DOCSLIB.ORG

United States Patent (19) 11 Patent Number: 5,036,292 Hjelm Et Al

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
United States Patent (19) 11 Patent Number: 5,036,292 Hjelm Et Al United States Patent (19) 11 Patent Number: 5,036,292 Hjelm et al. (45) Date of Patent: Jul. 30, 1991 (54) DECOUPLED ELECTROLYTIC CAPACITOR Pub. Sep. 1981, International Audio Review Hotline, (75 Inventors: John R. Hjelm, Minneapolis; Richard #13. D. Larson, Eden Prairie, both of "Unregulated Power Supplies and Power Amplifiers', Minn. pp. 194-210, No. 1 & 2, pub. Jul. 1976, International Audio Review. (73) Assignee: Audio Research Corporation, "Picking Capacitors', by W. G. Jung & R. Marsh, pp. Minneapolis, Minn. 52-62, Pub. Feb. 1980, Audio. (21) Appl. No.: 480,726 Primary Examiner-James B. Mullins (22 Filed: Feb. 16, 1990 Attorney, Agent, or Firm-Merchant, Gould, Smith, 51) Int. C.’.............................................. HO3F 3/181 Edell, Welter and Schmidt 52) U.S. C. .................................... 330/202; 330/297; 333/181 57 ABSTRACT 58) Field of Search ............... 330/202, 297, 306, 178, A filter capacitor network includes an inductor con 330/179; 333/167, 181; 381/120, 121 nected in series with an aluminum electrolytic capacitor (56) References Cited with the inductor and aluminum electrolytic capacitor bypassed with a capacitor having relatively better high U.S. PATENT DOCUMENTS frequency performance characteristics than the alumi 2,759,051 8/1956 Lockwood et al. ................ 179/171 num electrolytic capacitor. The inductor decouples the 3,290,578 12/1966 Ainsworth .... ... 321/9 3,746,963 6/1973 VeNard, II ............................. 321/2 aluminum capacitor from the network at middle and 4,232,272 1/1980 Fabri ............. ... 330/294 upper frequencies so that the bypass capacitor domi 4,639,663 1/1987 Ueno et al. ... ... 323/356 nates the characteristics of the network in that range. A 4,764,736 8/1988 . Usui et al. ........................... 330/294 signal coupling/DC blocking capacitor network of the same configuration is also disclosed. An amplifier de FOREIGN PATENT DOCUMENTS sign includes the filter network in the power supply. 1563054 2/1970 Fed. Rep. of Germany ...... 333/181 The filter network is also disclosed in an audio signal 306253 2/1929 United Kingdom................ 330/1.78 path for use in signal coupling/DC blocking. OTHER PUBLICATIONS "The Sonic Importance of Passive Parts", pp. 1-13, 6 Claims, 2 Drawing Sheets U.S. Patent July 30, 1991 sheet 1 of 2 5,036,292 PRIOR ART FIG.1 AC AUDIO INPUT SIGNAL DECOUPLED WITH AUDIO DC BAS OUTPUT SIGNA FIG. 4 U.S. Patent July 30, 1991 Sheet 2 of 2 5,036,292 5,036,292 1. 2 which substantially decouples the aluminum electro DECOUPLED ELECTROLYTIC CAPACTOR lytic capacitor from the network above a selected fre quency so that the bypass capacitor dominates the char TECHNICAL FIELD OF THE INVENTION acteristics of the network above the selected frequency. 5 The network thus provides that non-linearities and dis The present invention pertains generally to the field tortions introduced by the aluminum electrolytic capac of audio amplification, and more particularly to capaci itor are minimized in the performance of the network tive network designs in audio amplifiers. above the selected frequency. BACKGROUND OF THE INVENTION According to another aspect of the invention, there is It has been known for some time that the use and 10 provided an audio amplifier including a power supply design of passive circuit elements in high quality audio utilizing the capacitive network as a filter capacitor amplifiers has been overlooked as a result of a preoccu network. pation with active circuitry design. (See, for example, According to still another aspect of the invention, IAR Hotline, No. 13, September 1981, "The Sonic Im there is provided an audio amplifier wherein the capaci portance of Passive Parts', by J. Peter Moncrieff, pub 15 tive network is used in a signal coupling path in the lished by IAR, 2449 Dwight Way, Berkeley, California amplifier. 94704). As a result, in many designs the benefits of im proved active circuitry are not fully attained due to BRIEF DESCRIPTION OF THE DRAWINGS imperfections and distortions introduced by improper FIG. 1 is a simplified schematic diagram of a prior art or less than optimized passive component designs. Ac 20 capacitive network including an electrolytic capacitor cordingly, increasing attention has been turned to the and bypass capacitor; design and use of passive elements in high quality audio FIG. 2 is a schematic diagram of a capacitive net amplifier designs. The present invention pertains to work including an electrolytic capacitor and a bypass capacitive networks and the design of power supplies capacitor according to the present invention; and passive signal paths in audio amplifiers. 25 FIG. 3 is a schematic diagram of an audio amplifier The large energy storage requirement for power including a power supply utilizing the capacitive net supplies in audio amplifiers makes aluminum electro work of FIG. 2 according to the present invention; and lytic capacitors highly desirable as filter capacitors. A FIG. 4 is a schematic diagram of an audio amplifier filter capacitor smooths the rectified AC voltage, stores signal path utilizing the capacitive network of FIG. 2 electrical energy, and bypasses unwanted frequencies. 30 according to the present invention. Electrolytic capacitors, however, have more inherent inductance and other imperfections than most other DETAILED DESCRIPTION OF THE types of capacitors, resulting in poor response, particu INVENTION larly at higher frequencies. The relatively high inherent inductance of an aluminum electrolytic capacitor limits 35 Referring now to FIG. 1, there is shown a conven its ability to bypass and promptly deliver fast transients tional, prior art capacitor network 10 including a large of power to the audio amplifier at higher frequencies. aluminum electrolytic capacitor 12 and a small film or Their other imperfections-namely, resistive losses; tantalum bypass capacitor 14 connected in parallel variation with aging, temperature, voltage, and fre therewith. Capacitor 12 has a capacitive element 13 and quency; and non-linearities due to dielectric absorption an inherent inductance 16. As noted hereinabove, in factors-introduce signal distortion which degrades the ductance 16 degrades the frequency response of capaci quality of sound in audio amplifier applications. These tor 12, while its other imperfections introduce addi limitations are usually remedied by bypassing the elec tional signal distortion. trolytic capacitor with a smaller film or tantalum capac Tantalum or film bypass capacitor 14, having a much itor that has fewer imperfections and better characteris 45 better characteristics and response at high frequencies tics at higher frequencies. However, the electrolytic improves the response of network 10 by allowing a capacitor nonetheless negatively affects the response better optimized path for middle and high frequency characteristics of the network such that its performance signals through the network. Nonetheless, aluminum at higher frequencies is less optimal than it would be if electrolytic capacitor 12 negatively affects the perfor the electrolytic capacitor was absent. 50 mance characteristics of the network at all but the high Aluminum electrolytic capacitors are sometimes de est frequencies of concern in audio applications (above sirable in audio amplifier signal coupling/DC blocking 20 KHz), where the inherent inductance 16 is typically applications where high capacitance is required. Again, great enough to substantially "choke' off and decouple however, the poor response characteristics of electro capacitor 12 from the network. As a result, the more lytic capacitors at the higher frequencies usually re 55 optimal performance characteristics of bypass capacitor quires that they be used in conjunction with a smaller 14 are not fully realized. bypass capacitor; and, again, less than optimal perfor Referring now to FIG. 2, there is shown the im mance at higher frequencies is attained due to degrada proved network 20 according to the present invention. tion introduced by the electrolytic capacitor. Network 20 includes, in addition to electrolytic capaci tor 12 and smaller bypass capacitor 14, an inductor 30 in SUMMARY OF THE INVENTION series with electrolytic capacitor 12. The value of in According to one aspect of the invention there is ductor 30 is chosen so as to substantially "choke' off provided a capacitor network for use in audio applica and decouple capacitor 12 from the network 20 above a tions. The network comprises an inductor, an aluminum certain, selected transition frequency in the mid-range, electrolytic capacitor connected in series with the in 65 preferably at the point where its performance begins to ductor, and a smaller bypass capacitor connected to degrade significantly. The bypass capacitor 14 thus bypass the inductor and the aluminum electrolytic ca dominates the response characteristics of network 20 pacitor. The inductor is chosen to have an inductance above the selected transition frequency while capacitor 5,036,292 3 4. 12 remains active in the network at the low frequencies form, those of skill in the art will recognize that many where it is most needed to store large amounts of en modifications and changes may be made thereto with ergy. The overall performance characteristics of the out departing from the spirit and scope of the invention network are, therefore, improved over that of network as set forth in the claim appended hereto. 10. Moreover, the need to compensate for the imperfec 5 We claim: tions in the electrolytic
Load more

Recommended publications
  • Introduction What Is a Polymer Capacitor?
    ECAS series (polymer-type aluminum electrolytic capacitor) No. C2T2CPS-063 Introduction If you take a look at the main board of an electronic device such as a personal computer, you’re likely to see some of the six types of capacitors shown below (Fig. 1). Common types of capacitors include tantalum electrolytic capacitors (MnO2 type and polymer type), aluminum electrolytic capacitors (electrolyte can type, polymer can type, and chip type), and MLCC. Figure 1. Main Types of Capacitors What Is a Polymer Capacitor? There are many other types of capacitors, such as film capacitors and niobium capacitors, but here we will describe polymer capacitors, a type of capacitor produced by Murata among others. In both tantalum electrolytic capacitors and aluminum electrolytic capacitors, a polymer capacitor is a type of electrolytic capacitor in which a conductive polymer is used as the cathode. In a polymer-type aluminum electrolytic capacitor, the anode is made of aluminum foil and the cathode is made of a conductive polymer. In a polymer-type tantalum electrolytic capacitor, the anode is made of the metal tantalum and the cathode is made of a conductive polymer. Figure 2 shows an example of this structure. Figure 2. Example of Structure of Conductive Polymer Aluminum Capacitor In conventional electrolytic capacitors, an electrolyte (electrolytic solution) or manganese dioxide (MnO2) was used as the cathode. Using a conductive polymer instead provides many advantages, making it possible to achieve a lower equivalent series resistance (ESR), more stable thermal characteristics, improved safety, and longer service life. As can be seen in Fig. 1, polymer capacitors have lower ESR than conventional electrolytic Copyright © muRata Manufacturing Co., Ltd.
    [Show full text]
  • Aluminum Electrolytic Vs. Polymer – Two Technologies – Various Opportunities
    Aluminum Electrolytic vs. Polymer – Two Technologies – Various Opportunities By Pierre Lohrber BU Manager Capacitors Wurth Electronics @APEC 2017 2017 WE eiCap @ APEC PSMA 1 Agenda Electrical Parameter Technology Comparison Application 2017 WE eiCap @ APEC PSMA 2 ESR – How to Calculate? ESR – Equivalent Series Resistance ESR causes heat generation within the capacitor when AC ripple is applied to the capacitor Maximum ESR is normally specified @ 120Hz or 100kHz, @20°C ESR can be calculated like below: ͕ͨ͢ 1 1 ͍̿͌ Ɣ Ɣ ͕ͨ͢ ∗ ͒ ͒ Ɣ Ɣ 2 ∗ ∗ ͚ ∗ ̽ 2 ∗ ∗ ͚ ∗ ̽ ! ∗ ̽ 2017 WE eiCap @ APEC PSMA 3 ESR – Temperature Characteristics Electrolytic Polymer Ta Polymer Al Ceramics 2017 WE eiCap @ APEC PSMA 4 Electrolytic Conductivity Aluminum Electrolytic – Caused by the liquid electrolyte the conductance response is deeply affected – Rated up to 0.04 S/cm Aluminum Polymer – Solid Polymer pushes the conductance response to much higher limits – Rated up to 4 S/cm 2017 WE eiCap @ APEC PSMA 5 Electrical Values – Who’s Best in Class? Aluminum Electrolytic ESR approx. 85m Ω Tantalum Polymer Ripple Current rating approx. ESR approx. 200m Ω 630mA Ripple Current rating approx. 1,900mA Aluminum Polymer ESR approx. 11m Ω Ripple Current rating approx. 5,500mA 2017 WE eiCap @ APEC PSMA 6 Ripple Current >> Temperature Rise Ripple current is the AC component of an applied source (SMPS) Ripple current causes heat inside the capacitor due to the dielectric losses Caused by the changing field strength and the current flow through the capacitor 2017 WE eiCap @ APEC PSMA 7 Impedance Z ͦ 1 ͔ Ɣ ͍̿͌ ͦ + (͒ −͒ )ͦ Ɣ ͍̿͌ ͦ + 2 ∗ ∗ ͚ ∗ ͍̿͆ − 2 ∗ ∗ ͚ ∗ ̽ 2017 WE eiCap @ APEC PSMA 8 Impedance Z Impedance over frequency added with ESR ratio 2017 WE eiCap @ APEC PSMA 9 Impedance @ High Frequencies Aluminum Polymer Capacitors have excellent high frequency characteristics ESR value is ultra low compared to Electrolytic’s and Tantalum’s within 100KHz~1MHz E.g.
    [Show full text]
  • Technical Notes for Electrolytic Capacitor
    TECHNICAL NOTES FOR EL ECTROLYTIC CAPACITOR 2. MANUFACTURE OF ALUMINUM ELECTROLYTIC CAPACITOR Raw Aluminum Foil (1) Etching To obtain higher capacitance, surface area of aluminum foil for electrolytic capacitor increases through etching process. In etching process, aluminum foil is applied with DC or Etched Aluminum Foil AC current in a chloride solution to preferentially dissolve the surface. Surface area is increased by 60-150 times for low voltage foils and 10-30 times for high voltage foils. (2) Anodization(Formation of Dielectric Layer) Aluminum foil for electrolytic capacitor is further formed with anodic oxide film (Al2O3) on the surface as dielectric layer. Etched aluminum foil is immersed into a solution Formed Foil including ammonium salt of boric acid or phosphoric acid and applied with DC voltage so that the foil Aluminum Oxide becomes positive and the solution becomes negative. Then aluminum oxide film is formed on the surface in proportion to the applied voltage. The anodic oxide film, having the thickness of 13-15 angstrom/V (1.3-1.5 nm/V), is extremely thin, compact and highly Aluminum Substrate insulating. RUBYCON CORPORATION 2 TECHNICAL NOTES FOR EL ECTROLYTIC CAPACITOR Slitting (3) Slitting Process Etching and Forming are processed with wide roll of master foil. Then the master roll is slitted into individual rolls with specified width as per the specification. Stitching & Winding (4) Stitching and Winding Slit anode and cathode foils after slitting process are stitched with lead tabs and wound into cylindrical element together with spacer paper. Spacer paper is to contain liquid electrolyte that works as real cathode and restores damaged dielectric film, as well as maintaining the distance between anode and cathode foils constant to prevent short circuit.
    [Show full text]
  • Tantalum Hybrid® Capacitors
    7DQWDOXP+\EULG&DSDFLWRUV- The Capacitors with the Highest Available Power Density in Medium Voltage Range 'DYLGýHVSLYD Czech Technical University in Prague 7HFKQLFNi6W Prague - 6, 166 27, Czech Republic David A. Evans, president Evans Capacitor Company 72 Boyd Avenue East Providence, RI 02914 401-435-3555 [email protected] =X]DQD.HMtNRYi Czech Technical University in Prague Dept. Of El. Power Engineering 7HFKQLFNi6W Prague - 6, 166 27, Czech Republic Abstract Tantalum Hybrid electrolytic/electrochemical capacitors are very versatile compo- nents, used in a wide variety of applications. This paper deals with pulse discharge characte- ristics measurement and specific power determination of these capacitors. Capacitors ZLWK 100 V rated voltage were chosen for the measurement. The capacitors were repetitively dis- charged into a low resistance load. More than 140 surge discharges were made with each component. The results were statistically processed and are presented. Equivalent series resis- tance of Hybrid capacitors is calculated from these measurements and based on its magnitude the specific power of the components is determined. Simultaneously with tantalum Hybrid capacitors some aluminum electrolytic capacitors were measured and the results are presented as well. Based on these results the capacitors are then compared. Tantalum Hybrid capacitors have the highest volumetric specific power (related to its dimensions) in medium voltage range. Introduction Tantalum Hybrid capacitors take advantage of the best features of electrolytic and electrochemical capacitors. They combine an anode from an electrolytic capacitor, a cathode from an electrochemical capacitor and compatible electrolyte. The tantalum Hybrid capacitor is a series combination of an anodic dielectric oxide film capacitance, Ta2O5, and a high elec- trochemical capacitance, a film of the conductive metal oxide, RuO2.
    [Show full text]
  • Capacitors Capacitors
    Capacitors There seems to be a lot of hype and mystery concerning the sound of capacitors, the quality of capacitors and what capacitors actually do in a circuit. There are many types of capacitors including ceramic, polyester, polypropylene, polycarbonate silver mica, tantalum and electrolytic. Each has its own area of “expertise”. One type of capacitor will perform well in a particular application and perform poorly in another. A capacitor is simply two metal plates separated by a dielectric. An electrical charge is stored between these two plates. The plates and dielectric can be made form several different types of material. The closer the plates are, the higher the capacitance and the larger the area of the plates, the larger the capacitance. The dielectric material affects the capacitance as well. Here is some brief information about the particular types. Note: The unit of capacitance is the Farad. It is a very large unit and so we use the following to express capacitance Microfarad is one millionth of a farad. Picofarad is one millionth of a microfarad So 0.001mfd is equal to 1000 picofarad (pF) The above diagram shows a simple representation of a capacitor. The capacitor is shown in RED . In parallel with the plates of the capacitor is a resistance, InsInsIns-Ins ---ResRes of the insulation. Teflon has the highest resistance with polystyrene, polypropylene and polycarbonate coming in second. Third is polyester and then the ceramics COG, Z5U and XR7 with tantalum and aluminium last. Dap is the Dielectric Absorption. All capacitors when charged to a particular voltage and then the leads are shorted, will recover some of their charge after the short is removed.
    [Show full text]
  • MT-101: Decoupling Techniques
    MT-101 TUTORIAL Decoupling Techniques WHAT IS PROPER DECOUPLING AND WHY IS IT NECESSARY? Most ICs suffer performance degradation of some type if there is ripple and/or noise on the power supply pins. A digital IC will incur a reduction in its noise margin and a possible increase in clock jitter. For high performance digital ICs, such as microprocessors and FPGAs, the specified tolerance on the supply (±5%, for example) includes the sum of the dc error, ripple, and noise. The digital device will meet specifications if this voltage remains within the tolerance. The traditional way to specify the sensitivity of an analog IC to power supply variations is the power supply rejection ratio (PSRR). For an amplifier, PSRR is the ratio of the change in output voltage to the change in power supply voltage, expressed as a ratio (PSRR) or in dB (PSR). PSRR can be referred to the output (RTO) or referred to the input (RTI). The RTI value is equal to the RTO value divided by the gain of the amplifier. Figure 1 shows how the PSR of a typical high performance amplifier (AD8099) degrades with frequency at approximately 6 dB/octave (20 dB/decade). Curves are shown for both the positive and negative supply. Although 90 dB at dc, the PSR drops rapidly at higher frequencies where more and more unwanted energy on the power line will couple to the output directly. Therefore, it is necessary to keep this high frequency energy from entering the chip in the first place. This is generally done with a combination of electrolytic capacitors (for low frequency decoupling), ceramic capacitors (for high frequency decoupling), and possibly ferrite beads.
    [Show full text]
  • Solid Polymer Aluminum SMT Capacitors Tape Specifications Reel Specifications
    Application Guide, Solid Polymer Aluminum SMT Capacitors Tape Specifications Reel Specifications SPA ESRD ESRE ESRH SPA Type t2 = H + 0.3 mm ±0.2 mm W D– P A B EF P 1 P t ±0.3 + 0.1/–0.0 Ø ±0.2 2 ±0.2 ±0.2 1 A ±0.2 B Min. C ±0.5 D ±0.8 E ±0.5 W ±1.0 t 12.0 1.8 5.5 1.5 4.0 8.0 2.0 7.7 4.6 0.4 333.0 50.0 13.0 21.0 2.0 14.0 3.0 Tol.: ± mm unless otherwise specified Design Kits Design kits containing various ratings are available through the CDE web site. Typical Temperature Characteristics Capacitance Change at 120 Hz Dissipation Factor at 120 Hz 20 10 10µF/6.3V 10µF/6.3V 8 10 6 % ) 0 C ( DF ( % ) ǻ 4 -10 2 -20 0 -60 -20 20 60 100 -60 -20 20 60 100 Temperature (°C) Temperature (°C) CDE Cornell Dubilier • 1605 E. Rodney French Blvd. • New Bedford, MA 02744 • Phone: (508)996-8561 • Fax: (508)996-3830 • www.cde.com Application Guide, Solid Polymer Aluminum SMT Capacitors Typical Impedance and Equivalent Series Resistance ESRD (3.1 mm Ht.) 100.000 ESRD680M08R 68 uF/8 V Impedance/E.S.R. 10.000 ESRD121M04R 120 uF/4 V Impedance/E.S.R. 1.000 ESRD181M02R Ohms 180 uF/2 V Impedance/E.S.R. 0.100 0.010 0.001 0.1 1 10 100 1000 10000 100000 Frequency (kHz) ESRE 100.000 ESRE101M08R 100 uF/8 Vdc 10.000 Impedance/E.S.R.
    [Show full text]
  • AN-1099 Application Note
    AN-1099 APPLICATION NOTE One Technology Way • P. O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com Capacitor Selection Guidelines for Analog Devices, Inc., LDOs by Glenn Morita WHY DOES THE CHOICE OF CAPACITOR MATTER? Applications such as VCOs, PLLS, RF PAs, and low level analog Capacitors are underrated. They do not have transistor counts signal chains are very sensitive to noise on the power supply in the billions nor do they use the latest submicron fabrication rail. The noise manifests itself as phase noise in the case of technology. In the minds of many engineers, a capacitor is VCOs and PLLs and amplitude modulation of the carrier for simply two conductors separated by a dielectric. In short, RF PAs. In low level signal chain applications such as EEG, they are one of the lowliest electronic components. ultrasound, and CAT scan preamps, noise results in artifacts displayed in the output of these instruments. In these and It is common for engineers to add a few capacitors to solve other noise sensitive applications, the use of multilayer noise problems. This is because capacitors are widely seen by ceramic capacitors must be carefully evaluated. engineers as a panacea for solving noise related issues. Other than the capacitance and voltage rating, little thought is given Taking the temperature and voltage effects is extremely to any other parameter. However, like all electronic compo- important when selecting a ceramic capacitor. The Multilayer nents, capacitors are not perfect and possess parasitic resistance, Ceramic Capacitor Selection section explains the process of inductance, capacitance variation over temperature and voltage determining the minimum capacitance of a capacitor based bias, and other nonideal properties.
    [Show full text]
  • THE ELECTRICAL CHARACTERIZATION of TANTALUM CAPACITORS AS MIS DEVICES Brian Holman Clemson University, [email protected]
    Clemson University TigerPrints All Theses Theses 6-2008 THE ELECTRICAL CHARACTERIZATION OF TANTALUM CAPACITORS AS MIS DEVICES Brian Holman Clemson University, [email protected] Follow this and additional works at: https://tigerprints.clemson.edu/all_theses Part of the Electrical and Computer Engineering Commons Recommended Citation Holman, Brian, "THE ELECTRICAL CHARACTERIZATION OF TANTALUM CAPACITORS AS MIS DEVICES" (2008). All Theses. 393. https://tigerprints.clemson.edu/all_theses/393 This Thesis is brought to you for free and open access by the Theses at TigerPrints. It has been accepted for inclusion in All Theses by an authorized administrator of TigerPrints. For more information, please contact [email protected]. THE ELECTRICAL CHARACTERIZATION OF TANTALUM CAPACITORS AS MIS DEVICES A Thesis Presented to the Graduate School of Clemson University In Partial Fulfillment of the Requirements for the Degree Master of Science Electrical Engineering by Brian Holman August 2008 Accepted by: Dr. William R. Harrell, Committee Chair Dr. James E. Harriss Dr. Pingshan Wang 1 ABSTRACT Electrical characteristics of a new class of tantalum capacitor are presented. Specifically, this type of tantalum capacitor is manufactured by KEMET Electronics Corporation and utilizes Poly(3,4-ethylenedioxythiolphene) (PEDOT) as the cathode material. There are two capacitor varieties based on the polymerization method used for the PEDOT. One uses In-Situ polymerization, and the other uses Pre-Polymerization. Existing polymer Ta capacitors use In-Situ polymerization while Pre-Polymerization is a new technique of cathode application. We investigated both types of devices to determine what, if any, performance benefits were gained by using Pre-Poly. In a basic form Ta capacitors consist of a Ta anode, Ta2O5 dielectric, and PEDOT cathode polymerized to be a semiconductor.
    [Show full text]
  • Tantalum Capacitor
    Tantalum Capacitor As of Nov. 2004 Tantalum Capacitor ■ INTRODUCTION Tantalum capacitor are designed with excellent performance characteristics for filtering, blocking, and R.C tunning circuits. They are used extensively in industrial, commercial, entertainment and medical electronic equipment. They exhibit the proven characteristics of wide temperature range and long-term stability. The advantages of tantalum capacitor electrolytic capacitor consist of their chemical stability, the low thickness and high dielectric constant of the tantalum oxide layer, and the capability of sintering anodes with a very large surface from tantalum powder. The low reactivity of the tantalum oxide layer allows the employment of highly conductive electrolytes, and thus achieves a low series resistance. Capacitance and dissipation factor in relation to temperature and frequency thus prove to be very favourable. Additionally, there is also the wide temperature range of several types form -55℃ to +125℃. A further advantage of the dielectric being inactive is a leakage current that is smaller than of aluminium electrolytic capacitor which does not rise considerably even at dead storage. Tantalum electrolytic capacitor thus show a very long life during operation and storage. The capacitance of the tantalum electrolytic capacitor is very high due to the high dielectric constant and the low thickness of tantalum oxide layer. The use of sintered anodes with a large surface allows very small dimensions that cannot be reached or exceeded by any other capacitor. The tantalum electrolytic capacitor at issue are polarized capacitors. In the case of polarized electrolytic capacitor, the dielectric is structured in such a manner that the flow of current is interrupted in one direction.
    [Show full text]
  • Selecting and Applying Aluminum Electrolytic Capacitors for Inverter Applications
    Selecting and Applying Aluminum Electrolytic Capacitors for Inverter Applications Sam G. Parler, Jr. Cornell Dubilier Abstract— Aluminum electrolytic capacitors are widely used in all types of inverter power systems, from variable-speed drives to welders to UPS units. This paper discusses the considerations involved in selecting the right type of aluminum electro- lytic bus capacitors for such power systems. The relationship among temperature, voltage, and ripple ratings and how these parameters affect the capacitor life are discussed. Examples of how to use Cornell Dubilier’s web-based life-modeling java applets are covered. Introduction a knowledge of all aspects of the application environ- ment, from mechanical to thermal to electrical. The goal One of the main application classes of aluminum elec- of this paper is to assist you with selecting the right trolytic capacitors is input capacitors for power invert- capacitor for the design at hand. ers. The aluminum electrolytic capacitor provides a Capacitor ripple current waveform considerations unique value in high energy storage and low device impedance. How you go about selecting the right ca- Inverters generally use an input capacitor between a pacitor or capacitors, however, is not a trivial matter. rectified line input stage and a switched or resonant Selecting the right capacitor for an application requires converter stage. See Figure 1 below. There is also usu- (a) (b) Current Spectrum 2.5 2 1.5 Ck 1 0.5 0 1 10 100 1000 10000 k d=10% d=5% d=2.5% (d) (c) Figure 1: Inverter schematics. Clockwise: (a) block diagram of a typical DC power supply featuring an inverter stage, (b) motor drive inverter schematic shows the rectification stage, (c) typical inverter capacitor current waveforms, (d) relative capacitor ripple current frequency spectrum for various charge current duties (d=Ic/IL ).
    [Show full text]
  • Wet Electrolyte Tantalum Capacitors: an Introduction to the Basics
    VISHAY INTERTECHNOLOGY, INC. www.vishay.com Tantalum Capacitors Technical Note Wet Electrolyte Tantalum Capacitors: An Introduction to the Basics By Mike Mosier Tantalum electrolytic capacitors are the preferred choice in dielectric used in all tantalum electrolytic capacitors is applications where volumetric efficiency, stable electrical tantalum pentoxide. parameters, high reliability and long service life are the Tantalum pentoxide compound possesses high dielectric primary considerations. The stability and resistance to strength and a high dielectric constant. As capacitors are elevated temperatures of the tantalum/tantalum oxide being manufactured, a film of tantalum pentoxide is applied system make wet tantalum capacitors an appropriate to their electrodes by means of an electronic process. The choice for today's technology. Vishay is a pioneer and film is applied in various thicknesses and at various voltages leader in this field, producing a large variety of tantalum and although transparent to begin with, it takes on different capacitor types for industrial, military and aerospace colors as light refracts through it. This coloring occurs on the electronic applications. Tantalum is not found in its pure tantalum electrodes of all types of tantalum capacitors. state. Rather, it is commonly found in a number of oxide Rating for rating, tantalum capacitors tend to have as much minerals, often in combination with Columbium ore. This as three times better capacitance / volume efficiency than combination is known as tantalite when its contents are aluminum electrolytic capacitors. An approximation of the more than one-half tantalum. Important sources of tantalite capacitance / volume efficiency of other types of capacitors include Australia, Brazil, Canada, China, and several African may be inferred from the following table, which shows the countries.
    [Show full text]