[资源分享] LED控制

 楼主 | 2011-11-26 23:33 | 显示全部楼层 |阅读模式
Intelligent Controllers Bring out the Green in LEDs

By Stuart Woodrow Cypress
作者:Stuart Woodrow赛普拉斯

Today roughly 10 billion incandescent bulbs illuminate the earth and consume roughly a fifth of the world’s energy consumption. With current ecological trends to “go green” and conserve energy many are looking at new ways to save the planet. Solar Wind Hydro and other renewable sources of energy are being invested in to replace the coal and gas burning plants which are choking the environment.


Another alternative to conservation is to consume less energy through smart grids and intelligent systems which only consume energy when it is required. For lighting systems LEDs combined with intelligent sensor circuits look to be a very promising method to tackle the issue of high energy consumption.
or Solid State Lighting (SSL) consume approximately a third the power of incandescent bulbs and are much more efficient in the use of the power consumed. the pockets of manufacturers of these solutions.


Watt-sucking incandescent bulbs continue to dominate the residential lighting landscape even though they are incredibly inefficient and only transfer a small portion of the energy consumed into light.
The rest of the energy is wasted and dissipates as heat through the glass enclosure. Due to these inefficiencies
incandescent bulbs are starting to be phased out in many countries around the world.
Australia and Venezuela are leading the way with phase outs this year while the United States will embark on this process from 2012 through 2014.
Compact Fluorescent (CFLs) bulbs started this process and introduced power savings of 25% to the household consumer and while generating less heat.
In fact
a 20W CFL produces the same light output as a 75 Watt Incandescent bulb.


Consumers were lured to the transition from incandescent to CFLs in the late 1990s by cities and towns who offered rebate programs to cause the changeover.
Consumers were enticed by the opportunity to “go green” and realize the cost savings on their utilities bill.
this was not a positive experience for most as they suffered from poor light quality and could not dim the CFL bulbs with conventional wall dimmers. Additionally CFLs contain small traces of mercury and need to be properly disposed of to contain the hazardous material. Many of these bulbs will be recycled and disposed of properly but most will end up in landfills and will lead to ground water contamination. The adoption rate for CFLs has been slow and is estimated to be only about 11% of the homes in the United States.
CFL technology has improved greatly over the past 5 years but the desire for a more optimal solution continues to exist.


The advances in Solid State Lighting (SSL) Technologies are rapidly increasing the adoption rate of LED lighting in both the commercial and residential markets. The promise of longer lifetime better light quality and energy savings are touted as the major factors behind the sea change from incandescent and compact fluorescent luminaries to LED. The LEDs themselves promise to consume a third the power of their incandescent predecessor but it will take the intelligence of sensors and microcontrollers to truly bring the additional power savings and financial benefits of this truly “green” technology. It is anticipated that once the payback period is less than a year the majority of consumers will be willing to invest in LED-based lighting.


The next few years in the lighting industry will bring a pivotal moment in lighting history as countries in the EU Canada Brazil and many states in the US will govern change with regulatory steps to remove incandescent bulbs from their markets.
Local utilities in the United States are starting to introduce incentive programs for LED bulbs now which should bolster the adoption rate of LED-based lighting.
These incentives will allow consumers to offset the cost of today’s high-cost retrofit bulbs which are roughly five times the cost of their CFLs counterparts.


Lighting Science Group(LSGC) based in Satellite Beach FL recently announced that utilities under the Mass Save Program are now offering its customers in the Northeast rebates for retrofits new construction and other custom applications.
LSGC reported in its press release that it was chosen due to their rigorous LM-79 lighting performance testing on their DEFINITY line of LED bulbs
PROLIFIC Series streetlights and Shoebox fixture. Rebates from these Northeast Utilities will certainly reduce the cost barriers and increase the adoption rate of LED luminaires by the consumer.


The cost of today’s LED Luminaires is dominated by the LEDs Electronic Drivers Optics and Heat sinks.
Many manufactures of LED lighting are working to get these costs down while increasing the number of features to attract consumers. Others are working to add intelligence which can easily be integrated into the electronics used to drive the LEDs.


Most LED lighting luminaires use electronics to control the light output by pulsing the LEDs with a technology called Pulse Width Modulation (PWMs).
These PWMs control how much light output is generated by controlling the percent of time the LED is driven “on”.
This driving method also allows for the LED to be dimmed and can be made to work with conventional wall dimmers found in most homes. The electronics driver inherent in the design can also be used to further gate the function of the light output.
Widely available
sensors are the key to determining when light is required and how much so the LED Luminaire provides optimal efficient output.


Intelligent microcontrollers are plentiful in the marketplace today and most of them can be programmed to perform a variety of intelligent LED driving functions.
Many new integrated solutions are arriving on the technology front everyday as driver manufactures work to reduce component count and cost of the Bill of Materials(BOM) to their customers.
these products provide design engineers with all the building blocks required to build intelligent LED Drivers in a single monolithic thermally enhanced package.
PowerPSoC now integrates Cypress’ award winning programmable system (PSoC) on a chip with CSAs
Hysteretic Controllers a 5V DC-DC regulator and power FET s into a single integrated circuit.
This System-on-a-Chip(SoC) is an erector set of lighting functions enables designers the ability to create platforms of drivers which will span across all marketing requirements desired by their companies.
The ability to reconfigure power with this level of integration can simplify hardware design
lower testing time and decrease bill-of-materials costs.
PowerPSoC offers designers both digital and analog I/Os which allows for a wide variety of sensor interface options.

智能微控制器在当今市场上已经极大丰富,他们大部分都可以编程来执行多种智能LED驱动功能。每天都有许多新的集成方案出来,驱动厂商致力于为客户降低BOM器件数量和成本。最理想的情况是,这些产品能够提供给设计工程师一个单芯片方案,包含所有的建立智能LED驱动所需的模块。PowerPSoC现在整合了赛普拉斯的可编程片上系统(PSoC),包含了CSA,滞后控制器,一个5VDC-DC调节器和电源FET ,形成了一个单芯片集成电路。片上系统(SoC)是照明功能的设计基础。它使设计者拥有驱动设计的平台,可以满足他们公司所期望的所有市场需求。使用这一集成方案可以重新配置电力,可简化硬件设计,减少测试时间,降低BOM成本。PowerPSoC可以给设计者提供数字和模拟两种I /O,可以有多种传感器接口以供选择。

Figure 1.The Cypress PowerPSoC has dedicated power electronics for driving LEDs up to 1A and 32V per channel.
The onboard controller also has digital and analog I/Os which can interface most sensors to its internal A/D Converters

1。赛普拉斯的PowerPSoC有专门用于LED驱动的能耗电路,每通道最高可达1A32V。板上控制器还有数字和模拟I / O,可以连接大多数传感器到其内部A / D转换器。

Programmable controls for lighting have been around for years and used sensors to determine when the lights should be on off or dimmed to the right light levels for the environment.
Since many of the LED luminaires already have electronic controllers on board
these sensors can be easily interfaced to or integrated into the intelligent subsystem.
These sensors can be used to control a single light fixture or control the lights for an entire building complex.
Applications can range from using a photo sensor to control an LED spotlight in your driveway to using an occupancy sensor to reduce energy costs in commercial office buildings.


Sensors can be easily integrated into Intelligent Lighting Systems by interfacing them to decision making microcontrollers like PowerPSoC.
One of the most technologically advanced LED retrofit bulbs on the market today was developed by a company called MSiSSL(www.msissl.com) out of South Florida. The Intelligent PAR38
or iPAR-38 uses a Hall Effect Sensor interfaced to the PowerPSoC to determine the required output current desired by the user.
MSiSSL’s patented Powerband technology allows the flexibility of producing light outputs based on 10 watts
12 watts or 16 watts with a simple twist of the band.  “Retailers have different lighting needs throughout their stores and this one product can power down to save watts where the lighting needs are less or power up to provide additional punch where lighting needs are greater” said John Burke VP of Sales for MSiSSL.

传感器可以很容易地集成到智能照明系统,可以把他们连接到期望的处理器,例如PowerPSoC。目前市场上技术最先进的LED灯泡之一是由一家来自佛罗里达南部的叫MSiSSL(www.msissl.com) 的公司开发的。智能PAR38,或iPAR-38,使用霍尔效应传感器连接到PowerPSoC来确定用户期望的输出电流。MSiSSL的专利Powerband技术,采用简单的band方法可以有基于10瓦,12瓦,16瓦的灵活的光输出。”零售商在他们的商店有不同照明需求,这一产品可以在光线不太需要的地方降低功率节约能源,或者可以在需要强光的地方增加照明” MSiSSL的销售副总裁约翰·伯克这样说。

Fig. 2 MSiSSL’s intelligent iPAR-38 is one of the most intelligent LED retrofit bulbs on the market today.

2 MSiSSL智能iPAR-38是当今市场上的最智能的LED灯之一。

The iPAR38 will create lumen outputs of 550 lumens 650 lumens or 800 lumens based upon the position of the magnetic ring.  This will allow lighting specifiers to optimize their design both in terms of light output as well as light energy savings and all with one unique bulb.

根据磁环的位置不同,iPAR38可以输出550流明, 650流明或800流明。这将使得照明规格做到最优化设计,无论是从光输出还是光能量节省上,并且所有这些都是在一个灯泡上实现的。

MSiSSL’s Powerband™ Technology utilizes a Hall Effect Sensor implemented in the Cypress PowerPSoC to determine the amount of Lumens to drive from the LEDs.


Ambient Light sensors like the ON Semiconductor NOA1302 and the OSRAM SFH 5711 can be used by LED street lights to turn on when the sun goes down. These photodiode based sensors offer a spectral sensitivity which is similar to the human eye and can be used to adjust light output from LED luminaires with accurate precision. The output of these sensors is an analog voltage that can be easily characterized with A/D converters also available in the Cypress PowerPSoC. Alternatively the NOA1302 integrates the ADC on board and can be programmably controlled and communicated to by the PowerPSoC through instantiating and I2C bridge.The use of ambient light sensors and
microcontrollers can be used to output light proportionally to the light required corresponding to the natural light available.

环境光感应器例如安森美半导体的NOA1302 和欧司朗的SFH5711都可以用于LED路灯,当太阳下山时打开。这些光敏二级管传感器具有一种类似人类眼睛的光谱灵敏度,可以用来精确的调整LED灯光输出。这些传感器的输出是模拟电压,可以很容易地连接到赛普拉斯PowerPSoC 里的A / D转换器。或者,NOA1302可以板上集成ADC,通过PowerPSoCI2C编程控制和通讯。环境光感应器和微控制器的使用可以用来根据自然光线输出需要的适当的亮光。

Motion Detectors are another type of sensor which can be integrated into office buildings security systems and warehouses to only come on when motion is present.
Active motion sensors are available where a beam of light is injected from a transmitter to a receiver and differences are detected when the beam is crossed.
Alternatively passive motion sensors
also known as PIR (passive infrared) Sensors are typically used on security lights which detect the heat of a human body.


The devices themselves are simple electronic components similar to a photo sensor. The infrared light bumps electrons off a substrate and these electrons can be detected and amplified into a signal. PIR Sensors are used to detect the presence or occupancy of an object.


Figure 2. A Dual PIR Sensor is used to accurately detect motion


A recent Gateway report by the Department of Energy(DOE) demonstrated substantial energy savings in projects which retrofit their lighting projects with sensor based LED luminaires.
One of the projects was a T.J. Maxx parking lot in Manchester NH which retrofitted 22 high pressure sodium and 6 metal halide lamps with 25 LED luminaires.
The report highlights a 58% energy savings due to the LEDs and the use of occupancy sensors which could reduce the light output when cars were not present.
The payback period for this application is estimated to be around three years for this New Hampshire area business.

最近美国能源部(DOE) 发布的报告显示,在种类众多的照明项目中,以传感器为基础的LED照明设备确实节省了能源。其中一个项目是在Manchester NHT.J.Maxx停车场,这里有22盏高压钠灯,6盏金属卤素灯,25 LED灯。报告中强调,58%能源节省是由于LED以及传感器的使用,当没有汽车时可以减少光输出。在新罕布什尔州商业区域经营,这种应用的回收期估计大约为三年。
The Lighting Science Group recently reported that they had installed LED WallPack fixtures in bachelor housing facilities at US Naval Bases in Ventura County CA.
These outdoor luminaires were designed for perimeter security illumination and also incorporate occupancy sensors to properly manage energy usage.
LSGC’s press release reports
“The luminaires will last up to three times longer and will consume less than half the amount of energy than conventional light sources”.
The compelling testimony also proclaims
“To save additional energy each fixture contains and on-board occupancy sensor that reduces fixture wattage and light output from 35 to 10 watts when it senses inactivity after a set period of time”.

照明科学小组最近报告说,他们已经在加州Ventura County的美国海军基地的单身宿舍安装了LED 墙壁灯架。这些户外照明专门为边界安全照明设计,和传感器一起实现妥善地管理能源使用。LSGC的新闻发布中报告,“这种照明方式将比传统照明能持续长达三倍的时间,却只消耗少于一半的能源量”。同时还宣告,“为了节省额外的能源,每个灯架都包含板上传感器,以减少灯架瓦特数,当检测到一定周期没有活动后可以把光输出功率从35瓦降到10瓦”。

A wide variety of additional control sensors and logic exist today which will further enhance the intelligent lighting controller’s ability to conserve the world’s energy consumption.
humidity pressure audio and ultrasonic sensors are all available today and can be easily interfaced to intelligent lighting drivers to make decision upon required system light output.


As the popularity of LED Lighting grows over the coming years its inherent efficiency will lead to lower energy usage and costs around the globe. However we will continue to see more and more uses of lighting as can be seen with colored skyscrapers dotting our landscapes and the addition of many more sockets around our homes. LEDs have unlocked many new opportunities for lighting which were not possible with their incandescent counterparts. It will take the intelligence of microcontrollers and sensors to make sure we are “smart” with our energy usage and that we truly utilize the “green” advances whose time has come to fruition. Look to many established as well as upstart lighting companies to chase the green and bring truly “green” intelligent lighting luminaires to the market in the years to come.


 楼主 | 2011-11-26 23:34 | 显示全部楼层

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