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Optoelectronics/Displays??

Innovative LED drivers deliver energy savings

Posted: 04 Sep 2013 ?? ?Print Version ?Bookmark and Share

Keywords:LED light bulb? multi-level PWM?

A team of researchers from the Department of Electronic and Information Engineering of Hong Kong Polytechnic University has developed a LED driver that according to them could make LED light bulbs brighter and more efficient. The driver powers LED light bulbs with an innovative approach called multi-level PWM, which delivers remarkable improvements in terms of light quality and energy efficiency, when compared to pulse width modulation and linear driver approaches currently used in LED products, the researchers stated.

By traditional method of pulse width modulation, LEDs are fed pulsed current instead of steady DC. The drive current is turned ON and OFF at a rate faster than being perceptible by human eyes. Powering LEDs in pulses makes their light output easily controllable.

The research team, formed by Lai Yuk Ming, Loo Ka Hong and Michael Tse, gives the PWM method a new twist. The pulsed operation is redesigned in a way to maximise light output while minimising wasted energy in the form of heat. The result is higher lumen per watt. Loo Ka Hong said they achieved additional energy saving by up to 15 per cent.

When used in a large scale application, it can save a lot of energy. The LED billboard on One Times Square in New York is a good example. The math goes like this: The giant display uses 12 million bulbs and 250KW of power. If the billboard is on for 16 hours a day, the energy bill comes to $18,000 a month. A 12 per cent drop in energy consumption means $2,160 in energy savings. That's something to roll your eyes at.

Furthermore, it has lowered cooling requirements and needs smaller size heat sink compared to conventional methods. That means LED systems can be made smaller. With excellent dimming capability, the new MPWM driver allows manufacturers to create fully dimmable LEDs, which can be dimmed down to zero watts. These superior qualities pave way for brighter, smarter and more versatile LED lighting solutions.

Obviously, the novel technology allows a better product to be made. High illuminating performance combined with good thermal protection allowed manufacturers to create compact lighting solutions with a very high lumen output. And the additional cost is little because all of these qualities could be achieved with the use of low cost ICs. This could be music to the ear for LED manufacturers.





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