The difference between isolated and non-isolated

There are several trends are driving the development of LED lighting market. First of all is the high brightness LED efficiency of continuous improvement and very high reliability and high reliability of constant current LED driver power supply continues to emerge, followed by the global legislation to ban incandescent lighting (due to its low efficiency) and CFL energy-saving lamps gradually fade out (if broken, it will flow out of the environment harmful mercury). These factors are combined to make LED lighting become a long-term development trend. Of course, low system cost (including LED, thermal management system and LED driver) will always be the driving force for the wide use of LED general lighting. In fact, in many LED lighting products, failure is a common phenomenon, most of which is because of the failure of the power, rather than the failure of LED. At the design level, this means that the OEM must become a hot design expert. LED provide high efficiency, but they are also more heat than incandescent or energy-saving lamps. Because many LED lighting applications are enclosed in a very small space, it is difficult to use ventilation to heat dissipation. If there is no careful thermal design, the LED and the power drive circuit is easy because of high temperature and degradation or permanent failure.
As a product that allows the end user to be safe, it must consider the reliability of insulation and isolation. As a complete product, the surface of the product can be exposed to the part of the user must be isolated, can not let people get electric shock. And from the whole system, the isolation is inevitable, the difference is only set the location of the isolation. Some designers use isolated transformer design, so they can simplify the design of cooling and lamp shades. If you use non isolated driver design, the lights on the shell structure of the insulation requirements must be considered reliable. As a result of power supply, the isolation and non isolation schemes are all the same. The main challenge for the Chinese LED drivers is to find a low cost AC/DC driver, which can meet the performance of more stringent power factor and efficiency in low cost power supply system. In the future, the use of high quality, high reliability power supply will be no longer free of charge in the space constrained and there is a cooling system (such as LED lamps). However, in the end users have used a lot of life in 10000 hours or so…
LED driver power isolation and non isolation 7-5 is currently in the general LED lighting market, there is a non isolated design and isolated power supply. Non isolation design is limited to a dual insulation product, such as a light bulb replacement product, where the LED and the entire product are integrated and sealed in a non conductive plastic, so the end user does not have any risk of electric shock. The two level products are isolated, the price is relatively expensive, but in the user can be exposed to the LED and the output connection (usually in the case of LED lighting and street lighting applications), this product is essential. LED driver power supply with isolation transformers or electrical isolation means that the LED can be directly touched by hand without electric shock. Without the isolation transformer LED drive power still can with protective casing, so as to realize the mechanical part of the insulation, but this time the LED at work and not direct contact. Insulation type light bulb in the future will become the mainstream. Physical design determines that the drive is an isolated or a non – isolated. Safety rules usually require the use of two separate isolation layers. The designer can choose two kinds of physical isolation layer, or plastic mask and glass cover, and use of non isolated power supply. If the cost of physical isolation is too high, there is a mechanical difficulty or absorb too much light, it is necessary to solve the problem of electrical isolation in power. Isolated power supply is usually more than the same power level of non isolated power supply. Lighting designers must be in the design of each product in a lot of cost and design optimization work. Because it is suitable for different applications, it is a protective shield that is used in isolation. In general, they will be analyzed in many ways, such as cost and manufacturing process, efficiency and volume, reliability and safety requirements, and so on. With the high cost of the transformer, but also to make the LED lamps become more practical, to meet the needs of the end user to meet the needs of LED. When the incandescent lamp glass shell is easy to damage, a E27 type of ordinary light bulb can be replaced with LED lights. In addition, in the industrial area or office equipment in the application of the lamps do not need to contact the end user, such as street lamps and shopping malls lighting, then the LED lights do need to isolate the transformer.

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