Showing papers on "Capacitor published in 2001"

Vibration-to-electric energy conversion

Abstract: A system is proposed to convert ambient mechanical vibration into electrical energy for use in powering autonomous low power electronic systems. The energy is transduced through the use of a variable capacitor. Using microelectromechanical systems (MEMS) technology, such a device has been designed for the system. A low-power controller IC has been fabricated in a 0.6-/spl mu/m CMOS process and has been tested and measured for losses. Based on the tests, the system is expected to produce 8 /spl mu/W of usable power. In addition to the fabricated programmable controller, an ultra low-power delay locked loop (DLL)-based system capable of autonomously achieving a steady-state lock to the vibration frequency is described.

Non-contact type user input device

Abstract: PROBLEM TO BE SOLVED: To recognize the information of two or more points and the shape of an approaching object. SOLUTION: A non-contact type user input device is provided with a plurality of linear transmission electrodes, a transmitter supplying an AC current for transmission to the respective transmission electrodes, a plurality of linear reception electrodes arranged so as not to be in contact with the respective transmission electrodes and a receiver receiving the AC current flowing through the reception electrodes. A capacitor is formed at each intersection of the transmission electrode and the reception electrode, a parallel capacitor is formed corresponding to the approach of the fingertip of a user and the capacitance of the capacitor changes corresponding to the approaching degree of the fingertip. Recognition is performed by utilizing the change of the AC current passing through the capacitor between the electrodes.

The Energy Harvesting Eel: a small subsurface ocean/river power generator

Abstract: The Energy Harvesting Eel (Eel) is a new device that uses piezoelectric polymers to convert the mechanical flow energy, available in oceans and rivers, to electrical power. Eel generators make use of the regular trail of traveling vortices behind a bluff body to strain the piezoelectric elements; the resulting undulating motion resembles that of a natural eel swimming. Internal batteries are used to store the surplus energy generated by the Eel for later use by a small, unattended sensor or robot. Because of the properties of commercially available piezoelectric polymers, Eels will be relatively inexpensive and are easily scaleable in size and have the capacity to generate from milli-watts to many watts depending on system size and flow velocity of the local environment. A practical Eel structure has been developed that uses the commercially available piezoelectric polymer, PVDF. Future Eels may use more efficient electrostrictive polymer. Every aspect of the system from the interactions between the hydrodynamics of the water flow and structural elements of the Eel, through the mechanical energy input to the piezoelectric material, and finally the electric power output delivered through an optimized resonant circuit has been modeled and tested. The complete Eel system, complete with a generation and storage system, has been demonstrated in a wave tank. Future work on the Eel will focus on developing and then deploying a small, lightweight, one-watt power generation unit, initially in an estuary and then subsequently in the ocean. Such Eels will have the ability to recharge batteries or capacitors of a distributed robotic group, or remote sensor array, thus extending the mission life indefinitely in regions containing flowing water.

Conformal thin films over textured capacitor electrodes

Abstract: Method and structures are provided for conformal capacitor dielectrics over textured silicon electrodes for integrated memory cells. Capacitor structures and first electrodes or plates are formed above or within semiconductor substrates. The first electrodes include hemispherical grain (HSG) silicon for increasing the capacitor plate surface area. The HSG topography is then exposed to alternating chemistries to form monolayers of a desired dielectric material. Exemplary process flows include alternately pulsed metal organic and oxygen source gases injected into a constant carrier flow. Self-terminated metal layers are thus reacted with oxygen. Near perfect step coverage allows minimal thickness for a capacitor dielectric, given leakage concerns for particular materials, thereby maximizing the capacitance for the memory cell and increasing cell reliability for a given memory cell design. Alternately pulsed chemistries are also provided for depositing top electrode materials with continuous coverage of capacitor dielectric, realizing the full capacitance benefits of the underlying textured morphology.

A topology survey of single-stage power factor corrector with a boost type input-current-shaper

Abstract: A topological review of the single stage power factor corrected (PFC) rectifiers is presented in this paper. Most reported single-stage PFC rectifiers cascade a boost-type converter with a forward or a flyback DC-DC converter so that input current shaping, isolation, and fast output voltage regulation are performed in one single stage. The cost and performance of single-stage PFC converters depend greatly on how its input current shaper (ICS) and the DC-DC converter are integrated together. For the cascade connected single-stage PFC rectifiers, the energy storage capacitor is found in either series or parallel path of energy flow. The second group appears to represent the main stream. Therefore, the focus of this paper is on the second group. It is found that many of these topologies can be implemented by combining a two-terminal or three-terminal boost ICS cell with DC-DC converter along with an energy storage capacitor in between. A general rule is observed that translates a three-terminal ICS cell to a two-terminal ICS cell using an additional winding from the transformer and vice verse. According to the translation rule, many of the reported single-stage PFC topologies can be viewed as electrically equivalent to one another. Several new PFC converters were derived from some existing topologies using the translation rule.

Switched-capacitor power electronics circuits

Abstract: One of the main orientations in power electronics in the last decade has been the development of switching-mode converters without inductors and transformers. Light weight, small size and high power density are the result of using only switches and capacitors in the power stage of these converters. Thus, they serve as ideal power supplies for mobile electronic systems (e.g. cellular phones, personal digital assistants, and so forth). Switched-capacitor (SC) converters, with their large voltage conversion ratio, promise to be a response to such challenges of the 21st century as high-efficiency converters with low EMI emissions and the ability to realize steep step-down of the voltage (to 3 V or even a smaller supply voltage for integrated circuits) or steep step-up of the voltage for automotive industry or Internet services in the telecom industry. This paper is a tutorial of the main results in SC-converter research and design.

Integrated circuit capacitor

Abstract: Use of different materials for different conductive films forming plates or electrodes of one or more capacitors formed in a trench in a body of semiconductor materials allow connections to be made selectively to the plates. The films may be undercut by different etchants at respective connection apertures to avoid formation of connections or connections made by doped polysilicon of different conductivities forming connections to some plates of similarly doped polysilicon and blocking diode junctions with oppositely doped polysilicon. The blocking diodes may include a compensation implant to adjust reverse breakdown characteristics and provide transient and electrostatic discharge protection.

Science and technology of ferroelectric films and heterostructures for non-volatile ferroelectric memories

Abstract: We present in this article a review of the status of thin film ferroelectric materials for nonvolatile memories. Key materials issues relevant to the integration of these materials on Si wafers are discussed. The effect of film microstructure and electrode defect chemistry on the ferroelectric properties relevant to a high density nonvolatile memory technology are discussed. The second part of this review focuses on approaches to integrate these capacitor structures on a filled poly-Si plug which is a critical requirement for a high density memory technology. Finally, the use of novel surface probes to study and understand broadband polarization dynamics in ferroelectric thin films is also presented.

Fatigue-free samarium-modified bismuth titanate (Bi4−xSmxTi3O12) film capacitors having large spontaneous polarizations

Abstract: Fatigue-free and highly c-axis oriented Bi3.15Sm0.85Ti3O12 (BSmT) thin films were grown on Pt/TiO2/SiO2/Si(100) substrates using the method of metalorganic sol decomposition. The BSmT film capacitor with a top Pt electrode showed significantly improved values of the remanent polarization (2Pr) and the nonvolatile charge as compared to those of the Bi4−xLaxTi3O12 (x=0.75) film capacitor, recently known as the most promising candidate for nonvolatile memories. The 2Pr value of the BSmT capacitor was 49 μC/cm2 at an applied voltage of 10 V while the net nonvolatile switching charge was as high as 20 μC/cm2 and remained essentially constant up to 4.5×1010 read/write switching cycles at a frequency of 1 MHz. In addition to these, the capacitor demonstrated excellent charge–retention characteristics with its sensing margin of 17 μC/cm2 and a strong resistance against the imprinting failure.

Topologies for VSC transmission

Abstract: The increasing rating and improved performance of self-commutated semiconductor devices have made DC power transmission based on voltage-source power convertors (VSCs) possible. This technology is called VSC transmission. The main components in a DC scheme are depicted and their functions explained. The features of three main categories of convertor topology suitable for DC transmission are described. Three specific convertors viz. two-level, three-level diode-clamped and four-level floating-capacitor convertors for a 300 MW scheme are compared in terms of costs, DC capacitor volume, commutation inductance and footprint. The floating capacitor convertor is shown to yield the lowest system cost.

Capacitive sensing and data input device power management

Abstract: Capacitive proximity sensing is carried out by detecting a relative change in the capacitance of a “scoop” capacitor formed by a conductor and a surrounding ground plane. The conductor may be a plate provided in the form of an adhesive label printed with conductive ink. Charge is transferred between the “scoop” capacitor and a relatively large “bucket” capacitor, and a voltage of the bucket capacitor is applied to an input threshold switch. A state transition (e.g., from low to high, or high to low) of the input threshold switch is detected and a value (TouchVal) indicative of a number of cycles of charge transfer required to reach the state transition is determined. The presence or absence of an object or body portion in close proximity to or contact with a device can be determined by comparing TouchVal with a predetermined threshold value (TouchOff). TouchOff can be adjusted to take into account environmentally induced (non-touch related) changes in the capacitance of the scoop capacitor. Power management is provided in a user operated data input device utilizing proximity sensing and switching between three or more power states. Switching between the power states occurs based upon the presence or absence of input activity, and an operation instrumentality (e.g., a hand) in close proximity to or contact with the device. In an optical surface tracking cursor control device embodiment, switching to and from a BEACON state, which provides a reduced flash rate of a surface illuminating light source, is carried out based upon a detected presence or absence of a trackable surface.

On-chip capacitor

Abstract: An on-chip analog capacitor. Metal interconnect structures are used to form the capacitor, and the interdigitated fingers of like polarity within the interconnect structure are connected above and below to one another by metal vias to form a wall of metal which increases total capacitance by taking advantage of the via sidewall capacitance.

Power load-leveling system and packet electrical storage

Abstract: A capacitor-based electrical energy storage and distribution system capable of effectuating load-leveling during periods of peak demand on a utility (refer to figue 8). A capacitor (400) may be charged with electrical energy produced by the utility (510) during periods of low demand. Alternatively the electrical energy stored in the capacitors (400) can be discharged into the utility's distribution grid (510) to increase the amount of electrical energy available for use.

Method to reduce bit line capacitance in cub drams

Abstract: A new method is provided for the creation of the bit line contact plug. CUB capacitors typically are located adjacent to the bit line contact plug, a parasitic capacitance therefore exists between the CUB and the contact plug. Typical interface between the CUB and the bit line contact plug consists of a dielectric. By creating an air gap that partially replaces the dielectric between the CUB and the bit line contact plug, the dielectric constant of the interface between the bit line and the CUB is reduced, thereby reducing the parasitic coupling between the bit line contact plug and the CUB. This enables the creation of CUB capacitors of increased height, making the CUB and the therewith created DRAM devices better suited for the era of sub-micron device dimensions.

Switched capacitor defibrillation circuit

Abstract: A defibrillator circuit for generating a rectangular waveform across a patient from capacitively stored energy and employing a plurality of capacitors initially chargeable to a common voltage and thereafter sequentially switchable into parallel relation with one another so as to raise the voltage supplied to an H-bridge circuit from a point of decay back to said common voltage.

Methods for forming and integrated circuit structures containing ruthenium and tungsten containing layers

Abstract: Capacitors having increased capacitance include an enhanced-surface-area (rough-surfaced) electrically conductive layer or other layers that are compatible with the high-dielectric constant materials. In one approach, an enhanced-surface-area electrically conductive layer for such capacitors is formed by processing a ruthenium oxide layer at high temperature at or above 500° C. and low pressure 75 torr or below, most desirably 5 torr or below, to produce a roughened ruthenium layer having a textured surface with a mean feature size of at least about 100 Angstroms. The initial ruthenium oxide layer may be provided by chemical vapor deposition techniques or sputtering techniques or the like. The layer may be formed over an underlying electrically conductive layer. The processing may be performed in an inert ambient or in a reducing ambient. A nitrogen-supplying ambient or nitrogen-supplying reducing ambient may be used during the processing or afterwards to passivate the ruthenium for improved compatibility with high-dielectric-constant dielectric materials. Processing in an oxidizing ambient may also be performed to passivate the roughened layer. The roughened layer of ruthenium may be used to form an enhanced-surface-area electrically conductive layer. The resulting enhanced-surface-area electrically conductive layer may form a plate of a storage capacitor in an integrated circuit, such as in a memory cell of a DRAM or the like. In another approach, a tungsten nitride layer is provided as an first electrode of such a capacitor. The capacitor, or at least the tungsten nitride layer, is annealed to increase the capacitance of the capacitor.

Capacitive components for power electronics

Abstract: As the consumer and industrial requirements for compact, high-power density electrical power systems grow substantially over the next decade, development of high power/energy density capacitor technology is a major enabling technology component element. For microsecond to fractional-second electrical energy storage, discharge, filtering, and power conditioning, capacitor technology is unequalled in flexibility and adaptability to meet a broad range of requirements in the future.

Novel soft-switching DC-DC converter with full ZVS-range and reduced filter requirement. I. Regulated-output applications

Abstract: A novel soft-switching topology for DC-DC converters is proposed. It is well suited for applications in the range of a few hundred watts to a few kilowatts. It is essentially a hybrid combination of an uncontrolled half-bridge section and a phase-shift controlled full-bridge section, realized with just four switches. The main features of the proposed topology are zero-voltage-switching down to no-load without serious conduction loss penalty, constant frequency operation and, near-ideal filter waveforms. The improved filter waveforms result in significant savings in the input and output filter requirement, resulting in high power-density. The new topology requires two transformers and two DC-bypass capacitors. The combined VA rating of the two transformers is more than that of the single transformer of conventional full-bridge converters, for variable-input applications. In Part I of the paper, the converter operation is analyzed for typical switch-mode power supply applications, where the input voltage varies widely but the output voltage is fixed and is well regulated. Experimental results obtained from a 100 W/200 kHz proof-of-concept prototype confirm the superior features of the proposed hybrid configuration.

A new family of matrix converters

Abstract: A new family of matrix converters is introduced, that employs relatively simple voltage-clamped buses and can generate multilevel voltage waveforms of arbitrary magnitude and frequency. The basic configuration includes a nine-switch matrix that uses four-quadrant switch cells. Each four-quadrant switch cell resembles a full-bridge inverter and can assume three voltage levels during conduction. Semiconductor devices in a switch cell are clamped to a known constant DC voltage of a capacitor. Control of the input and output voltage waveforms of the proposed converter can be achieved through space vector modulation. Simulation results show how the converter can operate with any input and output voltages, currents, frequencies, and power factors while maintaining constant DC voltages across all switch cell capacitors.

A fast dynamic DC-link power-balancing scheme for a PWM converter-inverter system

Abstract: The authors propose a new power converter control scheme for a converter-inverter system. The strategy is to fully utilize the inverter dynamics in controlling the converter dynamics. The authors obtain the power dynamics for both converter and inverter systems, and control the converter power so that it matches the required inverter power exactly. Then, in the ideal case, no power flows through the DC-link capacitors and, thus, the DC-link voltage does not fluctuate even though a very small amount of the DC-link capacitance is used. In forcing the converter power to match the inverter power, the authors utilize the master-slave control concept. They control the DC-link voltage level indirectly through the stored capacitor energy in order to exploit the advantage of the linear dynamic behavior of the capacitor energy. This helps them to circumvent a complex control method in regulating the DC-link voltage. Through simulation and experimental results, the superiority of the proposed converter control scheme is demonstrated.

Apparatus for reducing power supply noise in an integrated circuit

Abstract: A main power supply continuously provides a current to a power input terminal of an integrated circuit device under test (DUT). The DUT's demand for current at the power input terminal temporarily increases during state changes in synchronous logic circuits implemented within the DUT. To limit variation (noise) in voltage at the power input terminal arising from these temporary increases in current demand, a charged capacitor is connected to the power input terminal during each DUT state change. The capacitor discharges into the power input terminal to supply additional current to meet the DUT's increased demand. Following each DUT state change the capacitor is disconnected from the power input terminal and charged to a level sufficient to meet a predicted increase in current demand during a next DUT state change.

Analog characteristics of metal-insulator-metal capacitors using PECVD nitride dielectrics

Abstract: The frequency dependence of PECVD nitride and LPCVD oxide metal-insulator-metal (MIM) capacitors is investigated with special attention for precision analog applications. At measurement frequencies of 1.0 MHz, nitride MIM capacitors show capacitance linearity close to that of oxide MIM capacitors, indicating potential for precision analog circuit applications. Due to dispersion effects, however, nitride MIM capacitors show significant degradation in capacitor linearity as the frequency is reduced, which leads to accuracy limitations for precision analog circuits. Oxide MIM capacitors are essentially independent of frequency.

High-Q LTCC-based passive library for wireless system-on-package (SOP) module development

Abstract: In this paper, we present the development and full characterization and modeling of a multilayer ceramic-based system-on-package component library. Compact high-Q three-dimensional inductor and capacitor topologies have been chosen and incorporated. A measured inductor Q factor as high as 100 and self-resonant frequency as high as 8 GHz have been demonstrated. The new vertically interdigitated capacitor topology occupies nearly an order of magnitude less of real estate while demonstrating comparable performance to the conventional topology. The low-temperature co-fired ceramic (LTCC) library has been incorporated into a 1.9-GHz CMOS power-amplifier design exhibiting a measured 17-dB gain, 26-dBm output power, and 48% power added efficiency. This power-amplifier module with fully integrated LTCC passives demonstrates a superior performance to those with full and partial on-chip passive integration.

A novel control method for input output harmonic elimination of the PWM boost type rectifier under unbalanced operating conditions

Abstract: This paper presents a new control strategy to improve the performance of the PWM boost type rectifier when operating under an unbalanced supply. An analytical solution for harmonic elimination under unbalanced input voltages is obtained resulting in a smooth (constant) power flow from AC to DC side in spite of the unbalanced voltage condition. Based on the analysis of the open loop configuration, a closed loop control solution is proposed. Simulation results show excellent response and stable operation of the new rectifier control algorithm. A laboratory prototype has been designed to verify the discussions and analyses done in this paper. Theoretical and experimental results show excellent agreement. Elimination of the possibility of low order AC and DC side harmonics due to unbalance is expected to materially affect the cost of DC link capacitor and AC side filter. The proposed method is particularly useful in applications where the large second harmonic at the DC link may have a severe impact on system stability of multiply connected converters on a common link.

Charge barrier flow-through capacitor

Abstract: Flow-through capacitors are provided with one or more charge barrier layers. Ions trapped in the pore volume of flow-through capacitors cause inefficiencies as these ions are expelled during the charge cycle into the purification path. A charge barrier layer holds these pore volume ions to one side of a desired flow stream, thereby increasing the efficiency with which the flow-through capacitor purifies or concentrates ions.

Metal oxynitride capacitor barrier layer

Abstract: Capacitor structures for use in integrated circuits and methods of their manufacture. The capacitor structures include a bottom electrode, a top electrode and a dielectric layer interposed between the bottom electrode and the top electrode. The capacitor structures further include a metal oxynitride barrier layer interposed between the dielectric layer and at least one of the bottom and top electrodes. Each metal oxynitride barrier layer acts to reduce undesirable oxidation of its associated electrode. Each metal oxynitride barrier layer can further aid in the repairing of oxygen vacancies in a metal oxide dielectric. The capacitors are suited for use as memory cells and apparatus incorporating such memory cells, as well as other integrated circuits.

Active matrix display

Abstract: An active matrix display is provided which eliminates variation of a threshold voltage of an active element inside a pixel and variation of a driving current due to the Early effect and supplies a desired driving current to a light emitting element of each pixel steadily and accurately. The active matrix display has current-voltage converter arranged in series in a supply path through which a driving current is supplied to a light emitting element and has a voltage control current source that is controlled by an output voltage of the current-voltage converter, thereby generating a monitor current having correlation with the driving current at the time of setting the driving current, controlling a gate voltage of a driving current generating transistor based on the monitor current such that a desired luminance can be realized and holding the control voltage in a capacitor.

Considerations of a shunt active filter based on voltage detection for installation on a long distribution feeder

Abstract: This paper deals with a curious phenomenon referred to as the "whack-a-mole" that may occur in a long-distance distribution feeder having many capacitors for power-factor correction. The idea of whack-a-mole is that installation of an active or passive filter on the feeder makes voltage harmonics increase on some buses, whereas it makes voltage harmonics decrease on other buses, especially at the point of installation. The distributed-parameter representation is applied to a simplified feeder, thus making it possible to perform analysis of the whack-a-mole. As a result, this analysis yields such a basic way as to avoid the whack-a-mole. Moreover, both theory and experiment clarify that installation of the active filter acting as a harmonic terminator on the end bus of the feeder can damp out harmonic propagation throughout the feeder without causing any whack-a-mole.

Dispatch of Main Transformer ULTC and Capacitors in a Distribution System

Abstract: This paper presents a dynamic programming method for solving reactive power / voltage control problems in a distribution system. The objective of this paper is to properly dispatch main transformers under load tap changers, substation capacitors, and feeder capacitors based on hourly forecast loads of each feeder section and primary bus voltage such that the total feeder loss can be minimized, voltage profile can be improved, and the reactive power flow into the main transformer can be restrained. The constraints that must be considered include the maximum allowable number of switching operations in a day for under load tap changer and each capacitor, and the voltage limit on the feeder and secondary bus voltage is limited. To demonstrate the usefulness of the proposed approach, reactive power /voltage control in a distribution system within the service area of the Yunlin District Office of Taiwan Power Company is performed. It is found that a proper dispatching schedule for each capacitor and under load tap changer can be reached by the presented method.

Integrated emi filter-DC blocking capacitor

Abstract: An integrated electromagnetic interference (EMI) filter capacitor and DC blocking capacitor is provided in a single monolithic casing of ceramic dielectric material. First and second sets of electrode plates are disposed within the monolithic casing to form the DC blocking capacitor, and ground electrode plates are disposed between selected portions of the first and second sets of electrode plates to form the EMI filter. In several of the embodiments, the first and second sets of electrode plates form a plurality of distinct DC blocking capacitors. The ground electrode plates cooperatively form, with the first and second sets of electrode plates, EMI filters for each of the distinct DC blocking capacitors. Discontinuous lead wires may be provided which extend at least partially into the casing, wherein a first segment of the lead wire is conductively coupled to the first set of electrode plates, and a second set of the lead wire is conductively coupled to the second set of electrode plates. Grounded shields also may be co-planarly disposed between adjacent components of the first and second sets of electrode plates to reduce cross-talk therebetween.