15,844 research outputs found

    Transistor-Level Synthesis of Pipeline Analog-to-Digital Converters Using a Design-Space Reduction Algorithm

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    A novel transistor-level synthesis procedure for pipeline ADCs is presented. This procedure is able to directly map high-level converter specifications onto transistor sizes and biasing conditions. It is based on the combination of behavioral models for performance evaluation, optimization routines to minimize the power and area consumption of the circuit solution, and an algorithm to efficiently constraint the converter design space. This algorithm precludes the cost of lengthy bottom-up verifications and speeds up the synthesis task. The approach is herein demonstrated via the design of a 0.13 μm CMOS 10 bits@60 MS/s pipeline ADC with energy consumption per conversion of only 0.54 pJ@1 MHz, making it one of the most energy-efficient 10-bit video-rate pipeline ADCs reported to date. The computational cost of this design is of only 25 min of CPU time, and includes the evaluation of 13 different pipeline architectures potentially feasible for the targeted specifications. The optimum design derived from the synthesis procedure has been fine tuned to support PVT variations, laid out together with other auxiliary blocks, and fabricated. The experimental results show a power consumption of 23 [email protected] V and an effective resolution of 9.47-bit@1 MHz. Bearing in mind that no specific power reduction strategy has been applied; the mentioned results confirm the reliability of the proposed approach.Ministerio de Ciencia e Innovación TEC2009-08447Junta de Andalucía TIC-0281

    SIRENA: A CAD environment for behavioural modelling and simulation of VLSI cellular neural network chips

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    This paper presents SIRENA, a CAD environment for the simulation and modelling of mixed-signal VLSI parallel processing chips based on cellular neural networks. SIRENA includes capabilities for: (a) the description of nominal and non-ideal operation of CNN analogue circuitry at the behavioural level; (b) performing realistic simulations of the transient evolution of physical CNNs including deviations due to second-order effects of the hardware; and, (c) evaluating sensitivity figures, and realize noise and Monte Carlo simulations in the time domain. These capabilities portray SIRENA as better suited for CNN chip development than algorithmic simulation packages (such as OpenSimulator, Sesame) or conventional neural networks simulators (RCS, GENESIS, SFINX), which are not oriented to the evaluation of hardware non-idealities. As compared to conventional electrical simulators (such as HSPICE or ELDO-FAS), SIRENA provides easier modelling of the hardware parasitics, a significant reduction in computation time, and similar accuracy levels. Consequently, iteration during the design procedure becomes possible, supporting decision making regarding design strategies and dimensioning. SIRENA has been developed using object-oriented programming techniques in C, and currently runs under the UNIX operating system and X-Windows framework. It employs a dedicated high-level hardware description language: DECEL, fitted to the description of non-idealities arising in CNN hardware. This language has been developed aiming generality, in the sense of making no restrictions on the network models that can be implemented. SIRENA is highly modular and composed of independent tools. This simplifies future expansions and improvements.Comisión Interministerial de Ciencia y Tecnología TIC96-1392-C02-0

    Energy consumption in networks on chip : efficiency and scaling

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    Computer architecture design is in a new era where performance is increased by replicating processing cores on a chip rather than making CPUs larger and faster. This design strategy is motivated by the superior energy efficiency of the multi-core architecture compared to the traditional monolithic CPU. If the trend continues as expected, the number of cores on a chip is predicted to grow exponentially over time as the density of transistors on a die increases. A major challenge to the efficiency of multi-core chips is the energy used for communication among cores over a Network on Chip (NoC). As the number of cores increases, this energy also increases, imposing serious constraints on design and performance of both applications and architectures. Therefore, understanding the impact of different design choices on NoC power and energy consumption is crucial to the success of the multi- and many-core designs. This dissertation proposes methods for modeling and optimizing energy consumption in multi- and many-core chips, with special focus on the energy used for communication on the NoC. We present a number of tools and models to optimize energy consumption and model its scaling behavior as the number of cores increases. We use synthetic traffic patterns and full system simulations to test and validate our methods. Finally, we take a step back and look at the evolution of computer hardware in the last 40 years and, using a scaling theory from biology, present a predictive theory for power-performance scaling in microprocessor systems
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