In this paper, we propose an approach for the analysis of power supply noise in the frequency domain for power/ground (P/G) networks of tree topologies. We model the P/G network as a linear time invariant (LTI) pseudo...
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In this paper, we propose an approach for the analysis of power supply noise in the frequency domain for power/ground (P/G) networks of tree topologies. We model the P/G network as a linear time invariant (LTI) pseudo-distributed RLC network and the gates (or cells) as time-varying current sources. Voltage fluctuation caused by the switching events is calculated based on the effective impedances seen by the corresponding current sources and the spatial correlation between the nodes of the power network. Superposition is applied to the LTI system to obtain the overall noise spectrum at any node of the power supply network. Inverse Fast Fourier Transformation (IFFT) is then performed on the frequency domain noise spectrum to obtain the time domain noise waveform. The proposed algorithm has a complexity of O(n2). Experimental results show that our approach can produce accurate noise waveforms.
In this paper, we propose a system-level power exploration methodology for embedded VLIW architectures based on an instruction-level analysis. The instruction-level energy model targets a general pipeline scalar proce...
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In this paper, we propose a system-level power exploration methodology for embedded VLIW architectures based on an instruction-level analysis. The instruction-level energy model targets a general pipeline scalar processor;several architectural parameters such as number and type of pipeline stages as well as average stall/latency cycles per instruction and inter-instruction effects are taken into account. The application of the proposed model to VLIW processors results intractable from the point of view of both spatial and temporal complexity (which grow exponentially w.r.t. the number of possible operations in the ISA). To reduce this complexity, the basic model has been extended by assuming that the energy associated with a long instruction is given by the sum of the energy associated with the single operations of the long instruction and the single pipeline stages. The instruction-level energy model has been applied to a simplified VLIW architecture to demonstrate the validity of the proposed approach.
A tool is presented that gives a high-level estimation of the power consumed by an analog continuous-time OTA-C filter when given only high-level input parameters such as dynamic range and signal swing. When used in c...
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A tool is presented that gives a high-level estimation of the power consumed by an analog continuous-time OTA-C filter when given only high-level input parameters such as dynamic range and signal swing. When used in combination with estimators for other building blocks (ADC's, DAC's, mixers,...) a truly high-level analog system exploration becomes feasible such as needed for architectural exploration of telecom systems. In literature only fundamental relations exist for analog filters, that predict the power with an error of orders of magnitude, which makes them hard to use in real system design. ACTIF combines existing filter synthesis methods with new behavioral models for transconductance stages in a novel way to obtain an optimized high-level yet accurate power estimation. To verify the presented approach, two recently published design examples are compared with the results from ACTIF.
In coupling delay computation, a Miller factor of more than 2X may be necessary to account for active coupling capacitance when modeling the delay of deep submicron circuitry in the presence of active coupling capacit...
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In coupling delay computation, a Miller factor of more than 2X may be necessary to account for active coupling capacitance when modeling the delay of deep submicron circuitry in the presence of active coupling capacitance. We propose an efficient method to estimate this factor such that the delay response of a decoupling circuit model can emulate the original coupling circuit. Under the assumptions of zero initial voltage, equal charge transfer, and 0.5VDD as the switching threshold voltage, an upper bound of 3X for maximum delay and a lower bound of -1X for minimum delay can be proven. Efficient Newton-Raphson iteration is also proposed as a technique for computing the Miller factor or effective capacitance. This result is highly applicable to crosstalk coupling delay calculation in deep submicron gate-level static timing analysis. Detailed analysis and approximation are presented. SPICE simulations are demonstrated to show high correlation with these approximations.
We address optimizing multi-valued (MV) logic functions in a multi-level combinational logic network. Each node in the network, called an MV-node, has multi-valued inputs and single multi-valued output. The notion of ...
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We address optimizing multi-valued (MV) logic functions in a multi-level combinational logic network. Each node in the network, called an MV-node, has multi-valued inputs and single multi-valued output. The notion of don't cares used in binary logic is generalized to multi-valued logic. It contains two types of flexibility: incomplete specification and non-determinism. We generalize the computation of observability don't cares for a multi-valued function node. Methods are given to compute (a) the maximum set of observability don't cares, and (b) the compatible set of observability don't cares for each MV-node. We give a recursive image computation to transform the don't cares into the space of local inputs of the node to be minimized. The methods are applied to some experimental multi-valued networks, and demonstrate reduction in the size of the tables that represent multi-valued logic functions.
We have designed and implemented a new class of fast and highly scalable placement algorithms that directly handle complex constraints and achieve total wirelengths comparable to the state of the art. Our approach exp...
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We have designed and implemented a new class of fast and highly scalable placement algorithms that directly handle complex constraints and achieve total wirelengths comparable to the state of the art. Our approach exploits recent advances in (i) multilevel methods for hierarchical computation, (ii) interior-point methods for nonconvex nonlinear programming, and (iii) the Fast Multipole Method for the order N evaluation of sums over the N(N - 1)/2 pairwise interactions of N components. Significant adaptation of these methods for the placement problem is required, and we have therefore developed a set of customized discrete algorithms for clustering, declustering, slot assignment, and local refinement with which the continuous algorithms are naturally combined. Preliminary test runs on benchmark circuits with up to 184,000 cells produce total wirelengths within approximately 5-10% of those of GORDIAN-L [1] in less than one tenth the run time. Such an ultra-fast placement engine is badly needed for timing convergence of the synthesis and layout phases of integrated circuit design.
The energy dissipation associated with driving long wires accounts for a significant fraction of the overall system energy. This is particularly the case with the increasing importance of the inter-wire parasitic capa...
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The energy dissipation associated with driving long wires accounts for a significant fraction of the overall system energy. This is particularly the case with the increasing importance of the inter-wire parasitic capacitance in deep sub-micron technology. A closed form solution for estimating the energy dissipation of a data bus is presented that uses an elaborate parasitic wire model. This includes the distributed RLC effects of wires as well as the coupling between wires. We also propose a general class of coding techniques to reduce energy dissipation for data transmission by trading-off between computation and communication costs. An algorithm is presented to design efficient coding strategies to minimize energy. When the effects of interwire capacitance are taken into account, the best coding strategy is not to simply minimize transitions - an approach followed by previous research. Instead, Transition Pattern Coding (TPC) modifies the transition profile to minimize energy, and in many cases higher transition activity can result in lower energy. Results show that up to a factor of 2 reduction in energy.
The incremental, 'construct by correction' design methodology has become widespread in constraint-dominated DSM design. We study the problem of ECO for physical design domains in the general context of increme...
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The incremental, 'construct by correction' design methodology has become widespread in constraint-dominated DSM design. We study the problem of ECO for physical design domains in the general context of incremental optimization. We observe that an incremental design methodology is typically built from a full optimizer that generates a solution for an initial instance, and an incremental optimizer that generates a sequence of solutions corresponding to a sequence of perturbed instances. Our hypothesis is that in practice, there can be a mismatch between the strength of the incremental optimizer and the magnitude of the perturbation between successive instances. When such a mismatch occurs, the solution quality will degrade - perhaps to the point where the incremental optimizer should be replaced by the full optimizer. We document this phenomenon for three distinct domains - partitioning, placement and routing - using leading industry and academic tools. Our experiments show that current CAD tools may not be correctly designed for ECO-dominated design processes. Thus, compatibility between optimizer and instance perturbation merits attention both as a research question and as a matter of industry design practice.
Communication designs form the fastest growing segment of the semiconductor market. Both network processors and wireless chipsets have been attracting a great deal of research attention, financial resources and design...
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Communication designs form the fastest growing segment of the semiconductor market. Both network processors and wireless chipsets have been attracting a great deal of research attention, financial resources and design efforts. However, further progress is limited by lack of adequate system methodologies and tools. Our goal in this tutorial is to provide impetus for development of communication design techniques and tools. The first part addresses network processors (NP) that we study from three viewpoints: application, architecture, and system software and compilation tools. In addition to summary of main issues and representative case studies, we identify main system design issues. The second part of the tutorial focuses on wireless design. The main emphasis is on platform-based design methodology that leverages on functional profiling, architecture exploration, and orthogonalization of concerns to facilitate low-power wireless communication systems. The highlight of the paper, an in-depth study of the state-of-the-art wireless design, PicoRadio, is used as explanatory design example.
Sub-micron feature sizes have resulted in a considerable portion of power to be dissipated on the buses, causing an increased attention on savings for power at the behavioral level and RT level of design. This paper a...
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Sub-micron feature sizes have resulted in a considerable portion of power to be dissipated on the buses, causing an increased attention on savings for power at the behavioral level and RT level of design. This paper addresses the problem of minimizing power dissipated in switching of the buses in data path synthesis. Unlike the previous approaches in which minimization of the power consumed in buses has not been considered until operation scheduling is completed, our approach integrates the bus binding problem into scheduling to exploit the impact of scheduling on reduction of power dissipated on the buses more fully and effectively. We accomplish this by formulating the problem into a flow problem in a network, and devising an efficient algorithm which iteractively finds maximum flow of minimum cost solutions in the network. Experimental results on a number of benchmark problems show that given resource and global timing constraints our designs are 22% power-efficient over the designs produced by a random-move based solution, and 18% power-efficient over the designs by a clock-step based optimal solution.
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