Showing papers on "Tantalum capacitor published in 2012"

ESR estimation method for DC-DC converters based on improved EMD algorithm

Abstract: Aluminum electrolytic capacitors are usually used in DC-DC converters as smoothing capacitors. According to the statistics data, they are the weakest among various power components in the DC-DC converter. With the increase of the running time, the performance degradation of electrolytic capacitors reflects in electrical parameters, mainly the Equivalent Series Resistance (ESR) and capacitance. The best indicator of the output filter capacitor failure is the increase of ESR. And the output ripple voltage of the converter increases with respect to ESR. Monitoring the ESR variation of the electrolytic capacitor, achieving by voltage and current ripple, can estimate the health state of the converter.

Process-compatible decoupling capacitor and method for making the same

Abstract: Provided is decoupling capacitor device. The decoupling capacitor device includes a first dielectric layer portion that is deposited in a deposition process that also deposits a second dielectric layer portion for a non-volatile memory cell. Both portions are patterned using a single mask. A system-on-chip (SOC) device is also provided, the SOC include an RRAM cell and a decoupling capacitor situated in a single inter-metal dielectric layer. Also a method for forming a process-compatible decoupling capacitor is provided. The method includes patterning a top electrode layer, an insulating layer, and a bottom electrode layer to form a non-volatile memory element and a decoupling capacitor.

Method of making dielectric capacitors with increased dielectric breakdown strength

Abstract: The invention is directed to a process for making a dielectric ceramic film capacitor and the ceramic dielectric laminated capacitor formed therefrom, the dielectric ceramic film capacitors having increased dielectric breakdown strength. The invention increases breakdown strength by embedding a conductive oxide layer between electrode layers within the dielectric layer of the capacitors. The conductive oxide layer redistributes and dissipates charge, thus mitigating charge concentration and micro fractures formed within the dielectric by electric fields.

Electrical breakdown in capacitor dielectric films: Scaling laws and the role of self-healing

Abstract: Despite a great number of reports on high-energy density dielectric materials, very little attention is paid to determining realistic energy densities of larger scale devices made of these materials. These materials are typically evaluated with very short duration voltage withstand tests on very small sample areas, typically on the order of a few seconds and a few cm2. Conversely, full-scale devices require very long operational lifetimes on the order of years, and dielectric areas as large as several hundreds of m2. Practical components must also include additional material such as major insulation and packaging, resulting in volumetric efficiencies much less than 100%. Increases in total dielectric area, operating time, and packaging inefficiencies reduce practical energy densities by one to two orders of magnitude. Here we highlight the limitations of scaling up such results to high energy density capacitors as well as demonstrate the effect of self-healing and its necessity in high-energy-density, high-total-energy devices.

Lifetime prediction for tantalum capacitors with multiple degradation measures and particle swarm optimization based grey model

Abstract: A lifetime prediction method for high-reliability tantalum (Ta) capacitors was proposed, based on multiple degradation measures and grey model (GM). For analyzing performance degradation data, a two-parameter model based on GM was developed. In order to improve the prediction accuracy of the two-parameter model, parameter selection based on particle swarm optimization (PSO) was used. Then, the new PSO-GM(1, 2, ω) optimization model was constructed, which was validated experimentally by conducting an accelerated testing on the Ta capacitors. The experiments were conducted at three different stress levels of 85, 120, and 145 °C. The results of two experiments were used in estimating the parameters. And the reliability of the Ta capacitors was estimated at the same stress conditions of the third experiment. The results indicate that the proposed method is valid and accurate.

Characterization of Tantalum Polymer Capacitors

Abstract: Overview Reviewed data Caution must be taken when accelerating test conditions Data not useful to establish an acceleration model Introduction of new failure mechanism skewing results Evidence of Anti-Wear-Out De-doping of polymer Decreased capacitance Increased ESR Not dielectric breakdown Needs further investigation Further investigation into tantalum polymer capacitor technology Promising acceleration model for Manufacturer A Possibility for use in high-reliability space applications with suitable voltage derating.

Mim capacitor and fabrication method thereof

Abstract: A method of fabricating a metal-insulator-metal (MIM) capacitor is disclosed, wherein after capacitor trenches have been formed in a dielectric layer by dry etching, a wet etching process is further applied to the dielectric layer to etch the one or more capacitor trenches. By taking advantage of an isotropic characteristic of the wet etching process, the corners of the one or more capacitor trenches are rounded after the wet etching. Accordingly, a lower electrode, an insulator and an upper electrode formed thereafter over the dielectric layer and the surfaces of the one or more capacitor trenches will also have similar rounded corners at corresponding positions. Such design may substantially reduce the risk of occurrence of point discharge in the resulting MIM capacitor and hence may improve the operational reliability of the capacitor.

Electrolytic capacitor and method of manufacturing electrolytic capacitor

Abstract: An electrolytic capacitor according to the present invention includes a wound element formed by winding an anode body consisting of a band-shaped metal foil and a dielectric coat provided on the surface of the metal foil and a cathode body consisting of a band-shaped metal foil in the longitudinal direction. The electrolytic capacitor includes a first conductive polymer layer provided on the surface of the anode body. The first conductive polymer layer is provided to be more thickly present on an end portion of the anode body in the width direction than on a central portion of the anode body in the width direction on the surface of the anode body.

Method of using multilayer capacitor

Abstract: PROBLEM TO BE SOLVED: To reduce the acoustic noise of a substrate by a single element in a method of using a multilayer capacitorSOLUTION: A multilayer capacitor includes: a stack 10 that includes a stack of a plurality of dielectric layers; first capacitor electrodes 11, second capacitor electrodes 12, and third capacitor electrodes 13 that are disposed inside the stack 10; and a first external electrode 21, a second external electrode 22, and a third external electrode 23 that are disposed on the outer surface of the stack 10 and are connected to the first capacitor electrodes 11, the second capacitor electrodes 12, and the third capacitor electrodes 13, respectively The first capacitor electrodes 11 and the second capacitor electrodes 12 form first capacitance portions C1 by facing with each dielectric layer interposed therebetween, and the second capacitor electrodes 12 and the third capacitor electrodes 13 form second capacitance portions C2 by facing with each dielectric layer interposed therebetween The first external electrode 21, the second external electrode 22, and the third external electrode 23 are connected to an external circuit so that the phase of a first AC voltage supplied to the first capacitance portions C1 and the phase of a second AC voltage supplied to the second capacitance portions C2 are shifted

Thermal resistance of snap-in type aluminum electrolytic capacitor attached to heat sink

Abstract: Aluminum electrolytic capacitors are standard components in power electronic equipment. Their performance and lifetime strongly depends on their operation temperature. Hence, controlling their temperature is essential for reliable operation of the equipment. For standard snap-in type capacitors, which are common in low power converters (<∼20 kW), direct air cooling is the standard solution. This paper presents ways to improve the cooling performance by attaching the capacitor to a heat sink. Two different configurations are investigated: Heat removal through the base of the capacitor and heat removal through its sidewalls. When applied with an aluminum heat sink in natural convection, both methods provide significantly reduced thermal resistances, approximately 66% lower compared to direct air cooling by natural convection.

Thin film high dielectric constant metal oxides prepared by reactive sputtering

Abstract: High dielectric constant, low loss dielectric thin film materials produced by reactive RF sputtering have been investigated for use as capacitor dielectrics in integrated circuits, using oxides of niobium, tantalum, titanium, hafnium, and zirconium and mixtures of these with aluminum oxide. High breakdown fields and low leakage currents are found for the best materials and a reduction in capacitor area of a factor of >3 compared with Si3N4 capacitors of the same value, using a simple production process compatible with semiconductor device manufacturing.

High temperature capacitors with high energy density

Abstract: Power electronics are a key technology for hybrid and plug-in electric drive vehicles (EDV) and represent 20% of the material costs. DC bus capacitors are one of the critical components in EDV power inverters and they can occupy ∼35% of the inverter volume, contribute to ∼23% of the weight, and add ∼25% of the cost. Current polypropylene (PP) film capacitors have dielectric constant K of 2.2 and temperature stability lower than 105 °C. We recently developed a modified Polyvinylidene fluoride (PVDF) which combines high dielectric constant, low dielectric loss, low leakage current, high dielectric breakdown strength, and high temperature stability. The modified PVDF capacitor film also has graceful failure feature which is critical to applications demanding high reliability and long lifetime. The thermoplastic nature of the modified PVDF ensures that they can be processed into thin capacitor film using inexpensive melt extrusion and biaxial orientation process. In this report, DSC and dielectric spectroscope test results of the novel capacitor film will be presented.

Capacitor structure and fabricating method thereof

Abstract: The present invention provides a method for fabricating a capacitor structure, including the steps of: providing a substrate; forming a first conductive structure and a dielectric structure over the substrate, wherein the first conductive structure is enclosed by the dielectric structure; forming a first trench in the dielectric structure, so that a first surface of the first conductive structure is exposed through the first trench; forming a first capacitor electrode and a capacitor dielectric layer on a bottom and a sidewall of the first trench and on a top surface of the dielectric structure, so that the first capacitor electrode is electrically contacted with the first surface of the first conductive structure; and removing the first capacitor electrode and the capacitor dielectric layer on the top surface of the dielectric structure; forming a second capacitor electrode on a surface of the capacitor dielectric layer. A capacitor structure is also provided.

Thermal treatment method for nanometer tantalum powder

Abstract: The invention relates to a heat treatment method for nanometer tantalum powder. A tap density meter is used for carrying out tapping treatment on the nanometer tantalum powder before nanometer conglomeration treatment, so the preparation of tantalum powder blank blocks is not needed. Compared with the prior art with the treatment capability of 0.9g nanometer tantalum powder every time, the method provided by the invention has the advantages that 100 to 200g of nanometer tantalum powder can be treated every time, the treatment efficiency is greatly improved, meanwhile, the oxygen content of the obtained conglomerated nanometer tantalum powder is lower than 0.1 percent, the requirement that a tantalum capacitor requires the oxygen content of the tantalum powder being lower than 0.3 percent can be completely met, and the engineering production can be favorably realized. Compared with tantalum powder blank blocks in the prior art, the tantalum powder subjected to the tapping treatment has the advantages that the density and the hardness of blank blocks obtained after the heat treatment are low, before the deoxygenation treatment, the crushing treatment is not needed, the generation of tantalum powder sharp corners is avoided, and the adverse influence on the subsequent tantalum capacitor manufacturing and the capacitance volume is eliminated.

Conductive polymer dispersion for manufacturing solid electrolytic capacitor and solid electrolytic capacitor manufactured by using the same

Abstract: PROBLEM TO BE SOLVED: To provide a conductive polymer dispersion for manufacturing a solid electrolytic capacitor capable of manufacturing the solid electrolytic capacitor having excellent equivalent series resistance, capacitance and withstand voltage, and the solid electrolytic capacitor manufactured by using the same.SOLUTION: A conductive polymer dispersion for manufacturing a solid electrolytic capacitor containing at least of a compound represented by a general formula (1), a conductive polymer and a dispersant, and the solid electrolytic capacitor manufactured by using the same.

Graphene electrolytic capacitor

Abstract: The disclosure describes an improved electrolytic capacitor, more specifically, an electrolytic capacitor with a graphene-based energy storage layer and dielectric, and a method of making the improved electrolytic capacitor. The electrode with layered graphene energy storage and dielectric layers may be used in a variety of electrolytic capacitor configurations.

Solid electrolytic capacitor and method for manufacturing same

Abstract: A solid electrolytic capacitor includes: an anode body; a first dielectric layer formed on the anode body and including metal oxide; a second dielectric layer formed on the first dielectric layer and including an insulating polymer; a third dielectric layer formed on the second dielectric layer and including a dielectric substance having a higher dielectric constant than that of the metal oxide; and a solid electrolyte layer formed on third dielectric layer.

Thermal modeling of through hole capacitors

Abstract: Through the course of this paper transient thermal conditions were investigated for through hole capacitor models built in SolidWorks. Firstly, the influences of the shape, casing material are determined, after which lifelike models for aluminum electrolytic, ceramic and plastic film capacitors are built and their efficiency regarding forced cooling and thermal power dissipation is investigated.

Solid electrolytic capacitor and method of producing same

Abstract: To provide a solid electrolytic capacitor capable of high performance, the capacitor including: an anode element made of tantalum or niobium; a dielectric film disposed on the anode element; and a solid electrolytic layer disposed on the dielectric film, the dielectric film including: a first dielectric film made of an oxide of the tantalum or niobium, formed on a surface of the anode element; and a second dielectric film made of a composite metal oxide having a perovskite structure, formed on the first dielectric film.

Electrolytic capacitor and method for manufacturing same

Abstract: A capacitor element includes an anode foil, the first oxide film on a surface of the anode foil, a solid electrolyte layer formed using π-conjugated conductive polymer dispersing material on the first oxide film, and a cathode foil on the solid electrolyte layer. The cathode foil faces the first oxide film across the solid electrolyte layer. An electrolytic capacitor includes the capacitor element, an anode terminal connected to the anode foil, and a second oxide film on a surface of the anode terminal. The second oxide film provided on the anode terminal has higher water repellency than the first oxide film provided on the anode foil. This electrolytic capacitor can reduce a leakage current.

Solid tantalum electrolytic capacitor and preparation method thereof

Abstract: The invention discloses a solid tantalum electrolytic capacitor which comprises a tantalum anode body, a Ta2O5 dielectric coated film, a conducting layer, a graphite layer and a silver coating, wherein the Ta2O5 dielectric coated film is positioned on the surface of the tantalum anode body, the conducting layer is positioned on the Ta2O5 dielectric coated film, and the graphite layer and the silver coating are coated on the conducting layer The solid tantalum electrolytic capacitor is characterized in that the conducting layer is a mixed system of a compound carbon nano-tube and a conducting high-molecular material, wherein the compound carbon nano-tube is a magnetic carbon nano-tube grafted on the conducting high-molecular material, and the length direction of the compound carbon nano-tube is vertical to the surface of the tantalum anode body In the invention, the compound carbon nano-tube in oriented arrangement is adopted in the conducting layer, the electrical conductivity of the conducting layer is increased, and the equivalent series resistance of the capacitor is reduced, so that the high-frequency characteristic of the capacitor is improved Meanwhile, because the carbon nano-tube has excellent thermal conductivity, the capacitor has higher heat resisting property, the working life of the capacitor is prolonged, and the drain current is reduced

Process for producing electrolytic capacitors and capacitors made thereby

Abstract: A process for preparing a solid electrolytic capacitor comprising application of a non-ionic polyol prior to application of a conducting polymer layer.

Separator for aluminum electrolytic capacitor, and aluminum electrolytic capacitor

Abstract: A separator is provided for an aluminum electrolytic capacitor includes a porous cellulose film having excellent impedance characteristics and short-circuit resistance characteristics, and an aluminum electrolytic capacitor is also provided using the separator. The porous cellulose film is formed of dissolved and regenerated cellulose without forming a cellulose derivative. The regenerated cellulose is obtained by forming in a film form a cellulose solvent obtained by dissolving cellulose in an amino oxide solvent, immersing the resulting cellulose solvent in water or a poor solvent of the amino oxide solvent so as to coagulate and regenerate the cellulose, removing the cellulose from the amino oxide solvent, and drying the resulting cellulose.

Cathode piece of high-capacity tantalum capacitor and preparation method

Abstract: The invention provides a novel cathode piece of a high-capacity tantalum capacitor, which is capable of obviously saving precious metal Ru, and a preparation method for the novel cathode piece The cathode piece is formed by RuO2-TiO2-Ta2O5/ Ta or Ti, wherein the RuO2-TiO2-Ta2O5 is a composite coating of the cathode piece with the following components in parts by mass: 40-70 percent of RuO2, 15-50 percent of TiO2 and 10-20 percent of Ta2O5, and a Ta or Ti substrate is a cathode piece substrate; and the Ta or Ti piece is 005-01mm in thickness The preparation method for the cathode piece comprises the following steps of: painting alcohol precursor mixed liquor prepared from ruthenium acetate, RuO2-Ta2O5 gel powder and Cl6H36O4Ti or C8H20O4Ti to the cleaned and coarsened Ta or Ti substrate and drying at the temperature of 100-150 DEG C; then, performing thermal decomposition at the temperature of 250-400 DEG C for 30-60 minutes to obtain the RuO2-TiO2-Ta2O5/Ta or Ti cathode piece The cathode piece provided by the invention has the advantages that the preparation process is simple; the production equipment is simple; the product cost is low; the performance is stable; and the industrial production and application are easy

Method for manufacturing tantalum capacitor anode block through mixed powder in thermal field environment

Abstract: The invention relates to a method for manufacturing a tantalum capacitor anode block through mixed powder in a thermal field environment and belongs to the technical field of electronic components. The method sequentially comprises the steps of (1) conducting heat treatment on tantalum powder with different mean grain sizes in an inert gas environment at the temperature of 700 DEG C-1400 DEG C for 10min-1h to form clusters; (2) evenly mixing the rough powder cluster binding agent; (3) scattering fine powder clusters on the surfaces of rough powder clusters and evenly mixing; (4) conducting thermal field heating on mixed clusters in the step (3), removing solvent in the binding agent; (5) tiling mixed powder in the step (4) on an opening evaporator boat for drying with a blower; and (6) completing later working procedures according to the existing process. Contraction rate of a compression molded tantalum core after firing is obviously improved, no particle is crushed or blocks a gap, electrostatic capacity of a manufactured capacitor is greatly improved, and leakage current and loss are substantially reduced.

Life Prediction of Tantalum Capacitors Based on PSO-GM Model

Abstract: Life prediction for Tantalum (Ta) capacitors is difficult by using conventional time-to-failure analysis method. Degradation analysis, which deals with parameters of performance degradation, is an efficient method to estimate reliability for highly reliable parts like Ta capacitors. Based on grey theory, the GM(1,2) model, a degradation analysis method for life prediction was proposed. Since the accuracy of GM(1,2) model was influenced deeply by parameters, weight parameter  was optimized by particle swarm optimization method(PSO), and PSO-GM model was established. The practical test showed that the prediction errors were reduced by using the proposed PSO-GM model. It indicates that the proposed method is valid and accurate.

Study on the effect of the voltage upon the electrolytic capacitors mounted in reverse polarity

Abstract: This paper presents an experimental study on the effect of the voltage on the electrolytic capacitors mounted in reverse polarity The experiments indicate that if the capacitors are charged with a constant current, the voltage across them tends to slowly oscillate due to the fact that the leakage current becomes very high instead of being closely to 0 The study is performed on 3 types of electrolytic capacitors from NCC: 4700 µF, 3200 µF and 2200 µF All of the 3 types of capacitors are indicating a similar behavior

Method for preparing ruthenium oxide coating on inner wall of tantalum shell of electrolytic capacitor

Abstract: The invention discloses a method for preparing a ruthenium oxide coating on the inner wall of a tantalum shell of an electrolytic capacitor, belonging to capacitor cathode preparation methods. The method comprises the following steps of: mixing a ruthenium compound and valve metal powder to a powder mixture, and mixing the powder mixture and a solvent to obtain a slurry; evenly applying the slurry onto the inner wall of the tantalum shell, and drying; putting the dried tantalum shell into a coating furnace, and introducing steam to carry out thermal decomposition; dissolving ruthenium halide into deionized water to obtain an electrolyte, and adding additives to adjust the pH value to 1-5; and injecting the electrolyte into the tantalum shell, introducing a direct current, of which the current density is 5-50mA/cm , to carry out electroplating for 10-30 minutes, putting the electroplated tantalum shell into the coating furnace, and introducing steam to carry out heat treatment for 1-3 hours. The electrolytic capacitor cathode made by the method disclosed by the invention can increase the capacitance of the liquid tantalum capacitor with the same volume by more than one time, and the equivalent series resistance is smaller; and thus, the invention provides a method for preparing an electrolytic capacitor cathode.