Low-Power Microcontroller Could Give Boost to Energy Harvesting

Texas Instruments Inc. istaking aim at power reduction in the newest generation of its well-known MSP430microcontroller, which is said to offer an active current consumption that'sthree times better than its previous generation.

TI engineerssay the power reduction could serve to enable some select portableapplications to operate without batteries, instead using so-called "energyharvesting" to power small devices.

"Thepotential for this is really quite high," says Kevin Belnap, product marketingmanager for the MSP430 group at TI. "The active power is so low, it gets youdown to the point where applications like energy harvesting really begin tomake sense."

The latestgeneration of TI's MSP430 microcontroller is said to offer the industry'slowest power consumption for devices operating up to 25 MHz, offering 160muA/MHz (microamps per megahertz) active power consumption and 1.5 muA instandby. TI engineers say the active power figure is three times betterthan its predecessor, even while using twice as much flash memory. By designingthe new MSP430 in this way, the company plans to eventually integrate moreperipherals, particularly USB and RF capabilities.

"With thevery low active current of this device, it just makes a lot of sense tointegrate RF and USB," Belnap says.

TI addssome customers are already using the device in energy harvesting. AdaptivEnergy, a maker of miniaturepiezoelectric actuators, is using it on a product called the Joule-Thief, whichcollects and stores energy from tiny mechanical vibrations and then uses theharvested energy to power the MSP430. Enough energy is harvested from theapplication to implement a full Zigbee wireless system without batteries. Belnapsays such applications wouldn't be possible at the higher power draws ofearlier microcontrollers.

Other applicationsfor the device include home security systems, remote metering and portablemedical equipment, all of which could possibly use smaller batteries as aresult of the MSP430's miniscule current draw. Some energy harvesting systemscould also employ the new MSP430 to operate without batteries, instead drawing powerfrom solar cells or even human body temperature.