In the unqualified test items, the actual test power of […]
In the unqualified test items, the actual test power of the lamp and the product's declared power do not meet a small proportion. As early as 2010, China has issued the national standard GB / T24908-2010 "Performance Requirements for Self-ballasted LED Lamps for General Lighting", Article 5.3 requires that "When the lamp is operated at rated voltage and rated frequency, its actual power consumption and rated The difference in power should not be greater than 15% or 0.5W ", and the International Electrotechnical Commission also requires in IEC62722-1 paragraph 7 that" the deviation between the nominal and actual values of the electrical parameters of the luminaire should not be greater than 10% ".
The author believes that the causes of product power deviations are as follows:
First, due to cost pressure, the production process cut corners and cut materials, eliminating the necessary product testing process, unqualified products have not been eliminated in the factory, so as to better fill the market.
Secondly, the LED lamp bead has insufficient heat dissipation design margin, assembly process, and the deviation of the incoming material causes the lamp bead to overheat, and the forward voltage drop (Vf) drops out of control, causing the actual power of the lamp to deviate from the lower limit.
Third, the driving power of the lamp is poor in thermal stability, and the output current temperature drift is large, which directly causes the lamp power to deviate in a large range.
Fourthly, in order to reduce the purchase cost of LED lamp beads, the LED beads Vf distribution BIN was not selected according to the design requirements, which caused the actual LED power consumption to deviate from the design center value.
Fifth, the optional drive power supply has a low constant current accuracy (generally 5% -8%), and cannot adapt to the various Vf BINs of lamp beads.
