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1124 results found, displaying items 21 - 40
Cool Ceramics Help Simplify LED Heat Dissipation
Light-emitting diodes (LEDs) suffer from heat problems that understandably can limit their success as a light source. Much attention is given to the heatsink, and less is given to the layers and barriers between the LED and the heat-dissipating surface. A change of concept and material allows for significant gains in thermal management and reliability in addition to a simplified system. Using ceramics as a heatsink, circuit carrier, and part of...
Build An Efficient 500-W Solar-Power Inverter Using IGBTs
With the global trend toward green power and affordable energy gaining momentum, applications such as home appliances, lighting, and power tools, as well as other industrial equipment and uninterruptible power systems (UPSs), are rapidly tapping the benefits of solar energy, converting the sun’s power to the desired alternating current (ac) or direct current (dc) at the required voltage. To efficiently generate the desired output voltage and...
Bob's Mailbox
HI BOB, I like your bridge amplifier (“What’s All This Bridge Amplifier Stuff, Anyhow?”). I can’t figure out what the VREF driven offset into the first stage does (It is just a tiny bias, so if the input goes ±12 µV, the circuit will keep on working. /rap) and I can’t figure out what the diode-configured transistor in the...
Medical Devices Get A Prescription For Wafer-Level Chip-Scale Packaging
Portable health appliances and services are becoming ubiquitous. Constantly on, they must be efficient and “invisible.” This brings new challenges regarding low power consumption and small size. Waferlevel chip-scale packages (WLCSPs) now enable medical treatments that were previously impossible to implement. These new applications include invasive sensing, medical implants, and disposable, portable monitors. But to get the most out of WLCSPs in...
Smart-Grid Report Maps Opportunities For U.S. Engineers
In late June, the Electric Power Research Institute (EPRI) released its “Report to NIST on the Smart Grid Interoperability Standards Roadmap.” The National Institute of Standards and Technology (NIST) had engaged EPRI and other Smart Grid stakeholders to develop a draft interimstandards roadmap that NIST could use to begin developing standards. The document runs 291 pages, and the Smart Grid probably offers the potential for as much engineering work in the...
Talking Electronics For A Few Days In Sunny Wales
Just recently, I was invited by International Business Wales (IBW) to visit several electronics companies operating in Wales, U.K., as well as attend the S2K conference. Leaving JFK airport late on a sunny day, I expected rain and gloom during my stay. Surprisingly, the weather was as nice in Wales as it was when I left the U.S., and it remained that way for the duration of the trip. IBW PLANS FOR RENEWABLE ENERGY We...
Move Your Thermal Strategy For Air-Cooled Electronics Up In The Design Flow
There are two golden rules to thermal design: start simple and start early. The heat-flow path from the junction to the ambient, usually air in the local environment, determines a component’s temperature. Controlling temperature is therefore a system design challenge. Designers should employ a top-down approach that increases confidence in the thermal design as the design progresses (see the...
Tool Automates Power Optimization Of Embedded SoC Memories
System-on-a-chip (SoC) design teams have long labored to optimize their creations for power, but doing so in the memory portions of the devices has lagged behind. Today’s memory-IP (intellectual property) providers build complex power-management schemes into their products, yet the design of the control logic to take maximum advantage of these schemes is daunting. Attempts to get a handle on dynamic power consumption using sleep modes are...
USB Isolator Simplifies Safety In Medical, Industrial Apps
In embedded applications that use the PC architecture, the USB interface has supplanted RS-232 for remote control, diagnostics, firmware updates, configuration of operational settings, and data exchange. As with its predecessor, one drawback to USB in medical and certain industrial applications is the lack of a provision for isolation in the basic standard, though mains-powered patient monitors require it for safety cer tification, and...
Auto Electronics Revs Up For "Greener" Pastures
The automobile and electronics industries are struggling mightily through this economic tumult. Straddling these two giants, however, is a shining beacon—auto electronics. At last year’s Convergence Conference, a panel of experts from General Motors, Ford, Chrysler, Honda, and BMW suggested that the cost of electronics in a car will increase beyond the oft-quoted 20% figure and climb to 40% to 50%. Getting more extreme, Honda senior...
Measuring Mains Current Doesn't Have To Be Difficult
Monitoring the current taken by a mains-powered appliance can be a challenge, particularly if the application demands an inexpensive solution that must provide galvanic isolation for user safety. Common solutions employ either a current-sense resistor or current-sense transformer to convert the line current to an ac voltage that’s then converted into a proportional dc voltage. The dc voltage may then be processed using various techniques to provide a...
Monolithic Programmable Constant Current Source Is A New Basic Building Block
Linear Technology’s LT3092 is a 0.5- to 200-mA, twoterminal, low-temperature-coefficient, constant-current- source IC. Conceptually, it’s simple, but there has never been an IC like it. You can build various circuits to provide the same functionality, yet never before could you have bought a standalone IC that does the job so simply and elegantly. Questions arise. What’s it good for? Why didn’t anybody make one before this? How did Linear come to develop...
Proton Polymer: The Key To Double-Layer Supercaps For High-Voltage Applications
The turn of the century saw the debut of a double-layer supercapacitor technology, the proton polymer. Since its introduction, there has been much success in pulse supercapacitor applications due to the intrinsically high conductivity associated with the proton-conducting polymer separators and nanoparticle carbon powders used in these capacitors. These components exhibit a capacitance range from 5 mF to 1 F, equivalent series resistance ...
Bolster Overcurrent Protection With Chip Fuses
Chip fuses assume two roles in electronics: protecting end users from injury, and preventing damage to circuitry. These functions benefit both the owner and the vendor of a given piece of equipment. Over the last 10 years, market demand for electronic devices serving information technology, mobile, and consumer applications has risen dramatically. Alongside the rapidly increasing demand comes the greater risk of unexpected conditions in electronic...
Design A Linear Li-ion Battery Charger For Portable Systems
Energy-storage devices such as batteries continue to change how people live. Every year sees greater daily usage of battery- powered personal electronic devices. Moreover, demands for longer run times and smaller sizes are driving continuous growth in both the battery and semiconductor industries. When the time to develop next-generation batteries takes longer than Moore’s Law, the need arises for highly integrated, feature-rich ICs that deliver...
Thin Is In At The Embedded Systems Conference, At Least For Energy Cells
Whenever I’m at a conference, I’m frequently asked for my opinion about the “best of show.” Since I know this question is coming, I try to be prepared with a really great product or technology. At the recent Embedded Systems Conference in San Jose, I thought the best of show was the Thinergy micro energy cell (MEC) from Infinite Power Solutions. At least one engineer I spoke with...
Energy Scavenging Offers Endless Power Possibilities
The universe is full of energy, and efforts to harvest that ambient energy are as old as the windmill and sailing ships. The convergence of three exponentially improving technologies, however, is creating striking new opportunities for ambient energy harvesting that can power applications unthinkable only a few years ago. The key to unlocking these opportunities is effectively managing minuscule amounts of power. Talk about extracting energy from the...
Changes To IEEE 1625 Establish A High Bar For Battery Design
Several years ago, some laptop fires scared the public and prompted widespread recalls by some of the most reputable lithium- ion (Li-ion) cell manufacturers. The long-lasting repercussions in the battery industry ranged from cell supply shortages to public misconception about the safety of portable electronics. Individual companies have taken many steps to ensure that these events do not recur, and the industry has joined forces to unify safety...
Bob's Mailbox
DEAR MR. PEASE, The “Financial Floobydust” section of your latest piece is, I think, anything but floobydust (Jan. 15; ED Online 20410). I believe you have touched upon a fundamental weakness at the core of so much financial and macroeconomic modeling, black-box investing, and other quantitative aspects of high finance. As you...
The Many Faces Of Custom Power
Under the pressures of product performance, price, and the need to increasingly reduce their time-to-market, many OEMs don’t have the luxury of spending a lot of time on the power solution. Consequently, they look to power providers that can expeditiously accomplish their power requirements as they need them. However, “as they need them” is the key. Suppliers can make an innovative power product. But in the end, if it isn’t in a form factor or served...
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