Ac LED is only 'game' into the biggest rumors

1, LED single grain LED chip driver ac voltage within the 4 v, no matter how high driving voltage can be in series, get to the appropriate driving voltage. This is other light source incomparable advantages. CFLS need complex drive circuit, LED by concatenated in accordance with different voltage, such as grid impedance matching. Incandescent tungsten filament length and diameter, the ball bubble resistance impedance, to meet different driving voltage. LED with different number of concatenated are in the same way, though the LED is not pure resistance load. Today we don't discuss how the LED driver is the most appropriate, analyzed the feasibility of AC and DC drive for the market. Hundreds of single grain is ac LED LED on the wafer level concatenated and become, can under the mains ac high voltage rectifier lit by oneself, then concatenated resistance or constant current source, maintain within a suitable driving power. Based on this design early on Christmas lights string has been used, is transplanted to the LED grain encapsulation JinQing. To compatible with the voltage standard, is divided into four parts series, in the half value is 110 v, 220 v voltage, unified specifications. Ac LED is correct in theory, feasible, 50 - mains 60 hz single series LED work respectively in both positive and negative half cycle, no matter how you design, on the whole the same. LED is not like incandescent impedance load, small voltage fluctuations will make the LED brightness change is bigger, easier to see. Communication LED to the AC voltage stability has certain requirements, because LED the volt-ampere characteristics of steep, 10% of the voltage change can cause severe current fluctuation. Such as forward voltage from 3. 3 v to 3. 6 v, current is increased from 20 ma to 34 ma, increased by 70%. Surging is fatal to the LED current, voltage lower will not damage the LED, brightness fluctuations affect the degree of customer experience.

we as shown in figure 2, the high voltage DC LED lamp string used to drive, regardless of analyzing specific details. AC bridge pile rectifying, then LED utilization 50% increased, and LED the number and the cost is reduced by 50%. Price is low, rectifier bridge technology limited integration rectifier bridge is very uneconomical. Rectifier bridge is small, easy to be accepted by volume, directly using AC design LED is not economic. Is due to the ac voltage sine wave, so through the LED current is sine wave, utilization rate is not as high as direct current (dc) use of LED. Is the light of the overall average output, not like the same range of dc is so high. Started Seoul semiconductor LED designed the communication, careful friends will find on display next to the LED is a rectifier bridge, Seoul has to realize the importance of the cost. Taiwan industry research institute and other enterprises have developed AC leds, but mass production is not so smooth, cost is an important factor, in principle is feasible is not the same as the market is feasible.

2, dc high voltage LEDLED multichip concatenated encapsulation is the trend of the future, in combination of quantity and careful consideration on the way. Can be seen from the above analysis, the design cost of AC LED and light effect is not appropriate, can't become a mainstream way, not to say anything practical application. Rectifier dc LED after the formation of communication LED of strong competition, therefore AC leds can be widely used. In the foreseeable future AC LED is only a 'game', decided it would be in addition to the bureau of market rules. Since think much chip concatenated is a trend, it must be DC drive mode. Multichip concatenated need LED wafer level support, too much gold wire connection on the photosynthetic efficiency and production are all obstacles. More chips encapsulation wafer level concatenated plus COB combination, is the optimum way. Wafer level concatenated best within 10 PCS, coupled with COB gold thread connection. Such COB way chipset distributed heat, will greatly reduce the demand for packaging substrate. Thermal resistance is reduced, the LED junction temperature so reduced. At the same time increase the number of large LED wafer level concatenated yield.

like AC LED too centralized way of packaging, packaging to good heat dissipation and high insulation, is contradictory to each other. Mains hundred volts high-pressure processing, packaging costs will be high, also not conducive to good for heat dissipation design. This article discussed in detail in this article represent only individual opinions.