Power Hotspot

Forget about doggie bags. Several of San Francisco's finest restaurants will be turning table scraps into electricity with technology from the University of California, Davis. Using an anaerobic phased solids digester, the Biogas Energy Project will process eight tons of organic matter a week into energy. Each ton can produce enough electricity to power 10 average California homes for a day. While many wastewater treatment plants and livestock farms use...

Given: V = L di/dt I(t) = I(t0) + 1/L × ∫ V(t) dt Rearrange: (L/V) × (I(t) - I(t0)) = dt Using the formula: PWM on-time = (L/V) × 2 × (IDESIRED - ISTART) For most applications, the input voltage can't change very quickly-because of large input-filter capacitors. Therefore, you needn't calculate the time-consuming divide operation (L/V) for every execution of the control algorithm....

Digital control of switch-mode power supplies (SMPSs) is becoming practical thanks to the evolution of low-cost, high-performance devices with peripherals designed for power-conversion applications. Also, current-mode control is challenging voltage-mode techniques for SMPS digital designs. Combining digital control with current-mode topologies can bring higher performance than combinations of analog or voltage-mode approaches. Early SMPS designs used voltage-mode control. A...

Timing is everything in dc-dc conversion. A high-resolution, 16-channel pulse-width-modulation (HRPWM) module from Texas Instruments can control the edge position to a 150-ps accuracy. This is a neat trick for the 100-MHz TMS320F28044, since it doesn't generate a faster clock internally to handle the 24-bit PWM support (Fig. 1). Instead, the chip uses the upper 16 bits in a conventional fashion with counter/compare ...

The IEEE 802.3af Power over Ethernet (PoE) standard employs two of the four pairs in a CAT5 cable to deliver 48 V dc to a device. The device can use up to 15 W, which is more than sufficient for a wide range of peripherals (e.g., Voice-over-IP (VoIP) telephones and a variety of control and monitoring devices). The existing PoE standard suits industrial Ethernet use, but it isn't optimal for a number of reasons. Most industrial automation systems run at 24 V, and most...

Another company has joined PowerDsine in introducing a Power-Over-Ethernet (PoE) controller that anticipates the higher power capabilities addressed by the IEEE 802.3at PoE Plus task force. While PoE Plus is still very much a work in progress, Texas Instruments has introduced a 26-W powered-device (PD) controller. TI's eight-pin TPS2376-H lets designers implement a non-standard PD that draws up to 26 W from power-source equipment (PSE) with a minimum of 52 V...

This year's Emerging Technologies Conference at MIT left me more on-edge than energized. The message from a keynote panel was a wakeup call to the seriousness of global warming and the need for immediate action. "It's not too late, but we must move away from fossil fuels... or ruin the planet for the next 50 generations," said Joseph Romm, founder and executive director of the Center for Energy & Climate Solutions. Romm urged a massive investment in alternative energy as well...

From the time he took his first job in America at a metal plating factory in 1870 until his death in 1937, Edward Weston strove for perfection. "The fact is that Weston never did and never could relax mentally," wrote David Woodbury in his book, A Measure of Greatness: A Short Biography of Edward Weston. "His preoccupation with whatever he happened to be doing was vast and devastating... His drive to accomplishment was grim and sometimes...

Charles Proteus Steinmetz was both an electrical engineering genius and a great forward thinker in educational and social issues. In the scientific field, Steinmetz is remembered for many electrically related inventions. He invented a commercially successful alternating-current motor, identified and explained the Law of Hysteresis governing power losses, developed a user-friendly method to manage and calculate values for alternating current, and invented...

What are HVICs? High-voltage integrated circuits (HVICs) translate low-voltage control signals to levels that are suitable for driving power switches in high-voltage applications. HVICs also can translate signals from high voltage levels to lower voltage levels. A basic HVIC might provide simple-up or shift-down capability, while a more advanced one might provide half- or full-bridge drive capabilities. Yet another might be...

A typical digital camera lens system can be extremely clever and effective. Yet it's also mechanically complex, requiring intricate gears and motors. Size, cost, and power consumption are key considerations, especially in camera phones. A new system, though, may remove those limitations. Rogers Corp. and Varioptic have collaborated to create a miniature high-resolution auto-focus system that uses a liquid lens (Fig. ...

A complete line of power cables and cable accessories from Pulizzi Engineering features a variety of plug types and lengths. There are over 30 stock versions, including NEMA 5-15P to IEC C19, NEMA L6-20P to IEC C19, and European Shucko to IEC C19 cord sets. The variety of power cables enables one power distribution unit to be used anywhere in the world. Standard configurations include 120-, 208-, and 230-V versions available in both 15- and 20-A ...

If point-of-load (POL) regulators were small and efficient enough, you could just stick them inside the package with a processor or FPGA chip and think back to the days when chips simply ran on 12- or 5-V power bussed around a circuit board. In one stroke, all of those tiresome power design issues of sequencing and loop response would be lifted from the circuit-designer's shoulders and turned over to the chip makers. Something like that scenario got a little closer late last...

Intel's latest releases of its 64-bit Core 2 Duo and Core 2 Extreme processors incorporate a number of enhancements, including power-management features targeted at mobile devices. The desktop and server versions incorporate Intel's Advanced Smart Cache for its dual-core chips, which include a shared L2 cache that allows full utilization by a single core if the other core is idle. The mobile versions' Deeper Sleep with Dynamic Cache Sizing feature will flush the cache during periods of...

The foiled airliner bombings last month reaffirm the challenge to keep a step ahead of terrorists. Also, the fifth anniversary of the Sept. 11 attacks reminds us that the U.S. suffered a "failure of imagination" in our threat analysis and that our intelligence must not be locked in silos if we want to anticipate the terrorists' next move. When it comes to imagining new electronics for the military and homeland security, a similar information exchange is...

Ray Baughman, director of the University of Texas' NanoTech Institute, sees a time when military leaders will send robots into battle. "They could fight ahead of American soldiers, take a bullet for American soldiers, and then, after giving them a shot of alcohol or diesel fuel, will fight on." Baughman is one of thousands of research scientists working at academic laboratories across the nation developing military-funded gadgets and systems that often end up becoming...

What is hot-swapping? During hot-swapping, a module can be plugged into or unplugged from a live supply bus without affecting the overall system operation. The idea probably comes from telephone line cards, whose edge connectors were designed with fingers of different lengths. When the cards were inserted into the backplane, ground was always connected first, followed by the power bus and the I/O pins. That was sufficient for the simple and robust electronics of the...

As recently as two years ago, brushless motors were significantly more expensive than brush motors. However, advances in design and materials have triggered dramatic price drops in brushless motors. Today, the cost differential between these two motor technologies is only about 10%. Brushless motors with the same horsepower as brush motors are smaller and lighter. Because they lack this brush-commutator interface, brushless motors exhibit lower acoustic noise....

Bridge power is an interesting niche in the power-supply world because of the way it continually turns to outside-the-box technology. Bridge supplies are a subset of uninterruptible power supplies (UPSs) for data centers and telecommunications central offices (COs). They're only called upon to supply power for the seconds or minutes that elapse between a utility failure and the time the normal UPS is fully online, or until power is restored. The battery bank mandated for all...