The Application of Dimmable LED Spots and Bulbs

Apr 9th, 2012 | Posted by | Filed under LED Light

Among the issues of dimmability is one of the latest challenges still yet to be fully solved. is theoretically easy, because analogue dimming, that is the adjustment of current, has long been an option. However, this method only works safely when used with one bulb. Systems of LEDs require a more sophisticated method of dimming. The two basic forms of dimming are the PWM or Pulse-Width-Modulation and the analogue dimming, both of which are switched-mode regulators. These two types are similar in the sense that they both control the time-averaged current through the diode.

Analogue dimming is a very simple way of dimming, it is the adjustment of cycle-by-cycle of the LED current regulated with a potentiometer. The current is adjusted to the LED increasing and decreasing its intensity.

The disadvantage of analogue dimming is that it only works safe as long as we dim a single light bulb. Systems of LED lights require a more refined technique. The difficulty of dimming a system of LED lights is that there are many types of LEDs, requiring different methods for dimming. If there is a system of lights we would like to dim, the various LEDs may react diversely to the same amount of current, and as the current is reduced some LEDs can turn off later or sooner than others. Also, analogue dimming largely changes the colour of the light, similarly to when it is used with incandescent lights.

The most frequently used technique of dimming LEDs is Pulse-Width Modulation, which is basically the cutting of the phase at a certain frequency. PWM switches the devices between fully on and fully off at a frequency that cannot be told by the human eye, therefore LED bulbs always run on the forward current recommended. The frequency of switching determines the brightness of light, so the longer the lights are “on” the brighter the light will be. This is the same technique used in incandescent light dimmers as well, except that incandescent lights react to current more slowly, and therefore require a different frequency.

Two types of Pulse-With Modulation signals are used often with dimming light: the leading-edge and the trailing edge techniques. These two are different ways of cutting the phase, and result in separate dimming technologies. The most frequently used dimmers of LEDs use solely the leading-edge technology. Dimmers marked as R or RL are suitable for most dimmable LEDs, since they work with the leading edge technology and do not include electronic transformers. TRIAC drivers, or devices governed by the DMX and digital addressable lighting interface (DALI) protocols and, in the future, may include wireless (RF) as a control option, that is dimmers that turn or slide with a knob, all work with dimmable LEDs.

Alas leading edge technologies controlled with a touch or push button, are often powered by an electric transformer, excluding many dimmable LEDs.

The other sort of phase-cutting method is trailing borders technique, typically employed in MOSFET or is not ideal to the huge majority of dimmable LEDs. among the the most latest inventions appearing for the marketplace are on the way to be the RAIS light technology. RAIS lamps provide a higher level of performance and appear to operate with all sorts of dimmers obtainable for the market. however RAIS solutions is nonetheless new, and its long-term result on LEDs have not been completely tested. If they prove for getting trustworthy their ask for equally domestically and commercially, can turn out for getting considerably safer and much less difficult than earlier dimmable LED lights’.

In the ever-evolving solutions of LED lights, dimmable LEDs are nonetheless for getting developed to additional compatibility and considerably better performance. because there is no basic rule for what dimmer your LED could possibly be ideal for, in any way occasions look at the specialized particulars using the distributor. ask for of LED lights with non-compatible dimmers may ruin the LEDs, plus they are, in the moment, not the cheaper option of lighting.