LEDs push for high brightness and power in 2008

Mason Chan, technical marketing, Zetex Semiconductors, shares his insights on what to expect in the LED industry in 2008. Excerpts:



What were the major trends and challenges in the LED industry in 2007?

LED lighting was an exciting area in 2007. The efficacy or the lighting efficiency of LEDs reached a level which was comparable to the widely used fluorescent tubes and compact fluorescent lamps (CFL). In the past, the efficacy of LEDs could be as high as fluorescent counterparts but only in the laboratory or only available at low light output levels. Starting in the second half of 2007, commercially available LEDs reached an efficacy level of 70 lumens per Watt or even higher. This year, 100 lumens per Watt products will be available in the market. This will speed up the adoption of LEDs as an emerging light source, especially in the general lighting sector.

There are two major reasons to use LED technology – long life expectancy and potential for energy reduction. Since LEDs need special electronic controls to make them efficient and stable, lighting design engineers have started to develop good driver ICs. Lighting design engineers demand highly integrated, easy-to-use solutions to keep the circuit size small while maintaining high efficiency.



The driver plays an important role to prolong the lighting fixture life. The expected lifespan of an LED is more than 50,000 hours. This poses challenges to provide such highly efficient, compact and lasting solutions. Fortunately, we have anticipated our customers’ requirements so we are already capable of delivering the best solutions to help them today. For example, we have the ZXLD1350 solution – a continuous mode inductive step-down converter designed for driving single or multiple series connected LEDs from a voltage source higher than the LED voltage. This device is small enough to fit into the base housing of a “MR16” LED lamp. A new kit set will also be launched soon which will further simplify the solution in a two-chip kit. This will help lighting engineers to minimize the effort needed for the electronic design, giving lighting design engineers more time on other tasks such as thermal management and optical design.



What technological leaps will take place in the next few years?

A lot of the discussion focuses on general illumination – things like LEDs will replace traditional light bulbs or fluorescent tubes in homes and offices. There are many other applications on the way such as display backlights, automotive front lights, etc. People will see these areas become more popular in 2008.



Moreover, the light output of a high brightness LED (HB LED) is increasing at 30 to 50 percent per year. The total light output per LED is also increasing. A Zetex LED partner announced a new LED module recently which gives 1,000 lumens. This is more or less 15 times brighter than that of a normal 1W LED output. To cope with such power-hungry LEDs, we have to provide powerful, efficient and small driver ICs to control the LED. Our products already meet the requirements of high power LEDs. In fact, the 1,000-lumen module was driven by our ZXLD1360. In 2008, the trend could be an even higher power requirement for LED drivers. In addition, greater control features will be required – for example, digital or wireless interfaces. These factors pose some challenges to traditional analog IC suppliers.



You mentioned that LEDs will replace traditional light bulbs in the future. What needs to be done for this to happen?

In the LED lighting sector, the essential requirements are still efficiency and the capability to drive an increasing number of LEDs. Efficiency is always essential in LED lighting because a key incentive to switch to LEDs as light source is the expected high efficacy. An efficacy over 100 lumens per Watt is a common desire which is higher than the current common solutions like fluorescent tube based technology. LEDs are also expected to approach or even exceed other high efficacy solutions such as high intensity discharge (HID) lighting. Customers expect LED drivers to achieve an efficiency of 90 percent or higher to optimize the overall system efficiency. I believe that Zetex is in a good position to meet such requirements.



What LED product functions would you develop or focus on in 2008?

Energy efficiency, ease-of-use, compact size, and flexibility are the key directions for Zetex’ new products. Customers can find the industry’s smallest HB LED driver IC with efficiency up to 95 percent from our portfolio today, and we will continue to expand our product portfolio to meet the industry’s future needs.