FPGA vs ASIC

FPGA --- Field-Programmable Gate Array
ASIC --- Application-Specified Integrated Circuit
A field-programmable gate array (FPGA) can be purchased off-the-shelf and programmed by the user, whereas an application-specific integrated circuit (ASIC) is manufactured to a customer’s specification. This distinction has not changed since the dawn of both technologies.


Time-to-market and configurability
The configurability of an FPGA is its most priced asset. Its ability to rapidly implement or reprogram the logic for a specific feature, or to modify the functionality that was previously instilled in it, is why designers run after it.



“Even if a vendor has new features to add at a later stage in the released product, he still has the freedom to decide whether to implement that feature in software or hardware based on applicability. Time-to-market for handling change-requests in FPGA is much less than in ASICs,” explains Manisha Mankar, architect—digital design, Robert Bosch Engineering and Business Solutions.

Indeed, this is one of the primary reasons why designers are opting for FPGAs.

“There are two key factors driving the demand for FPGAs today: The programmable imperative, i.e., the inherent capability of an FPGA that allows it to be tailored to the needs of the customer and the insatiable bandwidth requirements of the mobile generation today. Given this, FPGAs are increasingly replacing ASICs and ASSPs for more and more applications across different verticals such as telecommunications, aerospace, medical, automotive and industrial to name a few,” adds Neeraj Varma, director-sales, Xilinx India.

 Performance and power efficiency
While FPGAs used to be selected for lower-speed, less complex or volume designs in the past, today’s FPGAs easily push the performance barrier. With increase in logic density and other features such as embedded processors, DSP blocks and high-speed serial at low price points, FPGAs are an interesting proposition. The industry has shown that high-end FPGAs are growing in volume, handling high-speed applications and complex designs.Earlier, FPGAs were viable only for prototyping or low-density applications. Now they meet the needs of very high-volume applications such as consumer products and other moderate-volume high-density appli-cations as well.
The fact that ASICs are built for specific applications allows them to have a very high density of useful logic gates on the chip and use resources optimally. Hence higher gate count and lower power consumption give ASICs a competitive edge over FPGAs. 

High volume production

For high-volume production, costs associated with building a custom ASIC chip are said to be increasing, especially since technology nowadays is ever more complex. As we move towards advanced nodes, cost considerations multiply exponentially. For instance, the development cost for ASIC at 28nm is 40 per cent more than at 40nm. At 20nm, it is estimated to be 70 per cent over that of 28nm.

Best of both the worlds
While FPGAs are excellent for designing and prototyping digital logic into medium-volume, medium-density applications, their high unit cost makes things difficult. On the other hand, the low unit cost of ASICs is one of the main reasons why these are considered for high-volume manufacturing.

What if there were a way to get the best of both the worlds? Well, designing a new product around FPGA allows design modifications to be quickly made throughout the development process. Once this design is complete and approved for production, the FPGA design can be migrated to an ASIC design and then produced, cutting the production unit cost greatly.

    

LEDs for Solid-state Lighting

Solid-state electronics has been transforming our lives for many decades by bringing us increasingly small, cheap and efficient devices and appliances. Our modern life-styles have come to be defined by our access to an increasingly wide assortment of technologically advanced equipment for personal and group use. From smart phones to personal music players and from satellite navigators to tablet computers the benefits of modern electronics are all around us. In this continuing tradition, solid-state lighting now seems set to revolutionise the way we light our surroundings - indoors and outdoors. Its impact is already being felt globally and in the coming years it will further entrench its position as one of the defining technologies of the twenty-first century. 




Lighting technology has changed remarkably little since its inception more than a hundred years ago. We still illuminate our homes and offices with lamps that bear a striking resemblance to Thomas Edison’s invention in the late nineteenth century. Indeed the basic design of incandescent light bulbs has remained essentially the same over the years and with that their efficiencies have also changed very little. The development of tungsten-halogen lamps in the nineteen-fifties did raise the efficiency somewhat but it still remained woefully low. The later development of fluorescent lighting resulted in a big improvement in efficiency but even that is now considered insufficient in our increasingly energy-conscious world. Moreover, their use of toxic and environmentally hazardous mercury has always remained a cause for concern. The emergence of highly efficient diode-based solid-state lighting over the past decade has, therefore, been widely welcomed and acknowledged as the next logical step in the evolution of lighting technology.

Solid-state light emitters were invented in the nineteen sixties as semiconductor pn-junction diodes capable of emitting coloured light. These light-emitting diodes (LEDs) were made from materials such as gallium arsenide and gallium arsenide phosphide. For many years, LEDs only served as small indicator lights for electronic equipment. They were ubiquitous in everything from portable transistor radios to televisions and telephones. Epoxy-packaged low-power LEDs are still around in essentially the same form in which these devices have been used for several decades.  In later years, LEDs were also used to build dot-matrix displays that found particular favour in countries of the far-east. Even today a visitor to such places as Hong Kong, Singapore or Tokyo cannot escape the overwhelming concentration of advertising LED bill boards in city centres. Traffic light is another application where LEDs made an early appearance.

A typical LED-based traffic light utilising clusters of low-power red, amber and green LEDs is shown in figure.

LEDs were traditionally available in most colours except blue which made it impossible to build full-colour displays using a combination of red, green and blue light emitters. A blue-emitting LED was a long sought after goal and, therefore, it caused much excitement when a practical blue LED was reported by a researcher at a small Japanese electronics company. Following figure  shows an LED wafer with many individual blue LEDs, undergoing testing on an assembly line. Shuji Nakamura’s invention of the blue LED at Nichia Corporation resulted in the proliferation of LEDs in all kinds of applications. Its development also gave rise to the white LED which consists of a blue LED chip coated with a light-emitting material called a phosphor. The phosphor gets excited by the blue light from the LED chip and converts a large amount of the blue light into yellow light. The resulting light – a combination of yellow emission from the phosphor and the residual un-converted blue light – appears white to our eyes. The availability of white LEDs soon started people thinking about the possibility of using these devices for illumination purposes.

 
 Early LEDs were low-power devices, capable of running at no more than a quarter of a watt of power dissipation. While this was adequate for use as indicator devices and even for multi-colour dot-matrix displays, space lighting demanded higher power devices. This was a formidable problem once because high power LEDs have to use larger chips that also produce much more heat than the tiny chips used in conventional low-power LEDs. It took several years for device packaging technology to advance to the point where half watt LEDs could become commercially available. Companies such as Philips and General Electric spearheaded these developments, resulting in the eventual availability of watt-class white LEDs. Once these devices became available, systems designers set thinking about designing lighting systems that could take advantage of the many benefits offered by LED-based luminaires.

A radical departure from conventional means of generating light, LEDs have features that make them especially suited for lighting applications. Their small size, extreme efficiency in converting electrical energy to light, availability in many colours (including white) and absence of any environmentally harmful substance that might pose a problem during disposal make them ideal as light sources for any conceivable application. Little wonder then that LED-containing lighting systems are finding increasing acceptance all over the world. The market for LEDs and solid-state lighting systems has been growing at close to 25% per annum for the past several years and by all indications will continue to do so for the foreseeable future.

 The first luminaires to be designed with high power white LEDs were shaped to resemble traditional tungsten filament light bulbs. These so-called retrofit bulbs have standard screw or bayonet bases to fit in existing lamp sockets. The argument was that this was the quickest way to market for LED lamp makers as it required no modification of existing lighting infrastructure. In spite of their significantly higher cost, the sales of retrofit LED light bulbs have been rising over the past five years. Manufacturers cite their very long lifetimes as the feature that offsets their purchase price – a typical LED light bulb can last for 10,000 to 20,000 hours before needing replacement. Compare this with the typical 800 hours lifetime of a tungsten incandescent bulb and the higher cost of an LED bulb doesn’t seem too onerous. The increased cost of these bulbs results from the need to incorporate a complete power supply inside every bulb, as LEDs only operate with low voltage DC power. The power supply is also the most vulnerable part of any LED bulb because the failure of any of its components can render the bulb useless. The actual LEDs themselves are much less prone to failure and are the reason manufacturers are able to quote such ambitious figures for their products.Above figure 3 shows the interior of an 8 watt bulb containing 6 surface mount power LEDs. With prolonged use, LEDs tend to grow dimmer and a bulb’s useful life is considered over once its LEDs drop to half of their initial brightness. The fall in brightness is caused by a slow degradation of the LED chip and the colour conversion phosphor. The fact that LED bulbs do not fail abruptly like incandescent bulbs also reduces chances of untoward accidents.

                                                      A 12 Watt LED bulb from Philips

Sensitive Smart Skin : New Technology

An array of piezotronic transistors capable of converting
mechanical motion directly into electronic controlling signals

Knitting  zinc oxide nano-wires vertically, researchers of Georgia Institute of Technology have fabricated arrays of piezoelectric transistors which are capable of converting mechanical motion directly into electronic controlling signals.It can sense touch with the same level of sensitivity as the human fingertip, which could result in better bots and prosthetic.

"Any mechanical motion, such as the movement of arms or the fingers of a robot, could be translated to control signals," lead author Zhong Lin Wang of Georgia Tech's School of Materials Science and Engineering said in a news release. "This could make artificial skin smarter and more like the human skin. It would allow the skin to feel activity on the surface."
The transparent and flexible arrays use about 8,000 taxels. A taxel is a touch-sensitive transistor that can generate piezoelectric signals independently, i.e., emit electricity when mechanically agitated. Each of those two-terminal transistors are constructed with 1,500 zinc oxide nano-wires(500-600 nanometers in diameter). In the array the vertical piezotronic transistors are placed between top and bottom electrodes which are made of indium tin oxide aligned in orthogonal cross-bar configurations. A thin layer of gold is deposited between the top and bottom surfaces of the zinc oxide nano-wires and the top and bottom electrodes, forming Schottky contacts. A thin layer of the polymer Parylene is then coated onto the device as a moisture and corrosion barrier.The array density is 234 pixels per inch, the resolution is better than 100 microns, and the sensors are capable of detecting pressure changes as low as 10 kilo-pascals (resolution comparable to that of the human skin), Wang said. The Georgia Tech researchers fabricated several hundred of the arrays during a research project that lasted nearly three years.

Figure shows a scanning electron microscopy image (A) and topological profile image of fabricated strain-gated piezotronic transistor array. An optical image shows (B) the transparent and flexible SGPT array on flexible substrate

The arrays are fabricated on flexible substrates

In the laboratory, the research group has fabricated arrays of 92 X 92 transistors. The researchers used a chemical growth technique at approximately 85 to 90 degrees Celsius, which allowed them to fabricate arrays of strain-gated vertical piezotronic transistors on substrates that are suitable for microelectronics applications.
 The research group measured the tiny polarization changes when piezoelectric materials such as zinc oxide are placed under mechanical stress. Zinc oxide is used because it can accumulate current. In those transistors, then piezoelectric charges control the flow of current through the nano-wires.Passing the control is known as  “strain-gating.” The technique only works in materials that have both piezoelectric and semiconducting properties. These properties are seen in nano-wires and thin films created from the wurtzite and zinc blend families of materials, which includes zinc oxide, gallium nitride and cadmium sulfide.
The arrays could help give robots a more adaptive sense of touch, provide better security in handwritten signatures and offer new ways for humans to interact with electronic devices. "This is a fundamentally new technology that allows us to control electronic devices directly using mechanical agitation," Prof Wang said. "This could be used in a broad range of areas, including robotics, MEMS, human-computer interfaces, and other areas that involve mechanical deformation."

 Potential Applications:

•     Multidimensional signature recording, in which not only the graphics of the signature would be included, but also the pressure exerted at each location during the creation of the signature, and the speed at which the signature is created.
•     Shape-adaptive sensing in which a change in the shape of the device is measured. This would be useful in applications such as artificial/prosthetic skin, smart biomedical treatments and intelligent robotics in which the arrays would sense what was in contact with them.
•     Active tactile sensing in which the physiological operations of mechanoreceptors of biological entities such as hair follicles or the hairs in the cochlea are emulated.

Future work will include producing the taxel arrays from single nano-wires instead of bundles, and integrating the arrays onto CMOS silicon devices. Using single wires could improve the sensitivity of the arrays by at least three orders of magnitude, Wang said.
The research was reported April 25, 2013 in the Journal Science online and will be published in a later version of the print journal. The research has been sponsored by the Defense Advanced Research Projects Agency (DARPA), the National Science Foundation (NSF), the U.S. Air Force (USAF), the U.S. Department of Energy (DOE) and the Knowledge Innovation Program of the Chinese Academy of Sciences.

Source : Georgia Institute of Technology

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Amrit Mandal is a final year B.tech (EE) Student, Admin of this blog. He likes to work in the renewable energy field-specially in solar energy field.
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Bajaj Auto quadricycles RE60 ready for launch

It is expected to be a revolutionary product. Bajaj Auto quadricycles RE60 is finally ready for launch, it is awaiting government nod. here are details about mileage and price

Quadricycle is a new concept and Bajaj Auto is trying its best to get the approval for its light four wheel vehicle from the Indian government. The company says it is neither an auto-rickshaw nor a car, but a quadricycle that it wants o sell cheaply in the market.




 The company recently showcased its product to the whole world and says its demand is going to be substantial not just in the country, but in many other foreign nations who would fall for it immediately.

Bajaj that is second largest two-wheeler manufacturer in the country and is the number one manufacturer of three wheelers or auto-rickshaws in the country has excited a large number of people across the country by claiming that its quadricycle will run 35-40 kilometre on every litre of petrol. To be true, even Tata’s much talked about Nano doesn’t give more than 20 kilometre average on a single litre of petrol. In a country where petrol is among the costliest in the world, a good mileage is going to be a huge attraction for everyone.

Meanwhile the company has said that it is waiting for the government-appointed committee to come up with the final rules on quadricycles. While it is waiting and waiting for the approval from government on the issue, deputy Prime Minister of Singapore is expected to visit Bajaj Auto on May 4 to discuss export potential for the RE60. Meanwhile talking about the release date of RE60a top Bajaj Auto official RC Maheshwari says, “At present, a committee comprising of government officials and auto industry executives who are members of SIAM, are finalizing the rules for quadricycles. We understand the process of final inclusion of the new class in the Central Motor Vehicle Rules would take few more months”. But aside from government approval, everything else seems to be ready for launch.

Many have talked about the product being unsafe. But a step ahead from the original auto rickshaw, Bajaj RE60 is packed with a powerful 214 cc engine having maximum power output of 20 bhp. The light vehicle weighing 450 kg is expected to give an average of 35 to 40 kmpl. Given the stats, speculations are rife that following its launch, the auto rickshaws plying on the road would soon be a thing of past. Though the initial set of the vehicle would be fitted with a petrol engine, the Bajaj Auto has spent three and half years developing the RE60 and designing the platform in such a manner that the vehicle could be fitted with fuel options like CNG, diesel, and electric power train in the future.

About the Author

Amrit Mandal is a final year B.tech (EE) Student, Admin of this blog. He likes to work in the renewable energy field-specially in solar energy field.
Follow Us on Twitter #REnergy_Blog

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Soaring on the power of the sun: World's most advanced solar plane flies

                                    

The world's most advanced solar-powered plane successfully carried out its latest test flight on Tuesday, soaring at 3,000 feet above the Bay Area of California and the iconic Golden Gate Bridge.



 

The Solar Impulse, which weighs only about 3,500 pounds, runs completely on power from the sun drawn from 12,000 solar cells that send energy into batteries that power propellers running on four electric motors.

Tuesday's flight was a technical test run to prepare for a planned cross-country trip beginning in early May.

Read more @ Dailymail