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Proceedings ArticleDOI
Haoran Wu, Shu Ji, Fred C. Lee, Xinke Wu 
01 Nov 2011
54 Citations
The LED driver should have the capability of providing multiple constant current source regardless to the LED forward voltage variations.
The results can be used to help know the general and complete voltage effects.
Detailed analyses show that the ambient temperature has a significant influence on optical characteristics of low-power SMD LED.
In actual measurement as well as in thermal simulation, the proposed LED lamp structure showed excellent thermal properties, compared with surface mound device-printed circuit board (SMD-PCB) package LED lamp.
Through the constant current and constant voltage dimming scheme, the LED has smoothed temporary voltage transient and will extend the lifetime of a LED lamp.
This validates the extension of PET theory equations for low-power SMD LED.
The results obtained implicate that the electric wire pattern along with LED arrangement and HS size needs to be designed carefully in thermal management of SMD-LED packages.

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