current-sampling sense amplifier (LCCS-SA) for the suppression of the read power consumption by operating in near-threshold region. The proposed LCCS-SA adopts the technology of offset cancellation and single-ended differential circuit structure to compensate the effect of the leakage current. The bit-line (BL) leakage-induced read failure is effectively suppressed in near-threshold region. Monte Carlo simulation demonstrates that the proposed LCCS-SA can operate at a supply voltage of 0.4 V and achieves 4.4 times lower read energy per bit compared to the conventional current-sampling-based SA.

Capacitive Omnidirectional Position Sensor Using a Quarter Wave Resonator

An open environment, omnidirectional sensing method is presented that utilizes the mechanics of a quarter wave resonator (QWR). A highly sensitive response to external perturbations is formed as approaching objects alter the stray capacitance around the resonator, causing the system’s frequency to change. The detection range of the experimental system exceeds a 1 m radius around a 150 mm tall device. A theory is presented that predicts the voltage distribution on the QWR and further explores the maximum horizontal distance at which the voltage distribution changes due to an approaching object. The relationship between the excitation voltage versus the distance of various approaching objects is characterized as well as the vertical displacement response, sensor resolution, and the power consumed by the device. Two resonators connected to a classic differential amplifier circuit are used to demonstrate the detection of the velocity and direction of an approaching object. The advantages of the reported approach include low fabrication cost, low power consumption, and omnidirectional detection.

Self-heating compensation in uncooled microbolometer read-out without using IR-shielded (blind) references

In this paper, a self-heating compensation method for uncooled microbolometers is presented. In this method, unlike the conventional use of IR-shielded (blind) references, the current from active sensors adjacent to each other are used to compensate for the undesired self-heating effect. Eliminating the need for IR-shielded references can simplify the fabrication process, resulting in lower costs. Moreover, using the adjacent sensor as the reference makes the read-out circuit insensitive to parameter mismatches in the sensor array. The thermal offset effect due to limited cooling time is also investigated in this paper. It is shown that the proposed structure can completely cancel the thermal offset effect. The proposed read-out has been designed in the standard 0.18-μm CMOS technology considering an array with 352 × 288 pixels. The simulation results show that the proposed blind-less structure can achieve 25% more compensation than the common differential blind-based circuit in the presence of 20% resistance mismatch and 10% thermal constant mismatch.

Comparative Research of Neuron Circuits

Abstract: Spiking neurons can be implemented in hardware, for example, to model large neural systems, simulate real-time behaviour, and interface bi-directionally between brains and machines. Circuit solutions used to implement silicon neuron circuits depend on the application requirements. Various neuron circuits are presented in this thesis, including spike-event generators (Axon Hillock neuron circuits), above-threshold neuron circuits (Quadratic Integrate and Fire neuron circuits), and differential pair integrator circuits. Cadence's tool simulates these circuits using 180nm technology. Comparing these circuits is based on their working properties and simulation results, and their features are demonstrated with experiments.

108 Defining a bi-stable network switch that governs stem cell self-renewal and differentiation in squamous cell carcinoma

Stem cell – like tumor propagating cells self-renew to drive clonal expansion or differentiate into post-mitotic cells without tumorigenic potential in squamous cell carcinomas. This fate choice is governed by a transcriptional network comprised of SOX2-PITX1-TP63 driven self-renewal and KLF4 dependent differentiation circuits. Yet, how stem cell – like tumor propagating cells switch from self-renewal to differentiation remains elusive. Here, we report that this cell fate choice is governed by a bi-stable Klf4 enhancer that is occupied by the transcription factor SOX2 in self-renewing or KLF4 in differentiating squamous cell carcinoma cells, dependent on whether SOX2 is phosphorylated.

CORRECTION SCHEMES FOR THE GYROMAGNETIC COMPASS

In connection with the significant progress in the improvement of sensitive elements (gyroscopes, accelerometers, magnetometers), as well as the increased possibilities of information processing by computational means, it became necessary to use modern algorithms for constructing correction systems for the gyromagnetic compass.&#x0D; The object of research is the correction circuits: with an adaptable proportional-integral-differential (PID) controller, with a Fuzzy controller, with a Kalman filter for correcting the gyroscopic meter according to the magnetic heading sensor. In this case, the well-known scheme of a gyromagnetic compass with a torque proportional-integral (PI) correction is taken as the basis for comparison. Smoothing of the oscillatory error of a magnetic compass, which may be predominant, is considered. The subject of research is the accuracy characteristics in the steady state.&#x0D; The study is carried out by simulating the operation of a gyromagnetic compass. The root mean square error (rms) and the mean value of the error are taken as the correction characteristics. At the same time, the transitional process of the initial exhibition is also controlled.&#x0D; In the algorithms under study, new solutions are applied.&#x0D; In the differential PID channel, a quarter-period delay of the dominant oscillations is applied, and the gain of the differential channel is adjusted according to the oscillation frequency. This setting allows you to almost completely smooth out the oscillatory error of the gyromagnetic compass by compensating for the oscillatory error with the received signal in the differential circuit.&#x0D; In the Kalman filter scheme, the resulting heading error estimate is in antiphase with the error. After the introduction of a delay in the estimate for half a period of fluctuations, the estimate almost completely corresponds to the error. As a result, the oscillatory error can be almost completely eliminated in the instrumental heading value.&#x0D; The article shows that all three investigated correction schemes show better characteristics in comparison with the known basic scheme. The highest accuracy can be achieved when applying the Kalman filter with the necessary settings for the perturbation, observation and initial error matrices.&#x0D; The simplest to implement is a circuit with an adaptable PID controller. Its characteristics are close to the scheme with the Kalman filter.