Citation: Galante-Sempere, D.;
Ramos-Valido, D.; Khemchandani,
S.L.; del Pino, J. Area-Efficient
Integrated Current-Reuse Feedback
Amplifier for Wake-Up Receivers in
Wireless Sensor Network
Applications. Sensors 2022, 22, 1662.
https://doi.org/10.3390/s22041662
Academic Editor: Jaime Lloret
Received: 14 December 2021
Accepted: 16 February 2022
Published: 21 February 2022
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Article
Area-Efficient Integrated Current-Reuse Feedback Amplifier for
Wake-Up Receivers in Wireless Sensor Network Applications
David Galante-Sempere * , Dailos Ramos-Valido, Sunil Lalchand Khemchandani and Javier del Pino
Institute for Applied Microelectronics (IUMA), Department of Electronics and Automatic Engineering,
University of Las Palmas de Gran Canaria (ULPGC), Campus Universitario de Tafira,
35017 Las Palmas de Gran Canaria, Spain; dramos@iuma.ulpgc.es (D.R.-V.); sunil@iuma.ulpgc.es (S.L.K.);
jpino@iuma.ulpgc.es (J.d.P.)
* Correspondence: dgalante@iuma.ulpgc.es
Abstract:
Wireless sensor network (WSN) applications are under extensive research and development
due to the need to interconnect devices with each other. To reduce latency while keeping very low
power consumption, the implementation of a wake-up receiver (WuR) is of particular interest. In
WuR implementations, meeting high performance metrics is a design challenge, and the obtention of
high-sensitivity, high data rate, low-power-consumption WuRs is not a straightforward procedure.
The focus of our proposals is centered on power consumption and area reduction to provide high
integrability and maintain a low cost-per-node, while we simultaneously improve circuit sensitivity.
Firstly, we present a two-stage design based on a feedback technique and improve the area use, power
consumption and sensitivity of the circuit by adding a current-reuse approach. The first solution
is composed of a feedback amplifier, two op-amps plus a low-pass filter. The circuit achieves a
sensitivity of –63.2 dBm with a power consumption of 6.77
µ
A and an area as low as 398
×
266
µ
m
2
.
With the current-reuse feedback amplifier, the power consumption is halved in the second circuit
(resulting in 3.63
µ
A), and the resulting circuit area is as low as 262
×
262
µ
m
2
. Thanks to the nature
of the circuit, the sensitivity is improved to –75 dBm. This latter proposal is particularly suitable
in applications where a fully integrated WuR is desired, providing a reasonable sensitivity with a
low power consumption and a very low die footprint, therefore facilitating integration with other
components of the WSN node. A thorough discussion of the most relevant state-of-the-art solutions
is presented, too, and the two developed solutions are compared to the most relevant contributions
available in the literature.
Keywords:
wake-up receiver; radiofrequency envelope detector; tuned radiofrequency; low power;
energy efficient; wireless sensor network; complementary metal-oxide semiconductor
1. Introduction
WSN applications are under extensive research and development due to the need
to interconnect devices with each other. Both industry and academia have shown an
increasing interest in promoting internet of things (IoT) and internet of everything (IoE)
devices to boost connectivity and enable complex, coordinated tasks. A WSN can be
constructed by several low-cost, low-power wireless devices characterized by a simplistic
structure. They also require a very low level of human interaction for maintenance. In this
sense, a WSN node is designed with a long lifespan, as in many situations, the nodes are
under critical environmental conditions and the batteries are hard to replace. Conventional
radios play a crucial role in WSN nodes’ operation since they are frequently one of the most
expensive components in terms of power consumption [
1
]. A common solution to obtain
significant power savings consists in duty cycling the radio interface [
2
]; this is applied by
turning it off and on again to save power using hibernation or sleep modes, or using it only
when necessary, as defined by the unscheduled IEEE 802.11 communications protocol. The
Sensors 2022, 22, 1662. https://doi.org/10.3390/s22041662 https://www.mdpi.com/journal/sensors
