PSpice Model Research Articles

Modeling of the Electrical Conductivity of DNA

The authors have developed a PSpice model of the electrical behavior of DNA molecules for use in nanoelectronic circuit design. To describe the relationship between the current through DNA and the applied voltage we used published results of the direct measurements of electrical conduction through DNA molecules. The experimental dc current-voltage (-) curves show a nonlinear conduction mechanism as well as the existence of a temperature dependent semiconductive voltage gap. A weighted least-squares polynomial fit to the experimental data at one temperature, with fitted temperature dependent polynomial coefficient of the linear term, was used as a mathematical model of electrical behavior of DNA. An equivalent electrical circuit was created in PSpice in which DNA was modeled as a voltage-controlled current source described by the mathematical model that includes temperature dependence . PSpice simulations with this model generated - curves at other temperatures that were in excellent agreement with the corresponding experimental data (average deviation 5%). This is important because having models of DNA molecules in the form of equivalent electronic circuits would be useful in the design of nanoelectronic circuits and devices.

Impedance matching of a coaxial Marx generator with a relativistic field emission limited diode

The impedance matching between the coaxial Marx generator and the relativistic field emission limited diode (RFELD) is investigated by using PSpice simulations. The PSpice model of the coaxial Marx generator has been built and verified by comparing the output voltage wave forms with the results of Kubota et al. [Y. Kubota, J. Kodaira, and A. Miyahara, Jpn. J. Appl. Phys. 20, 2397 (1981)]. By varying the passive resistive loads, the impedance of the coaxial Marx generator can be determined. In the PSpice simulation, we employ the analog behavioral modeling to describe the current-voltage characteristics of the RFELDs. The output characteristics including the voltage, current, and output power wave forms have been obtained. It is found that the output characteristics of the RFELDs with an effective work function of around 0.4 eV are in good matching with the coaxial Marx generator. The simulation results show a degradation in pulse duration or beam power for the cases of the RFELDs with higher or lower effective work functions. With our method, the impedance matching of the RFELDs with the coaxial Marx generator can be achieved and the corresponding output characteristics can be determined.

Crosstalk fault modeling in defective pair of interconnects

The manufacturing defect in the interconnect lines can lead to various electrical faults, e.g. defect due to under-etching effect/conductive particle contamination on interconnect line can lead to increased coupling capacitances between the two adjacent interconnects, which, in turn, can eventually result in crosstalk fault in the deep sub-micron (DSM) chips. In this paper, we describe the line-defect-based crosstalk fault model that will be helpful in analyzing the severity of the defect/fault, as the crosstalk fault occasionally leads to various signal integrity losses, such as timing violation due to excessive signal delay or speed-up, logic failure due to crosstalk positive/negative glitch above/below logic low/high threshold and also reliability problem particularly due to crosstalk glitch above logic high threshold. Our crosstalk fault model is very fast (at least 11 times faster than PSPICE model) and its accuracy is very close to PSPICE simulation results when the defect/fault is located in the middle of interconnects, whereas for the defects located at the near-end/far-end side of aggressor–victim the model accuracy differs marginally.

Studying an approach solution of i/o buffer information specification (IBIS) model

Modern electronic products must possess high speed, light weight, low power consumption, and small physical size. Signal Integrity (SI) is a significant technology for designing high‐speed printed circuit boards (PCB), known as HS‐PCB. In SI analysis of HS‐PCB, its interconnection and the I/O Buffer Information Specification (IBIS) model are two major components to be simulated. Generally, an IBIS model can be obtained from the IC design house, constructed by measuring the necessary information, or converting from the Pspice model. This paper presents a methodology for constructing an IBIS model. Our proposed model can fit the strict requirements of its IC datasheet. We created the buffer model using Pspice tools, entered the necessary parameters into this buffer model, converted it into various assignment models, and then simulated all assignment pins. The error rate between our proposed model and its datasheet is within 1%. Our method can be applied to SI simulation.

PSPICE controlled-source models of analogous circuit for Langevin type piezoelectric transducer

The design and construction of wide-band and high efficiency acoustical projector has long been considered an art beyond the capabilities of many smaller groups. Langevin type piezoelectric transducers have been the most candidate of sonar array system applied in underwater communication. The transducers are fabricated, by bolting head mass and tail mass on both ends of stacked piezoelectric ceramic, to satisfy the multiple, conflicting design for high power transmitting capability. The aim of this research is to study the characteristics of Langevin type piezoelectric transducer that depend on different metal loading. First, the Mason equivalent circuit is used to model the segmented piezoelectric ceramic, then, the impedance network of tail and head masses is deduced by the Newton’s theory. To obtain the optimal solution to a specific design formulation, PSPICE controlled-source programming techniques can be applied. A valid example of the application of PSPICE models for Langevin type transducer analysis is presented and the simulation results are in good agreement with the experimental measurements.

A Time-domain Reflectometry Method for Automated Measurement of Crack Propagation in Composites during Mode I DCB Testing

This article describes a new technique for automated measurement of crack initiation, growth, and propagation in composite materials during mode I double cantilever beam (DCB) testing. The proposed method uses time-domain reflectometry (TDR) to detect changes in geometry and electromagnetic properties (dielectric or magnetic) along a transmission line that can be embedded in or bonded to the surface of the specimen. Two types of transmission line TDR sensors are evaluated (IM7 carbon fiber and ARACON) during DCB tests. A P-SPICE transmission-line simulation model is used to verify the baseline signal response for the DCB sensor and the sensitivity for crack detection, with good agreement. Comparison with standard visual methods in DCB testing showed excellent correlation in crack location, crack propagation (LC), and the interlaminar fracture toughness (GIC) values. The TDR sensor design and model-based parametric studies are carried out to determine optimal sensor geometry and configuration. The results demonstrate that the TDR-based method can measure crack propagation parameters at high resolution and accuracy, in an automated manner using low-cost sensors.

Design, Fabrication and Application of 4H-SiC Trenched-and-Implanted Vertical JFETs

This paper reports recent progress in the development of a vertical JFET, the purely vertical JFET based on trenched-and-implanted vertical JFET (TI-VJFET) approach that eliminates the need of epitaxial regrowth at middle of device fabrication and the need of a merged lateral JFET to control the vertical JFET. Different structures have been designed to target breakdown voltages ranging from 600V to 1.2kV. Vertical channel width uniformity has been studied, showing the feasibility of achieving below 0.1um variation for reasonably flat wafers of good thickness uniformity. Pitch size of the designs has been reduced compared to early report. Gate trench width has been reduced from 3.8um to 2.3um, aimed at increasing the device current capability. Fabricated device cells have been tested and packaged into multi-cell 30A TI-VJFETs which have been characterized of DC and switching characteristics at room and elevated temperatures. Very fast current rise/fall times of <10ns were observed from RT to 200°C. PSpice model for TI-VJFET has been developed and applied to the performance prediction of 3-phase SiC power inverter, suggesting a high efficiency 97.7% at 200°C junction temperature without using soft-switching scheme. Preliminary experimental demonstration of a PWM-controlled three-phase inverter based on SiC TI-VJFET power board is reported.

Propagation velocity profile in a cross-section of a cardiac muscle bundle from PSpice simulation.

BackgroundThe effect of depth on propagation velocity within a bundle of cardiac muscle fibers is likely to be an important factor in the genesis of some heart arrhythmias.Model and methodsThe velocity profile of simulated action potentials propagated down a bundle of parallel cardiac muscle fibers was examined in a cross-section of the bundle using a PSpice model. The model (20 × 10) consisted of 20 chains in parallel, each chain being 10 cells in length. All 20 chains were stimulated simultaneously at the left end of the bundle using rectangular current pulses (0.25 nA, 0.25 ms duration) applied intracellularly. The simulated bundle was symmetrical at the top and bottom (including two grounds), and voltage markers were placed intracellularly only in cells 1, 5 and 10 of each chain to limit the total number of traces to 60. All electrical parameters were standard values; the variables were (1) the number of longitudinal gap-junction (G-j) channels (0, 1, 10, 100), (2) the longitudinal resistance between the parallel chains (Rol2) (reflecting the closeness of the packing of the chains), and (3) the bundle termination resistance at the two ends of the bundle (RBT). The standard values for Rol2 and RBT were 200 KΩ.ResultsThe velocity profile was bell-shaped when there was 0 or only 1 gj-channel. With standard Rol2 and RBT values, the velocity at the surface of the bundle (θ1 and θ20) was more than double (2.15 ×) that at the core of the bundle (θ10, θ11). This surface:core ratio of velocities was dependent on the values of Rol2 and RBT. When Rol2 was lowered 10-fold, θ1 increased slightly and θ2decreased slightly. When there were 100 gj-channels, the velocity profile was flat, i.e. the velocity at the core was about the same as that at the surface. Both velocities were more than 10-fold higher than in the absence of gj-channels. Varying Rol2 and RBT had almost no effect. When there were 10 gj-channels, the cross-sectional velocity profile was bullet-shaped, but with a low surface/core ratio, with standard Rol2 and RBT values.ConclusionWhen there were no or few gj-channels (0 or 1), the profile was bell-shaped with the core velocity less than half that at the surface. In contrast, when there were many gj-channels (100), the profile was flat. Therefore, when some gj-channels close under pathophysiological conditions, this marked velocity profile could contribute to the genesis of arrhythmias.

Transverse propagation in an expanded PSpice model for cardiac muscle with gap-junction ion channels.

Transverse propagation was previously found to occur in a two-dimensional model of cardiac muscle using the PSpice software program for electronic circuit design and analysis. Longitudinal propagation within each chain, and transverse propagation between parallel chains, occurred even when there were no gap-junction (g-j) channels inserted between the simulated myocardial cells either longitudinally or transversely. In those studies, there were pronounced edge (boundary) effects and end-effects even within single chains. Transverse velocity increased with increase in model size. The present study was performed to examine boundary effects on transverse propagation velocity when the length of the chains was held constant at 10 cells and the number of parallel chains was varied from 3 to 5, to 7, to 10, and to 20. The number of g-j channels was either zero, both longitudinally and transversely (0/0), or 100/100. Some experiments were also made at 100/0, 1/1, and 10/10. Transverse velocity and overall velocity (both longitudinal and transverse components) was calculated from the measured total propagation time (TPT), i.e., the elapsed time between when the first action potential (AP) and the last AP crossed the zero potential level. The transverse g-j channels were placed only at the ends of each chain, such that propagation would occur in a zigzag pattern. Electrical stimulation was applied intracellularly between cells A1 and A2. It was found that, with no g-j channels (0/0), overall velocity increased almost linearly when more and more chains were placed in parallel. In contrast, with many g-j channels (100/100), there was a much flatter relationship between overall velocity and number of parallel chains. The difference in velocities with 0/0 channels and 100/100 channels was reduced as the number of chains was increased. In conclusion, edges have important effects on propagation velocity (overall and transverse) in cardiac muscle simulations.

Nonlinear effects in varactor-tuned resonators

This paper describes the effects of RF power level on the performance of varactor-tuned resonator circuits. A variety of topologies are considered, including series and parallel resonators operating in both unbalanced and balanced modes. As these resonators were designed to produce oscillators with minimum phase noise, the initial small signal insertion loss was set to 6 dB and, hence, QL/Q0 = 1/2. To enable accurate analysis and simulation, S parameter and PSPICE models for the varactors were optimized and developed. It is shown that these resonators start to demonstrate nonlinear operation at very low power levels demonstrating saturation and lowering of the resonant frequency. On occasion squegging is observed for modified bias conditions. The nonlinear effects are dependent on the unloaded Q (Q0), the ratio of loaded to unloaded Q (QL/Q0), the bias voltage, and circuit configurations with typical nonlinear effects occurring at -8 dBm in a circuit with a loaded Q of 63 and a varactor bias voltage of 3 V. Analysis, simulation, and measurements that show close correlation are presented.

Effect of transverse gap-junction channels on transverse propagation in an enlarged PSpice model of cardiac muscle.

BackgroundIn previous PSpice modeling studies of simulated action potentials (APs) in parallel chains of cardiac muscle, it was found that transverse propagation could occur between adjacent chains in the absence of gap-junction (gj) channels, presumably by the electric field (EF) generated in the narrow interstitial space between the chains. Transverse propagation was sometimes erratic, the more distal chains firing out of order.MethodsIn the present study, the propagation of complete APs was studied in a 2-dimensional network of 100 cardiac muscle cells (10 × 10 model). Various numbers of gj-channels (assumed to be 100 pS each) were inserted across the junctions between the longitudinal cells of each chain and between adjacent chains (only at the end cells of each chain). The shunt resistance produced by the gj-channels (Rgj) was varied from 100,000 MΩ (0 gj-channels) to 1,000 MΩ (10 channels), 100 MΩ (100 channels) and 10 MΩ (1,000 channels). Total propagation time (TPT) was measured as the difference between the times when the AP rising phase of the first cell (cell # A1) and the last cell (in the J chain) crossed 0 mV. When there were no gj-channels, the excitation was transmitted between cells by the EF, i.e., the negative potential generated in the narrow junctional clefts (e.g., 100 Å) when the prejunctional membrane fired an AP. For the EF mechanism to work, the prejunctional membrane must fire a fraction of a millisecond before the adjacent surface membrane. When there were many gj-channels (e.g., 100 or 1,000), the excitation was transmitted by local-circuit current flow from one cell to the next through these channels.ResultsTPT was measured as a function of four different numbers of transverse gj-channels, namely 0, 10, 100 and 1,000, and four different numbers of longitudinal gj-channels, namely 0, 10, 100 and 1,000. Thus, 16 different measurements were made. It was found that increasing the number of transverse channels had no effect on TPT when the number of longitudinal channels was low (i.e., 0 or 10). In contrast, when the number of longitudinal gj-channels was high (e.g., 100 or 1,000), then increasing the number of transverse channels decreased TPT markedly.ConclusionThus, complete APs could propagate along a network of 100 cardiac muscle cells even when no gj-channels were present between the cells. Insertion of transverse gj-channels greatly speeded propagation through the 10 × 10 network when there were also many longitudinal gj-channels.

Repolarization of the action potential enabled by Na+ channel deactivation in PSpice simulation of cardiac muscle propagation.

BackgroundIn previous studies on propagation of simulated action potentials (APs) in cardiac muscle using PSpice modeling, we reported that a second black-box (BB) could not be inserted into the K+ leg of the basic membrane unit because that caused the PSpice program to become very unstable. Therefore, only the rising phase of the APs could be simulated. This restriction was acceptable since only the mechanism of transmission of excitation from one cell to the next was being investigated.Methods and resultsWe have now been able to repolarize the AP by inserting a second BB into the Na+ leg of the basic units. This second BB effectively mimicked deactivation of the Na+ channel conductance. This produced repolarization of the AP, not by activation of K+ conductance, but by deactivation of the Na+ conductance. The propagation of complete APs was studied in a chain (strand) of 10 cardiac muscle cells, in which various numbers of gap-junction (gj) channels (assumed to be 100 pS each) were inserted across the cell junctions. The shunt resistance across the junctions produced by the gj-channels (Rgj) was varied from 100,000 M? (0 gj-channels) to 10,000 M? (1 gj-channel), to 1,000 M? (10 channels), to 100 M? (100 channels), and 10 M? (1000 channels). The velocity of propagation (θ, in cm/s) was calculated from the measured total propagation time (TPT, the time difference between when the AP rising phase of the first cell and the last cell crossed -20 mV, assuming a cell length of 150 μm. When there were no gj-channels, or only a few, the transmission of excitation between cells was produced by the electric field (EF), i.e. the negative junctional cleft potential, that is generated in the narrow junctional clefts (e.g. 100 A) when the prejunctional membrane fires an AP. When there were many gj-channels (e.g. 1000 or 10,000), the transmission of excitation was produced by local-circuit current flow from one cell to the next through the gj-channels.ConclusionWe have now been able to simulate complete APs in cardiac muscle cells that could propagate along a single chain of 10 cells, even when there were no gj-channels between the cells.

A comparative study for the development of a thermal odoscope for the wearable dynamic thermography monitoring

Background The need of the reliable continuous monitoring of temperature is rising in many clinical applications. Today the use of thermography has become central for instance in the analysis of breast cancer, for the survey of inflammatory processes and certain skin areas during physical exercise. The core of the problem is the development of an ad hoc instrument, because traditional methodologies such as infrared and liquid crystals are no longer suitable. Material and methods We developed a dedicated simulation set-up using Matlab R12 procedures (The Mathworks, USA) and P-spice models (Interlink, USA). We simulated the realisation and use of three different equipment configurations for thermography, one based on PTC sensors, another on thermocouples, a third one on specific integrated silicon components. We also bench tested one prototype. Results The results showed the feasibility of the realisation of the instrument and the validity of the data obtained by means of the simulation.

Dynamics of MEMS electrostatic driving using a photovoltaic source

In this paper we study the potential use of a photovoltaic source as direct drive of electrostatic actuators, mainly for two reasons: first, because the I– V characteristic of a PV array has the shape of a current source limited in voltage and, second, because direct drive with galvanic isolation can be implemented at high voltages without using any dc/dc converter. We have used a standard PSpice model for a PV series array and a PSpice model of an electrostatic actuator. For sake of generality, the model for the PV array is the same one would like to use for the output circuit of a number of opto-couplers connected in series. Main parameters are: irradiance, I– V curve, and voltage, current and movement of the actuator (deflection) as a function of time. The number and surface of individual solar cells can be tailored to drive specific MEMS switches of high pull-in voltage value. As an example, a 14 cells-PV array, with a short circuit density current I sc = 1.2 nA, and open circuit voltage V oc = 8.7 V, would drive an electrostatic actuator having a pull-in voltage of 8.3 V, with three orders of magnitude lower kinetic energy than the equivalent voltage-drive. Both, this reduction in the kinetic energy at the impact, as well as the low hold-on voltage in the photovoltaic actuation reduce the electric field across the dielectric, which may lead to better reliability performance.

Design of SPICE Lib: A Modelica library for modeling and analysis of electric circuits

SPICELib is an object-oriented model library, written in the Modelica language, that implements some of the modeling and analysis capabilities of the circuit simulator PSpice. A novel approach has been adopted in the SPICELib design. It arises from considering that the reasons behind the success of PSpice include: the quality of the device models, the variety of supported analyses and the good performance of the numerical simulation. As a consequence, SPICELib is conceived to mimic not only the PSpice device models, but in addition PSpice capability to perform a variety of circuit analyses and the PSpice algorithms to calculate the circuit bias point, which is the most problematic analysis from the numerical standpoint. The fundamental hypotheses and the architecture of SPICELib library are discussed, in addition to the modeling of the supported analyses and devices. A case study is fully developed, in order to illustrate SPICELib use and validation. SPICELib version 1.1 (release October 2003) is free software, and it can be retrieved from the website: http://www.modelica.org/Conference2003/papers.shtml.

Toward simple robust control of single or current-sharing DC /DC converters driven by deterministic or random switching

In this paper, the multivariable robust approach is used to obtain simple controllers for both single and current- sharing (paralleled) DC/DC converters. Linear time-invariant nominal model of the power stage is derived and asymptotic uncertainty bounds are constructed to cover the parametric uncertainty, nonlinear effects in control, CMC switching effects and random switching control. Robust model of the current-sharing converters is developed and joint framework for the frequency domain robust design is proposed for both single and current-sharing configurations. The feasibility of the approach is demonstrated by two design examples: random control of the single unit buck converter and deterministic control of the three paralleled buck units. Several robust controllers are designed and verified for robustness and performance in the closed-loop with the Matlab and pSpice models.

A Low-Voltage Wide-Swing Programmable-Gain Current Amplifier

A CMOS low-voltage, wide-swing continuous-time current amplifier is presented. Exhibiting an open-loop architecture, the circuit is composed of transresistance and transconductance stages built upon triode-operating transistors. In addition to an extended dynamic range, the current gain can be programmed within good accuracy by a rapport involving only transistor geometries and tuning biases. Low temperature-drift on gain setting is then expected. In accordance with a 0.35 μm n-well CMOS fabrication process and a single 1.1 V-supply, a balanced current-amplifier is designed for a programmable gain-range of 6–34 dB and optimized with respect to dynamic range. Simulated results from PSPICE and Bsim3v3 models indicate, for a 100 μApp-output current, a THD of 0.96 and 1.87% at 1 KHz and 100 KHz, respectively. Input noise is 120 pA√Hz @10 Hz, with S/N e 63.2 dB @1%-THD. At maximum gain, total quiescent consumption is 334 μW. Measurements from a prototyped amplifier reveal a gain-interval of 4.8–33.1 dB and a maximum current swing of 120 μApp. The current-amplifier bandwidth is above 1 MHz.

An Improved High-Intensity Discharge Lamp Model Including Acoustic Resonant Effect on the Lamp Arc Resistance

An improved physical high-intensity discharge lamp model that combines the concept of acoustic resonance prediction based on the geometric structure of the lamp, energy balance equations, and lamp arc resistance modeling is proposed. It can be incorporated into a PSpice model for prediction of lamp voltage and current under both low and high frequency operations. In particular, variation of lamp arc resistance due to acoustic resonance at high-frequency operation is incorporated into the model. The validity of the model has been confirmed with measurements.

Physical CAD Model for High-Voltage IGBTs Based on Lumped-Charge Approach

A new insulated gate bipolar transistor (IGBT) model developed on a physical basis is presented. The Lumped-Charge method has been revised in order to point out a more general methodology for implementing the model into a circuit form. As an example, a version of the model for the popular PSPICE simulator is presented. The N-channel IGBT structure is described by means of an evolution of the PSPICE level-1 metal oxide semiconductor field effect transistor model. An accurate mobility model has been included to precisely predict the voltage drop in the ON state. Simulation results agree well with the experiments both in static and in switching operations. The comparison between the proposed and the native IGBT PSPICE model shows the better behavior of the former. The reasons for this result have been verified by means of two-dimensional MEDICI simulations. Moreover, the proposed model is able to predict the device behavior also in critical operations like its latchup during a turn-off under short-circuit conditions.

Static and cyclic relaxation studies in nonconductive adhesives

Adhesives interconnection systems are now commonly used in flip chip package for bonding metallic bump to substrate metallization. However, one major limitation of these adhesives is the problem of degradation in the mechanical contact between bump and substrate metallization which causes drastic increase in contact resistance. This problem is caused by the stress relaxation of the adhesive over a period of time. In addition, because these devices are subjected to variations in electrical and thermal loads, they experience corresponding cyclic mechanical straining which results in cyclic relaxation that has distinguished characteristic apart from static relaxation. The study showed that cyclic relaxation has dependency on hold time, no-load time and ramp rate. PSpice modeling has been used to understand the cyclic relaxation phenomenon in the adhesives. The accuracy of PSpice modeling used to mimic the linear viscoelasticity behavior of the adhesive has been found to be within 5% error compared to the experimental results.