Showing papers on "Tantalum capacitor published in 2013"

Stacked Switched Capacitor Energy Buffer Architecture

Abstract: Electrolytic capacitors are often used for energy buffering applications, including buffering between single-phase ac and dc. While these capacitors have high energy density compared to film and ceramic capacitors, their life is limited. This paper presents a stacked switched capacitor (SSC) energy buffer architecture and some of its topological embodiments, which when used with longer life film capacitors overcome this limitation while achieving effective energy densities comparable to electrolytic capacitors. The architectural approach is introduced along with design and control techniques. A prototype SSC energy buffer using film capacitors, designed for a 320 V dc bus and able to support a 135 W load, has been built and tested with a power factor correction circuit. It is shown that the SSC energy buffer can successfully replace limited-life electrolytic capacitors with much longer life film capacitors, while maintaining volume and efficiency at a comparable level.

Vapor phase polymerization deposition of conducting polymer/graphene nanocomposites as high performance electrode materials.

Abstract: In this paper, we report chemical vapor phase polymerization (VPP) deposition of novel poly(3,4-ethylenedioxythiophene) (PEDOT)/graphene nanocomposites as solid tantalum electrolyte capacitor cathode films. The PEDOT/graphene films were successfully prepared on porous tantalum pentoxide surface as cathode films through the VPP procedure. The results indicated that the high conductivity nature of PEDOT/graphene leads to the decrease of cathode films resistance and contact resistance between PEDOT/graphene and carbon paste. This nanocomposite cathode film based capacitor showed ultralow equivalent series resistance (ESR) ca. 12 mΩ and exhibited better capacitance-frequency performance than the PEDOT based capacitor. The leakage current investigation revealed that the device encapsulation process does not influence capacitor leakage current, indicating the excellent mechanical strength of PEDOT-graphene films. The graphene showed a distinct protection effect on the dielectric layer from possible mechanical damage. This high conductivity and mechanical strength graphene based conducting polymer nanocomposites indicated a promising application future for organic electrode materials.

Anomalous Currents in Low Voltage Polymer Tantalum Capacitors

Abstract: Low voltage Polymer Ta capacitors fabricated with porous Ta anodes, anodic oxide films of Ta as a dielectric, and poly(3,4ethylenedioxythiophene) (PEDOT) cathodes were investigated. The polymer cathodes were formed by either pure in-situ polymerization or hybrid polymerization, with in-situ PEDOT inside the porous anodes and a pre-polymerized PEDOT cathode on the external surface of the anodes. Anomalous transient current, DC leakage, and breakdown voltage were observed and investigated at normal and reverse polarities in a broad range of temperatures and voltages. Anomalously high transient current in the ampere range was observed when a pulse of rated voltage at normal polarity (+ on the Ta anode) was applied to the capacitors, and anomalous DC current was observed when rated voltage was applied at low temperature. This effect was significantly more pronounced in the hybrid devices, but significantly decreased in all cases with humidification. The anomalous currents were explained by the presence of dipoles, charged polymer chains, in the conducting polymer cathode at its interface with the dielectric.

Solid Electrolytic Capacitor for Use Under High Temperature and Humidity Conditions

Abstract: A solid electrolytic capacitor that is capable of exhibiting good electrical properties even under the extreme conditions of high temperature and humidity levels is provided. More particularly, the capacitor contains a capacitor element that includes a sintered porous anode body, a dielectric that overlies the anode body, and a solid electrolyte that overlies the dielectric. The solid electrolyte contains a conductive polymer and an organometallic coupling agent. The capacitor also contains a moisture barrier layer that overlies the solid electrolyte and is formed from a hydrophobic elastomer that has a low surface energy such that it is not readily wettable by an aqueous medium.

Solid Electrolytic Capacitor with Enhanced Wet-to-Dry Capacitance

Abstract: A capacitor for use in relatively high voltage environments is provided. During formation, anodization may be carried out in a manner so that the dielectric layer possesses a relatively thick portion that overlies an external surface of the anode and a relatively thin portion that overlies an interior surface of the anode. In addition to employing a dielectric layer with a differential thickness, the solid electrolyte is also formed from the combination of pre-polymerized conductive polymer particles and a hydroxy-functional nonionic polymer.

Vapor Phase Polymerization Deposition Conducting Polymer Nanocomposites on Porous Dielectric Surface as High Performance Electrode Materials

Abstract: We report chemical vapor phase polymerization (VPP) deposition of poly(3,4-ethylenedioxythiophene) (PEDOT) and PEDOT/graphene on porous dielectric tantalum pentoxide (Ta2O5) surface as cathode films for solid tantalum electrolyte capacitors. The modified oxidant/oxidant-graphene films were first deposited on Ta2O5 by dip-coating, and VPP process was subsequently utilized to transfer oxidant/oxidant-graphene into PEDOT/PEDOT-graphene films. The SEM images showed PEDOT/PEDOT-graphene films was successfully constructed on porous Ta2O5 surface through VPP deposition, and a solid tantalum electrolyte capacitor with conducting polymer-graphene nano-composites as cathode films was constructed. The high conductivity nature of PEDOT-graphene leads to resistance decrease of cathode films and lower contact resistance between PEDOT/graphene and carbon paste. This nano-composite cathode films based capacitor showed ultralow equivalent series resistance (ESR) ca. 12Ω and exhibited excellent capacitance-frequency performance, which can keep 82% of initial capacitance at 500 KHz. The investigation on leakage current revealed that the device encapsulation process has no influence on capacitor leakage current, indicating the excellent mechanical strength of PEDOT/PEDOT-gaphene films. This high conductivity and mechanical strength of graphene-based polymer films shows promising future for electrode materials such as capacitors, organic solar cells and electrochemical energy storage devices.

Solid electrolytic capacitor and improved method for manufacturing a solid electrolytic capacitor

Abstract: An improved process for forming a capacitor, and improved capacitor formed thereby is described. The process includes: providing an anode comprising a dielectric thereon; applying a first layer of an intrinsically conducting polymer on the dielectric to form a capacitor precursor; applying at least one subsequent layer of an intrinsically conducting polymer on the first layer from a dispersion; and treating the capacitor precursor at a temperature of at least 50°C no more than 200°C at a relative humidity of at least 25 % up to 100%, or fusing the layered structure by swelling the layered structure with a liquid and at least partially removing the liquid.

Solid electrolytic capacitor with improved performance at high voltages

Abstract: A solid electrolytic capacitor that comprises a sintered porous anode, a dielectric layer that overlies the anode body, and a solid electrolyte overlying the dielectric layer is provided. The anode is formed from a finely divided powder (e.g., nodular or angular) having a relatively high specific charge. Despite the use of such high specific charge powders, high voltages can be achieved through a combination of features relating to the formation of the anode and solid electrolyte. For example, relatively high press densities and sintering temperatures may be employed to achieve “sinter necks” between adjacent agglomerated particles that are relatively large in size, which render the dielectric layer in the vicinity of the neck less susceptible to failure at high forming voltages.

Design and Analysis of Electrical Properties of a Multilayer Ceramic Capacitor Module for DC-Link of Hybrid Electric Vehicles

Abstract: Multilayer capacitors with high ripple current and high capacitance were manufactured. The electrical properties of these capacitors were characterized for potential application for DC-link capacitors in hybrid electric vehicle inverters. Internal electrode structures were designed to achieve high capacitance and reliability. A single multilayer capacitor showed 0.46 3F/cm₃ of capacitance, 0.65% of dielectric loss, and 1450 V to 1650 V of dielectric breakdown voltage depending on the design of the internal electrode. The capacitor module designed with several multilayer capacitors gave a total capacitance of 450 3F, which is enough for hybrid electric vehicles. In particular, an equivalent series resistance of 4.5 m7 or less will result in 60 A rms , thereby reaching the allowed ripple current for hybrid electric vehicles.

Dielectric composition, multilayer ceramic capacitor using the same, and method for manufacturing multilayer ceramic capacitor

Abstract: A dielectric composition includes a base main component including Ba and Ti and an accessory component, wherein a ratio of domain width/grain size of the dielectric composition is in the range of 0 to 0.2, a multilayer ceramic capacitor using the same, and a method for manufacturing a multilayer ceramic capacitor. It is possible to provide a dielectric composition that can implement a higher dielectric constant and good high temperature withstand voltage characteristics in the same grain size condition. It is expected that this effect can be effectively applied to the development of ultra high capacity MLCCs having a thin dielectric by implementing the same capacity while increasing the thickness of the dielectric than the case of applying the conventional dielectric material.

Stable solid electrolytic capacitor containing a nanocomposite

Abstract: A solid electrolytic capacitor that includes an anode body, dielectric overlying the anode body, and solid electrolyte that overlies the dielectric is provided The solid electrolyte includes a nanocomposite that contains a plurality of nanofibrils dispersed within a conductive polymer matrix The nanofibrils have a relatively small size and high aspect ratio, which the present inventors have discovered can dramatically improve the thermal-mechanical stability and robustness of the resulting capacitor

Linear-hyperbranched polymers as performance additives for solid electrolytic capacitors

Abstract: Provided herein is an improved capacitor and a method for forming an improved capacitor. The method includes providing an anode and forming a dielectric on the anode. A linear-hyperbranched polymer is formed and a conductive polymer dispersion is prepared comprising at least one conducting polymer, one polyanion and the linear-hyperbranched polymer. A layer of the conductive polymer dispersion if formed wherein said dielectric is between the anode and the layer.

Elimination of electrolytic capacitor through high-voltage driving of LED aided by third-order harmonic current injection

Abstract: In this paper, the concept of high-voltage driving of LED is proposed to reduce the output voltage ripple of LED driver circuits by decreasing the AC current flowing through the output capacitor, leading to the potential replacement of electrolytic capacitor with other capacitor types having significantly longer lifetime. It also enables a direct driving of the LED load without the need for a second stage for voltage step-down. To further reduce the output voltage ripple's amplitude or output capacitor's size, the well-known third-order harmonic current injection technique can be incorporated. A general design procedure including the effect of harmonic current injection is proposed and verified experimentally.

High-temperature sheet-type tantalum capacitor and manufacturing method thereof

Abstract: The invention discloses a high-temperature sheet-type tantalum capacitor and a manufacturing method of the high-temperature sheet-type tantalum capacitor. The manufacturing method of the high-temperature sheet-type tantalum capacitor comprises the steps that an anode is designed, namely, the weight of tantalum powder is calculated according to formation voltage which is 2-6 times of the nominal voltage, and a porous matrix anode tantalum core is formed through sintering; dielectric film is formed, namely, aqueous solution with electrolyte being boric acid or nitric acid or phosphoric acid or ammonium dihydrogen phosphate or ethylene glycol is selected as formation solution, and tantalum pentoxide dielectric film which is uniform in thickness and good in uniformity is formed on the surface of the anode tantalum core; a manganese dioxide cathode is manufactured, namely, the anode tantalum core is put into manganous nitrate with different proportions, repeated operation is conducted, and a manganese dioxide cathode layer is formed; the high-temperature sheet-type tantalum capacitor is assembled. The high-temperature sheet-type tantalum capacitor can resist high temperature of 200 DEG C, has good high-temperature-resisting capacity, and is small in size, good and stable in performance, and capable of being widely applied to the fields of power supply control parts of airplane noses or guided missiles or the like and the fields of petroleum drilling electronic circuits and the like.

Single pattern high precision capacitor

Abstract: An integrated circuit contains a high precision capacitor having a bottom plate, a dielectric layer over the bottom plate, a capacitor opening in the dielectric layer exposing, and not overlapping, the bottom plate, a capacitor dielectric layer covering sidewalls and a bottom of the capacitor opening, a top plate covering the capacitor dielectric layer in the capacitor opening, and a capacitor planarizing dielectric layer covering the capacitor top plate in the capacitor opening. A top surface of the capacitor planarizing dielectric layer and a top edge of the capacitor top plate are substantially coplanar. The top plate does not extend laterally beyond the capacitor opening. A method of forming the integrated circuit the high precision capacitor is also disclosed.

230C Hermetically Sealed SMD Tantalum Capacitors

Abstract: Certain electronic applications, such as oil and gas exploration drilling, are continuously demanding ever higher operating temperatures. Recently operating temperature requirements have increased from 200°C to 230°C with an increased operating life from hours to one thousand hours and beyond. This need is linked with the continuous development of oil drilling heads and sensors and their use for deeper drilling or drilling in more difficult geological conditions. Capacitors with high capacitance value are a common part of the electronic boards used in these applications, but over 125°C/175°C, available capacitor choice is very limited. Tantalum SMD capacitor technology has proved its reliability in operation up to 175°C and there is a limited choice of special designs up to 200°C. Long life wet tantalum capacitors up to 200°C are available from multiple sources, or up to 230°C with reduced operational life from a single source. Hermetically sealed MnO2 tantalum capacitors have demonstrated their ability t...

Method for recovering tantalum, silver and manganese in waste and old tantalum capacitor

Abstract: The invention provides a method for comprehensively recovering a plurality of metals in a tantalum capacitor The method comprises the following steps: mechanically crushing the waste and old tantalum capacitor, separating metals from nonmetals to obtain metal materials, carrying out reduction acid dipping of the metal materials, filtering to obtain a manganese-containing solution, and carrying out extraction and impurity removal to obtain a manganese salt; and mixing filter residues obtained after the reduction acid dipping and filtration with carbon black and a chlorine salt, carrying out high temperature roasting in a chlorinator for reacting to generate tantalum chloride, arranging a condensation system at the upper portion of the chlorinator to condensate and recover tantalum chloride, rectifying the obtained tantalum chloride solid to obtain high-purity tantalum chloride, reducing the tantalum chloride to obtain high-purity tantalum powder, washing unreacted residues obtained after the roasting with hot water, adding ammonia water, filtering to obtain a silver-ammonia solution, and adding a reducing agent for reducing to obtain silver powder The method has simple and practical steps, and is helpful for the resource recovery and the environmental protection

Integrated circuit devices with capacitor and methods of manufacturing the same

Abstract: An integrated circuit device with capacitors and methods of forming the integrated circuit device are provided. The methods may include forming a first lower capacitor electrode pattern on an inner surface of a hole in a mold layer. The first lower capacitor electrode pattern may have a hollow cylindrical shape and an opening in an upper surface. The method may further include forming a second lower capacitor electrode pattern plugging the opening and an upper surface of the second lower capacitor electrode pattern may be planar. The first and the second lower capacitor electrode patterns may comprise a lower capacitor electrode including a void. Additionally, the method may include removing the mold layer to expose the lower capacitor electrode, forming a dielectric layer on the lower capacitor electrode, and forming an upper capacitor electrode layer on the dielectric layer.

Thin Film Capacitors Embedded in Polymer Dielectric

Abstract: A substrate comprising a capacitor comprising metal electrodes and a ceramic or metal oxide dielectric layer, the capacitor being embedded in a polymer based encapsulating material and connectable to a circuit via a via post standing on said capacitor.

Capacitor e.g. plate-type capacitor, for use in e.g. generator utilized for conversion of mechanical energy into electrical energy, has dielectric layer, where gas-filled volumes are arranged in pores of dielectric layer

Abstract: The capacitor (12) e.g. plate-type capacitor (10), has a dielectric layer (18) arranged between layered electrode elements (14, 16) i.e. films and plates, and composed of a dielectric material e.g. elastomer material such as rubber, cross-linked polyurethane, silicone and thermoplastic elastomer material, or liquid. The dielectric layer is formed as a foam layer (20) with pores (22) e.g. micropores, mesopores and macropores. Gas-filled volumes (24) are arranged in the pores. Powder-like particles are arranged in the dielectric layer and made of another dielectric material i.e. barium titanate.

Method for manufacturing cathode of total-tantalum electrolytic capacitor

Abstract: The embodiment of the invention discloses a method for manufacturing a cathode of a total-tantalum electrolytic capacitor. The method comprises the following steps of: blasting sand to polish the inner surface of a tantalum housing of the total-tantalum electrolytic capacitor; adding graphene oxide into a dispersing solvent for dispersing to obtain graphene oxide dispersion liquid; adding the graphene oxide dispersion liquid into the tantalum housing, so that the graphene oxide in the graphene oxide dispersion liquid is dispersed on the inner surface; carrying out reduction treatment onto the graphene oxide which is dispersed on the inner surface; and forming a ruthenium oxide layer on the inner surface by an electrochemical method. According to the method disclosed by the embodiment of the invention, the graphene oxide and the ruthenium oxide are compound, so that not only can the area of the cathode of the total-tantalum capacitor be greatly increased, but also the effective area of the tantalum capacitor can be increased; and a pseudocapacitor is introduced onto the tantalum housing, so that the capacity of the capacitor is improved.

Power converter based test bench design for aluminum electrolytic capacitor development

Abstract: Aluminum electrolytic capacitors are applied in most of power electronic systems. The current shape of the DC-link capacitors in the PWM converters is similar to a bipolar square wave signal. The standards of Aluminum electrolytic capacitors doesn't contain electrical tests such kind of stress caused by the PWM control methods. The paper briefly presents the construction and structure of Aluminum electrolytic capacitors for power electronics and describes the actual generally applied test methods. Afterwards the real stress of the Aluminum electrolytic capacitors in PWM applications is investigated. According to the simulation results a test bench is proposed and presented.

High efficiency MW-band rectenna using a coaxial dielectric resonator and distributed capacitors

Abstract: This paper presents experimental studies on the improvement of RF-DC conversion efficiency of the rectenna using a high Q λ/4-coaxial dielectric resonator and distributed capacitors at 850 MHz. The conventional rectenna using an LC resonator has ohmic and dielectric losses due to a shunt capacitor. In order to eliminate these losses, it is effective to disperse current by using distributed capacitors, such as a film capacitor. To achieve an ultimate efficiency, we have constructed a rectenna using both a coaxial dielectric resonator and a film capacitor. Using the developed rectenna, charge-up experiments to supply power to a super-capacitor at an input power of -10 dBm were performed and its ability to achieve a long-life operation of an LCD clock device was confirmed.

Methods for manufacture a capacitor with three-dimensional high surface area electrodes

Abstract: A method for making a capacitor having improved capacitance efficiency which results from increasing the effective area of an electrode surface is disclosed. Specifically, an improved “three-dimensional” capacitor may be constructed with electrode layers having three-dimensional aspects at the point of interface with a dielectric such that portions of the electrode extend into the dielectric layer. Advantageously, embodiments of a three-dimensional capacitor drastically reduce the space footprint that is required in a circuit to accommodate the capacitor, when compared to current capacitor designs. Increased capacitance density may be realized without using high k (high constant) dielectric materials, additional “electrode-dielectric-electrode” arrangements in an ever increasing stack, or serially stringing together multiple capacitors.

Monitoring of metalized film capacitors degradation with impedance nonlinearity measurement

Abstract: Self-healing capacitors fabricated of metalized polypropylene film as the dielectric material are widely used in power electronics. Self-healing process makes elimination of local defects in these capacitors possible and extends the life-time of them. It was shown that the measuring of capacitor V/A characteristic nonlinearity is usable and effective tool for monitoring of capacitor quality. Six capacitors of this type were aged in an oven at the temperature of 90 °C for 1000 hours under normal ambient conditions and changes caused by ageing were monitored with the nonlinearity measurement. It was found that nonlinearity of capacitor grows with the time of ageing.

Square high energy tantalum hybrid capacitor

Abstract: The utility model discloses a square high-energy tantalum hybrid capacitor. The square high-energy tantalum hybrid capacitor comprises a capacitor cavity composed of a square tantalum housing and a square insulated tantalum cap; and is filled in sequence with an anode tantalum core made from compression of tantalum powder of high specific volume, a cathode layer coated with RuO2 and a plurality of isolation layers. The utility model aims to provide a square high-energy tantalum hybrid capacitor, increase the capacity of the tantalum capacitor, reduce material cost and facilitate processing and manufacturing.

Scaling and optimization of high-density integrated Si-capacitors

Abstract: This paper focuses on the scaling and optimization of metal-isolator-metal capacitors integrated in 3D Si structures. Scaling to high capacitance density is aimed by the use of high-k dielectrics and a significant area enhancement realized through silicon pattering with increasing aspect ratios. By material and process optimization the capacitors show excellent IV and CV characteristics with high temperature and reliability performance independently of the 3D structure. A fully functional capacitor of 4mm2 consisting of 80 Mil trenches with an overall capacitance of 850nF can be demonstrated.

Epoxy molding compound for packaging tantalum capacitor and manufacturing method for epoxy molding compound

Abstract: The invention relates to an epoxy molding compound for packaging a tantalum capacitor and a manufacturing method for the epoxy molding compound, and belongs to the technical field of epoxy molding compounds. The epoxy molding compound for packaging the tantalum capacitor is characterized by comprising the following components in percentage by mass: 3 to 10 percent of multifunctional epoxy resin, 1 to 5 percent of multifunctional phenolic resin, 0.5 to 3 percent of reactive diluent, 0.5 to 2 percent of stress-releasing agent, 0.1 to 1 percent of accelerant and 70 to 90 percent of mineral filler. The manufacturing method comprises the following steps of: adding the components of the epoxy molding compound into a mixer, mixing the components uniformly, extruding the mixture by using a twin-screw extruder at the temperature of between 100 and 150 DEG C, cooling, crushing and performing pre-press molding to obtain the epoxy molding compound for packaging the tantalum capacitor. The epoxy molding compound for packaging the tantalum capacitor is halogen-free and antimony-free, can package tantalum capacitors at low temperature and under low pressure, and is low in stress, and high in moldability, relux resistance, wet resistance and reliability; the manufacturing method is convenient to operate, high in production efficiency, safe and reliable, and product quality is stable; and the epoxy molding compound is particularly suitable for packaging a polymer solid chip tantalum capacitor.

High-reliability non-solid electrolyte all-tantalum capacitor and manufacturing process thereof

Abstract: The invention discloses a high-reliability non-solid electrolyte all-tantalum capacitor. The capacitor comprises a tantalum shell, an electrolyte, insulators, cathodes, anodes, a positive outlet wire, a negative outlet wire and diaphragms, wherein the anodes and the cathodes are stacked in sequence; the diaphragms are sandwiched between adjacent anodes and cathodes. The manufacturing process of the capacitor comprises the following steps: arranging the cathodes and the anodes; placing a drainage spacer, a lower spacer, an upper spacer and a drainage ring on the topmost cathode in sequence; passing each anode lead through an insulator tantalum tube and covering the insulator tantalum tube with an insulator; injecting the electrolyte; fixedly butting the anode lead which penetrates the insulator tantalum tube against the positive outlet wire; finishing mounting. According to capacitor and the manufacturing process, each anode of the multi-core tantalum capacitor is led out individually, so that the risk of invalidation of the entire product caused by invalidation of a pellet in the tantalum capacitor is greatly reduced. All the performances of the original product are kept by the multi-anode lead-out mode, and the reliability of the product is greatly improved.