The majority of LEDs sold in the market today are DC driven, however there is an increasing number of manufacturers now applying AC-LED “driver-less technology”.
AC-LED manufacturers point out several disadvantages of DC-driven LEDs such as the increased size caused by the drivers, more difficult recycling process, poor conversion efficiency due to a electricity loss of least 20% caused by the drivers, additional heat caused by the drivers and more.
At the same time these manufactures praise the advantages of AC-LED, stating that “driver free technology means problem-free technology”. More advantages include the ability of AC-LED to be connected in long chains like LED-strips without problem, flicker-free light and most importantly a much better price due to the absence of an expensive driver.
However, AC-LED technology has still not come to a real market breakthrough due to some major disadvantages. AC-LEDs is non-polar, the AC-LED device is made up two strings of series connected in different connections. One string is illuminated during the positive and the other string during the negative cycle. The total forward Voltage is very high due to many p-n junctions in series on each string approaching the AC-input. Consequently, AC-LEDs must be designed for a specific Voltage and can not be interchangeable between e.g. 110V or 230V.
Further main disadvantages of AC-LEDs are limited brightness and less luminous efficacy compared to DC-LEDs, reduced reliability in case of the Voltage volatility (different lighting intensity or even breakdown of the lamp) and availability only in rather low Wattages up to 10W. Finally many end users fear high electric shock danger as the system works in the range of 220V AC or more and therefore AC-LEDs need to c
Companies like Seoul Semiconductor and Lynk Lab are working on the solution for such problems, especially on the improvement of luminous efficacy and a longer life span of AC-LEDs. However, AC-LEDs remains a technology in the earlier stages of its development and is currently not major enough to compete with, let alone replac DC-LED in regarding most general lighting applications. gm.