Power Hotspot

The relative dearth of recent power-over-Ethernet (PoE) product announcements made me think that 802.3af had hit some kind of plateau. Perhaps people are waiting for the IEEE 802.3af subcommittee to wrap up its classification issues and make some kind of general pronouncement about how the extra power in PoE-Plus would be delivered (see "Controller Anticipates PoE Plus," May 25, p. 26). Not quite. Silicon Laboratories has leapfrogged the competition in basic PoE...

Any week's e-mail includes new product announcements from power-supply OEMs, but I usually don't write about these releases unless they have something special to say about design. In fact, I'm encouraging companies that send me these announcements to explain how they engineered their products to be smaller, more efficient, more feature-packed, or whatever else might be their claim to fame. In this case, XP Power's EMA212 incorporates some interesting techniques to squeeze 212-W...

Dear Bob: When looking at datasheets or application notes that have the schematics of an IC in them, I often see very strange components; transistors with two, three, or even four collectors or emitters, and a component that looks like a capacitor where one plate is a resistor. The LM675 datasheet on page 5 has both of these. For example, check out Q12, Q15, Q16, and R23. Application Note 446B on the LM12 internal design also has these. On page 3, Figure 3, Q3 and Q4 have two...

The "power problem" for today's large systems-on-a-chip and ASICs is becoming intractable. Process scaling no longer is a viable means of meeting power-management needs. A design-based solution to the problem is going to be required, especially with 65-nm processes coming online. The Power Forward Initiative is the EDA industry's effort to surmount the obstacles to lower-power IC design. Spearheaded by Cadence Design Systems, eight founding companies have joined in the effort to...

Bluetooth is a great short-range wireless technology for cell phones, laptops, PDAs, headsets, peripherals, and other devices. But it quickly runs out of steam when the range goes beyond 10 m. It's particularly troublesome with enhanced data rate (EDR) Bluetooth applications that use the full-bore 3-Mbit/s rate. SiGe Semiconductor's SE2425U power amplifier (PA) may have the solution (Fig. 1). The Bluetooth specifications include...

You can't get rid of the mixer in any RF or wireless product. That makes a good mixer the very core of every RF design. But you don't have to worry about that thanks to Linear Technology's LT5560. It can be used for upconversion or downconversion in public service radios, WiMAX transceivers, RFID readers, VHF/UHF transceivers, satellite receivers, or cell-phone basestations. Its operational frequency ranges from 10 kHz to 4 GHz. Its double-balanced mixer core design maximizes...

The theme at the Spring Processor Forum, held in San Jose last month, was cool—as in low power. Many products that were presented use different techniques to deliver more performance for fewer watts, such as a novel Forth-based multicore mesh from IntellaSys (see "Cores That Share Chores," June 8, 2006, p. 37). Element CXI utilizes a mesh of computing elements that fit between the basic FPGA functionality and computing blocks of complete processors (...

It's seven tons of armor-plated all-wheel drive, and it lives up to its name. Developed by the National Robotics Engineering Center (NREC) at Carnegie Mellon University, Crusher is the latest robot in the military's Unmanned Ground Combat Vehicle Perceptor Integration (UPI) program. Representatives of the NREC say that this unique robot offers new strength, mobility, and autonomy features for the military's effort to keep troops out of harm's way. Crusher can...

Faster, more powerful processing. A better handle on nonlinear wave propagation. Higher-performance transducers. The development of specialized contrasting agents. Advances in image and real-time signal processing. All of these factors are contributing to a renaissance in ultrasonic medical imaging. Healthcare providers already have an array of impressive tools at their disposal. But ultrasound manufacturers aren't sitting tight, as they pioneer innovative machines for...

When designers think of passive components, they think of manufacturing tolerances for inductors and capacitors that are typically ± 20% or ± 10%. That's okay in theory, but not when these components are used in an actual application. Applying dc bias to a ceramic capacitor or current to an inductor, at a particular frequency, changes the characteristics of these components. Hence, the name ?active passives.? For example, a 10- µF , 0603, 6.3-V capacitor can measure as...

I was just on the phone explaining how to do an "error budget" analysis on some fairly simple circuits to a young engineer. Later, I mentioned this while I was visiting with my friend Martin, and he said he had been quite surprised when he found that many engineers in Europe were quite unfamiliar with the concept of an "error budget." How can you design a good circuit without being aware of which components will hurt your accuracy? When I was a kid engineer...

Power over Ethernet Plus (PoEP) is still a work in progress. At its March meeting, the IEEE 802.3at PoEP Task Force was still considering test methods simply for evaluating the current-carrying capacity of bundled data wires, and most discussions centered on powered-device classification. Yet earlier this month, PowerDsine raised the stakes by introducing a highpower controller, the PD83000, for fourpair Ethernet-cable power delivery. Intended applications include video-screen...

Consider the newest precharged floating-gate MOSFETs from Advanced Linear Devices as very fast alternatives for normally closed relays that consume virtually zero power, and you won't go far wrong. (Typical turn-on and turn-off delay is 10 ns.) These dual and quad n-channel depletion-mode devices are attractive for fail-safe circuits in alarms, battery backup circuits, energy harvesting, alternative energy, and many other applications (see the...

The accuracy and performance of battery-powered systems need not be sacrificed to achieve long battery life. Designers can use techniques that provide both high performance and low sleep-mode power consumption. Applications such as keyless entry, climate control, and security systems are inactive almost all the time, waking up periodically for just a few microseconds to poll sensors or respond to an interrupt. In these predominantly sleep-mode applications, sleep-mode current is...

Designers who target the global market must account for the differences in submarkets and accommodate them within the confines of their basic designs. Two variations on an electrical power-meter IC from Cirrus Logic vividly demonstrate this principle. In China, electricity once was unmetered and had limited reach. Today, the Chinese power grid is expanding rapidly, and citizens are expected to pay for what they use. The latter requirement presents a challenge to some end users'...

This is no tiny smart-charger IC for lithiumions. Instead, Absopulse Electronics' BCH501-BTC is a constant-voltage charger with high power density for big lead-acids. Only 6 by 2.63 by 13.82 in. and 5.7 lb, it nonetheless cranks out 500 W. Like its tiny IC brethren, it has some built-in intelligence. Battery-temperature compensation enables the charger to modify its output voltage so the charge voltage is reduced as the battery temperature rises and increased when the batteries...

Blame it on RF power amplifiers. Large and costly, they comprise roughly 40% of a basestation's cost. And since these amplifiers must transmit wide bandwidth signals of various modulation types, linearity is critical. But linear amplifiers (usually class AB) are very inefficient, leading to considerable power consumption and high heat output. Furthermore, required linearization techniques like feedforward and predistortion are costly and power-hungry, and they add to the...

More and more portable devices are incorporating Wi-Fi. You'll find it in digital cameras, personal digital assistants, and industrial wireless devices as well as in laptops. Power amplifiers for these applications must be able to meet the standard's extreme power output specifications, but they also should go easy on the power consumption. Avago Technologies' MGA-412P8 highoutput linear power amplifier primarily targets the 802.11b/g wireless local-area network market. Yet it...

The PV-1800 PC/104 GSM/GPRS modem board combines a GSM/GPRS dual-band 900/1800-MHz modem with its own 20-W power supply. The board also has eight isolated analog inputs with a 12-bit analog-to-digital converter, eight opto-isolated digital inputs, seven opto-isolated high-current (500-mA) digital outputs, and a spare RS232 port. TCP/IP over GPRS software is included. Its operating temperature ranges from ?20°C to 70°C. The PV-1800 costs $693. ...

From a silicon design perspective, the industry has long held the notion that power consumption can be reduced simply by porting chips forward to the next process technology node. Yet as more consumer electronics move from 130-to 90-nm mixed-signal ICs, power reductions no longer scale with technology advances and finer geometry. To select the most power-efficient chips, systems developers must look beyond process shrink capabilities and rely upon their semiconductor provider's intellectual...