By Harsha Medu and Girija Chougala,
Power consumption is critical in today’s embedded systems. Emerging low
power applications include battery-pow-ered Internet of Things (Io T) sensor
nodes, wearables, and medical electronic
devices that are power and energy-constrained. With the ultimate goal to reduce
overall system power and increase battery
life, these applications rely heavily on low
power processors and energy-efficient
memory solutions. The memory requirement can be fulfilled by several memory
technologies available in the market.
Each of these technologies have unique
advantages. Ferroelectric RAM (FRAM)
is finding its way into more applications,
because of its instant non-volatility, low
operating power, fast write speed, and
Non-Volatile Memory in Io T
The Internet of Things is the world of
connected devices. It encompasses all
things connected to the Internet. Data
is collected in a central system, or in the
cloud from various “Things,” that sense
their environment. The collected data is
then used to obtain meaningful results and
make process decisions. Results or commands can be sent to various “Things”
through the interconnected networks.
Key attributes of an Io T device are
self-existence and connectivity. When the
Io T device is not connected, it should be
capable of collecting meaningful data and,
if required, make decisions locally. This is
called computing at the edge. When con-
nected, it becomes part of a bigger network,
working as a team to achieve a larger goal.
Consider a smart city. Sensors installed
in the city capture details such as traffic
movement, events that are happening,
availability of parking spaces, and so on.
Parking lot sensors in standalone operation can guide drivers to an available
parking space. When multiple parking lots
are connected, the available parking spaces within the entire city can be shown.
Drivers could even reserve a space online,
making parking in the city much easier.
Io T technology can be deployed in
places where continuous power can’t be
supplied. This requirement has major
implications on the way Io T nodes
(Figure 1) are designed. Many of today’s
devices are powered by batteries, harvest-ed energy, or a combination of both. In
energy-constrained environments, Io T
designers must select low power components that can save overall system power.
Power-efficient memory plays an import-
ant role in reducing overall system power.
With the rapid growth of the Io T
market, Io T applications require various
types of memories. In sensor-based Io T
nodes, nonvolatile memories play an im-
portant role. As remote nodes sense their
environment, they transmit data to the
central collector or upload to the cloud.
Using a non-volatile memory in a remote
sensor node increases the reliability of
the system, giving developers the option
to trade off between data size, time, and
power. This is especially important in
energy harvesting applications.
Consider a remote Io T device harvest-
ing energy from the sun to sense the tem-
perature and humidity of the surrounding
environment. The designer must ensure
there is enough power to transmit reliably.
An important design consideration is the
transmission data size and duty cycle to
minimize power consumption, thus opti-
mizing use of the available power. In these
scenarios, adding a non-volatile memory
increases system reliability. Logging data
Low Power Memory for IoT
Wearables and Portable
Figure 1: A typical Io T Node