Welcome to this module on XLamp LEDs from CREE. This module will overview the XLamp LED family and discuss the key features and applications of Xlamp products. This ‘fastcast’ is 12 pages in length and last just over 10 minutes.
In comparison to Standard LEDs, High power LEDs operate at higher currents - more than ten fold compared to standard LEDs – and emit more light and consequently glow brighter. The increased power required to produce this light has the effect of also producing more heat. The definition of a Power LED is one that operates at greater or equal to 1W. In contrast Standard LEDs consume less power and produce less heat. However, despite the increased heat exhibited by High Power LEDs, their heat dissipation design is better due to comparatively lower junction temperature, enabling a longer life span.
Lighting-class LEDs can now deliver the brightness, efficiency, lifetime, improved color temperature range, and white-point stability required for general illumination. Lighting-class LEDs offer efficient, directional light that lasts at least 50,000 hours. LED operational lifetime is not affected by shock or vibration damage. Shocks and vibration shorten the lifespan of a traditional light bulb. LED light sources give better light-beam uniformity than conventional light sources and simplify optical-system design.
CREE leads the industry in brightness and reliability for power LEDs with its XLamp LED family. Through XLamp LEDs, CREE is enabling the lighting industry with efficient, environmentally friendly LED light. XLamp LEDs lead the solid-state lighting industry in brightness while providing a reflow-solderable design that is optimized for ease of use and thermal management. Lighting applications featuring XLamp LEDs maximize light output and increase design flexibility, while minimizing environmental impact due to less landfill waste and hazardous materials such as mercury. An XLamp LED combines an LED chip, electrical and thermal connections, encapsulating substances, an optical element, and a phosphor system.
XLamp family includes royal blue, blue, green, amber, cyan, red-orange, red, cool white, and warm white LEDs. Mixing these colors enables the creation of any color in the visible spectrum. The lighting industry demands both high lumen maintenance and very stable color output from the incumbent lighting technologies. White high-power LEDs will experience shifts in white light output over their operational life. High-temperature conditions will accelerate these white point shifts. Therefore, Cree monitors the white light output of the XLamp LED over time under high-temperature conditions. XLamp offers 50 times the life of a typical incandescent bulb and 5 times the lifetime of an average compact fluorescent lamp. In fact, if you ran one Cree lamp for 6 hours per day every day, it would last for nearly 23 years. Thermal path between the LED junction and ambient conditions affect junction temperature which will cause light output reduction and accelerated chip degradation. XLamp LED packages uses a substrate with an extremely low thermal resistance in order to efficiently channel heat away from the LED junction and into the thermal path.
The main purpose of secondary optics is to change the light output pattern of the LED. This chart illustrates the luminous intensity performance to beam angle of the different XLamp LEDs.
In the most cases, power LEDs will be mounted on metal-core printed circuit boards (MCPCB), which will be attached to a heat sink. Heat flows from the LED junction through the MCPCB to the heat sink by way of conduction. The heat sink diffuses heat to the ambient surroundings by convection. In heat management design, designers must know what junction temperature they are operating at, and whether the product will reach the maximum value or not. If the designers can keep the junction temperature low, they will achieve longer life for the LEDs. Based on internal long-term reliability testing and standardized forecasting methods, XLamp LEDs will maintain an average of 70% lumen maintenance after 50,000 hours, provided the LED junction temperature is maintained at or below 80°Celsius.
LEDs will decrease in relative flux output as junction temperature (Tj) rises. Most LED data sheets list typical luminous flux at Tj = 25°Celsius, while most LED applications use higher junction temperatures. When using Tj > 25°Celsius, the luminous flux must be de-rated from the value listed on the LED’s data sheet.
This table describes the available color and luminous flux by listing the correlated color temperature (CCT) or dominant wavelength range for the entire family.
All XLamp LEDs are tested and sorted by color and brightness into a unique bin. Each bin contains LEDs from only one color and brightness group and is uniquely identified by a bin code. White XLamp LEDs are sorted by chromaticity (color) and luminous flux (brightness). Color XLamp LEDs are sorted by dominant wavelength (color) and luminous flux (brightness), or in the case of royal blue, radiant flux (brightness). Amber, red-orange and red LEDs are additionally binned into forward voltage bins. Kits contain LEDs from a number of similar bins and are fully defined by their part number.
Firstly, the design goals should be based either on an existing lighting performance or on the application’s lighting requirements. Then, the designer should specify any other goals that will influence the design, such as special optical requirements or being able to withstand high temperatures. Design goals will place constraints on the optical, thermal and electrical systems. Good estimations of efficiencies of each system can be based on these constraints. The combination of lighting goals and system efficiencies will drive the number of LEDs needed in the application. Once the design decisions have been made, the final steps are to build and evaluate a prototype luminaire.
Thank you for taking the time to view this presentation on Cree Xlamp LEDs. If you would like to learn more or go on to purchase some of these devices, you can either click on the link embedded in this presentation, or simple call our sales hotline. For more technical information you can either visit the Cree site – link shown – or if you would prefer to speak to someone live, please call our hotline number, or even use our ‘live chat’ online facility.
Module Introduction <ul><li>Purpose </li></ul><ul><ul><li>This module provides information about the CREE XLamp LEDs </li></ul></ul><ul><li>Outline </li></ul><ul><ul><li>Provide an overview of XLamp LEDs family </li></ul></ul><ul><ul><li>Discuss the key features and applications of XLamp LEDs </li></ul></ul><ul><li>Contents </li></ul><ul><ul><li>12 pages </li></ul></ul><ul><li>Duration </li></ul><ul><ul><li>10 Minutes </li></ul></ul>
High Power vs. Standard LEDS <ul><li>High Power LEDs </li></ul><ul><ul><li>Operate at higher current </li></ul></ul><ul><ul><li>Emit more light </li></ul></ul><ul><ul><li>Generate more heat due to higher power consumption (typically 1W) </li></ul></ul><ul><li>Standard LEDs </li></ul><ul><ul><li>Typical operating current of 20mA </li></ul></ul><ul><ul><li>Normal luminous intensity < 50mcd </li></ul></ul>
Basic Advantages of LED Light <ul><li>Energy efficient </li></ul><ul><ul><li>50% more efficient than metal halide lamp </li></ul></ul><ul><ul><li>35% more efficient than fluorescent lamp </li></ul></ul><ul><ul><li>80% more efficient than incandescent lamp </li></ul></ul><ul><li>Long lifetime </li></ul><ul><ul><li>5 times longer than metal halide lamp </li></ul></ul><ul><li>Inherently rugged </li></ul><ul><ul><li>No filament to break </li></ul></ul><ul><li>Instant on </li></ul><ul><ul><li>Able to reach full brightness in nanoseconds </li></ul></ul><ul><li>Environmentally friendly </li></ul><ul><ul><li>No mercury, lead, or other heavy metals </li></ul></ul>
Overview of XLamp ® LEDs <ul><li>Lighting-class LEDs </li></ul><ul><li>Designed to operate at high currents </li></ul><ul><li>Environmentally friendly </li></ul><ul><li>Leadless packages </li></ul>Lens Reflector LED Die & Phosphor Substrate
Key Features <ul><li>Full portfolio of color & white LEDs </li></ul><ul><li>Proven white point stability </li></ul><ul><li>Lifetime up to 50,000 hours </li></ul><ul><li>Electrically isolated thermal path </li></ul><ul><li>Tested to the highest standards in the LED industry </li></ul>
XLamp LED Thermal Management <ul><li>Note: It is recommended to operate XLamp LEDs with a heat sink </li></ul>T j = T a + (R th j-sp + R th sp-a ) x P d Tj – Junction temperature Ta – Ambient temperature Pd – Power dissipated = Forward Voltage (V f ) x Forward Current (I f ) Thermal Resistance between junction and solder point Thermal Resistance between solder point and ambient
Thermal Loss Junction Temperature (°C) Relative Luminous Flux
Typical Flux Characteristics Family Color CCT range (K) Wavelength (nm) CRI Luminous Flux @ 350mA XR-E Cool White 5000 - 10,000 - 75 80.6 - 107 Neutral White 3700 - 5,000 - 75 62.0 - 93.9 Warm White 2600 - 3,700 - 80 56.8 - 80.6 Royal Blue - 450 - 465 - 250mW - 350mW Blue - 465 - 485 - 23.5 - 30.6 Green - 520 - 535 - 67.2 XR-C Cool White 5000 - 10,000 - 75 56.8 - 80.6 Neutral White 3700 - 5,000 - 75 45.7 - 56.8 Warm White 2600 - 3,700 - 80 39.8 - 51.7 Royal Blue - 450 - 465 - 250 - 300 Blue - 465 - 485 - 13.9 - 18.1 Green - 520 - 535 - 39.8 - 51.7 Amber - 585 - 595 - 23.5 - 39.8 Red-Orange - 610 - 620 - 30.6 - 39.8 Red - 620 - 630 - 23.5 - 39.8 4550 Royal Blue - 455 - 465 - 50mW Blue - 465 - 475 - 2.9 - 6.3 Green - 520 - 535 - 8.2 - 10.7 Amber - 585 - 595 - 8.2 - 10.7 Red - 620 - 635 - 6.3 - 8.2
Design Process for Lighting Applications <ul><li>Define lighting requirements </li></ul><ul><li>Define design goals </li></ul><ul><li>Estimate efficiencies of the optical, thermal & electrical systems </li></ul><ul><li>Calculate the number of LEDs needed </li></ul><ul><li>Consider all design possibilities and choose the best </li></ul><ul><li>Complete final steps </li></ul>
Additional Resource <ul><li>For ordering the XLamp products, please click the part list or </li></ul><ul><li>Call our sales hotline </li></ul><ul><li>For additional inquires contact our technical service </li></ul><ul><li>Hotline For more product information go to </li></ul><ul><li>http://www.cree.com/products/ledlamps.asp </li></ul>