Slide 1: Understanding Power Inductor Parameters
Session 1: June 7th | 10:00 AM CEST | 1:00 AM PDT | 4:00 AM EDT Session 2: June 7th | 5:00 PM CEST | 8:00 AM PDT | 11:00 AM EDT Understanding Power Inductor Parameters Monolithic Power Systems Codico June 7, 2022 rev 20180504
Slide 2: Webinar Usage
Webinar Usage MPS is committed to protecting and respecting your privacy. We offer our expertise and training free of charge, and believe that making the content of, “Understanding Power Inductor Parameters” (“Webinar”) on 6/7/2022 available for future use may be valuable for the Webinar attendees,
Slide 3: Speakers
Speakers Sven Spohr Sebastian Product Manager, Passive Components Product Line Manager, Passive Components Monolithic Power Systems, Germany Codico, Austria Sven.Spohr@monolithicpower.com Sebastian.Gebhart@codico.com www.monolithicpower.com www.codico.com
Slide 4: Agenda
Agenda 1. What is an Inductor? 2. Technical Characteristics, Electromagnetism Basics • Inductance • Permeability • Inductor Losses 3. Important Parameters when Selecting an Inductor • Rated Current • Saturation Current • Resonance Frequency • Start of Winding 4. MPS Inductors Overview 5. Efficiency
Slide 5: Selecting an Inductor
Selecting an Inductor Voltage Weight Temperature ey Application Frequency Assembling mrS
Slide 6: What Is an Inductor?
What Is an Inductor? Wire wounded in coil shape with or without core o It opposes a change in current from a circuit • If current is increasing, inductors try to keep them from increasing Magnetic Field What is the main task of the inductor? -V+ I→ Opposes a change in current Current - + di • If cur
Slide 7: What Is an Inductor?
What Is an Inductor? • Inductors have the ability to store induced electric energy as magnetic energy Magnetic Field • With the change of current in time, the induced magnetic energy will change, causing electromotive force dφ di e=− =−L dt dt Current EMF e electromotive force (EMF) dφ change of mag
Slide 8: Inductance
Inductance µo µr A 2 L= N l • L Inductance Value Units Henry (H) • µo Constant of Nature (4𝜋10−7 ) • µr Relative Permeability • AM Area of the Coil • lM Length of the Coil • N Number of Turns µo µr A 2 L= N → L=AL N2 l Parameters Related to Core Material
Slide 9: Inductance
Inductance µo µr A 2 L= N l How to Increase Inductance: µ Higher Permeability Core Material l Reduce Effective Length of Core A Bigger Core Cross Sectional Area N2 Higher Number of Turns Balance Between Size, Weight, and Performance Smallest Package Possible to Reduce Weight Less Turns Possible to R
Slide 10: Permeability
Permeability Ability of a material to concentrate magnetic flux B=μo μr H Concentration of Magnetic Geometry Material Flux in the Core Number of Turns Frequency Current Temperature Current Pressure Increasing Permeability Increases Inductance Resonance Frequency
Slide 11: Permeability
Permeability Material Relative Permeability µr Air ~1 Iron (FE-Based) 50 to 150 The magnetic field remains the Nickel-Zinc 40 to 1500 same Manganese-Zinc 300 to 20000 Magnetic flux concentration can intensify by using highly permeable core material B = μo H B = μo μr H
Slide 12: Losses
Losses Copper Losses DC loss Heat dissipation of the inductor winding’s RDC AC loss Winding structure loss driven by the frequency Proximity Effect Skin Effect Core Losses Magnetic material loss Eddy Currents Hysteresis Loss
Slide 13: Copper Loss
Copper Loss PDC Copper Loss Heat dissipation of the inductor winding’s RDC Higher heat dissipated, power loss, and efficiency is reduced The best winding window shows the lowest RDC The core material has an impact as well (fewer turns) Current in Opposite Current in Same 2ρ PAC Copper Loss Direction
Slide 14: Copper Loss
Copper Loss PDC Copper Loss 2 R PDC =IDC DC Heat dissipation of the inductor winding’s RDC l R DC =ρ Ρ Resistivity (Cu) A l Length A Cross-Sectional Area l Round Wire Flat Wire Higher inductance Winding area is limited, maximum 𝐴 = 𝜋𝑟 2 inductance is reduced D = 0.785𝑚𝑚² Higher resistance…
Slide 15: Core Loss – Hysteresis Loss
Core Loss – Hysteresis Loss Magnetic Flux Density Domain Structure B Magnetic Magnetic Wall Domain 3 2 0 H =0 1 1 H 0 H Magnetic Field Strength 2 H 3 H = MAX State dependent behavior B,H
Slide 16: Rated Current
Rated Current Self-heating of the component caused by the wire’s RDC. The temperature rise is not standard, and varies from manufacturer to manufacturer. TOP = TAMB + ΔT TAMB Ambient Temp -40 to 85°C / -40 to ?°C ΔT Temperature Rise (Self-Heating) 20K / 30K / 40K / ?K TOP Operating Temperature Max.
Slide 17: Rated Current
Rated Current Pay attention to the maximum operating temperature conditions. The ambient temperature must be considered as well.
Slide 18: Saturation Current
Saturation Current When the current is passed through the coil, the coil generates a magnetic field. The magnetic core is magnetized by the field, and its internal magnetic domain rotates slowly. When the magnetic core is completely magnetized, the direction of the magnetic domains becomes consisten
Slide 19: Saturation Current
Saturation Current Drum Core Shielding Ring Type Lowest Saturation Semi-Shielded Type Low – Medium Saturation Drum Core Unshielded Type Medium Saturation Molded Type Highest Saturation The saturation current point extends when increasing the airgap Distributed airgap on molded inductors
Slide 20: Saturation Current
Saturation Current Inductance drops by 30% at the given current A smaller inductance or a larger package size allows inductors to handle higher saturation currents, but also dissipates more heat
Slide 21: Saturation Current
Saturation Current Ferrite Drum Core Composite Molded Hard Saturation Soft Saturation Inductance [µH] Inductance [µH] ISAT 25°C ISAT 25°C ISAT 100°C ISAT 100°C Current [A] Current [A]
Slide 22: Resonant Frequency
Resonant Frequency Self-resonant frequency needs to be much higher than the switching frequency
Slide 23: Start of Winding
Start of Winding The converter switch node is close to the start of winding side SoW Oriented to the SW Node • Avoids audible noise from harmonics • Reduces emissions caused by the inductor
Slide 24: MPL-AT Series
MPL-AT Series • MPL-AT (Tiny Molded Inductors) • Start of Winding Indication • Low-Profile Inductors • Low DCR • High Saturation Current • Soft Saturation • Stable over Temperature • Max Operating Temperature: 125°C • Sizes: 2010 / 2512 / 2514
Slide 25: MPL-AY Series
MPL-AY Series • MPL-AY (Molded Inductors) • Start of Winding Indication • Low DCR • High Saturation Current • Soft Saturation • Stable over Temperature • Max Operating Temperature: 125°C/155°C • Sizes: 3020 / 4020 / 1050 / 1265
Slide 26: MPL-AL Series
MPL-AL Series • MPL-AL (Low-Resistance Molded Inductors) • Start of Winding Indication • Flat Wire Construction • Lowest DCR • High Performance • High Saturation Current • Soft Saturation • Stable over Temperature • Max Operating Temperature: 155°C • Sizes: 4020 / 5030 / 5050 / 6050 / 6060 Flat Wire
Slide 27: MPL-SE Series
MPL-SE Series • MPL-SE (Semi-Shielded Inductors) • External Epoxy Resin for Better Magnetic Characteristics • Magnetically Shielded • Low DCR • High Current • Max Operating Temperature: 125°C • Sizes: 2512 / 4030 / 5040 / 6040
Slide 28: Efficiency
Efficiency Part Number L RDC IDC ISAT A/B/C MPS MPL-AL6060-100 10µH 24mΩ 6.9A 6.6A MPQ8883 500kHz Comparison 10µH MPL-6060-100 (Blue) Market A / B / C
Slide 29: Efficiency
Efficiency Part Number L RDC IDC ISAT A/B MPS MPL-AL6060-100 10µH 24mΩ 6.9A 6.6A MPQ8883 1000kHz Comparison 10µH MPL-6060-100 (Blue) Market A / B
Slide 30: Summary
Summary • An Inductor Reacts to Current Changes • Stores Induced Electric Energy as Magnetic Energy • Inductance Depends on the Core Material Characteristics and Number of Turns • Magnetic Flux Density Can Be Intensified by Highly Permeable Core Material • Losses • Rated Current • Saturation Current
Slide 31: Summary Codico
Summary Codico The COmponent Design In COmpany, better known as CODICO, incorporates the sales and support for high-quality active and passive components as well as connection technology products In a close cooperation with MPS since 2008 we offer following support: • Selection of parts according to
Slide 32: Q&A
Q&A Contact PowerMagnetics@monolithicpower.com Power Inductors Page and Inductor Selector Tool https://www.monolithicpower.com/en/products/inductor.html MPS Flyer – Power Inductors Brochure https://www.monolithicpower.com/en/support/product-literature.html