Quality of LED power supply
After so many years of experience with the lighting manufacturers, I often feel that the lighting manufacturers do not want to buy a good LED power supply, but do not know how to identify the LED power supply is good, but also worry about whether to spend a high price to buy low quality LED power supply .
Therefore, as a lighting manufacturer, the most difficult feedback is to buy LED power supply, because the quality of the power supply is difficult to detect, aging in its own factory for 4 hours, and some even aging for 24-72 hours, but these aging products are often in A 5% or higher ratio is bad for 3-6 months of shipment.
So if you identify the quality of the LED power supply? We can identify from the following points:
First, the driver chip
The core of the driving power supply is the IC, and the quality of the IC directly affects the entire power supply. The driver ICs of Dachang are all purchased by the crystal garden to find a large packaging factory. The driver IC technology of the small factory is directly copying the drive design of the big factory to find a small package factory to package, and can not guarantee the whole batch of ICs. Consistency and stability, resulting in inexplicable failure of the drive power supply after a period of use. Therefore, the IC on the LED power supply refuses to be polished, so that the lighting manufacturer can understand the cost of the IC solution and the accounting driver, and purchase the power supply product at a reasonable price.
Second, the transformer
The control chip can be regarded as the brain center of the power supply, and the power, temperature resistance, etc. are transformers. The transformer is responsible for completing the “AC-Magnetic-DC” and the energy overload will saturate the bomber. The core of the transformer is the core and the wire package.
Core quality is the core of the transformer, but like porcelain, it is extremely difficult to distinguish. The simple appearance is distinguished as: the appearance is crisp, dense and bright, and the back side is polished to the top. At present, the magnetic core used by Shanghai Nuoyi is the PC44 core of the mold opening, which ensures the high efficiency of the power supply.
The wire package is made of copper wire winding, and the quality of the copper wire is the key to affect the life of the transformer.
The same length of copper clad aluminum wire is 1/4 of the price of pure copper wire. Due to the cost pressure, the transformer manufacturer often mixes the transformer of the copper clad aluminum wire package inside. As a result, the burnout failure occurs when the temperature of the transformer rises, resulting in failure of the power supply and the entire lamp.
Therefore, many lamps, especially the built-in power supply lamps, often ship for about 6 months. And how to distinguish whether this copper wire is pure copper wire or copper clad aluminum? Use a lighter to ignite it, and quickly burn it out to be copper-clad aluminum. It is also possible to measure the resistance of the coil for identification.
Third, electrolytic capacitors and chip ceramic capacitors
The quality and life requirements of the input electrolytic capacitors may be known to everyone, and everyone pays great attention to them. However, people often ignore the quality requirements of the output capacitor. In fact, the life of the output capacitor has a great influence on the life of the power supply. The output has a switching frequency of up to 60,000 times per second, which causes the parasitic resistance of the capacitor to heat up, producing a scale-like substance, and finally the electrolyte is heated and blasted. Recommended output electrolytic capacitor: LED dedicated electrolysis, the general model starts with L. At present, our output electrolysis is Aihua’s high-life electrolytic capacitor.
Ceramic capacitors: The material is divided into X7R, X5R and Y5V, and the actual capacitance of Y5V can only reach 1/10 of the actual value. The nominal capacitance only refers to the operation at 0 volts. Therefore, this tiny chip resistor, poor options will also lead to cost price difference and greatly shorten the life of the power supply.
Fourth, circuit design and soldering process for power products
Discrimination of the pros and cons of design: Aside from the professional point of view, it can be distinguished by some intuitive methods, such as neat, generous, orderly, and clean and straight. A good engineer will not make a messy design. As for flying lines and manual components, it is a serious lack of technical strength.
Welding process: manual welding and wave soldering process. It is well known that the quality of wave soldering process in mechanized production is definitely better than manual soldering. Discrimination: Whether there is red glue on the back. (The solder paste process + soldering fixture can also achieve wave soldering, but the fixture cost is high).
Solder joint inspection equipment for patches: AOI. The device can detect the phenomenon of virtual welding, false welding and leakage welding during the patching process.
At present, the luminaire phenomenon occurs during the use of the luminaire for a period of time, which is basically caused by the power supply or the bead welding of the lamp bead.
The solder joint inspection of this product is extremely difficult to pass the aging test, so it is necessary to rely on AOI to detect the quality of the power patch.
Fifth, batch inspection of aging racks and high temperature aging rooms for power products
The best power products controlled by materials and production processes still need to be tested for aging.
Because the incoming inspection of electronic components and transformers is difficult to control. Only through the aging of the entire batch of power and the high temperature sampling of the high temperature room, the quality stability of the batch power supply and the safety of the materials are detected.
The role of high-volume high-temperature sampling: the current power failure is between 1% and 1%, and only thousands of high-temperature aging will find such failure.
High-temperature rooms can simulate the harsh environment of power supply work. Under the strict inspection conditions, batch problems can be found, such as unreasonable design, poor raw materials, failure in the deduction of lamps, and high-voltage switch impact.
Long-term aging at room temperature: Screening for random failures such as virtual welding, leakage welding, and collision, filtering out early failure of components, and effectively reducing the failure rate of finished products (one percent down to one thousandth).
At room temperature aging, it is very expensive to use aging equipment and personnel. The factory with a daily output of 100,000 power supplies, the aging equipment covers at least 500 square meters, more than 10,000 aging, and the pipeline is aging, which is rare in the industry.