Amrutur Bharadwaj and Sagar Gubbi – Department of Electrical Communication Engineering, Indian Institute of Science, Bangalore
The research: Developing a circuit that can be integrated into the battery of a computer or smartphone and can help the device function for a longer time in one cycle of charging. In other words, finding the optimum level of supply voltage which will keep energy consumption at a minimum.
As computers and smartphones become smaller by the day, the size of batteries that power them is also decreasing. On the other hand, the need to keep the devices going on for longer periods of time is also increasing. This has led to a continuous research to reduce the energy that electronic circuits consume.
Modern-day computers and phones adjust their energy consumption to the extent of their usage. One of the ways of adjusting energy consumption is to control the voltage supplied to digital circuits. If the supply voltage is reduced, the energy consumption goes down, but the speed of operation also decreases.
If the supply voltage is lowered excessively, the energy consumption increases because a much longer time is taken to do the same amount of work. Thus, there is an optimum level of supply voltage at which the energy consumption is minimal. This optimum level varies from device to device and depends on other factors as well like ambient temperature or the activity level of the device. Finding this level is key to maximising the duration of a battery-operated system to operate in a one-charge cycle.
We have developed a tiny digital circuit that, when integrated into the device, finds the optimum level of supply voltage at which the energy consumed by the device would be minimum. In a way, this digital circuit monitors the other circuits in the device and tells the power management subsystem what voltage to supply.
The significance of our work lies in the fact that we have managed to show that this task can be done using only digital circuits which are more resilient than analog circuits to semiconductor process technology advancements.
Our work has important applications in Biomedical Systems and Internet Of Things (IOT). Biomedical applications include continuous monitoring of physiological parameters such as temperature, heart rate, breathing rate, oxygen saturation, blood pressure, intra ocular pressure in patients susceptible to glaucoma (diabetics).
Other sensing applications include long-term monitoring of structural integrity of bridges, buildings and monitoring nitrate content, etc. in soil. In remote sensing as well, battery life is a key issue. Our circuit might come handy in these kind of situations.Our work has applications in Biomedical Systems and Internet Of Things (IOT).
Sagar Gubbi can be reached at firstname.lastname@example.org
Amrutur Bharadwaj can be reached at email@example.com
— As told to Amitabh Sinha