Dimmable LED Lighting – Energy Efficient Dimming Technology

v:* {behavior:url(#default#VML);}o:* {behavior:url(#default#VML);}w:* {behavior:url(#default#VML);}.shape {behavior:url(#default#VML);} Normal 0 false false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} LED technology has rapidly evolvedover the last ten years.  Because LED bulbs now have high power and warmwhite options, a focus has shifted towards dimmability.  This transitionproves pivotal for residential and business acceptance of LED l ighti ng.  Can LED lights dim ?  Has the LEDtechnology advanced enough, or do most consumers need to wait a few more yearsfor the next LED lighting revolution?  Dimmable LED lighting provides anaffordable, efficient, high quality lighting option on standard dimmers. LED Driver LED lighting requires constant DCvoltage or current to easily adapt to different power supplies safely whilehaving longer standby power.  Each LED needs 2-4V of DC power and severalhundred mA of current.  Having a series of LED diodes on a bulb or lightfixture requires higher voltage, provided by the LED driver.  An LEDdriver is a self-contained power supply that has output matched to theelectrical characteristics of your LED or array of LEDs.  It convertsincoming voltage to the proper low-voltage DC power required by the LEDs. Drivers should deliver a consistent current over a range of loadvoltages. LEDs must be protected fromline-voltage fluctuations because changes in voltage can produce adisproportional change in current, which in turn changes light output. LEDlight output is proportional to current and is rated for a current range. Ifcurrent exceeds the manufacturer recommendations, the LEDs can become brighterbut their light output can degrade at a faster rate due to heat, shorteninguseful life. The LED driver regulates the current flowing through the LEDduring operation and protects it from voltage fluctuations. LED Dimming Technology Dimming drivers can dim LEDs by areduction in the forward current, pulse width modulation (PWM) via digitalcontrol, or more sophisticated methods.  LED drivers are the crucialcomponent in dimming technology for LED lighting solutions. Most dimmingdrivers operate using the PWM method. With this method, the frequency couldrange from a hundred modulations per second to as high as hundreds of thousandsof modulations per second, so that the LED appears to be continuously lightedwithout flicker. A benefit of the PWM method is that it enables dimming withminimal color shift in the LED output. Dimming causes LEDs to experience asimilar shift in spectral power distribution as an incandescent lamp. Pulse width modulation presents atechnique to safely dim an LED from 5% to 100% of full luminous flux. When the LED is pulsed with current while varying the duty cycle of thecurrent waveform, the LED rapidly transitions between on and off.  Therelative times spent give the impression of being dimmed.  Dimming designis based on technology of frequency and peak current modulation, which provideseven and stable dimming.  This technique is common for dimmable lights,especially incandescent.  Dimming does not result in a loss of efficiency.During dimming, the LEDs are still operated at the same voltage and current asduring full light output. In addition, lamp life is not affected by dimming, asis sometimes the case with frequently dimmed fluorescent lighting. Most LED drivers are compatible with commercially available0-10V control devices and systems such as occupancy sensors, photocells,wallbox dimmers, remote controls, architectural and theatrical controls, andbuilding and lighting automation systems.  In the USA, most dimmers workon the basis of the TRIAC technology.  Many LED drivers are testedand designed to work on these dimmer options.  LEDs can also work withdevices governed by the DMX and digital addressable lighting interface (DALI)protocols and, in the future, may include wireless (RF) as a control option. The technology behind LED lightingcontinues to evolve and progress.  The LED drivers dim LEDs by a reductionin the forward current via pulse control or through digital control.  MostLED drivers are compatible with commercially available 0-10V control devicesand systems such as occupancy sensors, photocells, wallbox dimmers, remotecontrols, architectural and theatrical controls, and building and lightingautomation systems.  Dimming compatible LED bulbs has no negative resultson LED life.  Dimmable LED lighting provides an affordable, efficient,high quality lighting option on standard dimmers. For the full press release on dimmable LED technology click here . For the full 'Green' White paper on LED dimmable technology click here .

Was this helpful? 0 0 Comments

You're reading Dimmable LED Lighting – Energy Efficient Dimming Technology.