The File - Sep 16, 2008 - (Page 1)

India’s fortnightly focus on electronics design September 16-30, 2008 Power ICs address green energy demands By Ramprasad Ananthaswamy Director Power Management Products Texas Instruments India When you look around at all the appliances that are running—lights, fans, automobiles etc. —you simply cannot imagine life without all these. But the flip side is that these devices and machines use tremendous amounts of energy. One way to address the increased energy demand around the globe is to install and commission additional fossil, hydroelectricity or nuclear power plants. These power plants definitely have a significant impact on the environment. Although this impact is inevitable, it can be minimised in two ways: in the generation and use of renewable energy, and more fundamentally, in the efficient use of available energy. Some line-powered and portable power applications efficiently convert power at the point of use. Considering the current trends, energy efficiency will soon become part of the daily vocabulary. Energy is essential to life and its conservation has become an absolute necessity. By conserving Ananthaswamy: Every piece of circuitry in consumer devices today is trying to do more with less power. energy, we decrease the amount of pollutants released into the air and thereby help to keep it clean in order to ensure the continuity of the human race. 250 million cell phones get plugged into wall chargers at the end of each day in India today. The battery charge time based on the brand of the phone varies anywhere from two to six hours. After the batteries are fully charged, the chargers still stay plugged into the wall outlets. These chargers incur losses in the internal electronic circuitry that can amount up to a watt of power from the wall outlet. 250 million cell phone charges with each dissipating a watt-hour can add up to 250MW hours. This is just one example of the consumer equipment that stays plugged into the wall. There are millions of TV sets, growing numbers of digital still cameras, camcorders, PCs and laptops that also consume power. The list is endless and the amount of wasted power is enormous. Human behaviour is not easily modified. Not many people get up in the middle of the night to unplug the cell phone charger from the wall after the mobile phone is completely charged. However, one can definitely sense when the cell phone battery charge current tapers off as the battery gets charged and automatically turns the charger off or runs the charger intermittently. This sense circuitry and the associated power conversion control circuit (conversion is required to convert 230Vac to 5Vdc) are packaged in the form of an IC and can be made part of every piece of equipment that plugs into the wall. In a worldwide initiative, Green continued on page White LED flash drivers brighten DSCs By Greg Lubarsky Applications Engineer National Semiconductor Corp. Inside News 4 6 Legislation drives move to low-power design Innovations clean up design from start to finish In the cellular handset market, the inclusion of high-pixel-count imagers integrated into the handset has almost become standard. As the resolution of these imagers in- creases, the need for brighter flash sources also increases. The use of Xenon flash bulbs has long been the main illumination choice in digital cameras. The mobile handset board area for non-telephone related functions is sparse and the Xenon approach is often impractical due to solution size. Luckily for handset manufacturers, the recent advancements in high power white LEDs have been dramatic. Manufacturers of white LED flash diodes now have products that can deliver light outputs greater than 70lumens, and can handle pulsed currents greater than or equal to 1A. Along with these advancements come new questions the handset designer must answer. How much PCB area can be used? What added flash related features are needed? How much power can the flash driver be allowed to use? How much illuminance is needed to take a decent picture? Answering these questions can greatly aid the designer in the selection of a flash LED driver. In Focus 12 Use non-maskable interrupt to manage dynamic power in MCUs Sponsors 2 5 7 9 11 13 National Semiconductor Tech Insights Texas Instruments National Instruments Microchip Technology DigiKey Solution size One of the first questions a handset designer must ask is how much board area can be devoted continued on page 10 www.eetindia.com http://www.eetindia.co.in/SEARCH/SUMMARY/technical-articles/battery.HTM?ClickFromNewsletter_080916 http://www.eetindia.co.in/SEARCH/SUMMARY/technical-articles/PCB.HTM?ClickFromNewsletter_080916 http://www.eetindia.co.in/SEARCH/SUMMARY/technical-articles/digital camera.HTM?ClickFromNewsletter_080916 http://www.eetindia.com/STATIC/REDIRECT/Newsletter_071001_GS01.htm http://www.eetindia.co.in/SEARCH/SUMMARY/technical-articles/LED driver.HTM?ClickFromNewsletter_080916 http://www.eetindia.com/STATIC/REDIRECT/Newsletter_071001_EETI02.htm

Table of Contents for the Digital Edition of The File - Sep 16, 2008

EETimes India - September 16, 2008
Contents
National Semiconductor
Legislation Drives Move to Low-power Design
Tech Insights
Innovations Clean Up Design From Start to Finish
Texas Instruments
National Instruments
Microchip Technology
Use Non-maskable Interrupt to Manage Dynamic Power in MCUs
DigiKey

The File - Sep 16, 2008