Showing papers on "Capacitor published in 1983"

Fully integrated active RC filters in MOS technology

Abstract: A fully integrated continuous-time low-pass filter has been fabricated with CMOS technology. The device implements an active RC network using integrated capacitors and MOS transistors operated in the nonsaturation region as voltage-controlled resistors. The filter topology is fully balanced for good linearity and for good power supply rejection. The cutoff frequency is voltage adjustable around 3 kHz, allowing compensation for process and temperature variations. For 5-V power supplies a dynamic range of over 94 dB has been achieved.

Compact electrical power supply for signal processing applications

Abstract: The present invention relates to a compact electrical power supply which derives electrical energy from a low frequency medium voltage source (eg a 120 V 60 Hz ac main), and converts the electrical energy to a low voltage format suitable for solid state signal processing equipment The supply entails in succession bridge rectification means, a dc-dc boost converter, a capacitor storage bank, and a half bridge converter, either resonantly or non-resonantly operated The converters operate at frequencies substantially above audible frequencies in the interests of compactness The design provides a high input power factor (inductive) with minimum EMT, and provides a lengthened voltage hold up after loss of power

Optimal resetting of the transformer's core in single ended forward converters

Abstract: The transformer's core in single ended forward converters is reset by a "magnetizing current mirror" consisting of a capacitor in series with an auxiliary switch which, during the OFF period of the primary switch, couples the capacitor to one of the transformer's windings to form a resonant circuit with the transformer's magnetizing inductance. The resonant circuit recycles the transformer's magnetizing energy by creating a mirror image of the magnetic flux between ON periods. This maximizes the flux swing available within a given core. The voltage stress on the primary switch is minimized as the voltage across the switch during the OFF period is approximately constant and automatically tailored to avoid dead time for arbitrary values of the switch duty cycle.

An Investigation of the Charge Conservation Problem for MOSFET Circuit Simulation

Abstract: MOSFET capacitor models implemented in circuit simulators currently do not guarantee charge conservation, which is extremely crucial for the simulation of dynamic RAM's, switched capacitor filters, and other MOS VLSI circuits. Several MOSFET capacitor models have been introduced in the literature; however, none of these models addresses the actual reasons of charge nonconservation in SPICE2. This charge conservation problem has been studied and the causes are found. Our investigations show that charge is the appropriate state variable, and that the nonconservation of charge in SPICE2 stems from a numerical integration problem quite independent of the device physics. A new charge model has been derived, implemented in SPICE2, and tested. The new model differs from the previous models in two respects. First, it uses both charge equations and capacitance equations. Second, the partitioning of the channel charge between the source and drain terminals is carried out by requiring the charge equations to satisfy self-consistent boundary conditions. A strong emphasis is placed on charge continuity, both in the conventional operating region and in the region of weak inversion and accumulation. Benchmark tests indicate that this new model conserves charge while reducing the simulation time by 18-85 percent compared to Meyer's model which was originally used in SPICE2.

Enhancement of the dielectric constant near a percolation threshold

Abstract: When one of the components of a mixture of two materials is a conductor, geometrical effects can lead to a dielectric constant for the mixture which is much greater than that of either constituent. Here we illustrate a simple example of this effect in a two-dimensional network consisting of randomly placed conductors and capacitors. The dielectric enhancement is obtained as a function of frequency and the concentration of conductors. The calculational technique used is the position-space renormalization group in which smaller units are combined iteratively to form larger units.

Optimal Choice of Fixed and Switched Shunt Capacitors on Radial Distributors by the Method of Local Variations

Abstract: This paper presents a method of optimally choosing fixed and switched shunt capacitors on radial distribution feeders, considering load growth, growth in load factor and increase in cost of energy. Mathematical models to represent cost saving due to energy loss reduction taking the growth factors into account, cost saving due to release in systam capacities, capacitor cost and voltage rise during off-peek hours, as a function of capacitive current flows in the feeder sections have been formulated. Cost functions have been defined for optimizing the choice of both fixed and switched capacitors. A direct search technique known as the Method of Local Viariations has been employed for solving the resulting discrete variational problem. The problem has also been solved using Dynamic Programming Approach for comparison. The proposed method has been illustrated through some actual cases of radial feeders existing in an Indian distribution network. The results highlighting the influence of the growth factors have also been discussed in this paper.

Comparison of 60Co Response and 10 KeV X-Ray Response in MOS Capacitors

Abstract: Recently there has been great practical interest in using low energy (10 keV) x-rays rather than the usual 60Co for radiation testing of microelectronic circuits. In this work we examine some of the mechanisms underlying the radiation response of MOS capacitors in these two environments. Specifically we measure the thickness dependent dose enhancement in thin SiO2 films, and we measure the field dependence of the recombination. We found significant dose enhancement for 10 keV x-rays for thin oxides, and the recombination is generally greater at field of practical interest for 10 keV x-rays than for 60Co. The implications of these results for device testing are discussed.

A New Out-of-Step Relay with Rate of Change of Apparent Resistance Augmentation

Abstract: A new concept in out-of-step protective relaying that has several advantages over conventional out-of-step relaying is developed. The technique involves augmenting apparent impedance or apparent resistance based control with computed rate of change of apparent impedance or resistance. By use of appropriate control laws plus adaptive features, a relay which can be set closer to stability limits is obtained.

Method of making high density VMOS electrically-programmable ROM

Abstract: A method of making an electrically-programmable memory array in which the memory elements are capacitor devices formed in anisotropically etched V-grooves, providing enhanced dielectric breakdown at the apex of the groove. After breakdown, a memory element exhibits a low resistance to a grounded substrate. The method includes forming access transistors in series with the memory elements, and polycrystalline silicon, deposited to form control gates of the access transistors, also forms address lines. Oxide is formed in the V-groove thinner than the gate oxide thickness formed for the access transistor, providing a lower programming voltage. These factors provide a very small, high speed device.

Burner ignition system

Abstract: An electronic ignition system for a gas burner is battery operated. The battery voltage is applied through a DC-DC chopper to a step-up transformer to charge a capacitor which provides the ignition spark. The step-up transformer has a significant leakage reactance in order to limit current flow from the battery during initial charging of the capacitor. A tank circuit at the input of the transformer returns magnetizing current resulting from the leakage reactance to the primary in succeeding cycles. An SCR in the output circuit is gated through a voltage divider which senses current flow through a flame. Once the flame is sensed, further sparks are precluded. The same flame sensor enables a thermopile driven main valve actuating circuit. A safety valve in series with the main gas valve responds to a control pressure thermostatically applied through a diaphragm. The valve closes after a predetermined delay determined by a time delay orifice if the pilot gas is not ignited.

Design of Interdigitated Capacitors and Their Application to Gallium Arsenide Monolithic Filters

Abstract: Theoretical expressions for the interelectrode capacitance and conductor losses for an array of microstrip transmission lines are presented. The effect of finite conductor thickness is included in the analysis by introducing equations for the effective width of the transmission lines. Good agreement between theory and experiment is observed up to 18 GHz. Experimental results obtained from a lumped-element GaAs monolithic bandpass filter are in excellent agreement with theory. The filter has 1.5-dB insertion loss at 11.95 GHz and greater than 22-dB loss in the stopband. The filter measures 0.58x 1.3x0.203 mm.

Display process and apparatus thereof incorporating overlapping of color filters

Abstract: A display apparatus comprises a first substrate provided with a thin film transistor array as a driving switching element and a second substrate provided with another electrode, and produces a display by electro-optical change generated between these substrates. Visibility of the display is improved in such a way that rays of light incident on the display apparatus are converted into diffusion light. Photoconductive material, in particular amorphous silicon, can be used by covering semiconductive portions of the thin film transistor array of the display apparatus with an intercepting member. In a display apparatus using a thin film transistor array as a driving switching element, a conductive surface electrically insulated from gate lines on a substrate on where the gate lines for the thin film transistor array are formed, such conductive surface acts as a counter electrode of capacitors for storing charge. Therefore the counter electrode of capacitors is separately formed from gate lines, and writing driving voltage can be set without taking effects of voltage change of gate lines into consideration. Shading layers comprising a plurality of color filters also cover each of the thin film transistors.

Radiation-Induced Interface States of Poly-Si Gate MOS Capacitors Using Low Temperature Gate Oxidation

Abstract: The effect of gate oxidation temperature on radiation-induced flatband and threshold voltage shifts and interface state buildup for steady-state Co60 irradiation have been studied for poly-Si gate MOS capacitors with pyrogenic and dry gate oxides. The smallest radiation-induced flatband and threshold voltage shifts can be achieved with a pyrogenic oxide grown at 850°C. Total dose effects, applied gate bias during the irradiation and oxide thickness dependence were also evaluated for low temperature pyrogenic oxide MOS capacitors. We obtained a 2/3 power law dependence of radiation-induced interface states on the total dose and the oxide thickness.

Specific material detection and measuring device

Abstract: A device for sensing the presence of and measuring the concentration of a specific non-aqueous particle or gas material in an environment, the device comprising an interdigitated capacitor having at least a pair of selected covering layers thereupon, said pair of layers comprising a first passive electrically insulative layer and a second material layer having a spacial relationship to said first layer, said second layer selectively permeable to the specific material to be sensed and measured; said second coating, when juxtaposed said first coating, selectively permitting permeability of the particular material sought to be sensed and measured, and when spaced apart, permitting passage through of the specific material in order that the material may migrate to the proximity of the first coating and thereby be sensed and measured. The presence of the specific material modifies the dielectric constant of the dielectric in the interdigitated capacitor electric field and thus the capacitor's capacitance, whereupon the interdigitated capacitor's capacitance is compared with a proximate temperature sensing interdigitated capacitor in a capacitance sensing circuit and by the change of the capacitance, the presence and concentration of the specific material determined.

Time‐dependent response of interface states in indium phosphide metal–insulator–semiconductor capacitors investigated with constant‐capacitance deep‐level transient spectroscopy

Abstract: Constant‐capacitance deep‐level transient spectroscopy measurements performed on InP‐SiO2 metal‐insulator‐semiconductor capacitors are reported for the first time. Two types of samples have been used, one of epitaxial InP with a free‐electron concentration n=1.4×1015 cm−3 and covered with an ‘‘undoped’’ SiO2 insulating layer, the other of bulk material with n=1016 cm−3 and covered with an HCl‐‘‘doped’’ SiO2 dielectric. Extensive experiments have been performed and a model has been proposed which successfully explains the corresponding results. This model is based on the assumption of a spatial and energetical distribution of interface states within the dielectric. The interaction of these traps with the conduction band takes place via a tunneling process during the capture of electrons and by a tunneling followed by a thermally activated transition during the emission process. The interface state density has been found to be about 1012 cm−2 eV−1 in the energy range between about 0.2 and 0.5 eV below the c...

Thin-film transistor circuit

Abstract: A thin-film transistor circuit used to drive a liquid crystal display (LCD) device is disclosed, which circuit includes a plurality of circuit components (C ij ) which are as arranged in the form of a matrix as to be connected with data lines (Y j , Y j+1 ) for supplying an image signal and with address lines (X i , X i+1 ) for supplying a gate pulse signal, whereby the circuit components control the picture element display in the unit picture element region of the LCD device. Each circuit component has a capacitor (26) connected to the unit picture element region (22) for temporarily storing the image signal, and a TFT transfer gate (20) having a gate electrode connected to one (X i ) of the address lines, a source electrode connected to one (Y j ) of the data lines, and a drain electrode connected to the capacitor (26). The transfer gate (20) performs the switching operation in response to the gate pulse signal, thereby transferring the image signal to the capacitor (26). A compensating pulse signal which is synchronized with the gate pulse signal and has a polarity opposite to that of the gate pulse signal is applied to the capacitor (26), thereby preventing a decrease in the image signal voltage across this capacitor (26) due to the parasitic capacitance component existing in the thin-film transistor (20).

New Approach for the Application of Shunt Capacitors to the Primary Distribution Feeders

Abstract: This paper deals with the application of permanent shunt capacitors to primary distribution feeders. Two distinct optimization techniques have been developed for selection of capacitor size and location depending on the location of the additional loads that can be served with the capacitors present. The objective cost function minimized includes revenues due to energy loss reduction in the feeder and released kVA at the substation. The minimization is subject to voltage drop constraints. These techniques have been applied to a typical rural distribution zone in Egypt and the results are briefly summarized.

Electronic flash device

Abstract: An electronic flash device fires one or a pair of flash tube sequentially for continuous shooting photography with a motor driven photographic camera, for substantially continuous illumination or for sequential illuminations at intervals, as well as fire the flash tube a single time for one shot photography. The flash device is provided with a main capacitor and an auxiliary capacitor which selectively energize the flash tube or tubes. The auxiliary capacitor is charged by the main capacitor and discharged to energize the flash tube for a small amount of flash light and short-time restoration of the flash firing circuit. When a pair of flash tubes are employed, they are alternatively actuated for the sequential firing and one of them is actuated for the single time firing. The pair of flash tubes are coupled with each other through a commutation capacitor and switch elements for quick repetition of their firings.

Magnetic recording medium

Abstract: PURPOSE:To increase greatly the recording density of a data recorder/reproducer, by using a staircase wave generating circuit to convert a digital data into a staircase wave having a modulated period and then to record it to a recording medium. CONSTITUTION:The staircase waves of different periods in accordance with 1 or 0 of the signal at a terminal Q which is obtained by latching a data signal (a) by a latching circuit 11. In other words, the half period T of the staircase wave is short and long when the data (a) is set at 0 and 1 respectively. Then the staircase wave is recorded on a magnetic tape 3 by a tape recorder 7. In the reproduction mode, an output signal (c) is supplied to a buffer 14 of a comparator 5. At the same time, the top or bottom point of the signal (c) is held by the values of a diode and a capacitor. Then the amplitude center potential of the signal emerges at a capacitor C4 through a resistance. An operational amplifier 15 compares the signal with its amplitude center to extract a square wave (d) which has a short period to a signal 0 and a long period to a signal 1 respectively. Thus, the recording density is greatly increased.

Liquid level and volume measuring method and apparatus

Abstract: A liquid level height within a tank is measured by means of an elongated multi-segment capacitance probe that includes a column of capacitors extending through a liquid level interface. Each capacitor of the probe is sequentially measured in response to microprocessor controlled instructions as part of a measuring unit located at the tank. Up to sixteen measuring units may be interconnected in a field and individually connected to a microcomputer system at a central station. The microcomputer system addresses each of the measuring units and sends a select signal to the microprocessor controller of the measuring unit to sequentially measure each capacitor of the probe. By identifying the capacitor at the liquid level interface, the height of liquid within a tank is computed by the microcomputer system. From this height measurement and stored tank data, the volume of liquid within a tank is calculated. Associated with each of the capacitors of the probe is a temperature sensor for generating a temperature correction factor for the volume calculation.

Storage capacitor optimization for one device FET dynamic RAM cell

Abstract: A process for providing different insulator systems for the storage capacitor and the FET in a single polysilicon one-device memory cell, such as a dynamic RAM cell, without requiring an additional masking level. In particular, the Hi-C or diffusion store ion implantation mask is used to implement this feature. This process can be used to provide different materials in the insulator system of the storage capacitor and the FET, or the same materials with different thicknesses.

Thin film capacitor with a dual bottom electrode structure

Abstract: A thin film capacitor having a dual bottom electrode is provided. The bottom electrode includes a first layer of metal and a second layer of platinum, the metal of the first layer having the characteristic of forming a stable intermetallic phase with platinum during heat treatment. The first layer metal may be selected from the group consisting of Hf, Zr and Ta. The thin film capacitor may be employed as a decoupling capacitor in VLSI devices.

High-frequency oscillator-inverter ballast circuit for discharge lamps

Abstract: A current fed high frequency oscillator-inverter ballast circuit includes a parallel resonant tank circuit for driving a pair of series connected discharge lamps via a series ballast capacitor. A regenerative power supply switches on when a fluctuating main DC supply voltage drops below a given level thereby providing a constant level auxiliary DC supply voltage to the oscillator inverter to maintain oscillation and lamp operation. When the main DC supply voltage exceeds said given level, the regenerative power supply switches out. The oscillation frequency is f 2 during operation of the main supply and automatically switches to a frequency f 1 when the regenerative power supply takes over. The frequency shift is automatic during each half cycle of a 60 Hz AC supply and is in a direction so as to maintain lamp current relatively constant. A novel high frequency leakage transformer may be provided to couple the high frequency inverter to the discharge lamp load to provide both a current limiting (ballast) action and automatic control of the lamp heater current to maintain high efficiency operation.

Reduction of harmonics in gas discharge lamp ballasts

Abstract: A gas discharge lamp ballast circuit operates at high frequency and is fed from a mains supply through a rectifier having a smoothing capacitor. The invention provides for the load to include an inductor and to return to the rectifier supply at a position isolated from the smoothing capacitor by one or more diodes, and for there to be a discharge path from the smoothing capacitor through the load to charge a control capacitor, and lower the load voltage to allow a rectifier current flow to the load. The smoothing capacitor is charged by current flowing from the inductor during a relaxation phase, to a voltage higher than the peaks of the rectifier. The smoothing capacitor voltage is maintained by proportioning the control capacitor size to cause rectifier current, and not smoothing capacitor discharge, to supply circuit and load losses.

A Current-Comparator-Based System for Calibrating Active/Reactive Power and Energy Meters

Abstract: A system for calibrating active/reactive power and energy meters under sinusoidal conditions using a current comparator bridge is described. Measurement can be made at any power factor from zero lag through unity to zero lead, positive or negative power, at 100 to 120 V, 1 to 5 A, and 50 or 60 Hz. The system features a digital oscillator, a thermal rms ac/dc voltage comparator, an automatically compensated capacitor for producing an accurate and stable reactive component, and a microcomputer for control and data reduction. The systematic uncertainty of the calibration system is estimated to be not more than 15 parts per million (ppm).

Circuit arrangement for keeping the temperature-dependent sensitivity of a differential-pressure measurement apparatus constant

Abstract: The differential-pressure measurement apparatus consists of a capacitive differential-pressure sensor 1 having two measurement capacitors C1 and C2 whose capacitance values vary with the differential pressure acting on the membranes 2 and 3, of two integrating elements 9 and 10 which are fed back via the measurement capacitors C1 and C2, and which convert their capacitance values into measurement signals, and of a computing element 12 which calculates the differential pressure from the measurement signals. In order that the sensitivity of the differential-pressure measurement apparatus can be kept free of defects and constant in a simple manner, the integrating elements 9 and 10 are supplied from a controllable oscillator 11, and a temperature-dependent control voltage is obtained from the measurement signals via a computing circuit 13, which control voltage, after comparison with a constant reference voltage which can be entered via the connection 15, provides follow-up control of the oscillator 11 in such a manner that the control voltage equates to the reference voltage.

Low cost thin film capacitor

Abstract: The present invention relates to a low cost method of fabricating capacitors within tight tolerance ranges The method involves forming, by vapor deposition or the like, discrete electrode areas on an insulating substrate, and depositing a dielectric layer over the substrate and the areas between the electrodes A further series of electrode are formed over the dielectric in partial registry with the first mentioned electrodes, and the substrate is thereafter diced to expose opposed edge portions of the resultant capacitors The capacitors are terminated preferably by a sputtering technique, the sputtered material being insulated from contact with the edge portions of non-exposed electrodes by the deposited dielectric