New Electronic Products Information

Although designed for general lighting applications of basic LED drive is simple, but when the phase cut dimming and power factor correction and other additional features, this design will become very complex. Without the function of power factor correction of non dimming led drivers generally includes an off-line switching power supply, with the adjusted to realize constant current output. This switch and standard off-line power supply and in the AC-DC adapter generic type is not much difference. This design can use the standard SMPS (switching power supply) circuit topology, such as Buck, boost and flyback converter.

Generally speaking, this means that the tunability will be derived from existing based on the working principle of the phase cut wall electronic dimmers, this principle was first used to the design of pure impedance incandescent lamp. Although other dimming methods, such as linear dimming with 0-10V or DALI may also meets the requirements, but they may be limited to high-end industrial class LED driver. So far, cutting tone light is quite extensive, apparently, LED lamp dimming can effectively will have a great advantage. Because the market there are many low cost of three terminal bidirectional thyristor switch dimmers on, so to ensure compatible LED driver with all categories is not realistic, especially the basic design is adopted by many dimmer, the performance is very limited. For this reason, the "Energy Star" project requires only LED drive manufacturers in a Webpage in detail which dimmers can be compatible with the product.

In the "Energy Star" specification, an additional requirement of note is the working frequency of LED must be greater than 150Hz, to eliminate the possibility of visible flicker. It means to not output current of LED power supply with any of a large number of frequency is linear frequency (50Hz or 60Hz) ripple two times.

In such as office lighting, public buildings and street lighting and other offline application, using LED lighting application more and more, and in the next few years will continue to maintain the trend. In these applications, high power LED will replace the linear or high power CFL fluorescent lamp, HID lamp and incandescent lamp. These applications require a LED drive, the typical power range is from 25W to 150W. In many cases, LED supported by the high brightness white LED array of a composition, usually adopts chip packaging forms. Used to drive the load current is usually at least 1 amp DC. Also the actual LED system AC current drive, but it is generally agreed that the DC system can provide a more ideal driving conditions for LED.

 

In the LED lighting equipment in need of current isolation, to prevent the risk of electric shock occurred in can reach the place, this risk may occur in most cases, unless the use of a mechanical system insulation. This is due to not need and fluorescent lighting equipment through the insulation to achieve security products, high power led module and the metal radiator. In order to achieve good thermal conductivity, need to form a barrier between the LED chip and heat sink, so that you do not need to meet the insulation requirements by adding insulating material. Therefore, the insulation is the best choice to form in the LED drive, but also shows the power converter topology technology is feasible.