Transient Circuit Research Articles

SCR-based transient detection circuit for on-chip protection design against system-level electrical transient disturbance

A new silicon controlled rectifier (SCR)-based transient detection circuit for on-chip protection design against system-level electrical transient disturbance is proposed. The circuit function to detect positive or negative electrical transients during system-level electrostatic discharge (ESD) and electrical fast transient (EFT) tests has been verified in silicon chip. The experimental results in a 0.18-μm CMOS process have confirmed that the new proposed detection circuit can successfully memorize the occurrence of system-level electrical transient disturbance events. The detection results can be cooperated with firmware design to execute system recovery procedures, therefore the immunity of microelectronic systems against system-level ESD or EFT tests can be effectively improved.

Fast Transient Low-Dropout Voltage Regulator With Hybrid Dynamic Biasing Technique for SoC Application

This brief presents a low-dropout (LDO) voltage regulator without output capacitors that achieves fast transient responses by hybrid dynamic biasing. The hybrid dynamic biasing in the proposed transient improvement circuit is activated through capacitive coupling. The proposed circuit senses the LDO regulator output change so as to increase the bias current instantly. The proposed circuit was applied to an LDO regulator without output capacitors implemented in standard 0.35- μm CMOS technology. The device consumes only 25 μA of quiescent current with a dropout voltage of 180 mV. The proposed circuit reduces the output voltage spike of the LDO regulator to 80 mV when the output current is changed from 0 to 100 mA. The output voltage spike is reduced to 20 mV when the supply voltage varies between 1.3 and 2.3 V with a load current of 100 mA.

Epicardial wave mapping in human long-lasting persistent atrial fibrillation: transient rotational circuits, complex wavefronts, and disorganized activity

To characterize the nature of atrial fibrillation (AF) activation in human persistent AF (PerAF) using modern tools including activation, directionality analyses, complex-fractionated electrogram, and spectral information. The mechanism of PerAF in humans is uncertain. High-density epicardial mapping (128 electrodes/6.75 cm(2)) of the posterior LA wall (PLAW), LA and RA appendage (LAA, RAA), and RSPV-LA junction was performed in 18 patients with PerAF undergoing open heart surgery. Continuous 10 s recordings were analysed offline. Activation patterns were characterized into four subtypes (i) wavefronts (broad or multiple), (ii) rotational circuits (≥2 rotations of 360°), (iii) focal sources with centrifugal activation of the entire mapping area, or (iv) disorganized activity [isolated chaotic activation(s) that propagate ≤3 bipoles or activation(s) that occur as isolated beats dissociated from the activation of adjacent bipole sites]. Activation at a total of 36 regions were analysed (14 PLAW, 3 RSPV-LA, 12 LAA, and 7 RAA) creating a database of 2904 activation patterns. In the majority of maps, activation patterns were highly heterogeneous with multiple unstable activation patterns transitioning from one to another during each recording. A mean of 3.8 ± 1.6 activation subtypes was seen per map. The most common patterns seen were multiple wavefronts (56.2 ± 32%) and disorganized activity (24.2 ± 30.3%). Only 2 of 36 maps (5.5%) showed a single stable activation pattern throughout the 10-s period. These were stable planar wavefronts. Three transient rotational circuits were observed. Two of the transient circuits were located in the posterior left atrium, while the third was located on the anterior surface of the LAA. Focal activations accounted for 11.3 ± 14.2% of activations and were all short-lived (≤2 beats), with no site demonstrating sustained focal activity. Human long-lasting PerAF is characterized by heterogeneous and unstable patterns of activation including wavefronts, transient rotational circuits, and disorganized activity.

Enhanced photoelectrocatalytic performance for degradation of diclofenac and mechanism with TiO2 nano-particles decorated TiO2 nano-tubes arrays photoelectrode

In this study, TiO2 nano-particles decorated TiO2 nano-tubes arrays (TiO2 NPs/TiO2 NTAs) photoelectrodes have been successfully prepared through anodization, combined with ultrasonic strategy, followed by annealing post-treatment. The morphology and structure of the as-prepared TiO2 NPs/TiO2 NTAs photoelectrodes were characterized by scanning electrons microscopy (SEM), N2 adsorption/desorption isotherms, X-ray diffraction (XRD) and UV–visible light diffuse reflection spectroscopy (DRS). In addition, the generation of hydroxyl radicals (OH) was detected by a photoluminescence (PL) spectra using terephthalic acid (TA) as a probe molecule. Furthermore, the photoelectrochemical (PECH) properties of TiO2 NPs/TiO2 NTAs photoanode were investigated through transient open circuit potential (OCP), photocurrent response (PCR) and electrochemical impedance spectroscopy (EIS). It was found that TiO2 NPs/TiO2 NTAs photoelectrode exhibited a distinct decrease of OCP of −0.219mVcm−2 and PCR of 0.049mAcm−2, while a significantly enhanced photoelectrocatalytic (PEC) efficiency of 63.6% (0.4V vs. SCE) for the degradation of diclofenac. Moreover, the enhanced PEC mechanism of TiO2 NPs/TiO2 NTAs photoanode was proposed. The high PEC performance could be attributed to the decoration of TiO2 NPs, which could improve the mobility and separation efficiency of photoinduced charge carriers under external potential.

67.4: Fast Transient Vth Compensation Circuit for AMOLED Displays with P‐type GOA Driving

AbstractA new approach has been developed to improve AMOLED's image quality. Fast Transient Compensation Mechanism (FTCM) provides a good ability on Vth compensation, based on sub‐pixel circuit structure consisting of 6 TFTs and 1 capacitor. Furthermore, the P‐type GOA in AMOLED panel is designed for pixel driving and enhances displaying quality at low gray scale.

Instantaneous Power Balance Analysis in Finite-Element Method of Transient Magnetic Field and Circuit Coupled Computation

An instantaneous power balance analysis of time-domain finite-element method for transient 2-dimensional (2-D) magnetic field and electric circuit coupled computation is presented. Based on the principle of instantaneous power balance and the technique of matrix analysis, formulations for the computation of instantaneous reactive power, active power and eddy-current loss in solid conductors are put forward. The merit of the proposed algorithm is that the integration method for the loss computation is exactly the same as that for the system equations. Therefore, additional numerical errors arising from the integration in loss computation can be avoided. It clarifies the methods for eddy-current loss computation in solid conductors. The precise identification of instantaneous real power and reactive power is expected to pave the way for a new and accurate approach to extract the instantaneous ac resistances and inductances of the equivalent electric circuit. The concept of instantaneous power balance can also be used for force and torque computations.

Construction of N, S codoped TiO2 NCs decorated TiO2 nano-tube array photoelectrode and its enhanced visible light photocatalytic mechanism

In the present work, N, S codoped TiO2 nano-crystallites (NCs) decorated TiO2 nano-tube arrays (N-S-TiO2 NCs/TNTAs) photoelectrodes have been successfully constructed through anodization method, followed by evaporation induced self-assembly (EISA) strategy. The structures of N-S-TiO2 NCs/TNTAs samples were characterized by scanning electrons microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron microscopy (XPS). Results indicated that TNTAs was partly covered by N, S codoped TiO2 NCs. Meanwhile, N elements coexisted in the forms of substitutional N (Ti–N and N–Ti–O) and interstitial N (Ti–O–N) in TiO2, while S elements were also incorporated into the lattice of TiO2 through substituting titanium atom and coexisted in the cationic forms of S6+ and S4+. In addition, optical and photoelectrochemical (PECH) properties of the as-prepared N-S-TiO2 NCs/TNTAs samples were investigated through UV–vis light diffuse reflection spectroscopy (DRS), transient open circuit potential (OCP), photocurrent response (PCR) and electro-chemical impedance spectroscopy (EIS). Furthermore, photodecomposition performances were evaluated by the yield of OH radicals and photocatalytic (PC) degradation of methyl blue (MB) under Xenon lamp irradiation. All results showed that N-S-TiO2 NCs/TNTAs photoelectrode exhibited intense visible light absorption ranging from 400 to 700nm, high transient photoinduced current of 0.115mAcm−2, open circuit photovoltage of −0.312mVcm−2, generation of hydroxyl radicals and PC efficiency of 59.7% for the degradation of MB. The enhanced PC performance could mainly be attributed to the decoration of N, S codoped TiO2 NCs, which could not only enhance the light absorption in visible region but also improve the transfer and separation efficiency of photoinduced charge carriers.

A family of memristor‐based reactance‐less oscillators

SUMMARYIn this paper, we present for the first time a family of memristor‐based reactance‐less oscillators (MRLOs). The proposed oscillators require no reactive components, that is, inductors or capacitors, rather, the ‘resistance storage’ property of memristor is exploited to generate the oscillation. Different types of MRLO family are presented, and for each type, closed form expressions are derived for the oscillation condition, oscillation frequency, and range of oscillation. Derived equations are further verified using transient circuit simulations. A comparison between different MRLO types is also discussed. In addition, detailed fabrication steps of a memristor device and experimental results for the first MRLO physical realization are presented. Copyright © 2013 John Wiley & Sons, Ltd.

Preparation and characterization of palladium nano-crystallite decorated TiO2 nano-tubes photoelectrode and its enhanced photocatalytic efficiency for degradation of diclofenac

TiO2 has been considered as a versatile candidate for the photoelectrochemical (PECH) application. In this study, Pd nano-crystallite decorated TiO2 nano-tubes (Pd/TNTs) photoelectrode was prepared through electrochemical deposition. The resulting Pd/TNTs samples were characterized by SEM, XRD, DRS and XPS. It was found that the decorated Pd nano-crystallite existed in the form of Pd0 with an average diameter of 30nm, and could improve the light absorption in visible region. In addition, PECH properties of Pd/TNTs photoanode were investigated through transient open circuit potential, photocurrent response, electro-chemical impedance spectroscopy (EIS) and Mott–Schottky analysis. Moreover, the generation rate of hydroxyl radicals (OH) was detected by a photoluminescence (PL) spectra using terephthalic acid (TA) as a probe molecule. Results showed that Pd/TNTs photoelectrode exhibited high transient photoinduced current of 0.094mAcm−2, open circuit photovoltage of −0.339mVcm−2 and effective photoelectrocatalytic (PEC) efficiency of 67.7% (0.4V vs. SCE) for the degradation of diclofenac (DCF). The high PC and PEC efficiency could mainly be attributed to the decoration of Pd nano-crystallite which could provide pathway for the transfer of photoinduced charge carriers. Furthermore, the contribution of series of active species was applied to clarify the enhanced PC mechanism.

Exploiting Parallelism by Data Dependency Elimination: A Case Study of Circuit Simulation Algorithms

The authors present a methodology geared towards EDA applications such as parasitic extraction, transient circuit simulation, and RF steady-state simulations.

Extrasynaptic glutamate and inhibitory neurotransmission modulate ganglion cell participation during glutamatergic retinal waves

During the first 2 wk of mouse postnatal development, transient retinal circuits give rise to the spontaneous initiation and lateral propagation of depolarizations across the ganglion cell layer (GCL). Glutamatergic retinal waves occur during the second postnatal week, when GCL depolarizations are mediated by ionotropic glutamate receptors. Bipolar cells are the primary source of glutamate in the inner retina, indicating that the propagation of waves depends on their activation. Using the fluorescence resonance energy transfer-based optical sensor of glutamate FLII81E-1μ, we found that retinal waves are accompanied by a large transient increase in extrasynaptic glutamate throughout the inner plexiform layer. Using two-photon Ca(2+) imaging to record spontaneous Ca(2+) transients in large populations of cells, we found that despite this spatially diffuse source of depolarization, only a subset of neurons in the GCL and inner nuclear layer (INL) are robustly depolarized during retinal waves. Application of the glutamate transporter blocker dl-threo-β-benzyloxyaspartate (25 μM) led to a significant increase in cell participation in both layers, indicating that the concentration of extrasynaptic glutamate affects cell participation in both the INL and GCL. In contrast, blocking inhibitory transmission with the GABAA receptor antagonist gabazine and the glycine receptor antagonist strychnine increased cell participation in the GCL without significantly affecting the INL. These data indicate that during development, glutamate spillover provides a spatially diffuse source of depolarization, but that inhibitory circuits dictate which neurons within the GCL participate in retinal waves.

Implementation of nanoscale double-gate CMOS circuits using compact advanced transport models

In this paper we present the results of the implementation of a nanoscale double-gate (DG) MOSFET compact model, which includes hydrodynamic transport model, in Verilog-A in order to carry out circuit simulation. The model in Verilog-A is used with the SMASH circuit simulator for the analysis of the DC and transient behavior electrical CMOS circuits. Template devices representative for a downscaled symmetric double-gate MOSFET was used to validate the models for n-channel and p-channel. A CMOS inverter and a ring oscillator have been analyzed. Comparison of its performance between the drift-diffusion (DD) and hydrodynamic transport model within the practical range of bias voltages has been highlighted.

The Finite Element Analysis of the Leakage Inductance for High Frequency Switching Mode Power Supply Transformer

In order to improve the stability and reliability of switch mode power supply, the mathematical model of high frequency transformer is established with considering the effects of the leakage inductance of the high frequency transformer on the working state of DC-DC full bridge converter circuit. A finite element analysis method for two dimensional transient field circuit directly coupled of transformer in the case of full bridge inverter is proposed. Transformer inductance parameters are calculated using the method of field energy, which may provides the basis for the design of switching mode power supply transformer.

A radiation-hardened-by-design technique for suppressing SET in charge pump of PLL frequency synthesizer

This paper presents a single event transient (SET) suppressor circuit, which can suppress the effect of SET in charge pump (CP) on the whole PLL frequency synthesizers, and at the same time it brings little negative effect to the system during normal operation. Because the proposed SET suppressor circuit only includes a resistor, a PMOS and an NMOS device, little area penalty is introduced. By preventing SET propagating from CP to low pass filter (LPF) and VCO when a single event strikes on CP output node, the system shows excellent hardness to SET in CP. Mixed simulations are performed on TCAD workbench. The results show that a single event with an LET at 80 MeV cm2/mg can only induce approximately 2.3 mV disturbance on the control voltage of VCO.

Establishing Best-Practice Modeling Approaches for Understanding Single-Event Transients in Gb/s SiGe Digital Logic

Single-event transient (SET) simulations of a Gb/s SiGe BiCMOS master/slave D flip-flop circuit are performed, employing both a decoupled current-injection SET modeling technique and a fully-coupled mixed-mode TCAD technique to model heavy-ion strikes to the storage and input cells. New insights are provided into the physical mechanisms underlying the single-event upset (SEU) sensitivity of high-speed SiGe digital latches and shift registers. A close analysis of the transient circuit behavior identifies the limitations of the current-injection approach in predicting SEU in fast SiGe digital logic. Furthermore, the physical ion track linear energy transfer (LET) is varied to establish the threshold LET for SEU using each simulation technique, further highlighting the SEU prediction error inherent to conventional decoupled modeling approaches. Finally, clocked mixed-mode circuit simulations are used to explain the fundamental SEU mechanisms and relate them to corresponding regions of the device-level SET.

Improving the Performance of P3HT–Fullerene Solar Cells with Side-Chain-Functionalized Poly(thiophene) Additives: A New Paradigm for Polymer Design

The motivation of this study is to determine if small amounts of designer additives placed at the polymer-fullerene interface in bulk heterojunction (BHJ) solar cells can influence their performance. A series of AB-alternating side-chain-functionalized poly(thiophene) analogues, P1-6, are designed to selectively localize at the interface between regioregular poly(3-hexylthiophene) (rr-P3HT) and PC(n)BM (n = 61, 71). The side chains of every other repeat unit in P1-6 contain various terminal aromatic moieties. BHJ solar cells containing ternary mixtures of rr-P3HT, PC(n)BM, and varying weight ratios of additives P1-6 are fabricated and studied. At low loadings, the presence of P1-6 consistently increases the short circuit current and decreases the series resistance of the corresponding devices, leading to an increase in power conversion efficiency (PCE) compared to reference P3HT/PC(61)BM cells. Higher additive loadings (>5 wt %) lead to detrimental nanoscale phase separation within the active layer blend and produce solar cells with high series resistances and low overall PCEs. Small-perturbation transient open circuit voltage decay measurements reveal that, at 0.25 wt % incorporation, additives P1-6 increase charge carrier lifetimes in P3HT/PC(61)BM solar cells. Pentafluorophenoxy-containing polymer P6 is the most effective side-chain-functionalized additive and yields a 28% increase in PCE when incorporated into a 75 nm thick rr-P3HT/PC(61)BM BHJ at a 0.25 wt % loading. Moreover, devices with 220 nm thick BHJs containing 0.25 wt % P6 display PCE values of up to 5.3% (30% PCE increase over a control device lacking P6). We propose that additives P1-6 selectively localize at the interface between rr-P3HT and PC(n)BM phases and that aromatic moieties at side-chain termini introduce a dipole at the polymer-fullerene interface, which decreases the rate of bimolecular recombination and, therefore, improves charge collection across the active layer.

Developmental profiles of infant EEG: Overlap with transient cortical circuits

ObjectiveTo quantify spectral power in frequency specific bands and commonly observed types of bursting activities in the EEG during early human development. MethodsAn extensive archive of EEG data from human infants from 35 to 52weeks postmenstrual age obtained in a prior multi-center study was analyzed using power spectrum analyses and a high frequency burst detection algorithm. ResultsLow frequency power increased with age; however, high frequency power decreased from 35 to 45weeks. This unexpected decrease was largely attributable to a rapid decline in the number of high frequency bursts. ConclusionsThe decline in high frequency bursting activity overlaps with a developmental shift in GABA’s actions on neurons from depolarizing to hyperpolarizing and the dissolution of the gap junction circuitry of the cortical subplate. SignificanceWe postulate that quantitative characterization of features of the EEG unique to early development provide indices for tracking changes in specific neurophysiologic mechanisms that are critical for normal development of brain function.

A Sensitivity Analysis Method for Equivalent Parameter Extraction of Transient Magnetic Field With Internal Circuits

A sensitivity analysis method for the equivalent parameter extraction of transient magnetic field problems with internally coupled circuits is presented. In contrast to conventional methods using physical meaning and physical relationships for parameter extraction, this method is based on a collection of mathematical system equations which include transient magnetic field equations and internal circuit equations. The extracted parameters include the collective effects of eddy currents, internal circuits, and mechanical motion. Compared with previous sensitivity analysis methods which extract only the equivalent inductance, the proposed algorithm extracts also the equivalent resistance. A laminated transformer with internal circuit is reported to validate and showcase the proposed method.

Development of the Corticothalamic Projections

In this review we discuss recent advances in the understanding of corticothalamic axon guidance; patterning of the early telencephalon, the sequence and choreography of the development of projections from subplate, layers 5 and 6. These cortical subpopulations display different axonal outgrowth kinetics and innervate distinct thalamic nuclei in a temporal pattern determined by cortical layer identity and subclass specificity. Guidance by molecular cues, structural cues, and activity-dependent mechanisms contribute to this development. There is a substantial rearrangement of the corticofugal connectivity outside the thalamus at the border of and within the reticular thalamic nucleus, a region that shares some of the characteristics of the cortical subplate during development. The early transient circuits are not well understood, nor the extent to which this developmental pattern may be driven by peripheral sensory activity. We hypothesize that transient circuits during embryonic and early postnatal development are critical in the matching of the cortical and thalamic representations and forming the cortical circuits in the mature brain.

Passivity Enforcement for Admittance Models of Distributed Networks Using an Inverse Eigenvalue Method

Most transient circuit simulators are based on admittance representations of the constituent circuit elements. It is therefore natural to use admittance parameter descriptions of linear networks, preferably in the form of rational transfer functions that can be directly implemented in the analysis. A problem arises when the measured or calculated frequency-domain response of a linear distributed network must be derived from data that has inherent error, is of limited bandwidth, or is not in the appropriate rational form. A reduced-order rational model that is causal, stable, and passive must be developed. Previous methods of deriving rational functions for the admittance parameters of a network do guarantee stability and causality, but passivity of the model must be assured through subsequent post-processing. Enforcing passivity requires modification of the state-space parameters of the model with consequent introduction of errors. This paper reports on a procedure to simultaneously achieve passivity, accuracy, causality, and stability in the development of an admittance macromodel described using a matrix of rational functions. An iterative inverse eigenvalue algorithm enforces passivity, and is applied by conjoining sets of eigenvalue and admittance constraints. These constraints form a monolithic projection matrix, which simultaneously addresses both passivity and accuracy of the model.