Study of AC-Driven LED
Date Issued
2008
Date
2008
Author(s)
Huang, I-Ting
Abstract
The purpose of this study to investigate the LED in the AC-driven, PWM driven, Triple driven, LED junction temperature changes in an instant whether over its restrictions. The method used to measure the pulse-driven junction temperature, and to identify LED dynamic model by Rake''s law.oth theoretical and experimental analyses have shown that the thermal system dynamics model of the LED fixture is 4th-order with 3 zeros and can be further reduced to a first-order biproper system. The use of AC full-wave rectifier, AC half-wave rectifier, PWM, such as triangular-wave-driven were simulated LED junction temperature changes in an instant. This study will be junction temperature limit is set to 80℃. The results can be seen by the PWM-driven approach can withstand greater over-current, followed by the triangular wave. Full-wave rectifier can withstand more than twice the rms-current changes will not lead to its junction temperature is too high to happen, half-wave rectifier analog waveform is the most bad-driven approach.
Subjects
LED junction temperature
AC-Driven
PWM-Driven
Type
thesis
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ntu-97-R94522827-1.pdf
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