Nonvolatile Processor Architecture Exploration for Energy-Harvesting Application Scenarios

Abstract

Every shift in the way our devices are connected or powered brings with it a potential for revolution in the usage and capabilities of the systems built around them. Just as the transition from wired to wireless telephones led to unprecedented changes in our communications and the shift from wall-power to battery-power transformed our expectations for computational systems, the shift from battery-powered systems to self-powered systems promises to fuel the next revolution in the Internet of Things (IoT). The ability to utilize ambient, scavenged energy, such as solar energy, radio-frequency (RF) radiation, piezoelectric effect, thermal gradients, etc., can liberate IoT devices from the lifetime, deployment, and service limitations of a fixed battery. However, the power supplied by energy-harvesting sources is highly unreliable and dependent upon ambient environment factors. Hence, it is necessary to develop specialized IoT architectures and systems that are tolerant to this power variation, and also capable of making forward progress on the computation tasks. In this chapter, one of the potential solutions called nonvolatile processor is introduced, in which nonvolatility feature is designed within a processor to overcome the unstable power supply through distributed energy, time efficient backup, and recovery operations. The chapter provides insights on the design space of different architectures, different input power sources, and policies for maximizing forward progress. Through exploration of the various factors involved in designing a battery-less energy-harvesting system, this chapter brings opportunities and accelerates the innovations of self-powered IoTs.