Ex-MIT company rethinks power-feasting amplifiers

November 1, 2012 by Nancy Owano weblog
Asymmetric multilevel outphasing (AMO) architecture. Credit: SungWon Chung et al.

(Phys.org)—Technologists generally agree that power amplifiers have proven to be inefficient pieces of hardware. Turning electricity into radio signals, they eat into the battery life of smartphones and they waste power. One may find that a cellular phone cannot stream live video without running down the battery in minutes. Now a team of engineers have come up with an alternative amplifier technology that can extend smartphone battery life. Eta Devices, based in Cambridge, Massachusetts with an office in Stockholm, and cofounded by two MIT electrical engineering professors, Joel Dawson and David Perreault, offers a new amplifier design. The result is described in Technology Review as a "blazingly fast electronic gearbox." The engineers call their approach "asymmetric multilevel outphasing (AMO)." It is able to "intelligently" select, among voltages that can be sent across the transistor, the one that minimizes power consumption.

In 2009, Dawson and Perreault, along with SungWon Chung, Philip Godoy, Taylor Barton, and Everest Huang, wrote a paper to describe AMO, calling it a new outphasing transmitter architecture in which "the supply voltage for each can switch among multiple levels." They said the AMO modulation technique was found to increase overall efficiency over a much wider output power range than the standard LINC system while maintaining high linearity. "This architecture results in significant efficiency improvement over previous methods."

Dawson, quoted in Technology Review, said that today's power amplifiers used in both phones and cellular base stations are inefficient, "pulling a lot of energy just to keep the thing on." The more data needed to send, the worse it gets. "With high data rate communication, you wind up needing far more than . This is why the phone is warm," he said.

Smartphone battery life, however, is not first in line for Eta Devices, which has been working on their concept, reaching various "milestones" along the way of their R&D. The company will attempt to prove itself next year in applications for Long Term Evolution (LTE) base stations. They hope to reduce base station energy usage by impressive amounts. In large base stations, the power amplifier takes as much as 67 percent of the power, with another 11 percent for air-conditioning. The new amplifier would reduce overall by half, according to Eta Devices CEO, Mattias Astrom.

The company will launch its product in February at Mobile World Congress in Barcelona. Next will come a chip-scale version of the technology, which is still in development, to increase the of smartphones. They hope for a smartphone chip that can lead to a single-power amplifier to handle the different modes and frequencies used by global standards, including CDMA, GSM, and 4G/LTE. Eta Devices has funding from Ray Stata, cofounder of Analog Devices and Stata Venture Partners.

Explore further: STMicroelectronics Introduces the 2x1W Stereo Amplifier for Portable Applications

Related Stories

DOCOMO Develops 8-Band Power Amplifier for Mobile Phones

January 8, 2010

NTT DOCOMO announced today that it has developed a prototype multi-band power amplifier that accommodates eight frequency bands between 700 MHz and 2.5 GHz, paving the way for lightweight, all-in-one mobile phones capable ...

DOCOMO develops compact multi-band power amplifier

May 20, 2011

NTT DOCOMO today announced that it has developed a prototype power amplifier for six frequency bands between 1.5 GHz and 2.5 GHz in a form factor smaller than multiple single-band power amplifiers conventionally used to provide ...

Recommended for you

Glider pilots aim for the stratosphere

November 20, 2015

Talk about serendipity. Einar Enevoldson was strolling past a scientist's office in 1991 when he noticed a freshly printed image tacked to the wall. He was thunderstruck; it showed faint particles in the sky that proved something ...

Tandem solar cells are more efficient

November 23, 2015

Stacking two solar cells one over the other has advantages: Because the energy is "harvested" in two stages, and overall the sunlight can be converted to electricity more efficiently. Empa researchers have come up with a ...


Adjust slider to filter visible comments by rank

Display comments: newest first

5 / 5 (1) Nov 01, 2012
There is nothing entirely new in this effort. Predistortion has been around for decades. Using envelope detection to adjust for linearity is not new either. Dynamic adjustment of bias is not new either. And adjusting the power supply is pretty obvious too.

It is unusual to see all this in one amplifier (there are multiple dimensions of adjustment that one can make here), but someone was bound to do it sooner or later.
2.3 / 5 (3) Nov 02, 2012
Let's suppose that this transducer doesn't stolen by the MIT profs, as some other sensors- https://connect.i...sr/blogs
not rated yet Nov 20, 2012
Perhaps avalanch transistors could generate high frequencys with a sawtooth wave voltage source.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.