Comparison between isolated power supply and non isolated power supply in LED lighting
At present in the general LED lighting market, there is a non isolated design and isolated power supply. Design is limited to non isolated double insulation products, such as bulb replacement products, including LED and the products are integrated and sealed in a non-conductive plastic, so the end user does not have any electric shock hazard. Secondary products are isolated, the price is relatively expensive, but the user can contact to the LED and the output terminal of the place (usually in the application of LED lighting and street lighting), 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.
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.
China led drive power supply manufacturers are likely to face major challenges is to find low cost AC / DC drives, in the power supply system with low cost to meet to implement more stringent power factor and efficiency of performance. 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 the 10000 hours before the light bulb, it is very difficult to prove its high quality is very difficult.
Isolated power supply is the use of the transformer to the 220V voltage through the transformer will be reduced to a lower voltage, and then the rectifier into a DC power output for the use of the computer. Because of main transformer coil to withstand voltage 220V, secondary coil are subject only to output low AC voltage and between the primary and secondary coils are not connected directly, so that the power supply isolation non isolated power supply is to use 220V direct input to the electronic circuit, in the electronic component buck output, input and output is directly connected via electronic components, so called non isolated power supply; both from the surface of the watch is the difference with and without transformer. But please note, some manufacturers in order to save costs, using in the main coil directly tap extraction of low voltage method, this approach appears to be a transformer, is not actually a secondary coil, is not isolated power supply.
Isolated power supply has the advantages that will not pose a threat to the human body, wide voltage performance is very good, non isolated now is also very mature, the voltage range than isolation of poor, the voltage range between the 110V-300V, and isolated power supply can do 60-300V. High and low electric current is very uniform and low efficiency, but the high efficiency is relatively low, and the non isolation type is more efficient. On the circuit structure is concerned: the current isolation scheme is more than the AC/DC of the Flyback circuit, and the circuit is more complex and the cost is high. The non isolated basic is the use of DC/DC (Boost) or the buck (Buck) circuit, the relative circuit is relatively simple, and therefore the cost is relatively low. |
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