From ever-shrinking dc-dc converters to brute-force industrial and benchtop power supplies, one of the top priorities for power designers has always been efficiency—eliminating the power losses when converting power from one form or level to another. For instance, not so long ago, we saw the shift from linear regulators and 50/60-Hz power transformers to high-frequency switching power supplies.
Today, the buzzword for efficiency is “green.” Emerging power sources flying under the green banner not only save costs in terms of power consumption and losses, they also are environmentally friendly—cleaner, if you will—particularly in the case of disposables.
Future Focus The drive for higher efficiencies with an eye on environmental concerns and mandates is here, and there’s no sign of it slowing down in the near or distant future. This opens doors and avenues for innovation.According to David Norton, VP of marketing at TDK-Lambda Americas, greater efficiency is a key quest. “The new 80 PLUS initiative has already been replaced by market-driven demands for a de facto 90 PLUS standard, with even higher efficiencies, especially in the area of single-output power supplies,” he says. “To achieve these higher efficiencies, technology innovations such as digital control and advanced component designs are, and will, be employed.”
Jeff Rodriguez, director of business development engineered solutions at XP Power North America, echoes the efficiency mantra. “The greatest focus of innovation in the power sources market for 2009 is increased efficiency for power supplies. The world is getting ‘greener,’ and power-supply manufacturers need to continue pushing the envelope with respect to power-conversion efficiency in order to meet the needs of our changing world,” he says.
“Customers are continually improving their end products with additional features and improved functionality, which translates to higher power consumption and oftentimes smaller mechanical packages. Thermal management also plays a key role in making products more efficient and allows for more power in smaller packages,” Norton adds.
Growth Markets Which markets will offer the greatest opportunity for growth in 2009? Any sector requiring low-cost, efficient power sources, right? “We are in an economy that is hungry for innovation and needs it to survive,” Rodriguez says.“Entrepreneurial innovation in all markets will hopefully be an area for growth potential from which we can all benefit. It’s no secret that companies are being conservative as the 2008 calendar year ends, but in 2009 we are anticipating technology leaders in their respective markets will continue to strive and create new areas of growth,” he says.
Norton narrows his focus to a market offering many growth opportunities, commercial LED lighting, which is still in its infancy. “This market will also be tough because power-supply manufacturers will have to balance efficiency with cost. The datacom market is starting to accept paying more for efficient power supplies because they have done the payback analysis,” he says.
Design Challenges The push for greater power-source efficiency comes with many considerations. Forgoing worldwide fiscal fiascos, what challenges will power-source designers and manufacturers face in 2009 and beyond?“I can see more diversified markets and stricter regulations, i.e., higher and flat efficiencies, RoHS (Restrictions on Hazardous Substances) expansions, smaller packages, active power factor correction (PFC), etc., causing challenges for power-source designers and a move away from commodity products,” says Norton.
“For example, LED lighting power supplies for the European market require PFC (power factor correction) even for very low-power supplies. And, these supplies have to meet harmonic content specs that exceed EN61000-3-2, meaning that a standard 20-W LED supply will need to include active PFC circuits. These trends will migrate globally,” he notes.
“The challenges are the same they have always been. As technology advances and the need for higher-performing products increases, manufacturers must consider the overall cost to the customer,” says Rodriguez. He also points out that strategies such as maximizing manufacturing efficiency and utilizing common base components across product families to improve economy of scale and purchasing leverage are vital to lowering overall costs.
State Of The Art Exemplifying the move toward higher efficiency and digital control, TDK-Lambda’s EFE front-end power supplies exploit an eight-bit MCU for digital control of the output and housekeeping. This cuts part counts by 25% and achieves a 45% smaller and 56% lighter design than comparable units. The 300-W EFE-300 and the 400-W EFE-400 single-output supplies deliver a 133% peak power capability for 10 seconds and efficiencies up to 90% (Fig. 1).With a typical efficiency of 88% at outputs above 70 W, XP Power’s ECM140 open-frame, single-output ac-dc power supplies deliver up to 148 W with 10 cfm of forced-air cooling (Fig. 2). Measuring 76.2 by 127 by 33 mm, they comply with IEC 60601-1/EN 60601-1 (medical) and IEC 60950-1/EN 60950-1 (industrial and IT) requirements. Models with outputs of 12, 15, 18, 24, or 48 V dc are available.