Electronic Design

I Turned The Lights Off, But What About Standby Power?

Preparing to leave my house for a Thanksgiving road trip, I followed my usual ritual of setting timers to control lamps, aiming for the right balance of lighting security and electricity conservation. But having just returned from the PowerSystems World show in Chicago, I was hit with a new concern. I thought about going around the house unplugging all the devices drawing "standby" power while I would be out of town. I found myself aware of just how many LEDs would be glowing around the clock while I was away.

The rapidly increasing number of electronically controlled devices and appliances that are, to some degree, "always on" is creating an ever-greater energy sink. (Hey, maybe mine will soon generate enough luminescence to make the house look like somebody is at home. At least the light-timer hassles will be eliminated!) In response, one of the design trends in evidence at Power Systems World was a growing number of options for creating more efficient standby power operation.

The computer, printer, VCR/DVD, and stereo are joined in today's wired home by more "always on" products: set-top boxes, home networks, and even network-connected appliances. This rising standby consumption simultaneously creates a greater payback for energy savings in standby-power design.

Regulatory and voluntary energy conservation programs are putting increased emphasis on standby-power reduction. The various global Energy Star specifications continue to help pull down standby target levels. The International Energy Agency (IEA) has championed the de facto goal of a 1-W standby level, with its 1-W Initiative for no-load, standby, and active-on supplies for all appliances by 2010. In the U.S., the federal government requires its agencies to purchase equipment using no more than 1 W in standby mode.

The California Energy Commission is proposing amendments to state appliance efficiency standards that include standby and no-load levels for power supplies and extend standards to audio and video equipment. The amendments are open for comment, but they're expected to go into effect in January.

At the Power show, I had a chance to visit Power Integrations, a leader in the low-standby-power movement. The company's Web site, www.powerint.com, includes Green Solutions pages with links to standby regulations and other resources. The standby-power savings "counter" on its home page shows that its EcoSmart Technology has saved consumers nearly $1 billion so far.

Power Integrations was promoting a new product family of switching power supplies for lower-power applications requiring tight output regulation. LinkSwitch-HF targets applications such as battery chargers and appliances that require fault protection and accurate control of output voltage and current. The products consume less than 300 mW while in no-load. These ICs sense when a power supply is in a low-power state and then lower the duty cycle and "cycle skip," supplying short bursts of power to the load, waiting for the device to wake up.

Also at the Power event, Fairchild Semiconductor announced integrated power switches that meet the 1-W initiative. The company's new offerings address the 100- to 250-W range switch-mode power supplies for applications such as televisions, DVD receivers, audio devices, and plasma display panels. The FSCQ series uses advanced burst-mode operation to offer standby power consumption under 1 W.

When chip suppliers go head to head in offering competitive solutions, designers gain new options for efficiency in standby power. Your creative application of these new ICs can bring great energy savings to the consumer with obvious benefits for the environment. The under-1-W initiatives seem like clear win/win goals to me, and I urge you to embrace them.

As a group, you have the chance to make a significant global impact. According to the Berkeley Lab, efficient designs can reduce standby power by 75%. Berkeley estimates that standby power use in the U.S. accounts for around 5% of residential electricity use, with U.S. consumers spending more than $4 billion on standby power every year. The IEA predicts an even greater potential global savings, with as much as 15% of worldwide household electricity consumption wasted in standby mode.

It's not always easy to get consumers interested in "green" programs, particularly if they face any element of inconvenience or up-front cost. But I see no reason for consumers to resist the cost savings they can achieve just by buying products with efficient standby modes. It's estimated that the average consumer is spending between $10 and $12 a month on standby power, throwing away nearly $150 a year. That's money that they could be reinvesting in new electronic toys!

For those of us who were schooled to always remember to shut off the lights when leaving the house, low-power standby is really an easy way to save.

TAGS: Components
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