Passive Components Capacitors PDF

Passive Components Capacitors 1 Basics 2 Technologies 3 Capacitors in Switched Mode Power Supplies ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 1 / 106 Passive Components Capacitors 1 Basics 1.1 Ideal Capaci...

Passive Components Capacitors 1 Basics 2 Technologies 3 Capacitors in Switched Mode Power Supplies ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 1 / 106 Passive Components Capacitors 1 Basics 1.1 Ideal Capacitance, mathematical Description 1.2 Calaculation of Capacitances 1.3 Real Capacitor, Equivivalent Circuit 1.4 Classification of Capacitors 1.5 Classification of Capacitors according their Application 2 Technologies 3 Capacitors in Switched Mode Power Supplies ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 2 / 106 1.1 Ideal Capacitance A capacitor is the technical realisation of the physical property of a capacitance C. It is a measure of the capacity of electric charges Q at a given voltage V. Q C Symbol of the capacitance: C V Unit of the capacitance: 1 F As 1F =1 V A capacitance has the value of 1 F, if a charge of 1 As increases the voltage by 1 V. ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 3 / 106 1.1 Ideal Capacitance Defining equation in differential form Defining equation in integral form The capactiance has the characteristic to differentiate voltages or to integrate currents, depending on the value impressed. ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 4 / 106 1.1 Ideal Capacitance Graphical symbol and sinusoidal waveforms For sinusoidal waveforms the current of a capacitor leads its voltage by 90 degrees. ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 5 / 106 1.1 Ideal Capacitance Periodical signals For periodical quantities the current of a capacitor is zero-mean. ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 6 / 106 1.1 Ideal Capacitance Energy content electrolytic capacitor metallized PP film capacitor NCC, KME series Kemet, PHE 450 series Ø x H = 16.5 mm x 25 mm W x H x L = 10.5 mm x 20.5 mm x 31.5 mm capacitance/voltage stored energy capacitance/voltage stored energy 4700 μF/10 V 235 mJ 1.2 μF/250 V 37.5 mJ 2200 μF/25 V 688 mJ 0.68 μF/400 V 54.4 mJ 220 μF/100 V 1100 mJ 0.39 μF/630 V 77.4 mJ 22 μF/400 V 1760 mJ 0.27 μF/1000 V 135 mJ ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 7 / 106 1.2 Calculation of Capacitances General Equation The numerator contains the charge (Coulomb‘s Law: Maxwell Equation of sources of electrical fields). The denominator contains the voltage across the electrodes. ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 8 / 106 1.2 Calculation of Capacitances Parallel-plate capacitor A: plate area d: plate separation ε: permittivity εr : relative permittivity ε0 : vacuum permittivity (permittivity of free space, electric constant) ε0: = 8.8542 · 10-12 As/(Vm) = 8.8542 pF/m ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 9 / 106 1.2 Calculation of Capacitances double wire circuit d: conductor spacing r: conductor radius Example: l = 6 cm d = 5 mm r = 2 mm ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 10 / 106 1.3 Real Capacitor non-ideal characteristics of real capacitors conductors for carrying the current have finite conductances current carrying conductors generate magnetic fields because of leakage currents the resistance between the electrodes is not infinite ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 11 / 106 1.3 Real Capacitor Equivalent circuit, simulation model C: capacitance RESR: equivalent series resistance LESL: equivalent series inductance Riso: insulating resistance ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 12 / 106 1.3 Real Capacitor More detailed equivalent circuit, simulation model ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 13 / 106 1.3 Real Capacitor Dissipation factor Dissipation factor tan δ is the ratio between the active and reactive power for a sinusoidal waveform voltage. It can be tought of as a measurement og the gap between an actual and ideal capacitor. tan δ is measured with the same set-up used for the series capacitance ESC. tan δ = ω ⨉ ESC ⨉ ESR = P / Q ESC: equivalent series capacitance ESR: equivalent series resistor (definition of tan δ using a series connection) ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 14 / 106 1.4 Classification of Technologies linear constant capacitors film capacitors papier capacitors ceramic capacitor electrolytic capacitors adjustable capacitors non-linear capacitors ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 15 / 106 1.5 Classification of Applications electric energy storage voltage smoothing carrying dynamic currents (AC currents) filtering (active, passive, AC/DC, EMC) reactive current compensation snubber circuits forming resonance circuits frequency dependent impedance ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 16 / 106 Passive Components Capacitors 1 Basics 2 Technologies 2.1 Overview 2.2 Dielectrics 2.3 Ceramic Capacitors 2.4 Film Capacitors 2.5 Electrolytic Capacitors 2.6 Double Layer Capacitors 3 Capacitors in Switched Mode Power Supplies ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 17 / 106 2.1 Overview Capacitors are available in a large number of different types and embodiments ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 18 / 106 2.1 Overview: Classification non polarized capacitors ceramic capacitors class 1 (C0G, H2G, P2H) class 2 (X7R, Z5U, Y5V...) film capacitors metallized paper metallized plastic film plastic film/foil polarized capacitors electrolytic capacitors aluminum electrolytic capacitors non solid, solid tantalum electrolytic capacitors non solid, solid supercapacitors ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 19 / 106 2.1 Overview: Classification ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 20 / 106 2.7 Overview: Comparison of Capacitors ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 21 / 106 2.2 Dielectrics Electric polarization P of a material Electric displacement field E: electric field strength D: electric displacement field strength (electric flux density) P: polarization density χ: electric susceptibility Electric polarizable materials increase the ability of storing electric charges and therefore they increase the capacity. Electric polarization is distinguished into orientation polarization, ionic polarizaion and electronic polarization. ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 22 / 106 2.2 Dielectrics Complex relative permittivity Complex impedance Dielectric dissipation factor (dielectric loss factor) (definition of tan δ using a parallel connection) ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 23 / 106 2.2 Dielectrics relative dissipation material permittivity factor copper oxide (CuO2) 18 titanium oxide (TiO2) 80 ceramic (SrBi)TiO3 1000 20... 200 x 10-4 water 81 air 1 epoxy resin 3... 5 paper 2... 3 polypropylene 2.2 3 x 10-4 glimmer 4... 12 1... 10 x 10-4 aluminum oxide 9.3 tantalpentoxide 42 noibpentoxide 42 ceramic, class 1 10... 500 ceramic, class 2 500... 20000 ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 24 / 106 2.2 Dielectrics Breakdown mechanisms of dielectrics avalanche breakdown acceleration of free electrons, which produce again further free electrons. Thermal breakdown Inhomogenities cause locally increased current densities, which cause consequently increased temperatures, which again increase the current density. Inner breakdown At local air inclusions the electric field will increase. Because of the continuous field strength of the normal vector (surface normal), which results from the boundary condition of electric fields, there will occur sparkovers in the air inclusions. Starting at large air pocket the sparkovers can spread to the electrods. ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 25 / 106 2.2 Dielectrics PET: polyester PEN: polyethylene naphtalate PPS: polyphenylen sulfide PP: polypropylene PET PP PEN PPS relative permittivity (1 kHz, 23°C) 3,3 2,2 3,0 3,0 application temperature range (°C) -55...+105 -55...+100 -55...+125 -55...+140 ΔC/C versus temperature range ±5 % ±2,5 % ±5 % ±1,5 % dissipation factor (10 kHz) 0,015 0,008 0,015 0,0025 dielectric strength 580 V/μm 650 V/μm 500 V/μm 470 V/μm spezific capacitance (nF ∙ V/mm3) 400 50 250 140 ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 26 / 106 2.2 Dielectrics dissipation factor depending on frequency for different dielectrics https://elektroniktutor.de/bauteilkunde/kondens.html (Quelle: Betz, Huber, Grundkenntnisse Elektrotechnik - Energietechnik / Nachrichtentechnik 1980) ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 27 / 106  2.3 Ceramic Capacitors Ceramic capacitors … have ceramic dielectrics (oxids) are available commerially in two main classes have in generall small capacitances, the range is between 1 pF and 100 μF (typical values: pF and nF range) are available for voltages between 4 V and 50 kV capacitance depends on voltage, temperature, frequency and operating hours have low EERS and low LESL, which results in high current capability and low losses are used in snubber circuits, as output capacitors and DC link capacitors http://www.novacap.com/pdfs/X7R_comm.pdf ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 28 / 106 2.3 Ceramic Capacitors Classification in terms of characteristics of the dielectric according voltage dependence ageing frequency dependence temperature dependence Classes of ceramic capacitors Class 1 low permittivity (< 50), low temperature dependence, high stability, low losses Class 2 high permittivity, acceptable temperature dependence, lightly non-linear, classification using three digits Class 3 very high permittivity, high dependence of capacity and losses on temperature, voltage and age ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 29 / 106 2.3 Ceramic Capacitors Caracteristics of Ceramic Capacitors Class 1 ceramic capacitors are based on CaZrO3 and have paraelectric atomic structure Class 2 ceramic capacitors are based on BaTiO3 and have typically ferroelectric atomic structure Class 2 ceramic capacitors have ferroelectric dipoles in domains, which align with AC fields, including domain wall heating and signal distortion Class 2 ceramic capacitors with BaTiO3 material have above Curie point cubic atomic structure without dipoles Class 2 ceramic capacitors with BaTiO3 material have below Curie point tetragonal atomic structure with dipoles Ceramic capacitors can generate electrical noise due to piezoelectricity Ceramic capacitors can generate audible noise due to electrostriction KEMET: Multilayer Ceramic Capacitors (MLCCs) ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 30 / 106 2.3 Ceramic Capacitors Different Models of Ceramic Capacitors - MLCC, SLCC - Disc, Stacked - Leaded MLCC Source: Introduction to Ceramic Capacitors, European Passive Components Institute (Vishay, AVX, TDK, API Technologies) ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 31 / 106 2.3 Ceramic Capacitors Class 2: Classification according EIA-198-Code change of capacitance low temperature upper temperature over temperature range X: -55 °C 4: +65 °C P: +/- 10 % Y: -30 °C 5: +85 °C R: +/- 15 % Z: -10 °C 6: +105 °C S: +/- 22 % 7: +125 °C T: +22/-33 % 8: +150 °C U: +22/-56 % V: +22/-82 % examples: X7R: -55 °C … + 125 °C, ΔC/C = +/- 15 % Z5U: +10 °C … +85 °C, ΔC/C = +22/-56 % ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 32 / 106 2.3 Ceramic Capacitors Construction of Multi Layer Ceramic Capacitor (MLCC) ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 33 / 106 2.3 Ceramic Capacitors SMD package dimensions notation length in mm width in mm 01005 0.4 0.2 0201 0.6 0.3 0603 1.6 0.8 1206 3.2 1.6 1808 4.5 2.0 1812 4.5 3.2 2220 5.7 5.0 2924 7.3 6.1 ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 34 / 106  2.3 Ceramic Capacitors Bode plot of impedance Class 1 (C0G) Class 2 (X7R) high quality factor low quality factor reference.: Kemet ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 35 / 106  2.3 Ceramic Capacitors Temperature coefficients Class 1 Class 2 please note the vertical scale Quelle: novacap ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 36 / 106  2.3 Ceramic Capacitors Voltage derating of the capacitance (DC bias) Capacitance: 1 µF, rated voltage 25 V, X7R, different size Source: RedExpert, Würth Elektronik, 2019 ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 37 / 106  2.3 Ceramic Capacitors Voltage derating of the capacitance (DC bias) Capacitance: 1 µF, rated voltage 25 V, X7R, different size Source: Stephan Menzel: ABC der Kondensatoren, Würth Elektronik, 2014 ECPE Training: Components of Switched-Mode Power Supplies, Capacitors, Erlangen+online, 2022-02-17, Page 38 / 106 2.3 Ceramic Capacitors Calculation of useful time (reduction of 20 % according the starting value) useful life load life lifetime 7000 h 5000 h leakage current not more than specified not more than specified capacity change within 30 % of initial value within 20 % of initial value not more than 300 % of not more than 200 % of dissipation factor specified value specified value applied voltage Vr Vr applied current Ir Ir applied temperature Tm 40 °C failure rate level