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44
Timing and Area Optimization for StandardCell VLSI Circuit Design
, 1995
"... A standard cell library typically contains several versions of any given gate type, each of which has a different gate size. We consider the problem of choosing optimal gate sizes from the library to minimize a cost function (such as total circuit area) while meeting the timing constraints imposed o ..."
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Cited by 16 (1 self)
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A standard cell library typically contains several versions of any given gate type, each of which has a different gate size. We consider the problem of choosing optimal gate sizes from the library to minimize a cost function (such as total circuit area) while meeting the timing constraints imposed on the circuit. After
Optimizing dominant time constant in RC circuits
, 1996
"... We propose to use the dominant time constant of a resistorcapacitor (RC) circuit as a measure of the signal propagation delay through the circuit. We show that the dominant time constant is a quasiconvex function of the conductances and capacitances, and use this property to cast several interestin ..."
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Cited by 16 (7 self)
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We propose to use the dominant time constant of a resistorcapacitor (RC) circuit as a measure of the signal propagation delay through the circuit. We show that the dominant time constant is a quasiconvex function of the conductances and capacitances, and use this property to cast several interesting design problems as convex optimization problems, specifically, semidefinite programs (SDPs). For example, assuming that the conductances and capacitances are affine functions of the design parameters (which is a common model in transistor or interconnect wire sizing), one can minimize the power consumption or the area subject to an upper bound on the dominant time constant, or compute the optimal tradeoff surface between power, dominant time constant, and area. We will also note that, to a certain extent, convex optimization can be used to design the topology of the interconnect wires. This approach has two advantages over methods based on Elmore delay optimization. First, it handles a far wider class of circuits, e.g., those with nongrounded capacitors. Second, it always results in convex optimization problems for which very efficient interiorpoint methods have recently been developed. We illustrate the method, and extensions, with several examples involving optimal wire and transistor sizing.
Delay and area optimization for discrete gate sizes under doublesided timing constraints,” CICC
, 1993
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Speeding up Pipelined Circuits through a Combination of Gate Sizing and Clock Skew Optimization
 Proc. Int'l Conf. on ComputerAided Design
, 1995
"... An algorithm for unifying the techniques of gate sizing and clockskew optimization for acyclic pipelines is presented in this paper. In the design of circuits under very tight timing specifications, the area overhead of gate sizing can be considerable. The procedure utilizes the idea of cycleborrow ..."
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Cited by 12 (0 self)
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An algorithm for unifying the techniques of gate sizing and clockskew optimization for acyclic pipelines is presented in this paper. In the design of circuits under very tight timing specifications, the area overhead of gate sizing can be considerable. The procedure utilizes the idea of cycleborrowing using clock skew optimization to relax the stringency of the timing specification on the critical stages of the pipeline. Experimental results verify that cycleborrowing using sizing+skew results in a better overall areadelay tradeoff than with sizing alone.
PowerDelay Optimizations in Gate Sizing
, 2000
"... The problem of powerdelay tradeoffs in transistor sizing is examined using a nonlinear optimization formulation. Both the dynamic and the shortcircuit power are considered, and a new modeling technique is used to calculate the shortcircuit power. The notion of transition density is used, with an ..."
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Cited by 9 (0 self)
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The problem of powerdelay tradeoffs in transistor sizing is examined using a nonlinear optimization formulation. Both the dynamic and the shortcircuit power are considered, and a new modeling technique is used to calculate the shortcircuit power. The notion of transition density is used, with an enhancement that considers the effect of gate delays on the transition density. When the shortcircuit power is neglected, the minimum power circuit is identical to the minimum area circuit. However, under our more realistic models, our experimental results on several circuits show that the minimum power circuit is not necessarily the same as the minimum area circuit.
Crosstalk Reduction by Transistor Sizing
 In Proc. ASPDAC
, 1999
"... In this paper we consider transistor sizing to reduce crosstalk. First, crosstalk noise dependency on wire width, wire spacing, driver and receiver sizes are discussed, and validated by experiments. Then transistor sizing for timing and noise is discussed and solved using optimization techniques. Ex ..."
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Cited by 9 (0 self)
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In this paper we consider transistor sizing to reduce crosstalk. First, crosstalk noise dependency on wire width, wire spacing, driver and receiver sizes are discussed, and validated by experiments. Then transistor sizing for timing and noise is discussed and solved using optimization techniques. Experimental results suggest that crosstalk violations can be removed by transistor sizing with very small area ovehead. I.
Numerically convex forms and their application in gatesizing
 in IEEE Transactions on ComputerAided Design of Integrated Circuits and Systems
, 2007
"... Abstract—Convexoptimization techniques are very popular in the very largescaleintegration design society due to their guaranteed convergence to a global optimal point. The table data need to be fitted into convex forms to be used in the convex optimization problems. Fitting the tables into posyno ..."
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Cited by 7 (1 self)
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Abstract—Convexoptimization techniques are very popular in the very largescaleintegration design society due to their guaranteed convergence to a global optimal point. The table data need to be fitted into convex forms to be used in the convex optimization problems. Fitting the tables into posynomials, which are analytically convex under logarithmic transformation, may suffer from the excessive fitting errors as the fitting problem is nonconvex. In this paper, we propose to directly adjust the lookuptable values into a numerically convex lookup table without any explicit analytical form. We show that numerically “convexifying ” the lookuptable data with minimum perturbation can be formulated as a convex semidefinite optimization problem, and hence, optimality can be reached in polynomial time. We also propose three algorithms to make the table data smooth to enable faster convergence of the convex optimizer. Results from extensive experiments on industrial cell libraries demonstrate 9.6 × improvement in fitting error over a welldeveloped posynomialfitting procedure. We illustrate the effectiveness of this model in a convex optimization problem by providing results for using our model in the optimal gate sizing of standard cells. We observe a 5.07 % improvement in the delay of International Symposium on Circuits and Systems (ISCAS) benchmark circuits over the posynomialfitting procedure. Index Terms—Convex optimization, gate sizing, semidefinite programming. I.
Optimal 2D cell layout with integrated transistor folding
 In Proceedings of International Conference on Computer Aided Design
, 1998
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