Many have little experience with electronics, being more familiar with standard florescent and incandescent bulbs. The literally million dollar question for these companies becomes how to set their lighting design apart from all the other competitors out there.

Currently, when most lighting customers think about differentiation, they think about using color LEDs for mixing light. These RGB, RGBA, etc. applications fit an interesting niche in both architectural and stage lighting designs.

 However, a lack of imagination has gripped the market in terms of taking many of these same principles and attacking the substantially larger White Light market.

Most engineers are currently creating "me-too" white light designs by taking "x" number of white LEDs from a manufacturer such as Lumileds, adding up the lumens to equal or surpass that of a fluorescent, hooking it up to a ballast, and calling it good. This does not appear to be a recipe for long-term success.

There are few technological advances that stop at the replacement level, and as customers gain a new perspective on the additional features of LEDs, it would be unfortunate to assume that there would be no further utilization.

This article will explore several examples of differentiating what appears at face value to be a simple LED design. Each of these examples deserves far more space than can be devoted to here, but should serve as a starting point for additional creativity.

The key to this step is the addition of basic intelligence to the circuit, generally in the form of a microcontroller. Intelligence is necessary to take advantage of what LEDs offer as much to white light designs as to color.

Tune to Temperature
The first example of a key differentiating feature is the ability to tune color temperature along the black body locus. It is relatively simple to imagine why one wants to mix color, and still there has yet to be substantial progress made towards the same principles with white light.

As lighting customers become more discerning, the option of any specific color temperature between 3000K and 6500K is appealing. This also means that designers can maintain a single white light fixture design that avoids the need for constant revision dependent on a Correlated Color Temperature (CCT) specification.

What is interesting to note about tuning white light is that it actually is normally done through mixing color LEDs. This originally was done with a simple RGB interface, but designers quickly noticed that the Color Rendering Index (CRI) was extremely poor.

CRI is important in order to reproduce an item's color as it would be under natural light, especially vital in such applications as display lighting. A merchant doesn't want good jewelry looking bland.

To alleviate this concern, designers have tried RGBA, RGGB, and RGBW, and each configuration has their advocates. Intelligence can ensure that whatever LED configuration a designer selects will have the best possible CRI by calculating the dimming percentages required to drive the LEDs efficiently. Companies such as Future Electronics have done excellent work in assisting designers with this often difficult process.

Even if a high CRI is not a top design requirement, some sort of simple tuning can be beneficial, this time only with two strings of white LEDs, cool and warm white. This approach can provide the same number of lumens while also allowing the designer an easy way to differentiate the product, especially from standard fluorescent bulbs.

Intelligence through Communication
A secondary form of intelligence and differentiation is in the form of communication. Even in static white applications, the process of retrofitting lighting fixtures in an existing infrastructure gives designers the unique ability to introduce networking features without the need for additional wiring.

This last advantage is important, because few designers want to require that installation, as it is quite cost prohibitive. Yet the differentiation potential of communication can be tremendous, as the setup allows for dimming and color temperature control to be controlled through a central hub.

Power Line Communication (PLC) is a technology that takes a carrier signal and routes it through existing power wiring, thus saving on installation costs. In one example, PLC is a 2.4 kbps FSK modem which can be robust over 100m distance, suitable for most home/office applications (Figure 1, below).

Since PLC can be voltage agnostic, it does not require substantial board redesigns for separate usages. It should be mentioned that PLC can encompass far higher bandwidths as well, as it is being pushed by some companies up to the 200 mbps level, which could be over power lines or also over Ethernet.

Figure 1: PowerLine Household Application

The use of various wireless communication technologies can also eliminate the need for home/office rewiring. The robustness of RF solutions has continued to improve, to the point of eliminating the interference from certain household objects such as the dreaded microwave.

Integrating wireless is less of a chore than in the past, as suppliers have introduced module solutions that utilize a simple serial interface for communication to a main microcontroller, eliminating the need to go through the challenge of such design steps as FCC certification.

Wireless options are especially interesting for the entertainment lighting market, where the light placement can then take full priority over additional wiring concerns.

Figure 2: WUSB Remote for Lighting Control

Peripheral Functionality
Even without turning to tuning or communication techniques, creative designers are still finding ways to make their products stand out in the market through the last discussed differentiating feature; peripheral functionality.

As energy costs continue to rise, companies are searching for additional ways to find value. One key regulation that has become a selling feature is the EnergyStar requirement, and has pushed designers to search for unique ways to manage energy usage.

Obviously this has been a standard selling feature for LEDs in general, as their efficiency can be up to four times that of standard replacement bulbs. Adding some peripheral controls to increase that efficiency can truly help a company stand apart. This can be done cheaply using an ambient light sensor or passive infrared sensor (PIR) (Figure 3 below)..

Figure 3: PIR Occupancy Senso

The basic functionality of an ambient light sensor or PIR sensor is fairly well known, so it will not be discussed here. The point is that tracking light or occupancy can dramatically decrease total energy usage of the fixture. Below are a few examples.

The ambient light sensor can track the available light depending on the time of day and adjust the dimming of an office lighting network accordingly. A PIR sensor can act as an occupancy sensor in an automobile, cubicle, or home, and turn on/off a light depending on the feedback. Even something as simple as the light on the front of a white goods appliance can utilize a simple sensor in order to only turn on when needed.

One final peripheral function that can be a key differentiating factor is the addition of capacitive control (Figure 4, below). This refers to the replacement of mechanical buttons or switches with a capacitive trace interface that has advantages in aesthetic appeal and in being hermetically sealed.

The explosion in popularity of this type of interface in the MP3 and cell phone market makes it an intriguing feature for lighting. Also, the number of capacitive solution providers is rapidly expanding, so the ability of a designer to find the right fit for their solution has improved.

Figure 4: Capacitive Lighting Remote from Philips

There are two easy examples of ways this technology can be utilized in the lighting market. The first is as a simple on/off switch or dimming slider. This is a basic low-pain addition to a company's first LED wall wash or table lamp. The slider can also be paired with the tuning white lights discussed earlier to select a specific color temperature.

An on/off switch can also become a proximity switch as the sensitivity of the capacitive loop is increased. Then a hand would only have to be waved near a light to turn it on. Again, this is a great feature that doesn't necessarily have to require any additional design work with the LEDs themselves.

All the options discussed in this article, from tuning white light to communication to peripheral functionality, can be integrated into a current design using existing application notes and firmware from microcontroller companies. Adding differentiation does not have to be a huge headache for a design team unused to semiconductor integration and can add features and value to an end product.

The LED market is a terrific opportunity for creative designers to carve a unique niche for themselves against their growing competition, and the features of LEDs means the applications in lighting are virtually limitless.

Designers who grasp these features will have a large advantage over their competition. The above differentiating concepts are the tip of the iceberg, and it will be exciting to see what other ideas drive the market moving forward.

Gavin Hesse received his BSEE from Seattle Pacific University and is now a Product Marketing Engineer for Cypress Semiconductor. He would like to acknowledge the role "real" engineers play in making him look good. When not helping conquer the world for PSoC, Gavin can normally be found enjoying Seattle Seahawks football in all its glory.