The high incidence of "quality" incidents of LED lighting products, on the one hand, is the absence of industry norms and supervision, and on the other hand, the company's own lack of quality awareness, defects in design capabilities and craftsmanship.
Taking the power deviation of LED lamps out of control as an example, this paper analyzes in detail the constant current accuracy of the driving power supply and the influence of the LED forward voltage drop distribution on the deviation of the lamp power. It is a reference for designers to improve the design quality of LED products.
Recently, various media have frequently reported incidents of unqualified quality of LED point light sources and LED line lights by national and local quality inspection departments. Wake up.
In the unqualified test items, the actual test power of the lamp does not meet the declared power of the product, which accounts for a large proportion. As early as 2010, my country 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 works at rated voltage and rated frequency, its actual power consumption and rated The power difference should not be greater than 15% or 0.5W", the International Electrotechnical Commission also requires in IEC62722-1 Clause 7 that "the deviation between the nominal value and the actual value of the electrical parameters of the lamp should not be greater than 10%".
In my opinion, the reasons for product power deviation are as follows:
1. Due to the pressure of cost, the production process cut corners and cut corners, eliminating the necessary product testing process, and the substandard products were not eliminated in the factory, and flowed to the market as shoddy products.
2. The heat dissipation design margin of the LED lamp bead is insufficient, and the deviation of the assembly process and incoming materials 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.
3. The optional driving power supply for the lamp has poor thermal stability and large temperature drift of the output current, which directly causes the lamp power to deviate in a large range.
4. In order to reduce the procurement cost of LED lamp beads, the LED Vf distribution BIN is not selected according to the design requirements, which causes the actual LED power consumption to deviate from the design center value.
5. The constant current precision of the optional driving power supply is low (generally 5%-8%) and cannot be adapted to the various Vf BINs of lamp beads.
Shenzhen SH LED Technology Co., Ltd. has very strict product requirements and absolutely does not allow any product problems. If there are any problems with the products, please feel free to contact us. We will deal with them seriously and will not evade responsibility. We are assured.