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How to identify the quality of LED power is good or bad?
Sep 05, 2017

How to identify the quality of LED power is good or bad

First, the driver chip: IC

Driving power is the core of the IC, IC directly affects the entire power supply. Manufacturers drive IC, are looking for large-scale packaging plant to find packaging; and small factory driver IC technology is directly copied manufacturers drive design solutions to find a small packaging plant to package, can not guarantee the normal batch of IC Consistency and stability, resulting in the drive power in the use of a period of time after the inexplicable failure. So the LED power on the IC, refused to polish, so that the lamp manufacturers understand the IC program and accounting-driven costs, so that a reasonable price to purchase power products.


Second, the transformer

Control chip can be regarded as the power of the brain center, and determine the power, temperature is the transformer. Transformer is responsible for the completion of "AC - magnetic - DC", the energy overload will be saturated fried. The core of the composition transformer is the core and the wire package.

Core quality is the core of the transformer, but as porcelain in general, very difficult to distinguish. Simple appearance identified as: the appearance of crisp, dense, bright, while the back of the polished holes were top grade. At present, Shanghai is the core of the use of the core for the open PC44 core, to protect the power of high efficiency.

The wire package is made of copper wire windings, and the quality of the copper wire is the key to the life of the transformer. The same length of copper clad aluminum wire is a 1/4 price of pure copper wire, due to cost pressures, often transformer manufacturers will be mixed with copper clad aluminum line package transformer inside. Which led to the transformer temperature rise when the burn failure, resulting in power and the whole lamp failure. So a lot of lamps, especially the built-in power supply lamps, tend to ship about 6 months orbital phenomenon. And how to identify the copper wire is copper or copper clad aluminum? Use a lighter to ignite, fast burn is copper clad aluminum. Also can measure the coil resistance to identify.


Third, the electrolytic capacitor and the patch ceramic capacitor

Input electrolytic capacitor quality and life requirements may we all know, we all attach great importance. But we tend to ignore the output capacitor quality requirements, in fact, the output capacitor life of the power supply life greatly affected. The output has up to 60,000 times per second switching frequency, resulting in capacitance of the parasitic resistance to increase heat, resulting in similar scale of the material, the final electrolyte temperature, burst pulp. Recommended output electrolytic capacitors: the use of LED-specific electrolysis, the general model to L at the beginning. At present, our output electrolysis is Aihua high life electrolytic capacitors.

Ceramic capacitors: material is divided into X7R, X5R and Y5V, and Y5V's actual capacity can only reach the actual 1/10, the nominal value only refers to the work at 0 volts. So this tiny chip resistors, poor options can also lead to cost difference between the price and greatly shorten the life of the power supply.


Fourth, the power supply circuit design and welding process

Design of the merits of the judge: put aside the professional point of view, you can through some intuitive way to distinguish, such as the layout of components neat, generous, orderly, bright and straight solder joints. A good engineer is not going to make a messy design. As for the fly line, hand-added components, it is a serious lack of technical performance.

Welding process: manual welding and wave soldering process, we all know, mechanized production of wave soldering process quality is certainly better than manual welding. Discrimination: whether there is red gum on the back. (Solder paste process + welding fixture can also be achieved wave soldering, but the rule with a high cost).

SMD of the solder joint detection equipment: AOI. The device can detect the solder process in the Weld, fake welding, leakage welding phenomenon.

The current lighting in the use of a flash for some time the phenomenon, basically due to power or lamp beads caused by Weld. And this product of the Weld Detection, is extremely difficult to pass out of the detection of aging, so we must rely on AOI to detect the quality of the power supply patch.


Fifth, the power products of the bulk of the aging test and high temperature aging room

Materials and production process control of the better power products, or the need to detect aging. Because the electronic components and transformer incoming detection is very difficult to control. Only through the entire batch of power supply aging and high temperature room high temperature sampling, to detect the quality of the batch power supply stability and whether the material has security risks.

The role of high-volume high-temperature sampling: the current power failure is between 1 to 1 per cent, only a few high-temperature aging will find such failure.

High temperature room can simulate the harsh environment of power supply work, in the strict conditions of the sampling, can be found in bulk problems, such as the design is unreasonable, poor raw materials, push the lamp failure, high voltage switch impact.

At room temperature for a long time aging: screening out Weld, leakage welding, collision and other random failure, filter out the early failure of components, effectively reduce the failure rate of finished products (one percent to one thousand).