LED drive power Competition: Isolated PK Nonisolated

　　Mainly from four aspects PK:

　　A security

　　First introduced what is now isolated, isolated power input and output means electrically connected through a transformer, the transformer of the conversion process are: Electric - Magnetic - Electric, and the earth is no connection, there is a danger of electric shock does not occur. Rather than isolation circuit is input directly after power is applied through the buck on the LED load, there is danger of electric shock.

　　So to what UL, CE ...... these safety certification, the non-isolated trouble, insulation and creepage distance is not enough, only from the physical structure of lighting design. Lamp is acceptable, but also plastic, but the bulb is such a fundamental aluminum shell, so PCB board and housing have reinforced insulation, originally bulb power available space is extremely small, so coupled with the strict creepage requirements, difficult to do.

　　As an end-user to allow safe use of the product, we will consider the reliability of insulation and isolation.

　　Second, the performance

　　Non-isolated transformer due to the scarcity of energy loss, the general efficiency can reach more than 91%, and a higher power factor. The isolation is generally at 88% efficiency, depending on the power, and so are isolated power heat is relatively large.

　　Non-isolated components have less stability than the poor, but why? Because non-isolated circuit is very sensitive to surge suppressing poor. In fact refers to the non-isolated power supply, when volume shipments, failure rates higher than isolated LED driver power supply, mostly because tore. The isolated power tore a lot of chances to be small, generally about 2-3% non-isolated.

　　Many grid voltage instability, will be non-isolated 300V through output, Jihuai chip, burn LED load. Isolation also, the phenomenon is the chip, MOS tube, constant-current loop full burn, but relatively much less isolated. Therefore, non-isolated surge varistor essential not sensitive can warranty are clouds.

　　Third, the cost and volume

　　Compared isolated power supply, non-isolated power supply is mainly to reduce the transformer, with minimal use of materials to design the architecture, so that the same product features, so the cost of non-isolated have a greater advantage. It is estimated that non-isolated power supply in China is very popular reason, ha ha.

　　Fourth, with the load range

　　In general, isolated power output load range of 30-42V, non-isolated load can range from 30-84V. Many LED manufacturers in the power of choice when overall flexibility are required in order to adapt the whole power supply 90-265V input voltage, load range requirements up to 84V, such a choice is there are some risks and hazards. When 90V input constant current power supply may lose function, THD these.

　　Non-isolated high voltage suitable for low current, the bigger the current cost is not cheaper than isolation.

　　Comprehensive comparison, these two power have their own advantages, focusing on non-isolated power supply high power factor and efficiency, reduce energy loss, while isolated power fluorescent overall emphasis on safety and the use of safety of life, the power factor and efficiency slightly inferior aspect of the non-isolated power supply, so different choice is a matter of opinion.