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The technology will first be used to address power base stations in developing countries, where diesel-powered generators consume billions of dollars of fuel per year

An MIT company has developed a new amplifier design that could significantly increase the power efficiency of smartphones.

Eta Devices, an MIT company based in Cambridge, Massachusetts, gave the power amplifier inside smartphones a much-needed efficiency boost to help save electricity consumed around the world.

The power amplifier in a smartphone turns electricity into radio signals. They use transistors to consume power in either output signal mode or standby mode. The efficiency can only be improved if the lowest amount of standby power is used, but this has been tricky so far because using low-power standby mode and suddenly jumping to high-power output signal mode leads to distorted signals. So both modes are kept high.

The amplifiers waste over 65 percent of their energy, which leads to a warm, draining battery in phones that send huge files or stream video. More charging per day leads to more electricity used around the globe. 

But Eta Devices is looking to change this. The company's new design, called asymmetric multilevel outphasing, is an electronic gearbox that chooses through various voltages that can be sent across a transistor and pinpoints the one that decreases power consumption the most. It does this 20 million times per second.

The new design not only does this when transmitting, but also receiving. When receiving, the gearbox sends out messages confirming when packets are received and letting the network know when they haven't. Packets are bits that make up a unit of Internet communications.

Eta Devices is looking to launch its new design in February 2013 at the Mobile World Congress. The technology will first be used to address power base stations in developing countries, where diesel-powered generators consume billions of dollars of fuel per year. From there, this new design will tackle the smartphone market around the world. It wants to create a smartphone chip with a single power amplifier that can juggle many different modes and frequencies.

Eta Devices expects that this new design can lead to smartphones using half the power they use today.

Source: MIT Technology Review

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no sense
By bobsmith1492 on 11/2/2012 7:01:11 AM , Rating: 4
What is this article trying to say? What does a smartphone power amplifier have to do with diesel generators?

Power amps in phones are typically class D amps and efficiencies easily reach >90% with modern designs... there's not much room for improvement there. In shutdown they are in the 10 nanoamp range so the talk of standby power savings is a moot point.

RE: no sense
By hkscfreak on 11/2/2012 7:23:40 AM , Rating: 4
This is the key part you are missing:

"using low-power standby mode and suddenly jumping to high-power output signal mode leads to distorted signals"

The new amplifier allows fast transitions from idle to use, allowing the radio to power down when it is not transmitting (for example,waiting for TCP data) and then quickly power back up to send the ACK. Similar to what Intel CPUs do (bottom two pictures):

Since the ratio of transmitted to received packets is fairly low for most standard internet traffic, this could realize huge power gains.

RE: no sense
By Stiggalicious on 11/2/2012 10:59:09 AM , Rating: 3
They're talking about the RF power amplifiers, not audio amplifiers. You certainly are correct in that class-D amplifiers are above 90% efficient nowadays, but RF amps are always less than 50% efficient (usually much lower than that).

RF amplifiers continue to be class-A or class-AB amplifiers (mostly class-A) and will remain that way since they offer lower distortion and can run at much higher frequencies than a class-D.

RE: no sense
By bobsmith1492 on 11/2/2012 12:36:35 PM , Rating: 2
RF amps, gotcha. It sounds like a class-G RF amplifier, then (multiple power rails).

EE perspective
By invidious on 11/2/2012 11:03:25 AM , Rating: 4
No offense, but it's funny watching people without electrical degrees try to talk about power electronics. Here is the real source for those interested.

The article is a little misleading on the implications of power amplifiers. "Power" is not meant to imply that is increases the power, all amplifiers do that in some form or another. It designates that the component is rated for high power applications. All transistors have heat loss and running more power through a transistor than it is rated for will smoke it. Regulars transistors are used for board level logic, power transistors would be used when you want to broadcast a wave signal out on an antenna.

The references to diesel generators are not really presented well either. This tech would make the cell tower equipment more efficient, not the diesel generators. It would reduce the load on the generators and the hope is that it would lead to reduced diesel fuel usage.

But it is far more likely is that the reduced operating cost will lead to more widespread deployment and stronger cell towers. History shows us that technology drives quality of live improvements and not resource conservation. The only things that drive resource conservation are politics and the availability of "better" resources.

RE: EE perspective
By MZperX on 11/2/2012 11:56:27 AM , Rating: 2
I was scratching my head too... the article reads like techno gibberish. Going from diesel generators to power amps to sending packets. Whaaa?

RE: EE perspective
By espaghetti on 11/2/2012 1:05:28 PM , Rating: 2
It's a Tiffany Kaiser article. What did you expect?
She uses every opportunity to point out how bad it is to use fossil fuels. Expect the story to somehow, no matter how disconnected, have a negative view on them.

Could another possible use be.....
By GotThumbs on 11/2/2012 9:20:50 AM , Rating: 2
for electric vehicles? I'm not knowledgeable enough about the technology to know, but I'm sure over time....greater efficiencies will be discovered as companies continue researching.

Sounds promising.

By invidious on 11/2/2012 10:29:52 AM , Rating: 3
No, this is for signal amplifiers, not electric motors. It could be used to make more efficient eletronics for cars like sat radio and blue tooth, but not the EV power train.

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