The design of led lighting power supply is divided into non-isolated design and isolated design. An isolated driver or an electrically isolated LED driver means that the LED can be touched directly without touching the battery. The LED driver power supply without the isolation transformer can still achieve partial mechanical insulation by means of the protective casing, but the LED at this time cannot be directly contacted during operation.
The physical design determines whether the drive is isolated or non-isolated. Security rules usually require the use of two separate isolation layers. Designers can choose between two physical barriers, a plastic diffuser and a glass shield, and use a non-isolated power supply. If physical isolation costs are too high, there are mechanical difficulties, or too much light is absorbed, electrical isolation issues must be addressed in the power supply. Isolated power supplies are typically larger than non-isolated power supplies of the same power level. Lighting designers must perform significant cost and design optimizations in each of the products they design.
Since it is suitable for different applications, whether it is an isolated insulating transformer or an isolated protective lamp housing, the designer will always have different opinions in different angles. Often, they analyze in many ways, such as cost and manufacturing processes, efficiency and volume, insulation reliability and safety specifications, and so on.
Drives with transformers cost more, but they also make LED luminaires more practical and meet the needs of end users who accidentally touch LEDs. When the incandescent glass casing is easily damaged, an ordinary bulb of the E27 model can be replaced with an LED lamp. In addition, luminaires in industrial areas or office equipment applications do not need to reach end users, such as street lights and mall lighting, where LED lights do require isolation transformers.
As a product that can be safely used by end users, the reliability of insulation and isolation must be considered. As a complete product, the parts of the product surface that are accessible to the user must be isolated and not subject to electric shock. From the perspective of the entire system, isolation is inevitable, the only difference is the location of the isolation. Some designers use isolated transformer designs so they can simplify heat dissipation and lampshade design. If a non-isolated drive design is used, reliable insulation requirements must be considered for structures such as lamp housings. Therefore, as a power driver, both isolated and non-isolated solutions exist simultaneously.
The main challenge that Chinese LED driver manufacturers may face is finding low-cost AC/DC drivers to achieve tighter power factor and efficiency performance in low-cost power systems.
In the future, the use of high-quality, high-reliability power supplies in systems where space is limited and where heat dissipation is difficult (such as LED luminaires) will no longer be free. However, it is quite difficult to prove that its quality is high before the end user has used many of the bulbs that last for about 10,000 hours.
Transformer-based isolated LED driver power supplies will have advantages and disadvantages for both mainstream isolated and non-isolated LED driver power solutions. We believe that Class II will be the mainstream because it simplifies LED cooling. Class I or II systems rely on grounding systems and, in most cases, are closely related to the installation location. Class II is more common, requiring two-stage or reinforced isolation, which requires transformer magnetic windings, insulation tapes, and physical isolation. ClassI systems require a grounded enclosure and/or mechanical barrier that is not required by the Class II system.
There are several trends that are driving the development of the LED lighting market. The first is the continuous improvement of high-brightness LED efficiency and the emergence of highly efficient high-reliability constant-current LED drive power, followed by global legislation prohibiting incandescent lighting (due to its low efficiency) and the gradual fading out of CFL energy-saving lamps (if broken) If it does, it will emit mercury that is harmful to the environment). The combination of these factors is making LED lighting a long-term trend. Of course, low system costs (including LEDs, thermal management systems, and LED drivers) are always the driving force for consumers to adopt LED general lighting.
In fact, in many LED lighting products, failure is a common phenomenon, mostly because of the failure of the power supply, not the failure of the LED.
At the design level, this means that the OEM must become an expert in system thermal design. LEDs provide high efficiency, but they also generate more heat transfer than incandescent or energy-saving lamps. Since many LED lighting applications are enclosed in a small space, it is difficult to dissipate heat by ventilation. Without careful thermal design, LEDs and power drive circuits can easily degrade or permanently fail due to high temperatures.
Tinplate (SPTE, tin-coated iron) is the common name of cold-rolled electroplated tin sheet, which refers to the cold-rolled low-carbon sheet steel or steel strip coated with commercial pure tin on both sides.
Characteristic advantage
1.Light permeability
In addition to triggering deterioration reactions in foods, light also causes changes in proteins and amino acids. The exposure of vitamin C to light makes it easier to interact with other food ingredients, resulting in a large loss. According to research and analysis, the loss of vitamin C in transparent glass bottles of milk is 14 times higher than that in dark bottles of milk, light will also cause milk to produce oxidative smell, as well as nuclide, methionine and other cracking and loss of nutritional value, tinplate can opaque light makes the highest preservation rate of vitamin C.
2.Good sealing
The barrier of packaging containers to air and other volatile gases is very important for the preservation of nutrients and sensory quality. The comparison of various juice packaging containers showed that the oxygen permeability of the container directly affected the Browning and vitamin C preservation of the juice. The preservation of vitamin C is better in metal cans, glass bottles, aluminum foil glue layers and cartons with low oxygen transmission rate, of which iron cans are the best.
3.Reduction of tin
The tin in the inner wall of the tin plate will interact with the oxygen remaining in the container during filling, reducing the chance of the food ingredients being oxidized. The reducing effect of tin has a good preservation effect on the flavor and color of light colored fruits and juices, so the juice cans filled with unpainted iron cans have better nutritional preservation than those filled with other packaging materials, and the Browning change is slight, the acceptance of flavor quality is better, and the storage period is extended.
Use
The application of tinplate is very wide, from as food and beverage packaging materials to grease cans, chemical cans and other miscellaneous cans, the advantages and characteristics of tinplate provide content in the physical and chemical properties of good protection.
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