Novel Power Management Chip Module to Enable Operation without Battery EnergyTechnology #2018-004
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The Internet of Things (IoT), while still in its infancy is shaping the future of many industries and will also impact our daily lives in significant ways. One of the key challenges of moving IoT devices from concept to reality is to have long-lasting operation under tightly constrained energy sources, thus demanding extreme power efficiency. IoT devices – such as sensors – are often deployed on a massive scale and in places that are usually remote and difficult to service regularly, thus making their self-sufficiency essential.
Currently, batteries in IoT devices are much larger and up to three times more expensive than the single chip they power. Their size is determined by the sensor node lifetime, which directly affects how often they need to be changed. This has an important bearing on maintenance cost and impact on the environment when batteries are disposed. To extend the overall lifetime, the battery is usually recharged slowly by harvesting some limited power from the environment, such as using a solar cell. However, existing IoT devices cannot operate without battery and they stop functioning every time the battery runs out of energy.
Battery indifference is the ability for IoT devices to continue operations even when its battery runs out of energy. This is achieved by operating in two different modes – minimum-energy and minimum-power. When battery energy is available, the chip runs in minimum-energy mode to maximise the battery lifetime. However, when battery is exhausted the chip switches to the minimum-power mode and operates with a tiny power consumption of about half a nanoWatt – this is about a billion times smaller than the power consumption of a smartphone during a phone call.
Figure 1: Battery-indifferent operation of sensor nodes with an integrated harvester to achieve sub-nW power when the battery is out of energy, while reducing energy when battery-powered.
NUS’ batteryless module for integrated circuits enables the uncommon capability to uninterruptedly sense, process, capture and timestamp events of interest and for such valuable data to be wirelessly transmitted to the cloud when battery becomes available again. Despite being in minimum-power mode when battery is not available, the reduced speed of microchip incorporating NUS’ technology is still adequate for numerous IoT applications that sense parameters varying slowly in time such as temperature, humidity, light, and pressure.
Electronics and Software
Stage of Development
Functional prototype under a 50 lux indoor light intensity, which is equivalent to dim light available at twilight and corresponds to nano-Watts of power.
This technology is very well suited for smart buildings, environmental monitoring, energy management and intelligent adaptation of living spaces to occupants’ needs.
NUS’ batteryless module for integrated circuits is indifferent to battery availability, addressing a previously unsolved challenge in battery-less chips.