Cree® XLamp® XQ-D LED A19 Lamp Reference Design Table of Contents Introduction Introduction..................................................................................... 1 This application note details the design of 60‑ and 75‑watt Design approach/objectives.......................................................... 2 equivalent A19 replacement lamps using Cree’s XLamp® The 6-step methodology................................................................. 3 XQ‑D LED. Built on the SC³ Technology® Platform, the XLamp 1. Define lighting requirements................................................. 3 XQ‑D LED is optimized to dramatically lower system cost in 2. Define design goals............................................................... 5 replacement lamp, non‑directional and outdoor area lighting 3. Estimate efficiencies of the optical, thermal & electrical applications, such as the price‑sensitive A19 replacement lamp systems.................................................................................. 5 market. These XQ-D A19 lamps are intended to be replacements 4. Calculate the number of LEDs.............................................. 9 for incandescent A19 lamps in omnidirectional indoor lighting 5. Consider all design possibilities......................................... 10 applications. This reference design shows how this can be 6. Complete the final steps: implementation and analysis... 11 accomplished without complicated, expensive optics. Conclusions................................................................................... 14 Bill of materials............................................................................. 15 CLD-AP136 rev 0C Application Note There are a number of replacement lamps currently on the market that use a “snow‑cone” design, in which a hemispheric dome covers LEDs mounted on a circuit board attached to a conic heat sink. These lamps can be sufficient for directional applications such as a floodlight but do not replicate the omnidirectional light pattern of an incandescent lamp familiar to consumers. This reference design betters the “snow‑cone” style www.cree.com/Xlamp design to produce two lamps that match the light pattern of an Reliance on any of the information provided in this Application Note is at the user’s sole risk. Cree and its affiliates make no warranties or representations about, nor assume any liability with respect to, the information in this document or any LED-based lamp or luminaire made in accordance with this reference design, including without limitation that the lamps or luminaires will not infringe the intellectual property rights of Cree or a third party. Luminaire manufacturers who base product designs in whole or part on any Cree Application Note or Reference Design are solely responsible for the compliance of their products with all applicable laws and industry requirements. Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/ or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. Cree, Inc. 4600 Silicon Drive Durham, NC 27703 USA Tel: +1.919.313.5300 1 XLamp ® XQ-D LED a19 Reference Design incandescent, enabling their use in omnidirectional applications and also enabling them to meet ENERGY STAR® intensity distribution requirements. The XLamp XQ-D LED’s lighting-class reliability and wide spread of light make it a particularly strong candidate for use in an A19 lamp. As shown in Figure 1, the XQ-D LED has a wider light distribution than the Lambertian distribution. The XQ-D LED also directs light backward. This unique light distribution of the XQ-D LED, when the LED is placed near the edge of the lamp as in this design, is a key feature that helps these A19 lamps to meet the ENERGY STAR light distribution requirements for 60‑ and 75‑watt equivalent replacement lamps. LED Pitch 1 LED 2 LED 1 LED 3 Q1 On-axis illuminance LED cross-over illuminance Q1 < Q 2 LED Pitch 2 LED 2 LED 1 Q2 On-axis illuminance LED cross-over illuminance Figure 1: Comparison of Lambertian light distribution (top) vs. XQ-D light distribution (bottom) Figure 2 shows the XLamp XQ-D LED light distribution. Figure 2: XQ-D light distribution Design approach/objectives In the “LED Luminaire Design Guide” Cree advocates a six‑step framework for creating LED luminaires and lamps. All Cree reference designs use this framework, and the design guide’s summary table is reproduced in Table 1. Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 2 XLamp ® XQ-D LED a19 Reference Design Table 1: Cree 6-step framework Step Explanation 1. Define lighting requirements • The design goals can be based either on an existing fixture or on the application’s lighting requirements. 2. Define design goals • • Specify design goals, which will be based on the application’s lighting requirements. Specify any other goals that will influence the design, such as special optical or environmental requirements. • • • Design goals will place constraints on the optical, thermal and electrical systems. Good estimations of efficiencies of each system can be made based on these constraints. The combination of lighting goals and system efficiencies will drive the number of LEDs needed in the luminaire. • Based on the design goals and estimated losses, the designer can calculate the number of LEDs to meet the design goals. 5. Consider all design possibilities and choose the best • • With any design, there are many ways to achieve the goals. LED lighting is a new field; assumptions that work for conventional lighting sources may not apply. 6. Complete final steps • • • • • Complete circuit board layout. Test design choices by building a prototype luminaire. Make sure the design achieves all the design goals. Use the prototype to further refine the luminaire design. Record observations and ideas for improvement. 3. Estimate efficiencies of the optical, thermal & electrical systems 4. Calculate the number of LEDs needed The 6-step methodology The goal of the design is two XLamp XQ-D LED-based A19 lamps that can replace incandescent lamps in omnidirectional applications, one a 60‑watt and the other a 75‑watt equivalent. These replacement lamp designs use the A19 form factor that is familiar to consumers. 1. Define lighting requirements Table 2 shows a ranked list of desirable characteristics to address in an A19 lamp design. Table 2: Ranked design criteria for an A19 lamp Importance Critical Important Characteristics Units Illuminance distribution footcandles (fc)/lux (lx) Electrical power watts (W) Luminous flux lumens (lm) Luminous efficacy lm/W Lifetime hours Operating temperatures °C Operating humidity % relative humidity Correlated color temperature (CCT) K Color rendering index (CRI) 100-point scale Table 3 below summarizes the ENERGY STAR requirements for all integral LED lamps.1 1 ENERGY STAR Program Requirements for Integral LED Lamps Eligibility Criteria – Version 1.4, Table 4 Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 3 XLamp ® XQ-D LED a19 Reference Design Table 3: ENERGY STAR requirements for integral LED lamps Characteristic Requirements Lamp must have one of the following designated CCTs (per ANSI C78.377-2008) consistent with the 7-step chromaticity quadrangles and Duv tolerances below. CCT and Duv Nominal CCT Target CCT (K) and Tolerance 2700 K 3000 K 3500 K 4000 K 2725 ± 145 3045 ± 175 3465 ± 245 3985 ± 275 Target Duv and Tolerance 0.000 ± 0.000 ± 0.000 ± 0.001 ± 0.006 0.006 0.006 0.006 Color maintenance The change of chromaticity over the minimum lumen maintenance test period (6,000 hours) shall be within 0.007 on the CIE 1976 (u’, v’) diagram. CRI Minimum CRI (Ra) of 80. R9 value must be greater than 0. Dimming Lamps may be dimmable or non-dimmable. Product packaging must clearly indicate whether the lamp is dimmable or not dimmable. Manufacturers qualifying dimmable products must maintain a web page providing dimmer compatibility information. Warranty 3-year warranty Allowable lamp bases Must be a lamp base listed by ANSI. Power factor Lamp power < 5 W and low voltage lamps: no minimum PF Lamp power > 5 W: PF > 0.70 Minimum operating temperature -20 °C or below LED operating frequency ≥ 120 Hz Note: This performance characteristic addresses problems with visible flicker due to low frequency operation and applies to steadystate as well as dimmed operation. Dimming operation shall meet the requirement at all light output levels. Electromagnetic and radio-frequency interference Must meet appropriate FCC requirements for consumer use (FCC 47 CFR Part 15) Audible noise Class A sound rating Transient protection Power supply shall comply with IEEE C62.41-1991, Class A operation. The line transient shall consist of seven strikes of a 100 kHz ring wave, 2.5 kV level, for both common mode and differential mode. Operating voltage Lamp shall operate at rated nominal voltage of 120, 240 or 277 VAC, or at 12 or 24 VAC or VDC. Table 4 summaries ENERGY STAR requirements for omnidirectional replacement lamps.2 Table 4: ENERGY STAR requirements for replacement omnidirectional lamps Criteria Item Requirements Minimum luminous efficacy • • LED lamp power < 10 W: 50 lm/W LED lamp power ≥ 10 W: 55 lm/W Lamp shall have minimum light output (initial total luminous flux) at least corresponding to the target wattage of the lamp to be replaced, as shown below. Target wattages between the given levels may be interpolated. Minimum light output Nominal wattage of lamp to be replaced (watts) Minimum initial light output of LED lamp (lumens) 60 75 800 1100 Luminous intensity distribution Products shall have an even distribution of luminous intensity (candelas) within the 0° to 135° zone (vertically axially symmetrical). Luminous intensity at any angle within this zone shall not differ from the mean luminous intensity for the entire 0° to 135° zone by more than 20%. At least 5% of total flux (lumens) must be emitted in the 135° to 180° zone. Distribution shall be vertically symmetrical as measured in 3 vertical planes at 0°, 45° and 90°. Maximum lamp diameter Not to exceed target lamp diameter Maximum overall length (MOL) Not to exceed MOL for target lamp Lumen maintenance ≥ 70% lumen maintenance (L70) at 25,000 hours of operation Rapid-cycle stress test Cycle times must be 2 minutes on, 2 minutes off. Lamp will be cycled once for every 2 hours of L70 life. 2 Ibid., Table 7A Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 4 XLamp ® XQ-D LED a19 Reference Design 2. Define design goals Table 5 shows the design goals for this project. Table 5: Design goals Characteristic 60-W Equivalent Lamp Unit Light output Target Goal Minimum Goal Target Goal 800 > 800 1100 > 1100 > 65 lm Efficacy 75-W Equivalent Lamp Minimum Goal lm/W 60 > 60 65 Power W < 15 < 14 < 17 < 16 CCT K 2700 2700 2700 2700 CRI 100-point scale 80 > 80 80 > 80 3. Estimate efficiencies of the optical, thermal & electrical systems We used Cree’s Product Characterization Tool (PCT) tool to determine the drive current for both lamp designs. For the 800‑lm target of the 60‑W equivalent design, we estimated 86% optical efficiency and 90% driver efficiency. We also estimated a solder‑point temperature of 95 °C. For the 1,100‑lm target of the 75‑W equivalent design, we estimated 86% optical efficiency, 88% driver efficiency and a solder‑point temperature of 105 °C. The PCT output highlighted in Figure 3 shows that, at 500 mA, nine XLamp XQ-D LEDs provide sufficient light output to meet the 60-W equivalent design goals. In an effort to use the minimum number of LEDs to meet the design goals, our initial testing indicated that eight XQ-D LEDs, still at 500 mA, would provide ample light output. As the results show, that proved to be true. LED System Comparison Report The PCT output highlighted in Figure 3 also shows that, at 300 mA, eighteen XQ-D LEDs provide sufficient light output to meet the 75-W 1 1 equivalent design goals. System: 800 Target Lumens : System: Target Lumens : Optical Efficiency: Flux LED 2 Model Cree XLamp XQ-D {WT} Q4 [100] Tsp (ºC) $ Price SYS # LED SYS lm tot SYS lm/W 95 Current (A) Current (A) LED 1 Model LED S (none)Model Flux Flux Price $ 1,100 Optical E Electrical Efficiency: 86% LED 1 L Model Cree XLamp XQ-D {WT} (ºC) 105Flux $ Price SYS # LED SYS lm tot SYS lm/W Price SYS W Q4 Tj [100] (ºC) 25Tj SYS W 0.200 26 1134 70.3 16.141 11 873.8 61.7 14.1648 #N/A #N/A #N/A #N/A #N/A 0.400 0.250 21 1116.7 67.3 16.581 0.450 10 871 59.6 14.6246 #N/A #N/A #N/A #N/A #N/A 0.300 18 1121.3 64.7 17.318 0.500 9 849.6 57.6 14.7488 #N/A #N/A #N/A #N/A #N/A 0.350 16 1135.9 62.4 18.205 0.550 8 810.8 55.8 14.5316 #N/A #N/A #N/A #N/A #N/A 0.400 14 1110.3 60.3 18.426 0.600 8 863.8 54.1 15.9644 #N/A #N/A #N/A #N/A #N/A 0.450 13 1134.5 58.3 19.458 0.650 7 800.3 52.5 15.2332 #N/A #N/A #N/A #N/A #N/A 0.000 #N/Aview of the #N/A #N/Aused and#N/A #N/Aequivalent #N/A #N/A #N/A Figure 3: PCT number of LEDs drive current for 60-W design (left) and 75-W equivalent A19 lamp#N/A design (none)Mode Flux $ Price #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A #N/A This document is provided for informational purposes only and is not a warranty or a specification. For product specifications, please see the data sheets available at www.cree.com. Copyright © 2009-2012 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree, the Cree logo and XLamp are registered trademarks of Cree, I Optical Requirements A major challenge for an LED-based A19 lamp intended to meet ENERGY STAR light output requirements is the intensity distribution beyond 90°, i.e., light emitted back toward the lamp base. Figure 4 is a graphic representation of the ENERGY STAR luminous intensity distribution requirement.3 Many LED‑based lamps on the market have a “snow‑cone” style design in which light is directed mainly forward 3 Op. cit., Appendix B Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 5 XLamp ® XQ-D LED a19 Reference Design and therefore are not able to meet this requirement. This design shows how the XLamp XQ-D LED enables an A19 lamp that is able to meet this requirement. Figure 4: ENERGY STAR luminous intensity distribution requirement Reflector At the core of this reference design is an internal reflector designed to reflect light from the LEDs into an omnidirectional pattern. The reflector is a custom Cree design. It is made from a thin‑wall plastic sheet painted white and formed to reflect light back toward the lamp’s screw base. The reflector is a vertical tube with the top angled outward at 45°. The tube is open at the top to allow axial light to exit the lamp. Figure 5 shows the internal reflector positioned in the A19 lamp to reflect light into the 90‑180° zone. Figure 6 is a mechanical drawing of the reflector.4 Figure 5: XQ-D A19 internal reflector Figure 6: XQ-D A19 reflector mechanical drawing dimensions in mm, tolerance ± 0.2 mm, ± 1° Diffuser Figure 7 is a mechanical drawing of the glass elliptical globe diffuser of the XQ-D A19 lamp.5 4 5 A 3-D model (STEP file) for the reflector is available. A 3-D model (STEP file) for the diffuser is available. Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 6 6 6 5 5 NOTICE NOTICE CREE CONFIDENTIAL. THISAND PLOT AND THE INFORMATION CREE CONFIDENTIAL. THIS PLOT THE INFORMATION CONTAINED ARE CONTAINED WITHINWITHIN ARE THE PROPRIETARY AND AND 6THE PROPRIETARY CONFIDENTIAL INFORMATION OF CREE, INC. THIS PLOT CONFIDENTIAL INFORMATION OF CREE, INC. THIS PLOT NOTICE MAY NOT BE COPIED, REPRODUCED OR DISCLOSED TO ANY MAY NOT BE COPIED, REPRODUCED OR DISCLOSED TO ANY CREE CONFIDENTIAL. THIS PLOT AND THE INFORMATION UNAUTHORIZED PERSON WITHOUT THE WRITTEN CONSENT UNAUTHORIZED PERSON WITHOUT THE WRITTEN CONSENT 6 5 CONTAINED OF CREE INC.WITHIN ARE THE PROPRIETARY AND OF CREE INC. CONFIDENTIAL INFORMATION OF CREE, INC. THIS PLOT NOTICE MAY NOT BE COPIED, REPRODUCED OR DISCLOSED TO ANY FIDENTIAL. THIS PLOT AND THE INFORMATION UNAUTHORIZED PERSON WITHOUTTHE WRITTEN CONSENT D WITHIN ARE THE PROPRIETARY AND OF CREE INC. TIAL INFORMATION OF CREE, INC. THIS PLOT E COPIED, REPRODUCED OR DISCLOSED TO ANY RIZED PERSON WITHOUTTHE WRITTEN CONSENT D D NC. 4 5 4 3 4 4 3 2 2 3 1 2 1 1 XLamp XQ-D LED a19 Reference Design 3 ® 2 1 D D D D D C C C C C 62.0 62.0 C C 64.0 62.0 64.0 Units: mm Ry24.5 Ry24.5 Tolerance: ± 0.2mm Globe consists of two elliptical curves Ry24.5 Ry23.5 Ry23.5 Ry24.5 Ry23.5 Rx32.0 Rx32.0 Rx31.0 Rx31.0 Ry23.5 B Units: Units: mm mm Tolerance: ± 0.2mm Tolerance: ± 0.2mm consists two elliptical GlobeGlobe consists of twoofelliptical curvescurves Units: mm Tolerance: ± 0.2mm Globe consists of two elliptical curves 64.0 64.0 62.0 B Rx32.0 Rx31.0 B Rx31.0 Rx31.0 Rx31.0 Ry28.7 48.0 48.0 49.0 49.0 48.0 49.0 B Rx32.0 Rx32.0 Rx32.0 Ry28.7 Rx31.0 Ry28.7 Rx32.0 B B Rx32.0 Rx31.0 B 49.0 48.0 Ry29.7 Ry29.7 Ry28.7 Ry29.7 Ry29.7 41.0 41.0 A A DRAWN BYDRAWN BY DATE A 41.0 43.0 43.0 6 5 Electrical Requirements 6 5 THIRD ANGLE PROJECTION 4 4 4 5 4 3 Fax (919) 313-5558 Fax (919) 313-5558 4600 Silicon DriveA Durham, N.C 27703 A (919) 313-5300 SBTC-00153 Phone SBTC-00153 Fax (919) 313-5558 Figure 7: Glass diffuser, GlassGlass SBTC-00153 SURFACE FINISH: 6 (919) 313-5300 Phone (919)Phone 313-5300 TITLE TITLE Glass 5 Silicon Drive 4600 Silicon4600 Drive Durham, Durham, N.C 27703 N.C 27703 CHECK DATE AFTER .5 ° X° AND ± X° .5 °± FINISH. DATE DRAWNPROJECTION BY THIRD ANGLE THIRD ANGLE PROJECTION T. Tong 9/3/2010 TOLERANCE UNLESS SPECIFIED: MATERIAL MATERIAL UNLESS OTHERWISE SPECIFIED FOR SHEETPARTS METAL PARTS ONLY FOR SHEET METAL ONLY 4600 Silicon Drive .XX ± .01 Z. Yuan DATE APPROVED DIMENSIONS ARE IN INCHES .X ± .X .06± ± .06 Durham, N.C 27703 TITLE .XXX .005 CHECK DATE DRAWING NO. DRAWING NO. SIZE SIZE AND AFTER FINISH. ± .03 .XX ± .XX .03 Phone (919) 313-5300 X° ± .5 ° T. Tong 9/3/2010 .XXX ± .XXX TOLERANCE UNLESS SPECIFIED: .010 FINAL PROTECTIVE .010± FINAL FINISH PROTECTIVE FINISH THIRD ANGLE PROJECTION Fax (919) 313-5558 MATERIAL FOR METAL PARTS .5 ° ONLY .XX ± .01 X° SHEET ± X° .5 °± DATE APPROVED A SCALE SCALE TITLE .XXX ± .005 .X63 ± .06 63 SURFACE FINISH: 2.000 SURFACE FINISH: 2.000 DRAWING NO. SIZE X° ± .5 ° .XX ± .03 .XXX ± .010 FINAL 3 3 2PROTECTIVE2FINISH FOR SHEET METAL PARTS ONLY MATERIAL X° ± .5 ° .X ± .06 REV. SCALE NO. SIZE 63 SURFACE FINISH: DRAWING 2.000 .XX ± .03 .XXX ± .010 FINAL PROTECTIVE FINISH 3 2 X° ± .5 ° dimensions in mm, tolerance ± 0.2 mm 6 DATE UNLESS OTHERWISE SPECIFIED UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE IN INCHES Z. Yuan Z. Yuan DIMENSIONS ARE IN INCHES DATE ANDFINISH. AFTER FINISH. CHECK CHECK DATE AND AFTER T. Tong TOLERANCE UNLESS SPECIFIED: T. Tong TOLERANCE UNLESS SPECIFIED: DATE DRAWN BY9/3/2010 9/3/2010 UNLESS SPECIFIED .XX.01 ± .01 .XX ± OTHERWISE DATE APPROVEDAPPROVEDDATE Z. Yuan DIMENSIONS ARE ± IN INCHES .005 .XXX ± .XXX .005 43.0 43.0 41.0 C SCALE 63 2 2.000 Glass C DIFFUSER_GLOBE_M2 SHEET REV. REV. DIFFUSER_GLOBE_M2 SBTC-00153 C CDIFFUSER_GLOBE_M2 -- -- OF -- SHEET SHEET OF OF 1 /1 DIFFUSER_GLOBE_M2 1 1 SHEET OF 1 /1 REV. -1 /1 1 1 /1 1 Driver The A19 form factor provides limited space for the driver. To meet ENERGY STAR requirements, a lamp operating at more than 10 W must be tested in a 45 °C environment between measurements, challenging a driver’s ability to maintain performance under high temperature. The A19 form factor also provides limited space for the heat sink, leading to a high solder point temperature (TSP) and driver operating temperature. For this reference design driver we selected two isolated, constant‑current drivers, shown in Figure 8, able to operate at high temperatures and be 89%-90% efficient. Figure 8: A19 lamp drivers for 60-W equivalent lamp (left) and 75-W equivalent lamp (right) Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 7 A XLamp ® XQ-D LED a19 Reference Design Thermal Requirements Thermal management is a major aspect of any LED-based lamp or luminaire design. For the 60-W equivalent lamp, we estimate that 70% of the approximately 15 W of input power, or about 10.5 W, will be converted to heat that must be dissipated, significantly better than the 54 W of power converted to heat by a 60-W incandescent lamp. For the 75-W equivalent lamp, 70% of the approximately 17 W of input power, or about 11.9 W, will be converted to heat that must be dissipated, significantly better than the 67.5 W of power converted to heat by a 75-W incandescent lamp. Circuit Board As shown in Figure 9, the 60-W equivalent A19 lamp design has seven XLamp XQ-D LEDs arranged in a circular pattern on a Cree‑designed metal‑core printed‑circuit board (MCPCB) and one XQ-D LED in the center of the board. To take maximum advantage of the light output pattern of the XQ-D LED, seven LEDs are located as close to the edge of the MCPCB as possible. Although not addressed in this reference design, using a different number of LEDs to achieve other lumen output levels is possible as long as the LED layout diameter is maintained. Figure 9: 60-W equivalent MCPCB The 75‑W equivalent lamp design uses an MCPCB that has a diamond‑like film as the dielectric layer and has performance close to that of a copper‑core board. As shown in Figure 10, the 75-W equivalent A19 lamp design has sixteen XLamp XQ-D LEDs arranged in a circular pattern on an MCPCB and two XQ-D LEDs in the center of the board. To take maximum advantage of the light output pattern of the XQ-D LED, sixteen LEDs are located as close to the edge of the MCPCB as possible. Figure 10: 75-W equivalent MCPCB Heat Sink This reference design uses a 36‑fin aluminum heat sink, shown in Figure 11, that serves as the mechanical frame for the lamp. The lightweight heat sink has slender fins that allow light to be directed back toward the lamp base. The heat sink is part of a kit that includes a driver housing and metal screw base. Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 8 XLamp ® XQ-D LED a19 Reference Design Figure 11: XQ-D A19 heat sink and driver housing attached to metal screw base We performed thermal simulation to verify this thermal design is sufficient. Figure 12 shows two views of the thermal simulation of the 60-W equivalent lamp. The simulated solder point temperature (TSP) was 93 °C. Figure 12: Thermal simulation of XQ-D A19 lamp 4. Calculate the number of LEDs Initial testing determined that eight XLamp XQ-D LEDs produce sufficient light to meet the 800‑lm design goal for the 60-W equivalent lamp and eighteen XQ-D LEDs produce sufficient light to meet the 1100-lm design goal for the 75-W equivalent lamp. The XQ-D LED offers a wide range of color temperatures. We selected a warm white LED for this A19 lamp design, shown highlighted in Table 6. Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 9 XLamp ® XQ-D LED a19 Reference Design Table 6: XQ-D order codes CCT Range Color Min. Neutral White 3700 K 80 CRI Minimum White 2600 K Warm White 2600 K Max. 5000 K 4300 K 3700 K Base Order Codes Minimum Luminous Flux @ 350 mA Calculated Minimum Luminous Flux (lm) Order Code Group Flux (lm) 700 mA R3 122 213 XQDAWT-00-0000-00000BFE5 R2 114 199 XQDAWT-00-0000-00000BEE5 Q5 107 187 XQDAWT-00-0000-00000LDE5 Q4 100 172 XQDAWT-00-0000-00000HCE7 Q3 93.9 164 XQDAWT-00-0000-00000HBE7 Q2 87.4 153 XQDAWT-00-0000-00000HAE7 Q4 100 172 XQDAWT-00-0000-00000LCE7 Q3 93.9 164 XQDAWT-00-0000-00000LBE7 Q2 87.4 153 XQDAWT-00-0000-00000LAE7 5. Consider all design possibilities A number of LED-based lamp designs currently on the market position the LEDs vertically on a stalk in the lamp or use secondary optics to produce an omnidirectional light pattern. This design employs other design aspects, listed below, to show that the XLamp XQ-D LED enables an A19 lamp offering superior performance. • The small size of the XQ-D LED allows the LEDs to be mounted low in the neck of the lamp. Figure 13 shows how this facilitates omnidirectional light output. PCB Position PCB Position Figure 13: Comparison of light output with LEDs mounted high (left) and low (right) in the lamp • The XQ‑D LED emits more of its light out the side than straight out. To take advantage of the XQ-D’s light distribution, the XQ-D LEDs are mounted close to the edge of the MCPCB. More than 5% of the XQ-D LED’s light shines backward, so positioning the LEDs near the edge of the MCPCB allows this light to continue toward the lamp’s base. • An internal reflector directs light toward the base of the lamp to help form an omnidirectional pattern. • Reflective film covering the MCPCB improves the lamp’s light output by reflecting light directed backward from the LED out of the lamp. • The heat sink not only dissipates heat, but its thin fins also enable light to be directed toward the lamp base. Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 10 XLamp ® XQ-D LED a19 Reference Design 6. Complete the final steps: implementation and analysis Using the methodology described above, we determined a suitable combination of LEDs, components and drive conditions. This section describes how Cree assembled the A19 lamp and shows the results of the design. Prototyping Details 1. We verified the component dimensions to ensure a correct fit. 2. Following the recommendations in Cree’s Soldering and Handling Application Note for the XQ-D LED, with an appropriate solder paste and reflow profile, we reflow soldered the LEDs to the MCPCB. The LEDs in the 60-W equivalent lamp are connected in series. The 75-W equivalent lamp has two strings of LEDs connected in parallel. The nine LEDs in each string are connected in series. 3. We cleaned the flux residue with isopropyl alcohol (IPA). 4. We applied a thin layer of thermally conductive compound to the back of MCPCB and secured it to the heat sink with screws. Consult Cree’s Chemical Compatibility Application Note for compounds safe for use with XLamp LEDs. 5. We fed the driver output wires through the heat sink and soldered them on the MCPCB terminal pads. 6. We tested the connection by applying power to the LEDs and verified that they lit up. 7. We inserted the driver into the driver housing and snapped the housing into the heat sink. An adhesive can be used to secure this connection. 8. We soldered the driver input wires to the metal screw base and screwed the base to the driver housing. 9. We attached reflective film to the MCPCB. 10. We secured the internal reflector to the heat sink with silicone adhesive. Consult Cree’s Chemical Compatibility Application Note for adhesives safe for use with XLamp LEDs. Figure 14 shows the lamp at this point in the assembly process. Figure 14: XQ-D A19 lamp just prior to final assembly step left: 60-W equivalent, right: 75-W equivalent Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 11 XLamp ® XQ-D LED a19 Reference Design 11. We attached the diffuser to the heat sink with silicone adhesive. 12. We performed final testing. Results Thermal Results Cree verified the board temperature with a thermocouple to confirm that the thermal dissipation performance of the heat sink aligns with our simulation. The solder point temperature of the 60-W equivalent lamp, measured with a thermocouple, was 90 °C, nearly a match with the simulation and showing that the heat sink is sufficient for this design. Based on the measured solder point temperature, the junction temperature (TJ) can be calculated as follows. For the 60‑W equivalent lamp: For the 75‑W equivalent lamp: TJ = TSP + (LED power * LED thermal resistance) TJ = TSP + (LED power * LED thermal resistance) TJ = 90 °C + ((.5 A *3 V) * 7.5 °C/W) TJ = 103 °C + ((.3 A *1.5 V) * 7.5 °C/W) TJ = 101.3 °C TJ = 105.6 °C Optical and Electrical Results Photometric and performance measurements were collected using Cree’s commercially available thermal, electrical, mechanical, photometric and optical (TEMPO) 24 service. The internal reflector has 93% optical efficiency. The diffuser has 91% optical efficiency. We obtained the results in Table 7 and following by testing the lamp at steady state after a 60-minute stabilizing time.6 The values in the table meet ENERGY STAR performance metrics for 60‑ and 75‑W equivalent lamps. Table 7: XQ-D A19 lamp steady-state results Characteristic Unit Results for 60-W Equivalent Lamp Results for 75‑W Equivalent Lamp Light output lm 842 1126 Power W 13.2 16.5 lm/W 64 68 CCT K 2778 2750 CRI 100-point scale 80 81 0.83 0.83 Lamp efficacy Power factor Figure 15 shows polar candela distributions for the XQ-D A19 lamps. The figure shows the shape of the light pattern from each lamp. The lamp outline is superimposed on the distributions to show that the measurements were taken with the lamps in a base‑up position. 6 Testing was performed using a 2‑meter integrating sphere and a Type C goniophotometer at Cree’s Durham Technology Center. IES files for the 60-W equivalent and the 75-W equivalent lamps are available. Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 12 XLamp ® XQ-D LED a19 Reference Design Figure 15: XQ-D A19 lamp outline (in green) superimposed on polar candela distribution (in blue) left: 60‑W equivalent lamp, right: 75‑W equivalent lamp The 3-D wire diagram in Figure 16 is a graphical representation of the candela intensity values for the XQ-D A19 lamps, also with the lamps in a base‑up position. Figure 16: 3-D wire diagram of XQ-D A19 candela intensity values Figure 17 shows that the XQ-D A19 lamps meet the ENERGY STAR luminous intensity distribution requirement. The dashed lines indicate the ENERGY STAR luminous intensity requirement in the 0‑135° zone. The lamps were measured in the base-up position. Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 13 XLamp ® XQ-D LED a19 Reference Design Figure 17: Luminous intensity distribution of XQ-D A19 lamps Conclusions This reference design illustrates the excellent performance of a high-performance A19 lamp based on the Cree XLamp XQ-D LED. The wide light output pattern of the XQ-D LED enables an A19 lamp that meets the ENERGY STAR light distribution requirements for 60- and 75‑W replacement lamps. Those interested in meeting the full battery of 45 °C ambient temperature ENERGY STAR test requirements might elect to use a different number of LEDs, which is possible with this design. For example, for the 60-W equivalent design, using four or five XLamp XQ-D LEDs would yield an omnidirectional lamp producing a lower lumen level, i.e., 450 lumens, 40-W equivalence. Additionally, using ten or twelve XLamp XQ-D LEDs would result in a 60-W equivalent lamp that operates at a lower junction temperature. The light pattern of this lamp makes it suitable for omnidirectional applications in which incandescent lamps are typically used and in applications in which the light pattern of a “snow‑cone” style lamp is less than optimal. The lighting‑class performance of the Cree XLamp XQ-D LED makes it an attractive design option for an LED-based A19 lamp. Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 14 XLamp ® XQ-D LED a19 Reference Design Bill of materials Table 8: Bill of materials for XQ-D A19 lamps Component Order Code/Model Number Company Web Link Base, driver housing, heat sink kit A19-M2 TaiSun Precision Parts www.hztaisun.com Cree, Inc. XQ-D A19 diffuser globe Diffuser Driver - 60-W equivalent lamp iw3620 iWatt, Inc. www.iwatt.com/iw3620.php Driver - 75-W equivalent lamp NCL30083 ON Semiconductor www.onsemi.com/PowerSolutions/product. do?id=NCL30083 LED XQDAWT-00-0000-00000LCE7 Cree, Inc. XQ-D product page MCPCB - 60-W equivalent lamp Cree, Inc. MCPCB - 75-W equivalent lamp Cree-SZTC-0402 RECI Optoelectronics www.reci-led.com Reflective film WhiteOptics™ White97 WhiteOptics LLC www.whiteoptics.com Cree, Inc. XQ-D A19 internal reflector Reflector Silicone adhesive SE 9184 White RTV Dow Corning www.dowcorning.com/applications/search/products/ details.aspx?prod=02511916&type=PROD Thermally conductive compound Silver Ice 710NS Timtronics www.timtronics.com/electricallyconductive.htm Reliance on any of the information provided in this Application Note is at the user’s sole risk. Cree and its affiliates make no warranties or representations about, nor assume any liability with respect to, the information in this document or any LED-based lamp or luminaire made in accordance with this reference design, including without limitation that the lamps or luminaires will not infringe the intellectual property rights of Cree or a third party. Luminaire manufacturers who base product designs in whole or part on any Cree Application Note or Reference Design are solely responsible for the compliance of their products with all applicable laws and industry requirements. Copyright © 2013-2016 Cree, Inc. All rights reserved. The information in this document is subject to change without notice. Cree®, XLamp® and SC3 Technology® are registered trademarks and the Cree logo is a trademark of Cree, Inc. ENERGY STAR® is a registered trademark of the U.S. Environmental Protection Agency. Other trademarks, product, and company names are the property of their respective owners and do not imply specific product and/or vendor endorsement, sponsorship or association. For product specifications, please see the data sheets available at www.cree.com. For warranty information, please contact Cree Sales at [email protected]. 15