LED green lighting technology and prospects

There are about 10 billion incandescent lamps currently lighting, and they consume about one-fifth of the world's energy. With the current "going green" ecological trend, in order to save energy, many people are looking for new ways to save our planet. Solar, wind, hydro and other renewable energy power generation are being built to replace coal and steam, which are harmful to the environment.

Another alternative to save energy is to consume less energy through smart grids and smart systems, consuming energy only when needed. For lighting systems, LEDs combined with smart sensor circuits appear to be a promising way to solve the problem of high energy consumption. LEDs, or solid-state light sources (SSL), consume about one-third the energy of incandescent bulbs, and they are a more efficient way to use energy. Manufacturers already have such solutions.

Watt-sucking incandescent bulbs continue to dominate the residential lighting landscape, even though they are inefficient and convert only a small fraction of the energy they consume into light. The rest of the energy is wasted and disappears through the glass cover as heat. Because incandescent bulbs are so inefficient, they have begun to be phased out in many countries around the world. Australia and Venezuela are currently leading the way, with the United States set to begin the process in 2012 through 2014. Compact fluorescent lamps (CFLs) have come into use, and they save 25% of the electricity a home consumes while producing less heat. In fact, a 20W CFL can produce the same amount of light as a 75W incandescent bulb.

The consumer switch from incandescent to CFLs was initiated in the late 1990s by offering rebates to people in cities and towns. Consumers were attracted by the idea of ​​"going green" and realizing cost savings on their bills. However, it was not a positive experience for many people, as they wanted the light to be dimmed, and CFLs could not be dimmed with a dimmer, and they contained small amounts of mercury, which is a hazardous material that requires proper disposal. Many bulbs are recycled and disposed of properly, but most are landfilled, which can lead to groundwater contamination. CFL adoption is low, estimated at only about 11% of homes in the United States. CFL technology has improved greatly over the past five years, but there is still no optimal solution.

Advances in semiconductor lighting (SSL) technology have led to a rapid increase in LED lighting in the commercial and residential markets. The promise of long life, better luminous effects, and more energy efficiency are the main factors for LED to replace incandescent and energy-saving lamps. LED consumes only one-third of the energy of its predecessor incandescent lamps. It can make full use of smart sensors and microcontrollers to truly bring additional energy savings and economic benefits, and is a truly "green" technology. Some experts expect that in less than a year, most consumers will be willing to use LED lighting.

In the next few years, the lighting industry will usher in a critical moment in the history of lighting, and many states in the European Union, Canada, Brazil and the United States will gradually take measures to withdraw incandescent bulbs from the market. Local utilities in the United States have begun to introduce incentive programs for LED lamps, which will accelerate the adoption of LED lighting. These incentives will compensate consumers for the high cost of purchasing new lamps, which is about five times the cost of energy-saving lamps.

The Lighting Science Group (LSGC), headquartered in Satellite Beach, Florida, recently announced that it will provide discounts to customers for utilities under the mass rescue plan in the transformation of old industrial bases in the Northeast, new construction and other user applications. In the LSGC news bulletin, it was reported that the selection reason was based on their rigorous LM-79 lighting performance testing on the LED lamp DEFINITY line, rich mass production series, and shoebox-style fixtures. These discounts in the Northeast will surely reduce cost barriers and increase the use of consumer LED lamps.

The cost of today's LED lamps is mainly composed of LEDs, electronic drivers, optics, and heat sinks. Many LED lighting manufacturers are working hard to reduce costs while adding features to attract consumers. Others are working hard to add intelligent controls that can be easily integrated into the LED driver electronics.

Most LED lighting fixtures use electronic controls to control the LED light output through pulse width modulation (PWM) techniques. These PWMs control how much light output is produced by controlling the percentage of time the LED is "on". This driving method can also dim the LED and can be used with traditional dimmers on the walls of most homes. The electronic drivers inherent in the design can also be used to further control the function of light output. Available everywhere, sensors are key to determining when light is needed and how much light is needed, so the LED fixture provides the best effective output.

Smart microcontrollers are already extremely abundant in the market today, and most of them can be programmed to perform a variety of smart LED driver functions. Many new integrated solutions are coming out every day, and driver manufacturers are committed to reducing the number of BOM devices and costs for customers. Ideally, these products can provide design engineers with a single-chip solution that contains all the modules needed to build smart LED drivers. PowerPSoC now integrates Cypress's programmable system-on-chip (PSoC), including CSA, hysteresis controller, a 5VDC-DC regulator and power FETs, forming a single-chip integrated circuit. The system-on-chip (SoC) is the design foundation for lighting functions. It enables designers to have a platform for driver design that can meet all the market requirements expected by their company. Using this integrated solution can reconfigure power, simplify hardware design, reduce test time, and reduce BOM costs. PowerPSoC can provide designers with both digital and analog I/O, and can have a variety of sensor interfaces to choose from.

Figure 1. Cypress's PowerPSoC has dedicated energy-saving circuitry for driving LEDs at up to 1A per channel at 32V. The onboard controller also has digital and analog I/Os to interface with most sensors to its internal A/D converter.

Programmable lighting has been around for years, using sensors to determine when lights should turn on, off, or adjust to the appropriate level based on environmental conditions. Because many LED light fixtures already have electronic controllers on board, these sensors can be easily connected or integrated into smart subsystems. These sensors can be used to control a single light fixture or control complex lighting for an entire building. Applications range from using a light sensor in a driveway to control LED spotlights to using sensors in commercial office buildings to reduce energy costs.

Sensors can be easily integrated into smart lighting systems by connecting them to the desired processor, such as PowerPSoC. One of the most technologically advanced LED bulbs on the market today was developed by a company called MSiSSL (www.msissl.com) in South Florida. The intelligent PAR38, or iPAR-38, uses a Hall effect sensor connected to a PowerPSoC to determine the output current desired by the user. MSiSSL's patented Powerband technology uses a simple band approach to allow for flexible light outputs based on 10 watts, 12 watts, and 16 watts. "Retailers have different lighting needs in their stores, and this product can reduce power to save energy where light is less needed, or increase lighting where bright light is needed," said John Burke, vice president of sales for MSiSSL.

The MSiSSL iPAR-38 is one of the smartest LED lights on the market today.

Depending on the position of the magnetic ring, the iPAR38 can output 550 lumens, 650 lumens or 800 lumens. This will allow the lighting specification to be optimized in terms of both light output and light energy savings, all from a single bulb.

The MSiSSL iPAR-38 is one of the smartest LED lights on the market today.

MSiSSL's Powerband technology is implemented using Hall-effect sensors in Cypress's PowerPSoC to determine the number of lumens being driven to an LED.

Ambient light sensors such as ON Semiconductor's NOA1302 and OSRAM's SFH5711 can be used in LED streetlights to turn on when the sun goes down. These light-sensitive diode sensors have a spectral sensitivity similar to that of the human eye and can be used to accurately adjust the LED light output. The output of these sensors is an analog voltage that can be easily connected to the A/D converter in Cypress PowerPSoC. Alternatively, the NOA1302 can integrate an ADC on board and be programmed and controlled and communicated through the I2C of the PowerPSoC. The use of ambient light sensors and microcontrollers can be used to output the appropriate amount of light required based on natural light.

Motion detectors are another type of sensor that can be integrated into office buildings, security systems, and warehouses, and will only turn on when there is motion. Active motion sensors can be used in the following situations: a beam of light is injected from the transmitter to the receiver, and differences are detected when the beams cross. Passive motion sensors, also known as PIR (passive infrared) sensors, are commonly used in security lights that can detect human body heat.

The device itself is a simple electronic component similar to a light sensor. The infrared light circuit can automatically detect and amplify it into a signal. Passive infrared sensors are used to detect the presence or occupancy of an object.

Dual passive infrared sensors for precise motion detection.

A recent report released by the U.S. Department of Energy (DOE) shows that sensor-based LED lighting equipment does save energy in a wide variety of lighting projects. One of the projects is in the TJMaxx parking lot in Manchester NH, which has 22 high-pressure sodium lamps, 6 metal halide lamps, and 25 LED lamps. The report emphasizes that 58% of the energy savings are due to the use of LEDs and sensors that can reduce light output when there are no cars. Operating in a commercial area in New Hampshire, the payback period for this application is estimated to be about three years.

The Lighting Science Group recently reported that they have installed LED wall fixtures in the bachelor quarters at the U.S. Naval Base in Ventura County, California. These outdoor lighting fixtures are designed specifically for perimeter security lighting and work with sensors to properly manage energy usage. The LSGC press release reports that "the lighting will last up to three times longer than traditional lighting while consuming less than half the energy." It also announced that "to save additional energy, each fixture contains on-board sensors that reduce the fixture wattage, and can reduce the light output power from 35 watts to 10 watts when a period of inactivity is detected."

The wide variety of additional control sensors and logic that exist today will further enhance the ability of smart lighting controllers to save the world’s energy consumption. Temperature, humidity, pressure, sound and ultrasonic sensors make up all the sensors available today, and they can be easily connected to smart lighting drivers to determine whether the system’s light output is needed.

As LED lighting grows and becomes more prevalent over the next few years, its inherent efficiency will reduce energy consumption and costs for the entire planet. We will continue to see more and more uses for lighting, from colorful skyscrapers dotting the landscape to adding more sockets to our homes. LEDs open up many new lighting opportunities that were not possible with incandescent bulbs. It will take full advantage of smart microcontrollers and sensors to ensure that we use energy "smartly" and truly take advantage of the benefits of "greening". This time has arrived. Many existing and new lighting companies are pursuing green and bringing true "green" smart lighting to the market in the years to come.