Better power amplifiers could double mobile battery life

Power drain on future mobile devices could be reduced by half using a more efficient power amplifier which is being developed by an MIT spin-ff company, Eta Devices. 

At the moment, mobile phone chips that turn electricity into radio signals are rather wasteful, providing only around 35 percent efficiency. This means that the majority of energy used to send information is lost to heat, draining battery at a swift pace.

According to TechnologyReview, MIT researchers at Eta Devices say that they have solved the problem by more intelligently determining the need to increase the power needed to send a signal. 

At the moment, power amplifiers use transistors that operate at two levels – standby, and output signal mode for when sending a signal.  However, the standby mode voltage is generally kept high, as big jumps from low to high power can distort the radio signal, and this creates large demands on power, depleting battery life.

The advance is essentially a “blazingly fast gearbox”, the researchers say, and is able to choose among different voltages that can be sent across a transistor used in the chip. This is done up to 20 million times a second, selecting the voltage that minimises power drain.

This method, called asymmetric multilevel outphasing, will help even when receiving a call, or downloading a video on smartphone for example, as the amplifier is busy even at this point, sending out receipts of packets.

Overall this could help double the efficiency of the power amplifier from the 35 percent achieved in most handsets.

The technology is still at the lab stage, but commercialisation, starting with LTE base stations, is expected to begin in 2013.