Chapter 3
Ultralow-Voltage Design of Nanometer CMOS Circuits for Smart Energy-Autonomous Systems
3.1 Introduction
The success of the semiconductor industry today owes a lot to high-volume products for consumer applications such as smart phones and laptop computers. However, there exist other categories of applications with different requirements in terms of processing capability, power consumption, and usability. Among them, energy-autonomous systems (EAS) is a promising application category. An EAS is defined as “an electronic system that has been designed to operate and/or communicate as long as possible in known/unknown environments providing, elaborating and storing information without being connected to a power grid” [4]. As EAS are not connected to a power grid, they either operate on a tiny battery with limited energy storage or harvest energy from their environment. Commercial EAS applications are mainly passive/active RFID tags, biomedical devices, and basic wireless sensors for industrial or habitat monitoring. On the research side, EAS have been studied for a while and recent system demonstration include new exciting applications such as biomedical implants [18, 20, 41, 68], eHealth devices [31, 35, 39, 54, 59], body-area networks [40, 38], nearly-perpetual environmental sensing [17], and insect motion control [21].
The minute power budget of EAS in the μW range requires ultralow ...
