2,371 research outputs found

    High-Performance Robust Latches

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    First, a new high-performance robust latch (referred to as HiPeR latch) is presented that is insensitive to transient faults affecting its internal and output nodes by design, independently of the size of its transistors. Then, a modified version of the HiPeR latch (referred as HiPeR-CG) is proposed that is suitable to be used together with clock gating. Both proposed latches are faster than the latches most recently presented in the literature, while providing better or comparable robustness to transient faults, at comparable or lower costs in terms of area and power, respectively. Therefore, thanks to the good trade-offs in terms of performance, robustness, and cost, our proposed latches are particularly suitable to be adopted on critical paths

    Impact of Bias Temperature Instability on Soft Error Susceptibility

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    In this paper, we address the issue of analyzing the effects of aging mechanisms on ICs' soft error (SE) susceptibility. In particular, we consider bias temperature instability (BTI), namely negative BTI in pMOS transistors and positive BTI in nMOS transistors that are recognized as the most critical aging mechanisms reducing the reliability of ICs. We show that BTI reduces significantly the critical charge of nodes of combinational circuits during their in-field operation, thus increasing the SE susceptibility of the whole IC. We then propose a time dependent model for SE susceptibility evaluation, enabling the use of adaptive SE hardening approaches, based on the ICs lifetime

    Modeling and Detection of Hotspot in Shaded Photovoltaic Cells

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    In this paper, we address the problem of modeling the thermal behavior of photovoltaic (PV) cells undergoing a hotspot condition. In case of shading, PV cells may experience a dramatic temperature increase, with consequent reduction of the provided power. Our model has been validated against experimental data, and has highlighted a counter-intuitive PV cell behavior, that should be considered to improve the energy efficiency of PV arrays. Then, we propose a hotspot detection scheme, enabling to identify the PV module that is under hotspot condition. Such a scheme can be used to avoid the permanent damage of the cells under hotspot, thus their drawback on the power efficiency of the entire PV system

    Low Cost NBTI Degradation Detection and Masking Approaches

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    Performance degradation of integrated circuits due to aging effects, such as Negative Bias Temperature Instability (NBTI), is becoming a great concern for current and future CMOS technology. In this paper, we propose two monitoring and masking approaches that detect late transitions due to NBTI degradation in the combinational part of critical data paths and guarantee the correctness of the provided output data by adapting the clock frequency. Compared to recently proposed alternative solutions, one of our approaches (denoted as Low Area and Power (LAP) approach) requires lower area overhead and lower, or comparable, power consumption, while exhibiting the same impact on system performance, while the other proposed approach (denoted as High Performance (HP) approach) allows us to reduce the impact on system performance, at the cost of some increase in area and power consumption

    Postdischarge assessment after a heart failure hospitalization: the next step forward.

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    Heart failure (HF) is the most frequent cause of hospitalization for patients >65 years of age. Mortality during the initial hospitalization ranges from 6% to 7% in Europe to 3% to 4% in the United States, depending on the length of hospital stay. Poor outcomes have universally been shown after discharge, with 60- to 90-day mortality rates of 5% to 15% and hospital readmission rates of 30%. Whereas the prognosis of patients with chronic HF has improved in recent years, there has been no change in the high risk of death or rehospitalization after an HF hospitalization. In addition to the lack of new therapies, incomplete relief from fluid overload, insufficient patient education, lack of implementation of evidence-based therapies, and poor postdischarge follow-up planning are among the main causes of these poor outcomes. A better assessment of the patient at the time of discharge and in the following weeks seems therefore as mandatory. This article outlines the main components of such a program. These include the personnel who should be involved, i.e. HF specialists and cardiologists versus non-specialists, the variables which should be assessed, i.e. those related with congestion and fluid overload, the times when they should be assessed, as the phase at highest risk is immediately after discharge from hospital, and, finally, the aims of such programs. We retain that an improvement of post-discharge follow-up will be able to significantly improve patients’ outcomes with a rate of success comparable, if not greater, to that which can be achieved by new therapies

    Old and new intravenous inotropic agents in the treatment of advanced heart failure

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    Inotropic agents are administered to improve cardiac output and peripheral perfusion in patients with systolic dysfunction and low cardiac output. However, there is evidence of increased mortality and adverse effects associated with current inotropic agents. These adverse outcomes may be ascribed to patient selection, increased myocardial energy expenditure and oxygen consumption, or to specific mechanisms of action. Both sympathomimetic amines and type III phosphodiesterase inhibitors act through an increase in intracellular cyclic adenosine monophoshate and free calcium concentrations, mechanisms that increase oxygen consumption and favor arrhythmias. Concomitant peripheral vasodilation with some agents (phosphodiesterase inhibitors and levosimendan) may also lower coronary perfusion pressure and favor myocardial damage. New agents with different mechanisms of action might have a better benefit to risk ratio and allow an improvement in tissue and end-organ perfusion with less untoward effects. We have summarized the characteristics of the main inotropic agents for heart failure treatment, the data from randomized controlled trials, and future perspectives for this class of drugs

    Scalable Approach for Power Droop Reduction During Scan-Based Logic BIST

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    The generation of significant power droop (PD) during at-speed test performed by Logic Built-In Self Test (LBIST) is a serious concern for modern ICs. In fact, the PD originated during test may delay signal transitions of the circuit under test (CUT): an effect that may be erroneously recognized as delay faults, with consequent erroneous generation of test fails and increase in yield loss. In this paper, we propose a novel scalable approach to reduce the PD during at-speed test of sequential circuits with scan-based LBIST using the launch-on-capture scheme. This is achieved by reducing the activity factor of the CUT, by proper modification of the test vectors generated by the LBIST of sequential ICs. Our scalable solution allows us to reduce PD to a value similar to that occurring during the CUT in field operation, without increasing the number of test vectors required to achieve a target fault coverage (FC). We present a hardware implementation of our approach that requires limited area overhead. Finally, we show that, compared with recent alternative solutions providing a similar PD reduction, our approach enables a significant reduction of the number of test vectors (by more than 50%), thus the test time, to achieve a target FC

    Low-Cost and High-Reduction Approaches for Power Droop during Launch-On-Shift Scan-Based Logic BIST

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    During at-speed test of high performance sequential ICs using scan-based Logic BIST, the IC activity factor (AF) induced by the applied test vectors is significantly higher than that experienced during its in field operation. Consequently, power droop (PD) may take place during both shift and capture phases, which will slow down the circuit under test (CUT) signal transitions. At capture, this phenomenon is likely to be erroneously recognized as due to delay faults. As a result, a false test fail may be generated, with consequent increase in yield loss. In this paper, we propose two approaches to reduce the PD generated at capture during at-speed test of sequential circuits with scan-based Logic BIST using the Launch-On-Shift scheme. Both approaches increase the correlation between adjacent bits of the scan chains with respect to conventional scan-based LBIST. This way, the AF of the scan chains at capture is reduced. Consequently, the AF of the CUT at capture, thus the PD at capture, is also reduced compared to conventional scan-based LBIST. The former approach, hereinafter referred to as Low-Cost Approach (LCA), enables a 50% reduction in the worst case magnitude of PD during conventional logic BIST. It requires a small cost in terms of area overhead (of approximately 1.5% on average), and it does not increase the number of test vectors over the conventional scan-based LBIST to achieve the same Fault Coverage (FC). Moreover, compared to three recent alternative solutions, LCA features a comparable AF in the scan chains at capture, while requiring lower test time and area overhead. The second approach, hereinafter referred to as High-Reduction Approach (HRA), enables scalable PD reductions at capture of up to 87%, with limited additional costs in terms of area overhead and number of required test vectors for a given target FC, over our LCA approach. Particularly, compared to two of the three recent alternative solutions mentioned above, HRA enables a significantly lower AF in the scan chains during the application of test vectors, while requiring either a comparable area overhead or a significantly lower test time. Compared to the remaining alternative solutions mentioned above, HRA enables a similar AF in the scan chains at capture (approximately 90% lower than conventional scan-based LBIST), while requiring a significantly lower test time (approximately 4.87 times on average lower number of test vectors) and comparable area overhead (of approximately 1.9% on average)
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