Showing papers on "Equivalent circuit published in 1986"

Accurate simulation of power dissipation in VLSI circuits

Abstract: It becomes increasingly more important to reduce the power dissipation as the number of devices in VLSI increases. Accurate simulation of power dissipation is desirable while circuits are analyzed with circuit simulators such as SPICE. An accurate method is presented for simulating the power dissipation with use of a dependent current source and a parallel RC circuit. The steady-state voltage across the capacitor reads the average power drawn from the supply voltage source. Simulation results are shown for CMOS circuits.

Application of Kramers‐Kronig Transforms in the Analysis of Electrochemical Impedance Data II . Transformations in the Complex Plane

Abstract: Algorithms have been developed to apply the Kramers-Kronig transforms in the analysis of experimental electrochemical impedance data. The application of these algorithms is illustrated by transforming calculated impedance data for an electrical equivalent circuit, by transforming experimental data for TiO/sub 2-/coated carbon steel in HCl/KCl solution at 25/sup 0/C, and by analyzing data for an aluminum alloy in 4M KOH at 60/sup 0/C. These transforms, coupled with statistical techniques, provide a powerful means of evaluating the validity of impedance data with respect to spurious errors that are present in either the real or imaginary component, and with respect to system stability.

Static and dynamic analysis of amorphous-silicon field-effect transistors

Abstract: Analytical expressions have been developed for the analysis of static and dynamic behaviour of hydrogenated-amorphous-silicon based field-effect transistors. The current/voltage, capacitances and transcapacitances/voltage characteristics are related to the material parameters. The characteristic temperature, Tc, of the exponential band-tail states distribution is shown to influence strongly their shape and magnitude. An exact integration of the potential in the structure has allowed us to give expressions for the source and drain resistances. Finally, we present an equivalent circuit of a-Si:H TFT which can be employed in circuit simulation for the optimisation of integrated circuits.

Implementation of Mason's Model on Circuit Analysis Programs

Abstract: Application a la conception de transducteurs d'ultrasons. Determination de leurs caracteristiques

Transmission line models for lossy waveguide interconnections in VLSI

Abstract: At high frequencies the waveguide nature of interconnections in VLSI circuits becomes important. Moreover, losses in interconnection are a major feature, not a perturbation. Here it is shown that even for such lossy waveguide structures an exactly equivalent RLGC transmission line can be found. Equations are given determining these transmission line parameters in terms of the waveguide propagation constant and complex average power, and also in terms of integrals over the electric and magnetic field varibles. The resulting L , C , and G parameters differ from the usual static values when losses are important, and R is not restricted to the usual formula based upon a perturbation treatment of the skin effect. Consequently, semiconductor substrates can be treated. "Current" and "voltage" are found to have an abstract meaning in the equivalent transmission line. For a waveguide in a medium where conductivity and permittivity vary with position (such as a many-layered medium) an explicit formula relating "current" and "voltage" to weighted averages of transverse waveguide fields is given. A brief discussion of the reformulation of Thevenin equivalent circuit parameters in terms of reflection coefficients avoids terms such as "open circuit voltage" that are difficult to interpret for the equivalent transmission line. The framework presented allows construction of equivalent circuits for lossy waveguide interconnections, drivers, and terminations that provide correct spatial dependence in the direction of propagation and correct power relations despite the abstract nature of "current" and "voltage" in these lines.

An Accurate FET Modelling from Measured S-Parameters

Abstract: A new modelling algorithm has been developed which extracts a small-signal microwave equivalent circuit of an FET from measured S-parameters. The combinations of properly selected circuit elements with an S-parameter to be least-squares fitted greatly improve the accuracy and consistency of modelling, The absolute accuracy of determining element values was estimated to be better than 3 %.

Partitioned-charge-based modeling of bipolar transistors for non-quasi-static circuit simulation

Abstract: The concept of partitioned-charge-based (PC) modeling of bipolar transistors is developed and demonstrated, and shown to be fundamentally superior to conventional quasi-static charge-control modeling, the basis of the common (capacitance-based) Gummel-Poon (GP) equivalent circuit. SPICE transient simulations with PC and GP models are contrasted to show a first-order accounting for non-quasi-static (NQS) delay in the PC model which is not accounted for in the GP model. Additional model contrasts in the small-signal domain, compared with exact ac solutions, confirm the superiority of the PC model, the characterization of which is in fact no more tedious than that of the GP model.

Fuzzy membership function circuit

Abstract: A programmable multi-membership function circuit comprises at least one or preferably two Z function circuits, at least one or preferably two S function circuits, and a fuzzy logic circuit for calculating fuzzy logic from the output of the Z function circuits and the output of the S function circuits. The fuzzy logic circuit comprises a MIN (intersection) circuit and a MAX (union) circuit, or the combination of these circuits.

Delay circuit for a monolithic integrated circuit and method for adjusting delay of same

Abstract: A delay circuit that can be implemented in a monolithic integrated circuit includes a plurality of capacitor/laser-fusible link series pairs. Delay of a binary output signal of the circuit with respect to an input transition is directly proportional to the amount of capacitance connected into the circuit. Because the laser-fusible links can selectively be opened with a laser, the amount of capacitance connected into the circuit can incrementally be reduced; thus, the delay of the circuit is reducibly adjustable to a desired value. By including a plurality of conductive element/laser-fusible link series pairs in the delay circuit, the delay of the circuit is also increasingly adjustable. A method for economically adjusting the delay of each of many like delay circuits embodied in a semiconductor wafer includes measuring a sample of the delays of the delay circuits, calculating an average delay, determining the difference between a desired delay and the average delay to determine an incremental amount of delay to eliminate or to add, determining from predetermined data which fusible links should be opened, and using a laser beam to open the appropriate links.

Methods for the modeling and fault simulation of complementary metal oxide semiconductor circuits

Abstract: A method for modeling complementary metal oxide semiconductor (CMOS) combinatorial logic circuits by Boolean gates taking into account circuit behavior effects due to charge storing and static hazards. Models are developed for both the faultless and faulty operation of each circuit. According to a further aspect of the invention, these models are used in a simulation procedure to evaluate the fault coverage of a large scale integrated circuit design built using a plurality of these circuits. In the evaluation procedure the faulty model is used only for a particular circuit whose failure performance is being tested and the faultless model is utilized for all other circuits. This procedure is continued until all of the individual gate circuits have been evaluated.

Performance calculation for single-sided linear induction motors with a double-layer reaction rail under constant current excitation

Abstract: A method for computing the performance of a single-sided linear induction motor (SLIM) with a double-layer reaction rail, under constant current excitation, is presented. This method takes into account the reaction of secondary eddy currents on the airgap field, transverse edge and longitudinal end effects, together with skin effect, saturation, nonlinear magnetic permeability, and hysteresis in the solid steel core of a reaction rail. In an equivalent circuit of the machine, the mutual and secondary impedances are found from a solution of the two-dimensional electromagnetic field distribution. Modifying factors account for configurations in which the width of the secondary conductive layer is different from that of the steel core, and in which the thickness of the conductive overhand is different from that over the steel core. Good correlation is obtained between analysis and test results from a large-scale linear induction motor (LIM) at Queen's University. The developed expressions are appropriate for small and large LIM's and may also be used for constant voltage excitation conditions.

Microwave Device Modeling Using Efficient l/sub 1/Optimization: A Novel Approach

Abstract: A powerful modeling technique which exploits the theoretical properties of the l/sub 1/ norm is presented. The concept of multicircuit measurements and its advantages for unique identification of parameters are discussed. Self-consistent models for passive and active devices are achieved by an approach that automatically checks the validity of model parameters obtained from optimization. A set of formulas is presented to evaluate the first-order sensitivities of two-port , S-parameters with respect to circuit elements appearing in an admittance or impedance matrix description of linear network equivalents. These formulas are used for devices with linear network models in conjunction with an efficient gradient based l/sub 1/ algorithm. Practical use of the efficient l/sub 1/ algorithm in complicated problems for which gradient evaluation may not be feasible is also discussed. Two different optimization problems are formulated which connect the concept of modeling to physical adjustments on the device. Detailed examples in modeling of multicoupled cavity filters and GaAs FET's are presented.

Voltage Distribution among the Coils and Turns of a Form Wound AC Rotating Machine Exposed to Impulse Voltage

Abstract: This paper describes a method of calculating voltage distribution in a stator winding exposed to impulse voltage. In this method, the voltage distribution in an equivalent-circuit representation of the stator winding is calculated. The winding is treated as an infinite number of identical coils connected in series, with each coil represented by an equivalent circuit including inductance, turn-to-ground capacitance and conductance, and with mutual inductance, capacitance, and conductance between turns. The impulse voltage is approximated by a Fourier series of components. The voltage distribution for each component is calculated, and the complete voltage distribution is obtained by summing the voltages due to each component. The complete calculating procedure, including the calculation of the equivalent circuit parameters has bee programmed in Basic language for computer calculation. Examples of the coil and turn voltages distributions calculated by this program and a comparison of calculated data with test data for a particular stator winding are included.

Application of transmission-line modelling (TLM) to thermal diffusion in bodies of complex geometry

Abstract: The use of the TLM method for modelling thermal diffusion in bodies of complex geometries is described. Both regular and irregular orthogonal meshes are used. Results are compared with those obtained using finite element analysis.

Relations between chord and slope conductances and equivalent electromotive forces

Abstract: Nonlinear current-voltage relations for ion movement across biological membranes have been observed and significantly complicate the interpretation of electrical measurements on these transport processes. To enable analysis of the electrical measurements two formalisms have evolved, chord and slope, by which equivalent conductances and electromotive forces (emfs) can be obtained. Because, in the presence of nonlinear relations between current and voltage, the chord conductances and emfs are generally not equal to their slope counterparts, it is imperative that they not be intermixed (8). However, when the functional relationship between the current and voltage is known, such as the Goldman-Hodgkin-Katz (GHK) flux equation, it becomes possible to compare the voltage dependencies of these parameters and examine interrelationships between them. In this communication analytical expressions are derived for the chord and slope conductances and emfs for transport of a single ionic species that obeys the GHK flux equation. Using these expressions, it is possible to convert electrical equivalent circuit parameters derived for one formalism to electrical equivalent parameters of the other formalism. Therefore data obtained using either formalism can be used to obtain values for intracellular activity and membrane permeability to the transported ion. Parallel analyses can be applied to other models of ion transport.

Multioctave bandwidth log-periodic microstrip antenna array

Abstract: The application of the log-periodic technique to the series-fed electromagnetically coupled overlaidpatch array allows antennas with flat conformal characteristics and wide bandwidths to be obtained. A k-s analysis of this and other microstrip array types indicate that the microstrip patch is not an optimum element for log-periodic arrays and that direct connection will result in arrays having a limited bandwidth. The addition of series capacitance to the patch equivalent circuit, implemented by electromagnetic coupling, allows an optimum to be approached. Log-periodic overlaid patch array design and measured results for an array with a 4:1 bandwidth are presented. These, together with a transmission-line analysis, indicate the array-design trade offs available and that the ultimate bandwidth is limited primarily by changes in the input return loss and radiation pattern due to the use of uniform thickness substrates.

Transient Response of a Transmission Line Excited by an Electromagnetic Pulse

Abstract: The transient response of a lossless transmission line of finite length excited externally by an electromagnetic wave of an arbitrary waveform is studied. By using the Laplace transformation, a solution of the transient current is obtained as a series of analytical functions. Inspection of the solution leads to the conclusion that the response currents at terminals of the line can be equivalently expressed by the components induced at both terminals, and, in addition, the multireflected wave when the line is mismatched. Furthermore, a new equivalent circuit for the coupling phenomenon is discussed. >

Basic circuitry particularly for construction of multivalued logic systems

Abstract: Disclosed are basic circuits operable in a current mode in multivalued logic circuit systems, analog circuit systems and the like Examples of the basic circuits are a successor, quantizer, adder, substracter, divider, multiplier, decoder, literal circuit, equivalence circuit, bilateral T-gate, complement literal circuit and h operator circuit These basic circuits are realized by using floating threshold switching circuits, floating window switching circuits, threshold SPDT switching circuits, and the like

Equalizer for digital transmission systems

Abstract: A post-equalizer and pre-equalizer circuit for use in communicating between nodes in a Pulse Amplitude Modulated (PAM) digital or analog communication system is described. The post-equalizer circuit comprises a first variable zero circuit, a second variable zero circuit, and a gain shaper circuit wherein the gain and frequency location of the zeros in the zero circuits combined with the gain of the gain shaping circuit are simultaneously controlled by a control circuit which generates a control voltage which is a monotonically increasing function of cable loss. In the case of a PAM digital communication system, the control voltage generates a signal equal to the difference between the equalized signal and the original transmitted signal which is used to vary the resistance of voltage variable resistors in the form of FET's in each of the zero circuits and gain shaper circuits. In the case of an analog system, the control voltage is derived from the sealing current that is determined by the DC resistance of the cable to be equalized. If the cable loss is above a predetermined value, a pre-equalizer circuit is switched into the transmit path of the communication system and provides a gain, zero and pole at predetermined frequencies which pre-compensates for the extra loss incurred in transmission over length greater than can be equalized by the post-equalizer. Additionally, a bi-quad ACE circuit is described which provides a hyperbolic relationship between the zero frequency location and circuit gain utilizing a cascode amplifier and emitter follower circuit with a feedback loop through a voltage variable resistor.

Method for calculating the properties of coupled-cavity slow-wave structures from their dimensions

Abstract: In the development of computer models of coupled-cavity travelling wave tubes, it is necessary to have some means of calculating the properties of the slow-wave structure. Direct calculation is difficult because of the complexity of the shapes involved. One possible method makes use of the equivalent circuit representation of the slow-wave structure. In the paper it is shown that the parameters of the equivalent circuit can be calculated from the dimensions of the structure. Once these parameters are known, it is very quick and easy to compute the phase change per cavity and the interaction impedance at any frequency. The results obtained by this method are compared with those of experiment and it is shown that useful accuracy can be obtained.

Design of Linear Induction Drives by Field Analysis and Finite-Element Techniques

Abstract: Two-dimensional field and finite-element analyses are complementary in evaluating the performance of single-sided linear induction machines, and can be used to develop a machine design for a given drive application. Electromagnetic analysis leads to an equivalent circuit of the machine with speed-and frequency-dependent parameters, in which top cap geometry, core hysteresis and saturation, skin effect, eddy current reaction, and both transverse-edge and longitudinal-end effects can be included. Finite-element analysis provides detailed information on the magnetic field distribution to aid in machine design.

Finite element analysis of H-plane rectangular waveguide problems

Abstract: The equivalent circuit parameters of rectangular waveguide H-plane junctions, bends and obstacles may be found by a two-dimensional finite element method. Results are presented for perfectly conducting and dielectric obstacles, and for a waveguide bend. Good agreement is obtained with previously published results.