How to increase the reliability of LED lighting systems?
An important reason is the low life expectancy of LED drive power drive power required for the life of aluminum electrolytic capacitors, the main reason for working long hours and the LED lights inside the ambient temperature is high, resulting in aluminum electrolytic capacitors will soon be consumed dry, life is much shorter, generally only work about 5,000 hours. The life of the LED light source is 50,000 hours, the working life of aluminum electrolytic capacitors have become the short rib of the LED drive power life.
Now some vendors in order to solve this problem, the invention of aluminum electrolytic capacitors, LED drive power program. But not all of the LED drive power suppliers are in favor of this approach. Chen Rong said: "At present there is no a in the mass production of LED drive power is a non-electrolytic capacitor-driven program, because without it, then a lot of test criteria to pass EMI testing and flicker-free test."
While the aluminum electrolytic capacitors, LED driver power scheme is usually more of these tests, if you replaced the film capacitors and ceramic capacitors or tantalum capacitors, the situation how? Film capacitors to achieve the same power capacity (typically 100-220uF), the volume on the be very large, and the cost is too high, the general capacity of the ceramic capacitor is too small, such as multiple ceramic capacitors to achieve such a large capacity, accounting for the board area and cost too much, tantalum capacitors have such a large capacity, one expensive , but the pressure is too low to meet the requirements, therefore replaced by any other type of capacitor is basically not too bulky, it is too expensive for these shortcomings, replaced by a smaller-capacity capacitor to eliminate the ripple effect of not so good, and exports the stringent certification testing indicators can not, therefore the quality of the LED drive power is still commonly used aluminum electrolytic capacitors.
Many suppliers claim that the non-electrolytic capacitors LED drive power program, it may just get rid of the aluminum electrolytic capacitor of the AC input, constant current output of aluminum electrolytic capacitors should be difficult to remove or replace.
NXP push a TRIAC dimming embedded drive power 13WLED bulb, the model based on the SSL2102 the drive power program using aluminum electrolytic capacitors. When I asked about the working life of the bulb, the working life of aluminum electrolytic capacitors will certainly affect the life of the LED light bulb, but can take some physical way to alleviate this problem, such as aluminum electrolytic capacitors on the PCB located close to the lamp tail, in general, closest to the LED light source part of the highest temperature can reach 100-200 ° C, followed by cooling metal casing part, generally about 100 ℃, the lowest light tail section, usually about 70 ℃, so long as attention to aluminum electrolytic capacitor located close to the tail lights, its life does not decay too hard. Our experiments show that its life can also reach 10,000 hours, equivalent to 10 years for the average home user, once a decade to change LED bulbs basically is acceptable.
From the structure of the LED drive power, Chen Rong, Japan and the United States will be non-isolated solutions for the mainstream because of their grid input voltage is only 110V. China and Europe will be isolated program for the mainstream, because the grid input voltage up to 220V isolated security of the scheme, although the cost may be high.
Top Led Ltd could use isolated power or non-isolated power for led tube according to the requirements.