Dr. Lai Yuk Ming, Dr. Loo Ka Hong and Prof. Michael Tse at the Hong Kong Polytechnic University Department of Electronic and Information Engineering have developed a high performance LED driver.

The new driver powers LED lights with an innovative approach called “multi-level” PWM (Pulse-Width Modulation), 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.

LED Driver Wave Form. Click image for the largest view.

LED Driver Wave Form. Click image for the largest view.

For example, a large-scale application would be the LED billboard on One Times Square in New York.  The giant display uses 12 million LEDs and uses 250 KW of power. If the billboard is on for 16 hours a day, the energy bill comes to US$18,000 a month. A 12% drop in energy consumption means US$2,160 in energy savings.

In the traditional method of pulse width modulation, LEDs are fed pulsed current instead of steady direct current. The drive current is turned on and off at a rate faster than perceptible by human eyes. Powering LEDs in pulses makes their light output easily controllable.

The innovative new approach of multi-level PWM 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 Hong Kong team gave the PWM a new specification. The pulsed operation is redesigned in a way to maximize light output while minimizing wasted energy in the form of heat. The result is higher lumen per watt. Dr Loo Ka Hong said they achieved additional energy saving by up to 15%.

Multi-level Pulse-Width Modulation LED Sample. Click image for the largest view.

Multi-level Pulse-Width Modulation LED Sample. Click image for the largest view.

Multi-level PWM (MPWM) lowers the cooling requirements and so needs smaller sized heat sinks 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 0 watt of power. These superior qualities pave way for brighter, smarter and more versatile LED lighting solutions.

For lighting designers it’s a demand finally met.

The world is switching to LEDs with huge energy demand and environmental benefits. If all the traditional light bulbs in the world were replaced with energy-saving ones, lighting energy use could be cut by 40%, according to the Worldwatch Institute. The Energy Saving Trust has similar projections, which said the resultant carbon saving would be the equivalent of taking 70,000 cars off the road.

So far as the greenest alternative to incandescent lamps, LEDs are a popular choice of lighting, but they are not perfect. Consumers are looking for a brighter and more natural glow matching up to incandescent light bulbs. The demand for brightness is even more pronounced in high power applications such as automobile headlights and architectural lighting.  LED research worldwide is looking to build the ideal substitute to the incandescent bulb.

It is interesting to see advanced LED lighting with a simple solution such as MPWM that brings about significant energy savings and useful broader applications.  The novel technology allows a better product to be made. High illuminating performance combined with good thermal protection allows manufacturers to create compact lighting solutions with a very high lumen output.  The additional cost is small because all of these qualities could be achieved with the use of low cost integrated circuits. There would also be savings in materials from the smaller heat sinks and support structure.  This should be a great advantage for LED manufacturers that would pass on to consumers.

This innovative applied technology has already attracted the attention of the international marketplace. Recently the team won a Gold Award at the 41st International Exhibition of Inventions of Geneva in April of 2013.

It’s only a matter of time until the LED is the dominant lighting technology.  This and other innovations are driving a far better product than we had expected just a few short years ago.


Comments

1 Comment so far

  1. green coffee bean extract on October 18, 2013 9:13 PM

    Hello it’s me, I am also visiting this website on a regular basis, this web
    page is actually fastidious and the viewers are genuinely sharing good thoughts.

Name (required)

Email (required)

Website

Speak your mind

css.php