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1124 results found, displaying items 101 - 120
You've Got High-Power Battery Questions, We've Got Answers
Historically, the nickel-cadmium (NiCd) cell has been the best solution for handheld applications with usage profiles requiring large current pulses. But new environmental regulations may have a marked effect on cells containing heavy metals such as cadmium. Meanwhile, a new variety of lithiumion (Li-ion) cells can support the high discharge currents required for many applications. Such batteries with high discharge rates represent a shift in Li-ion...
Power Over Ethernet-Plus PSE And PD Chips With Real Two-Event Classification Play Nicely Together
Last month, MicroSemi and Akros Silicon demonstrated the first compatibility between ICs for IEEE 802.11at Power over Ethernet Plus/HiPOE power source equipment (PSE) and powered devices (PDs). The PSE chip was MicroSemiâ??s PD64001, and the PD chip was Akros Siliconâ??s AS1135. Conducted by MicroSemi, the test predates the actual release of the final 802.11at standard. But the draft standard was released last fall, and an approved version is expected...
Power Formats: You Can Have It Your Way
Now that there are two competing industry formats to capture power intent for low-power designs—the Common Power Format (CPF) and the Unified Power Format (UPF)—design teams need to understand the similarities and differences between the two. A few design companies may be able to ignore one format or the other, but most design companies will use both formats. The first reference to the CPF file format came in early 2006, ...
Make The Universal Serial Bus Your Universal Power Supply
Why don’t all devices that draw less than 500 mA come with a Universal Serial Bus (USB) socket? Finding a charger these days hasn’t gotten any better, yet USB sockets are everywhere. Only a fraction of these devices, from cameras to cell phones to wireless headphones, has a USB socket, and it would be nice if that number would increase. So why bring the topic up here? Because you or one of our other readers will likely design or select the...
What's All This LED Power Stuff, Anyhow?
Recently, NSC put on a webcast with Howard Johnson, NSC’s Chris Richardson, and some guys from Philips and Future. As they had set it all up and presented it at the last minute, I didn’t know what points they were going to make. When they made their pitch, it all made perfect sense—but I wasn’t prepared to contribute very much. I sat there like a “fifth wheel,” not making many comments. But I did set up one experiment, which wasn’t shown on the webcast. I...
Customize Power Supplies Freely With A Digital Feedback Loop
Tighter power regulations and safety issues are demanding efficient and intelligent power supplies that can be monitored externally and manufactured cost-effectively, with minimal hardware changes. Power-supply engineering advances have shown that digital control of the power-conversion feedback loop enables designers to create more accurate and reliable power supplies with increased power density, at lower costs and with faster...
Putting All Your Power Adapters In One Basket
Welcome to this year’s edition of Electronic Design’s One Powerful Issue. In trying to decide what my contribution might be, I needed to look no further than my desk at home. Sitting on it are power adapters for a cell phone, PDA, Bluetooth headset, and notebook PC. This has become almost unmanageable for me, not to mention unsightly, since the cords run all over the desk and down the side to a power strip on the floor. What a mess. To make things...
Demanding Dynamic Loads: Can Power Devices Keep Up?
With each new generation of processor, the trend is toward lower voltages, higher currents, and faster dynamic loads. As a result, power-system designers are challenged to provide ever-faster transient response. They also have to do it using less board area while providing cost-effective and efficient power-systems solutions that offer the requisite performance. The question is if power devices can keep up. Power designers traditionally responded to the need...
Stop The Waste In Your Battery-Charger Conversion
Excess energy waste during battery charge is, of course, a bad idea for the environment and poor design practice. In fact, the problem has deepened to the point where it’s now an international regulatory agency issue. Battery-charger efficiency is more challenging to specify and measure than ac-dc power-supply conversion efficiency. It’s usually understood as the amount of energy stored in the battery relative to the energy consumed by the charger during...
New Techniques Enhance Efficiency Across All Loads
Engineers who design products that plug into the ac mains face upcoming efficiency mandates that will make power-supply design tougher—and, one hopes, more lucrative. To some extent, the same is true for designers of portable equipment, as consumers get used to ever more powerdraining features while simultaneously demanding equal or longer battery life. Back in the 1990s, the Environmental Protection Agency (EPA) created a voluntary labeling program...
High Efficiency Challenges Power-Management Design
The semiconductor industry has always forced the power-supply industry to follow its trendsetting lead. For the last decade, that trend has been to cram more transistors into a single package, particularly microprocessors. This led to microprocessors with smaller feature sizes and tighter spacing between internal components. To be operational, smaller feature sizes forced the processors to operate at a lower voltage. This, in turn, required lowervoltage power...
DC-DC Converter Makes Single-Cell Microcontroller
Silicon Labs has met the challenge of cutting power consumption to a single cell with its C8051F9xx, which fits into a 4- by 4-mm package (Fig. 1). Ranging from 0.9 to 3.6 V, its operating voltage is ideal for one- or twocell solutions. This 25 MIPS, 8051-compatible microcontroller has a 5-V tolerant I/O with a built-in 24.5-MHz (2% accuracy) clock. It also boasts a second,...
FPGA Gets The Hang Of Low Power
Until recently, low-power FPGAs were about as oxymoronic as bipartisan cooperation and bug-free code. But the FPGA landscape is changing for the better as more vendors can say with a straight face that they offer low-power FPGAs without having their marketing guy laughed out of the room. Not only that, but FPGAs also have been getting more and more design wins in battery-based portable applications in which low power consumption is...
10 FPGA Tricks Provide Power-Saving Treats
1. Select an FPGA with an ASIC-like power profile. That means no inrush power, no boot-up configuration power, ultra-low standby power (especially over extended temperature ranges), and low dynamic power. Low-power and secure in-system programmability allow secure design modifications and field upgrades. 2. Look for single-chip, small-form-factor (portable-friendly) FPGAs. The ASIC-like form factor is the smallest footprint available ...
Op Amp Cuts Power And Noise
For densely populated, thermally sensitive instrumentation applications that requires high-speed signal conditioning. Analog Devices’ single-channel 850-MHz ADA4857 high-speed voltage feedback op amp combines a number of desirable features. It burns only 5 mA, less than half that of other amps in its class. Also, it reduces input noise to 4.4 nV/vHz, also half that of competing amps. Its –91-dBc distortion specification at 10 MHz gives it a...
Smaller SFP+ Optical Transceivers Save Space And Power
The lower cost and wider availability of network interface cards (NICs) and other optical components have led to the recent upsurge in 10-Gigabit Ethernet (10GE) networking. According to a recent report by research firm IDC, installation of 10GE ports will more than double from 1.4 million in 2007 to over 3 million by 2010 as more and more network switches and other datacom equipment adopt 10GE technology. Avago’s SFP+ (small form-factor...
Get The Right Power Supply To Tackle Peaks And Valleys
A power supply with high peak-current capability can support loads that are higher than the nominal continuous power for short periods of time, without the unit shutting down or damage occurring. Typical constraints on this capability include time (duration of the current peak) and the percentage of time the supply must support the higher load (duty cycle). Products often requiring high peak current include print heads, pumps, motors, and disk...
Bob's Mailbox
DEAR RAP: You answered one question for me last year (“Why are FETs so expensive in India?”), and I now have another. How does a bipolar op-amp-based non-inverting dc amplifier amplify dc signals that are below a 0.6-V bipolar threshold (e.g., an LM358- based non-inverting dc amplifier)? (Okay, you want a gain of +1.5 or 2 or 3 for a small signal that is barely above ground, such as +0.1 or +0.2 V? And the LM358 uses a small...
Bob's Mailbox
DEAR EDITOR: At first I thought I picked up an April Fool issue, but no, you have Al Gore in the Tech Year in Review section honoring him for imploring engineers to turn green (Dec. 1, 2007, p. 45; ED Online 17958). What crap. Please cancel my subscription. –"RAY" Hello, Ray: There are several reasons to “turn green,” and Al Gore’s bleating about warming theories is only one of those reasons. Energy is expensive. Or haven’t you...
Patent Lawsuit Verdict Clouds Future For PMBus
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