Smart power chips for smart phones and other devices to greatly enhance battery life

01/07/2014 - 00:00

Smartphone battle moves from software to hardware with a crucial component to cut power consumption and allow faster data transmission.

Beyond the glitz of the International Consumer Electronics Show, the wireless industry faces a fundamental problem: more features and faster data transmission are draining phones’ batteries faster than ever.

Fortunately, there’s room for improvement inside the devices, in parts known as power amplifiers that turn electricity into radio energy. In phones, they typically consumer more power than any other component but waste half of it along the way, as lots of people can attest if they’ve watched their battery die (and their phone get warm) after an hour of streaming video. The same problem bedevils wireless networks’ base stations, which send and receive signals to and from individual phones.

Now a major effort is under way to develop smarter power amplifiers that significantly reduce waste. Eta Devices, an MIT spinoff based in Cambridge, Massachusetts, is preparing a base station module and a chip that it says not only decrease battery drain but work well in high-bandwidth applications for 4G LTE and future ultrafast technologies.

The fundamental problem is that the power needed for radio output fluctuates rapidly when a device is transmitting data at high rates. Existing power amplifiers maintain their voltage at a fairly high level at all times to be prepared for peak needs—but this is wasteful. Newer approaches adjust that level on the fly, following the “envelope” of the actual radio signal.

Such “envelope tracking,” or ET, technologies are the hottest hardware development in the mobile-phone industry. Last fall Qualcomm became the first company to ship a chip with such technology, which it says is the industry’s first for 3G and 4G LTE mobile devices.

The company says the chip helps lower electricity consumption by 20 percent and helps reduce a related problem—heat generation—by 30 percent, “allowing for longer battery life for end users, as well as enabling manufacturers to shrink the size of their devices,” says Peter Carson, Qualcomm’s senior director of marketing.

The envelope tracker is already in 10 phones, including the Samsung Galaxy Note 3 and Nexus 5. Many other component makers are scrambling to catch up, including Mediatek, RF Micro Devices, Skyworks, Texas Instruments, Analog Devices, Nujira, and Eta Devices.

The difficulty with ET, though, is that its efficiency plunges at higher data rates. Envelope trackers often require a relatively large capacitor to store and release bursts of energy while maintaining smooth and continuous voltage changes.