This chapter investigates the reliability of the integrated LED lamps with electrolytic capacitor-less LED drivers. Firstly, the impact of the interaction between the degradations of the LED light source and the driver on the lumen depreciation is studied. The electronic-thermal simulation was carried out to obtain the history of temperatures of LED and driver, the driver’s output current, and the luminous flux considering the variations of temperature and current throughout the operation life. It is found that the ultimate lamp’s lifetime is significantly less than the individual lifetimes of the preselected LED and driver. It is concluded that it is necessary to apply the electronic-thermal simulations to predict the lifetime of LED lamps when driver’s lifetime is comparable to the LED’s lifetime. Secondly, this chapter focuses on predicting the catastrophic failure of an electrolytic capacitor-free LED driver during the lumen depreciation process. Electronic-thermal simulations are utilized to obtain the lamp’s dynamic history of temperature and electrical current for two distinct modes: constant current mode (CCM) and the constant optical output (CLO) mode, respectively. A fault tree method is applied to calculate the system’s MTTF, and the LED’s lifetime also is calculated. The CLO mode increases the LED’s current exponentially to maintain the constant light output. As a result, junction temperatures of LEDs, MOSFET, and diode rise significantly, leading a shorter lifetime and MTTF. Compare with the current of the MOSFET, the increased junction temperature has larger effects on the failure rate. The MOSFET contributes more to the driver’s failure rate than the diode. For the CCM mode, junction temperatures increase slightly and have a little shorter lifetime and MTTF.
Original languageEnglish
Title of host publicationSolid State Lighting Reliability Part 2
Subtitle of host publicationComponents to Systems
EditorsWillem Dirk van Driel, Xuejun Fan, Guo Qi Zhang
Place of PublicationCham
PublisherSpringer International Publishing AG
Chapter16
Pages455-486
Number of pages32
Edition1
ISBN (Electronic)978-3-319-58175-0
ISBN (Print)978-3-319-58174-3
DOIs
Publication statusPublished - 2018

Publication series

NameSolid State Lighting Technology and Application Series
PublisherSpringer International Publishing
Volume3
ISSN (Print)2196-4203
ISSN (Electronic)2196-4211

    Research areas

  • Lifetime prediction, Mean Time To Failure (MTTF) , Maximum likelihood estimation, LED driver, Reliability , Electronic-thermal simulation

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