A19 Reference Design

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
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Fax (919) 313-5558
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4600 Silicon DriveA
Durham, N.C 27703
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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