An important method to extend the life of LED fluorescent tube
An important consideration for LED lighting is that the working life of the LED drive circuit and the LED itself should be comparable. Although there are many factors that affect the reliability of the drive circuit, the electrolytic capacitor has a crucial impact on the overall reliability. In order to prolong the working life of the system, it is necessary to analyze the capacitors in the application and select the appropriate electrolytic capacitors.
The effective working life of an electrolytic capacitor is largely affected by the internal temperature rise caused by the ambient temperature and ripple current. The rated life of electrolytic capacitors provided by electrolytic capacitor manufacturers is based on exposure to the highest rated temperature environment and maximum rated ripple current.
The typical rated life of a capacitor at 105°C may be 5,000 hours. The lower the actual working stress of the capacitor compared to the rated level, the longer the effective working life. Therefore, on the one hand, choosing an electrolytic capacitor with a long rated working life and a high-rated working temperature can certainly extend the working life. On the other hand, according to the actual stress and operating temperature, you can still choose a capacitor with a lower rated operating temperature and rated life, so as to provide a lower cost solution; consider maintaining proper stress and operating temperature in the design, which can effectively Extend the working life of the electrolytic capacitor, so that it can better match the life of the LED.
For example, the reference design chose ECA-1EM102 aluminum electrolytic capacitor, which has a rating of 1000μF, 25V, 850mA, 2,000 hours and 85°C. Under the assumption of an ambient temperature of 50°C, the useful life of this capacitor exceeds 120,000 hours. Therefore, try to make the LED drive circuit work under suitable temperature conditions and properly handle the heat dissipation problem, so as to achieve the matching problem of the LED drive circuit and the working life of the LED.
