LED driver power misunderstanding

1: Insufficient understanding of safety and EMC

Some companies tend to pay attention to safety regulations and ignore EMC. As a result, many products have “eaten big losses” on EMC and are finally returned by terminal customers. At present, many procurement personnel often only ask manufacturers whether they have UL/SAA safety regulations. However, many manufacturers on the market are applying for UL/SAA safety regulations first, but their products cannot actually pass EMC and EMS, that is, they have not passed the US mandatory. FCC and Australia's C-TICK.

The reason is that UL/SAA safety regulations are not technically difficult for manufacturers, because UL certification controls product safety, including insulation, temperature rise, etc., as long as the manufacturer has relevant documentation support and sufficient input costs, basically can pass Certification. The FCC/C-TICK's EMC is different. On the one hand, because the conduction interference, radiation interference and anti-interference of each power supply product require high technology to solve, the difficulty is increased a lot; on the other hand, EMC actually There are still contradictions with UL safety regulations, resulting in a long time span, and EMC is inconsistent with the efficiency of the power supply, which has a great impact on the temperature rise of the power supply. Therefore, in order to seize the market and cater to the needs of the "unidentified" procurement personnel, some manufacturers apply for the UL safety regulations of the products first, and then apply for EMC certification and rectification. Once they cannot pass the EMC, even if they need to be rectified, then I am afraid that it is a very minor change, it is ineffective for UL, not recognized! Finally, when it comes to the end customers, they are also unable to pass the ENERGY STAR and DLC testing certification, and even products will appear. After entering the US market, it was not checked out and could not be returned through the FCC.

In summary, the root cause of this phenomenon is that the US UL certification is voluntary application, which is non-mandatory certification, but the US market has a higher recognition of UL, and many domestic power supply manufacturers are catching this. A bit of loopholes, opportunistic, directly skip the US mandatory FCC certification to cater to the market's "appetite", did not tie the two certifications together; while the European CE and China's 3C certification is different, both safety and EMC are parallel Mandatory.

Therefore, please pay attention, do not think that UL is a high-level certification, in fact, hidden mystery, especially in the current aggressive and impetuous LED market, to be particularly careful and careful screening. Different from these opportunistic power companies, Dongguan Lingguan power supply products are the first to pass the EMC test and then go to the UL certification application, which is more reasonable and principle.

2: Efficiency and PFC (power factor)

Let us first explain the efficiency, which is the ratio of the output power to the input active power. This is a very important parameter for the LED driver . The larger the value, the lower the heat of the power supply, which can improve the light efficiency and service life of the overall luminaire, and also reduce the electricity bill for the end consumer.

The power factor is the ratio of the input active power to the total input power, and some of the power that is not used by the powered device is called reactive power, and the sum is the total input power. Now ENERGY STAR has certain requirements for PF, but it is not too strict. Both European and domestic requirements are based on traditional lamps. Only 25W or so has specific requirements. The higher the PF, the higher the power utilization rate of the grid. If the same amount of electricity is sent, it can be satisfied by using a thin copper wire to save power generation costs. This is of great help to the national grid, but it does not affect consumers. Big, but efficiency is more about individual consumers.

Three-point authentication power quality misunderstanding

1 Safety certification is only for product safety performance and electromagnetic interference test and control, to ensure that the product will not cause fire, electric shock, or to prevent other electronic equipment from being disturbed. However, the function and quality of the product are not controlled, so the evaluation of the functional test requires the manufacturer to control, grasp, or carefully evaluate and test the application.

2 LED power supply, especially the built-in power supply of the light source, is often limited by the internal size and volume and cannot be made too large. This will result in “the quality of the power supply certified by safety regulations is not comparable to the power supply that cannot be certified by safety regulations”.

This view may raise many people's doubts. The reason is that under the same size limit, the certified power supply requires more filtering inductors and capacitors, which reduces the storage space of the power device and the leakage inductance of the certified power supply. It is far greater than the power supply transformer that cannot be certified. The efficiency drop and the MOS peak voltage become high. It is a quality problem of the certified power supply. Therefore, under the same size and condition constraints, and the same scheme, materials and process, the certified power supply Quality stability is far worse than certification.

3 Through the above two points of answers, you may be worried about the quality of the power supply certified by the safety regulations. In fact, this is relative to the certified power supply, so you don't have to worry too much. Imagine that if a company invests hundreds of thousands or even millions of dollars for certification, it must be prepared to promote the product in large quantities, but only if it must have reliable product quality. In the early design verification and later process manufacturing, it is necessary to ensure its quality.

Applicants should be aware of where their product focus is. If the end customer emphasizes that there must be safety certification, then the power supply of the corresponding certificate manufacturer must be purchased; if the end customer does not require it, the focus of the product should be to ensure the reliability of the product, but the procurement can be certified but the performance and quality are reliable. The product, the power supply without certification, reduces the cost of procurement and greatly improves the reliability of the product.

Therefore, the industry always blames the LED light supply failure on the LED power supply, which is considered to be unreliable. In fact, this is just that the procurement application of everyone is not properly matched. Choosing the right product for you is the best solution!