application brief AB20 4
replaces AN
1149
4
Thermal Management
Considerations for SuperFlux LEDs
Thermal management is critical in the design of LED signal lamps because temperature affects
LED performance and reliability. The following section details the effects of temperature on
LEDs. In addition, thermal measurement techniques of LED signal lamps and recommended
design practices for proper thermal management are covered.
Table of Contents
Importance of Thermal Management
for High-Power LED Assemblies
Temperature Induced Effects on LED Light Output
Change in Dominant Wavelength (Color) as a Function
Of Junction Temperature
Temperature Induced Failures of LEDs
Thermal Modeling of LED Assemblies
Thermal Resistance of LED Automotive Signal Lamps
Junction to Ambient Thermal Resistance Measurement Procedure
Junction to Ambient Thermal Resistance Measurement
Estimating Junction to Ambient Thermal Resistance
Evaluating Junction Temperature and Forward Current
Light Output and Forward Current
Derating Example Cases
Recommended Design Practices for Proper Thermal Management
PCB Design
Maximum Metallization
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LED Spacing
Lamp Housing Design and Mounting of the LED Array
Circuit Design
Current Control
Power Dissipation
“Switching” Power Supplies
Ambient Temperature Compensation
Appendix 4A
Alternate Junction to Ambient Thermal Resistance
Measurement Procedure
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