High-power LEDs created a center of attention due to their
applications in energy-saving lighting systems, display, and many
other fields. Therefore, the optical and electrical characteristics of
LEDs at forward bias have a significant research value [1,2]. And
majority of research papers on the characteristics of LEDs focuses
on their optical and electrical properties under the DC mode. How-
ever, more requirements on LED illumination under the AC condi-
tion is undoubtedly increasing due to the emerging AC LED
systems into the market these days. It is generally known that
the AC driving is more efficient way of generating and transmitting
power systems compared with the DC mode. With proper design
considerations, LEDs can be driven more efficiently under AC operation than under DC operation. By this reason, there found some research activities recently on the AC driven LEDs . However,most of researches on AC driven LEDs focus on circuit design issue and it is hardly found reports on thermal behavior of LEDs under
the AC operation. Thermal resistance is an important thermal characteristic of LED package to calculate the junction temperature. The thermal characteristics of LED package and system under DC mode have
High-power LEDs created a center of attention due to theirapplications in energy-saving lighting systems, display, and manyother fields. Therefore, the optical and electrical characteristics ofLEDs at forward bias have a significant research value [1,2]. Andmajority of research papers on the characteristics of LEDs focuseson their optical and electrical properties under the DC mode. How-ever, more requirements on LED illumination under the AC condi-tion is undoubtedly increasing due to the emerging AC LEDsystems into the market these days. It is generally known thatthe AC driving is more efficient way of generating and transmittingpower systems compared with the DC mode. With proper designconsiderations, LEDs can be driven more efficiently under AC operation than under DC operation. By this reason, there found some research activities recently on the AC driven LEDs . However,most of researches on AC driven LEDs focus on circuit design issue and it is hardly found reports on thermal behavior of LEDs underthe AC operation. Thermal resistance is an important thermal characteristic of LED package to calculate the junction temperature. The thermal characteristics of LED package and system under DC mode have
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