In 2008, MEAN WELL officially released the first LED power supply – CLG-150 series and stepped into the potential LED market. Until now, the selling quantity of LED related products is uncountable. Hainvg a special opportunity, MEAN WELL received several pieces of the CLG-150 products which were manufactured in 2008. A detailed investigation and analysis were executed, and the result is shared below.

The number of the components could be from dozens to hundreds depends on the wattage and topology of power supply. Each component is applied to the design with its necessity. How to assure the exact lifetime and evaluate the reliability is the know-how in the LED industry. Basically, the lifetime evaluation is determined by critical components (ex: Fan, electrolytic capacitor…etc.). In order to provide the accurate product’s lifetime and quality assessment, the Lifetime evaluation of MEAN WELL design must pass the verification of ORT (ongoing reliability), DMTBF, thermal shock…etc.

This article is mainly for the discussion of electrolytic capacitor’s lifetime verification and evaluation. The aluminum electrolytic capacitor can be well affected by operation condition (ex: Temperature, Load). After a long time operation, the capacitance will reduce and the Dissipation Factor (tanδ) will increase then affect lifetime eventually. This phenomenon is called a diffusion effect, which means electrolyte diffuse to the sealing material, then spread externally. Normally, the lifetime of the aluminum electrolytic capacitor can be evaluated by using the law of Arrhenius (Reaction rate of chemical diffusion). Electrolyte dries up after a period of operation, causing capacitance to reduce and ESR increase. Half of the lifetime will be decreased when the ambient temperature rises 10℃. In contrast, if the temperature drops 10℃, the lifetime can be doubled.

The relation between lifetime & failure rate is demonstrated as below (Tube Curve Chart).