Lighting for Life

　　LED照明技術在工業和商業應用中的進步，需要低成本，堅固耐用，可靠的電源，以提供長期的使用壽命，往往在極端條件下。為了實現這些目標，必須了解所有部件的可靠性和壽命特性，并在設計過程中應用適當的考慮因素。

　　氣體放電照明多年來一直是商業和工業環境中的主要照明技術。然而，LED照明現在已經成為一個嚴重的競爭對手。LED照明的兩大優點是使用壽命長，維護成本低。由于這些優點證明了它們的價值，隨著全世界推出更多的系統，電燈背后的電子驅動程序必須可靠并能夠運行多年。LED驅動程序設計需要平衡許多妥協，但一個糟糕的組件選擇可能會產生災難性的后果。

　　An LED-based lighting system consists of the power supply， LED light emitter， and fixture （Figure 1）。 The lifetime of the system is determined by the shortest lifetime of any component within that system.

　　The power supply is constructed of many components， each of which has its own wear-out mechanism and consequent lifetime limitation. Figure 2 gives a breakdown of the lifetimes for the major components in an LED system.

　　For all practical purposes， the controller and other semiconductor components do not exhibit a lifetime limit. The life of the LED system is determined primarily by the LEDs and capacitors; this article will focus on those components.