Inspired by biology, neuromorphic systems have been trying to emulate the human brain for decades, taking advantage of its massive parallelism and sparse information coding. Recently, several large-scale hardware projects have demonstrated the outstanding capabilities of this paradigm for applications related to sensory information processing. These systems allow for the implementation of massive neural networks with millions of neurons and billions of synapses. However, the realization of learning strategies in these systems consumes an important proportion of resources in terms of area and power. The recent development of nanoscale memristors that can be integrated with Complementary Metal-Oxide-Semiconductor (CMOS) technology opens a very promising solution to emulate the behavior of biological synapses. Therefore, hybrid memristor-CMOS approaches have been proposed to implement large-scale neural networks with learning capabilities, offering a scalable and lower-cost alternative to existing CMOS systems.

Journal Paper - Materials, vol. 12, no. 7, article number 2745, 2019 MDPI AG
DOI: 10.3390/ma12172745    ISSN: 1996-1944    » doi

Blockchain technology can increase visibility in supply-chain transactions and lead to more accurate tracing of goods as well as provide evidence of whether a product is authentic or not. A shared, distributed ledger or blockchain alone, however, does not guarantee correct and trustworthy supply-chain traceability. We argue that blockchain technology (and any other digital traceability solution) must be enhanced with methods to "anchor" physical objects into information technology, Internet-of-Things and blockchain systems. Only when trust from the digital domain is extended to the physical domain can the movement of goods be accurately traced (e.g., for callbacks and provenance) and product authenticity determined. In this paper, we introduce the concept of crypto anchors, propose a classification and system architecture, and give implementation examples for different use cases and industries.

Journal Paper - IBM Journal of Research and Development, vol. 63, no. 2-3, article number 4, 2019 IBM CORP
DOI: 10.1147/JRD.2019.2900651    ISSN: 0018-8646    » doi

This paper studies the use of the body terminal as control voltage of ring oscillators implemented in Fully Depleted Silicon on Insulator (FD-SOI) CMOS. This technology allows to increase the body factor with respect to conventional (bulk) processes, thus allowing a wider tuning range of the threshold voltage. This effect is exploited in this work to improve the linearity of Voltage-Controlled Ring Oscillators (VCROs) to be used as building blocks of Analog-to-Digital Converters (ADCs). An intuitive analysis of basic VCRO current-starved inverter cells is carried out in order to derive an approximate expression of the voltage-to-frequency characteristic. Electrical simulations in a 28-nm node are shown to get insight about the influence of main design parameters and applied to the design of VCRO-based Sigma-Delta (SD) ADCs up to the layout level, whose performance metrics demonstrate the benefits of the presented approach.

Conference - IEEE Midwest Symposium on Circuits and Systems MWSCAS 2019

Millimeter-wave circuit design is extremely complex and time-consuming. One of the reasons is the dependence on electromagnetic simulators used to accurately predict the performance of the high amount of passive structures that compose such circuits. Also, achieving optimal performances is not trivial in the millimeter-wave regime. Although synthesis methodologies can aid the designer to achieve optimal circuit performances, the usage of electromagnetic simulators is prohibitive in such methodologies due to efficiency issues. In this work, a new synthesis methodology is presented where the accuracy of electromagnetic simulations can be included without losing efficiency.

Conference - Int. Conf. on Synthesis, Modeling, Analysis and Simulation Methods and Applications to Circuit Design SMACD 2019

Reliability in CMOS-based integrated circuits has always been a critical concern. In today′s ultra-scaled technologies, a time-varying kind of variability has raised that, on top of the well-known time-zero variability, threatens to shorten the lifetime of integrated circuits, both analog and digital. Effects like Bias Temperature Instability and Hot Carriers Injection need to be studied, characterized and modeled to include, and, thus, mitigate, their impact in the design of CMOS integrated circuits. This paper presents an array-based integrated circuit whose purpose is precisely that: to observe, quantify and characterize the impact of timedependent variability effects in a specific kind of circuits: Ring Oscillators.

Conference - Int. Conf. on Synthesis, Modeling, Analysis and Simulation Methods and Applications to Circuit Design SMACD 2019