There are many difficulties and problems in LED dimming technology. Scientists and technicians tended to find solutions and breakthrough from dimming methods of other traditional lighting technologies, like incandescent lamps, fluorescent lamps, to design appropriate LED dimmers. The current major dimming methods of traditional lights are Triac dimmers, electronic dimmers, remote control dimmers (IR or RF) and other dimmers for commercial purposes. In the next section, we will do some analysis and comparisons among these dimming technologies, see which one will be more suitable for LED dimmers.
Using electronic dimmers must change the wiring of lamps (generally, wall switches are only connected to the AC wire, unavailable to provide power to other electronic circuits), increasing the construction costs. Remote control dimmers are embedded with intelligent electronic circuits which can provide multiple advanced features, like RGB dimming technologies, etc. However, remote control dimming method also has disadvantages: compared with other dimming methods, remote controllers are much more expensive and easier to lose, not suitable for public places. Worse still, both electronic dimming method and remote control dimming method require dimmers from the same manufactures or producers, since they should be matched up in the same specification. That led lights to an embarrassing situation that products from different factories are incompatible with each other. Thus the currently market is very small and unlikely to widely spread.
Triac dimmers need not to change the circuit, which dramatically reduce the cost. Besides, functional variations among dimmers from different manufactures are ignorable. Triac dimmers are more popular in European and North America. Thus, in the process of replacing incandescent lamps by with LED lighting applications, matching between SCR dimming technology and dimmers is a must-be-solved problem. LED dimmers using SCR dimming method is a hot topic in the current market. But SCR dimming technology also has a lot of inadequacies:
1) The power factor will drop with the reduction of brightness of lamps.
2) Efficiency will deteriorate during the dimming process, since reducing brightness lead to the insufficient of the load, the premature closure of SCR, and consequently the unstable working conditions of lamps (flickers). In order to solve the flicker problem, usually bleeder or dummy load will be added into circuits.