Thermal Characteristics of LEDs: LED Fundamentals

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In this presentation on Thermal Characteristics of LEDs we will look at the basics of thermal management in LED devices.

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Thermal Characteristics of LEDs: LED Fundamentals

  1. 1. LED FundamentalsThermalCharacteristicsof LEDs08-16-2011
  2. 2. Energy Conversion LED* Incandescent Bulb 8% 20% 19% Visible Light IR 73% 80% Heat light eat light he l heat T ~ 3000 K TJ ~ 50 - 100°C * Varies depending on LED efficacy. Source: http://www1.eere.energy.gov/buildings/ssl/comparing_lights.htmlLED Fundamentals | Thermal Characteristics of LEDs | Page 2
  3. 3. Thermal Characteristics of LEDs LED Junction Temperature Light Output  Forward Voltage  LCW CQ7P Color Coordinates  Wavelength  Increasing LED Junction TemperatureLED Fundamentals | Thermal Characteristics of LEDs | Page 3
  4. 4. Light Output decreases with higher junction temperature g j p Data Sheet LCW CQ7P.PC Effect in the Design 800 90 lm 81 lm Luminous Flux [lm] 600 400 s 200 TJ = 25°C TJ = 80°C 0 LCW CQ7P: 90 lm @ 350 mALED Fundamentals | Thermal Characteristics of LEDs | Page 4
  5. 5. Forward Voltage drops down with higher junction temperatures p g j p Data Sheet LCW CQ7P.PC Effect in the Design LCW CQ7P  IF = 350mA  typ VF = 3.2 V typ. 32 TJ= 80°C: VF = -0.17 V typ. VF (350 mA; TJ = 80°C) = 3.03 VLED Fundamentals | Thermal Characteristics of LEDs | Page 5
  6. 6. Chromaticity Coordinates shifts to lower values with higher junction temperatures g j p Data Sheet LCW CQ7P.PC Effect in the design Cy Tj = 25˚C Tj = 80˚C CxLED Fundamentals | Thermal Characteristics of LEDs | Page 6
  7. 7. Dominant Wavelength increases with higher junction temperature g j p Data Sheet LR CP7P Effect in the Design TJ= 80°C: dom = 4nmLED Fundamentals | Thermal Characteristics of LEDs | Page 7
  8. 8. Thermal Ratings Data Sheet LCW CQ7P.PC Maximum Ratings Operation Temperature Range p p g Storage Temperature Range Max. Junction Temperature Characteristics Ch t i ti Thermal ResistanceLED Fundamentals | Thermal Characteristics of LEDs | Page 8
  9. 9. Designing with LEDs “Grouping Environment Grouping Environment” Application Environment LED Characteristics • Luminous Intensity • Luminous Flux • Wavelength • Color Coordinates  Each LED is measured in the • Forward Voltage  The application environment production with specific • Reliability R li bilit differs from the grouping conditions. environment.  LEDs are grouped into BINs  The temperature dependent according to the measured characteristics of the LED have characteristics. to be taken into account in the g design.LED Fundamentals | Thermal Characteristics of LEDs | Page 9
  10. 10. Disclaimer All information contained in this document has been checked with the greatest care. OSRAM Opto Semiconductors GmbH can however, not be made liable for any damage that occurs in connection with the use of these contents. OSRAM Opto Semiconductor GmbH makes no representations and warranties as to a possible interference with third parties intellectual property rights in view of products originating f i i ti from one of OSRAM Opto Semiconductor GmbHs partners, or in view of f O t S i d t G bH t i i f products being a combination of an OSRAM Opto Semiconductor GmbHs product and a product of one of OSRAM Opto Semiconductor GmbHs partners. Furthermore, OSRAM Opto Semiconductors GmbH cannot be made liable for any damage that occurs in p y g connection with the use of a product of one of OSRAM Opto Semiconductor GmbHs partners, or with the use of a combination of an OSRAM Opto Semiconductor GmbHs product and a product of one of OSRAM Opto Semiconductor GmbHs partners.LED Fundamentals | Thermal Characteristics of LEDs | Page 10
  11. 11. Disclaimer This document constitutes neither an offer to sell nor a solicitation to buy or subscribe for securities. Any such offer will be made solely on the basis of the Securities Prospectus yet to be approved by the German Financial Supervisory Authority (BaFin) and published thereafter. The information legally required to be provided to investors will be contained only in the Securities Prospectus. The information contained herein is not for distribution, directly or indirectly, in or into the United States of America (including its territories and possessions of any State of the U i d S S f h United States of A f America or the Di i of C l bi ) and must not b i h District f Columbia) d be distributed to U.S. persons (as defined in Regulation S under the U.S. Securities Act of 1933, as amended ("Securities Act")) or publications with a general circulation in the United States of America. This document is not an offer of sec rities for sale in the America doc ment securities United States of America. The securities have not been and will not be registered under the Securities Act and may not be offered or sold in the United States of America absent registration or an exemption from registration under the Securities Act The Act. Issuer does not intend to register any portion of the offering in the United States of America or to conduct a public offering of the securities in the United States of America. This document is not an offer of securities for sale in the United Kingdom Canada Kingdom, Canada, Japan or Australia.LED Fundamentals | Thermal Characteristics of LEDs | Page 11
  12. 12. Thank you for your attention.LED Fundamentals | Thermal Characteristics of LEDs | Page 12

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