Easy identification of LED power quality

Through years of working experience with luminaire manufacturers, we usually feel that luminaire manufacturers are reluctant to buy better LED power supplies. On the contrary, they do not know how to distinguish the purchased LED power supply, and they are also worried about whether they have paid a high price for a low-quality LED power supply. Therefore, as a lighting manufacturer, it is difficult to feedback the purchase of LED power supply. Because the quality of the switching power supply is difficult to check, it has been aged for 4 hours in its own processing plant, and some even aged 24-72 hours. However, this aged product is usually around 5% or higher within 3-6 months of delivery. Often, in such bad situations, luminaire manufacturers suffer, become customers, and lose customers.

What about assuming the quality of the LED power supply? We can identify it from the following aspects:
First: push the processing chip-IC.
The core content of the driving power supply is the integrated circuit, and the advantages and disadvantages of the integrated circuit can directly affect all switching power supplies. The driver integrated circuits of large factories are packaged in large and medium-sized packaging factories; the driver integrated circuit technology of small processing factories is to immediately copy the promotion scheme design of large factories, and find the packaging of small and medium-sized packaging factories, which cannot normally guarantee the consistency of batch integrated circuits. and reliability, resulting in the drive power being invalid for no reason after a period of use. Therefore, the integrated circuit on the LED power supply refuses to be polished, which is convenient for the lamp manufacturer to grasp the integrated circuit plan and calculate the promotion cost, so as to ensure the effective price of the switching power supply product.

Second: Transformer.
The operating processor can be regarded as the brain nerve center of the person who switches the power supply, while the output power and high temperature resistance are determined by the transformer. Transformers take on AC current – electromagnetic energy – DC power, and excess kinetic energy can saturate the machine. The core content of the transformer is the core and the wire package.
The quality of the core is key to the transformer, but like pottery, it is not easy to identify. The simple appearance identification is: the appearance is crisp, dense and bright, and the reverse side is polished and the exhaust port is a good product. At present, the magnetic core used by Shanghai Nuoyi is PC44 magnetic core, which is used for mold making, which ensures the high efficiency of the switching power supply.
The wire package is made of copper core wire winding. The product quality of copper core wire is an important part of the service life of the reaction transformer. Copper-clad aluminum cables of the same size are 1/4 the price of red copper wires. For reasons of cost and working pressure, transformer manufacturers often mix transformers with copper clad aluminum wire wraps. Then, when the transformer temperature rises, the damage is ineffective, rendering the switching power supply and the entire light ineffective. As a result, many lighting fixtures, especially those with recessed switching power supplies, typically fluctuate up and down after 6 months of delivery. How to distinguish whether the copper core wire is red copper wire or copper clad aluminum? Use a lighter to light and quickly burn copper clad aluminum. It can also accurately measure the resistance value of the solenoid coil.

Third: electrolytic capacitors and chip ceramic capacitors.
We all know that we all know the quality and service life of electrolytic capacitors, and we all take it seriously. However, we often overlook the product quality regulations for exporting capacitors. In fact, the lifetime of the derived capacitor is very detrimental to the lifetime of the switching power supply. The operating frequency of the power switch at the lead-out end reaches 6,000 times per second, resulting in an increase in the survival resistance of the capacitor and the production of chemicals like dirt. Finally, the lithium battery electrolyte heats up and explodes. It is strongly recommended to export electrolytic capacitors: choose the special electrolytic method for LED, and the general model specifications start from L. At this stage, our export electrolytic methods are all electrolytic capacitors with high service life of Aihua.

Ceramic capacitors: Materials are divided into X7R, X5R and Y5V, and the specific capacitance of Y5V can only reach 1/10 of the specific value, and the standard capacitance value only refers to 0 volts during operation. Therefore, this tiny resistance and poor selection will also lead to a cost difference, greatly reducing the service life of the switching power supply.

Fourth: circuit principle and welding method of switching power supply products.
Distinguish the quality of the design scheme: In addition to the technical professional perspective, it can also be distinguished according to some visual methods, such as reasonable layout of components, neatness, orderly atmosphere, bright welding, and clear height. A good technician is not prone to messy designs. For wiring, handcrafting and components are also major manifestations of a severe lack of technical energy.
Welding method: manual welding and peak welding process. As we all know, the peak welding process quality of mechanical automation must be superior to manual welding. Identification method: whether there is red glue on the back (auxiliary solder paste processing process + electric welding fixture can also complete peak welding, but the fixture cost is relatively high).

SMD spot welding inspection instrument: AOI. In the SMD link, the facility can check the condition of desoldering, false soldering, and missing parts.

At this stage, the lighting fixture will flicker after a period of use, which is mainly caused by the de-soldering of the switching power supply or the LED lamp beads. The desoldering inspection of this product is not easy to pass the aging inspection, so it is necessary to use AOI to check the patch quality of the switching power supply.

Fifth: Check aging racks and high temperature aging rooms in large quantities for switching power supply products.

No matter how good the raw materials and production are in the raw materials and production power products, or aging must be checked. It is difficult to supervise the incoming inspection reports of electronic components and power transformers. Only according to the aging of the switching power supply and the high temperature sampling inspection of the continuous high temperature room, can the quality reliability of the switching power supply and whether the raw materials have safety risks can be checked.

The effect of a large number of continuous high-temperature sampling inspections: The inefficiency of switching power supplies at this stage is between one thousandth to one percent, and this inefficiency will only be found when thousands of continuous high-temperature aging.

The continuous high temperature room can simulate the harsh natural environment in which the switching power supply operates. Sampling inspections under strict standards can reveal a large number of problems such as unscientific design schemes, poor raw materials, ineffective lighting fixtures, and impact of high-voltage circuit breakers.

Long-term aging at room temperature: select random failures such as desoldering, parts leakage, impact, etc. , filter out the initial inefficiency of the components, and reasonably reduce the failure rate of the finished product (1% to 1/1000).

At room temperature, aging consumes a lot of aging machinery, equipment and personnel. Every day, 100,000 processing plants switch power on and off. The aging machinery and equipment covers an area of ​​at least 500 square meters, with more than 10,000 aging positions, and the aging of the production line has been completed, which is rare in the industry.

Post time: Jul-28-2022