1. All material, text, graphics, images, design, icons and other copyrightable elements are the copyrighted property of Future Electronics or the original creator and may not be copied, reproduced, republished, displayed or distributed by any means, including but not limited to electronic, mechanical, photocopying, recording or otherwise, without the express prior written permission Future Electronics or the original creator. All rights reserved. © Future Electronics Inc Making LED Lighting Solutions Simple TM Conception et réalisation thermique Troyes, 23 février 2012 Thierry Suzanne Ingénieur d’application

2. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Designer’s Complaint… LEDs are specified @ single test current @ 25°C Tj My application is different! What is the real light output for my application?

3. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary LED Datasheet Specifications A new trend in the data- sheet characterization of the LEDs – The LEDs are tested and binned at real world operating conditions Hot Binning @ 85 o C

4. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary What is LED Junction Temperature LED Junction Temperature (Tj) Temperature directly on the LED chip/die What does tested and binned at 25 o C or 85 o C at a specific drive current of for example 700mA mean? – The LED was driven at 700mA and light output measurements were made while the junction temperature at the LED was maintained at 85 o C

5. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Measurement Point Application Brief AB33 http://www.philipslumileds.com/uploads/10/A B33-pdf http://www.philipslumileds.com/uploads/10/A B33-pdf

6. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Heat Generation LEDs are not 100% efficient  power consumed is not completely converted to light Approximately, 30% to 50 % (depending on the technology) is converted to light and the rest is converted to heat Heat Radiometric Power (power converted to light)

7. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Heat Flow LED thermal pad does not provide enough surface to dissipate the heat No heat in the light beam We add board, thermally conductive material and heat sink to transfer the heat from the LED junction to the air surrounding the LED Thermal Pad Heat generated by the LED is dissipated via the thermal pad underneath the LED No heat in LED’s main light beam

8. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Effects of Heat on LEDs Heat affects the LEDs in 5 different ways: – Light output – Color shift – Forward voltage shift – LED lifetime – Permanent damage

9. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Effects of Heat on LEDs 0% 50% 100% 150% 200% -40-20 0 20 406080 100120 Junction Temperature TJ [°C] Relative Light Output (LOP) Amber Red Green Blue White CyanRoyal Blue Reduces Light Output 100% light output at 25 o C 70C 90% AlInGaP: Red, Red-Orange, Amber InGaN: Royal-Blue, Blue, Green, Cyan, White More sensitive to heat

10. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Effects of Heat on LEDs Shifts dominant wavelength *

11. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Effects of Heat on LEDs TjTj 0 50 100 150 200 250 300 350 400 0.00.51.01.52.02.53.03.54.0 Forward Voltage (V) Forward Current (mA) Red, Reddish Orange, Amber(AlInGaP) Royal Blue, Blue, Cyan, Green, White (InGaN) V f  -2.0 to -4.0mV/°C LED Driver: V out = 43-48V @ 25 o C  V f =3.0V 15 LEDs: → 15 x 3.0 = 45V OK!! @ 87 o C  V f =2.85V 15 LEDs: → 15 x 2.85 = 42.75V Not OK!! VfVf

12. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Effects of Heat on LEDs (B50, L70) What is (B50, L70)?

13. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Lumen Maintenance - (Bxx, Lyy) Notation used to describe the average lumen maintenance characteristic of the LEDs. Lumen maintenance for SSL devices is typically defined in terms of the percentage of initial light output remaining after a specific period of time. (Bxx, Lyy) – Bxx: percentage of LEDs, on average – Lyy: percentage of light output remaining Example – (B50, L70) at 50000hours: – On average, the light output of 50% (B50) of the LEDs within the system will drop to lower than 70% (L70) of their initial light output after 50000hours.

14. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Effects of Heat on LEDs Reduces operating life ~50.0% ~155k ~165k ~175k (B50, L70)

15. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Effects of Heat on LEDs May cause severe damage Thermal management is critical

16. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Basic cooling considerations Conduction: – The transfer of heat energy through a substance or from one substance to another due to temperature difference Radiation ConductionConvection Convection: – The process in which hot air rises and cool air delves down. Hot air will cool down as it flows through the cooler air mass until it reaches equilibrium. Radiation: – The transfer of heat via electromagnetic waves through space

17. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Thermal Management It is critical to extract the heat away from the LED module and transfer it to ambient This can be done using the principles of conduction, convection and radiation

18. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Heat Sinks Efficiency of heat sinks depends mainly on: – Surface area The larger the surface area, the more heat dissipated – Structure or shape Proper structure increases turbulent airflow which creates a more efficient heat sink

19. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Heat Sinks – Material Use of materials with better thermal conductivity gives a more efficient heat sink –Ex. cooper 401 W/m-K vs. aluminum 235 W/m-K Laminar Flow Turbulent Flow

20. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Thermal Resistance R TH Thermal resistance describes how much that material resists the flow of heat through it — Units: o C/W or o K/W It changes with the material type, thickness, surface area, and power (number of LEDs) We want this number to be as low as possible to make sure heat flows easily from one point to another

21. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Thermal Resistance R TH LED thermal resistance: R TH junction to slug Board thermal resistance: R TH board Thermal interface material thermal resistance: R TH thermal interface Heat sink thermal resistance: R TH heatsink R TH = R TH board +R TH thermal interface +R TH heat sink +R TH junction to slug + + +

22. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Thermal Conductivity (k) Thermal Conductivity Units are in W/mK. The measure of a material’s ability to conduct heat (W/mK)

23. All material, text, graphics, images, design, icons and other copyrightable elements are the copyrighted property of Future Electronics or the original creator and may not be copied, reproduced, republished, displayed or distributed by any means, including but not limited to electronic, mechanical, photocopying, recording or otherwise, without the express prior written permission Future Electronics or the original creator. All rights reserved. © Future Electronics Inc Making LED Lighting Solutions Simple TM Case Study

24. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Scenarios: Scenario A: Passive Cooling Open Frame Closed Fixture Scenario B: Active Cooling Open Frame Closed Fixture

25. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary QLED – Thermal Simulation FLS has jointly developed with Qfinsoft, QLED, a thermal design and simulation software In parallel, FLS has launched a thermal design and simulation service to assist customers 4 FLS Engineers are assigned to carry out this service

26. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary What is QLED? FLS jointly developed QLED with Qfinsoft QLED is a thermal design and simulation software developed for modeling LUXEON LED lighting systems The accuracy of the LED models and their behavior were endorsed by Philips Lumileds

27. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary What is QLED? QLED is a virtual environment which allows customers to create different models. For example, models can range from: A single LED on a heat sink to Multiple LEDs on a custom made board within an enclosed space or casing with active cooling

28. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Benefits of Using QLED 1.It minimizes the number of design cycles, reduces development costs, and decreases time to market ConceptPrototypeTesting Product QLED ConceptProductPrototypeTesting

29. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary 2. Simple user interface Benefits of Using QLED Main Toolbar Simulation Manager 3D Toolbar Message Window Component Toolbar 3D Model View

30. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Key Features Provides very fast simulation results, with most simulations taking only minutes Offers an easy to use library system for material selection Includes a powerful, yet easy to use design optimizer

31. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary QLED Capabilities Simulation modes include: – Steady state: DC current (constant ON) – Transient: Pulse or strobe LEDs – Parameterized Trials – Optimization

32. All material, text, graphics, images, design, icons and other copyrightable elements are the copyrighted property of Future Electronics or the original creator and may not be copied, reproduced, republished, displayed or distributed by any means, including but not limited to electronic, mechanical, photocopying, recording or otherwise, without the express prior written permission Future Electronics or the original creator. All rights reserved. © Future Electronics Inc Making LED Lighting Solutions Simple TM Scenario A Passive cooling

33. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Fortimo DLM 1100lm Thermal path basic solution Temperatures: – 1 = test point Tc – 2 = heat sink @ module side – 3 = ambient Resistances: – R1 = LED DLM path 1-2 – R2 = heat sink path 2-3 1 3 2 3 2

34. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Fortimo DLM 1100lm Thermal Resistances R th c-hs R th hs-amb TcTc T hs T amb 0.2 K/WSide view Top view 1 3 2 3 3 1 2 1 2

35. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Fortimo DLM 1100lm Thermal resistance of heat sink Example of standard heat sink: Needed 4.214 K/W (max) Heat sink: Aavid Thermalloy – Length @ 4.01 K/W = 35 mm – Width= 76.2 mm, height= 38.1 mm, #fins= 8

36. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Thermal Simulation – Open Frame Ambient = 35 o C Tc ≈ 62 o C Matches the theoretical calculations LEDs junction temp. Tc

37. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Thermal Simulation – Closed Fixture Tc = 90 o C Exceed the max. Tc Thermal design must be modified Fully enclosed can (air tight) No vents for air to go in and out Steel Fixture Tc

38. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Solutions? – larger heat sink Larger heat sinks: – Tripled the heat sink height Tc ≈ 73 o C We still need to lower Tc to 65 o C Tc

39. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Solutions? – larger heat sink Fins extended to touch the fixture Tc ≈ 59 o C Tc

40. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Solutions? – vented fixture Vents on upper and lower sections of the fixture Tc ≈ 82 o C Even with larger heat sinks, it may be difficult to reduce Tc Tc

41. All material, text, graphics, images, design, icons and other copyrightable elements are the copyrighted property of Future Electronics or the original creator and may not be copied, reproduced, republished, displayed or distributed by any means, including but not limited to electronic, mechanical, photocopying, recording or otherwise, without the express prior written permission Future Electronics or the original creator. All rights reserved. © Future Electronics Inc Making LED Lighting Solutions Simple TM Scenario B Active Cooling

42. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Nuventix – Open Frame Each setting has a thermal resistance depending on the performance setting

43. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Nuventix – Open Frame At the standard setting and ambient temperature = 35 o C, Tc ≈ 44.7 o C Tc = P x R th(hs-ambient) + T ambient Tc = 13 x 0.75 + 35 = 44.75 o C

44. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary Nuventix – Closed Fixture Experimental testing SynJet to be modeled in QLED

45. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary

46. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary

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51. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary

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55. Making LED Lighting Solutions Simple TM © Future Electronics Inc. Confidential and Proprietary