Reducing energy consumption is a focal point of much research these days given the drive to gather data, link and embed intelligence into the myriad devices, equipment and machinery that go into facilitating modern digital lifestyles. This emerging “Internet of Things” has led researchers at MIT to develop a new radio transmitter design that is said to reduce energy leakage from wireless electronics devices and equipment 100-fold, thus dramatically increasing battery life for devices.
Developed by a research team led by Joseph F. and Nancy P. Keithley Professor of Electrical Engineering Anantha Chandrakasan, the new radio transmitter design also delivers enough power for Bluetooth wireless transmissions and even longer-range 802.15.4 wireless communications, according to an MIT News report.
“A key challenge is designing these circuits with extremely low standby power, because most of these devices are just sitting idling, waiting for some event to trigger a communication,” Chandrakasan explained. “When it’s on, you want to be as efficient as possible, and when it’s off, you want to really cut off the off-state power, the leakage power.”
Chandrakasan and team showcased their new radio transmitter design at the 2015 IEEE International Solid-State Circuits Conference (ISSCC), which took place in San Francisco this past February.
Prof. Chandrakasan, MIT electrical engineering and computer science graduate student Arun Paidmarri and research scientist Nathan Ickes reduce the energy leakage across semiconductor gates by applying a negative charge to it when the transmitter is idle. The negative charge drives electrons away from the leads, which makes the semiconductor a better insulator.
In tests performed on a prototype radio transmitter chip fabricated by Taiwan Semiconductor Manufacturing Company the team determined that the energy needed to apply negative charge to the gate was much less than that that would be lost through energy leakage. More specifically, they found that their circuit used only 20 picowatts of power to save 10,000 picowatts in leakage.
The new radio transmitter circuit design could reduce power consumption and increase battery life in information and telecommunications technology (ICT) devices and equipment as much as 100-fold – if it broadcasts only every hour or so, according to Hardesty’s report.
“Ultra-low leakage energy is critical for future sensor nodes that need the transmitter to be on only a very small percentage of time,” Baher Haroun, director of the Embedded Processing Systems Labs at Texas Instruments (TI) elaborated.