Lighting for Life

　　Lighting for Life

　　LED照明技术在工业和商业应用中的进步，需要低成本，坚固耐用，可靠的电源，以提供长期的使用寿命，往往在极端条件下。为了实现这些目标，必须了解所有部件的可靠性和寿命特性，并在设计过程中应用适当的考虑因素。

　　气体放电照明多年来一直是商业和工业环境中的主要照明技术。然而，LED照明现在已经成为一个严重的竞争对手。LED照明的两大优点是使用寿命长，维护成本低。由于这些优点证明了它们的价值，随着全世界推出更多的系统，电灯背后的电子驱动程序必须可靠并能够运行多年。LED驱动程序设计需要平衡许多妥协，但一个糟糕的组件选择可能会产生灾难性的后果。

　　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.