This Small Business Innovation Research (SBIR) Phase I project will research and develop state-of-the-art ultra-low power management integrated circuits (IC) for portable and energy harvesting solutions. The creation of floating gate technology for analog and power management applications will provide new methods and building blocks for solving ultra-low power consumption challenges needed for mobile and autonomous solutions. The novel modification of existing and newly developed analog processes and components will enable revolutionary high power, quality and reliable circuits, while maintaining an extremely low quiescent operating current. This is closely tied to energy harvesting solutions as the efficiency of transferring stored scavenged energy to electronic loads defines the size, cost, and adoption of autonomous systems. To make a harvesting system viable the modules will be highly efficient in their use of the available energy. An off-active switch module and an ultra-low quiescent current regulator will be developed utilizing floating gate techniques to obtain significant reductions in power consumption. The revolutionary off-active switch module, a function which does not exist in the market today, requires drawing near zero current from the battery when in the off-state. Low power regulators require ultra-low operating current levels needed to realize a harvesting system.
The broader impact/commercial potential of this project is to provide circuit module building blocks for energy harvesting systems in market spaces such as wireless sensor networks. This will enable several of the harvesting and storage technologies currently under development in the US, gain greater market acceptance, reduce energy demand from non-renewable sources, and create technical leadership in the US for this market space. With the availability of these building blocks and making them readily available, system designers will have IC solutions in place to reduce their time in creating their systems to leverage energy harvesting. Up-integration of these modules can then be tailored for each application quickly, reducing the system cost and time to market.
Triune Systems successfully demonstrated ultra-low-power analog circuit design techniques and a novel analog voltage reference structure to create Off Active™ load switch and linear regulator circuits with extraordinarily low operating currents. This is the first known implementation of a precision analog voltage reference operating at <1pA within a single poly complementary metal-oxide-semiconductor (CMOS) silicon manufacturing process and opens the door for a variety of new low-power end products and applications. The Off Active™ circuit is ideal for battery monitoring applications: the measured operating current of the entire circuit was approximately 100pA when off and 70nA when on at room temperature. These current levels and design features are revolutionary compared to any active battery monitoring and management products available on the market today. The linear regulator circuit that resulted from this project also delivered voltage regulation performance competitive to that of other market solutions at 1/50th of the operating and shutdown currents. This research also validated these design techniques in manufacturing flows from two different silicon foundry partners demonstrating their portability to other CMOS processes. In systems which rely on energy harvesting power sources, losses from the battery and power management circuits are critical. By leveraging the circuits demonstrated in this research, system designers can achieve ultra-low-power control solutions for battery powered applications. This, in turn, can shrink the size of existing products and enable new systems such as solar powered autonomous wireless sensors for heating central heating, ventilation and air conditioning (HVAC) control and remote fire detection. These circuit design principles are also applicable to broad handheld consumer applications such as cell phones and tablets.
