Abstract: The adjoint network reduction technique has been shown to reduce 50% of the computational complexity of constructing the congruence transformation matrix. The method was suitable for analyzing the special multi-port driving-point impedance of RLC interconnect circuits. This technique is extended for the general circumstances of RLC interconnects. Comparative studies among the conventional methods and the proposed methods are also investigated. Experimental results will demonstrate the accuracy and the efficiency of the proposed method.

Abstract: A method estimates the signal delay in a VLSI circuit and accurately estimates the delay and conversion time of a transmission signal in the circuit in order to prevent a designer of the VLSI circuit from erroneously judging the logic made by the designed circuit.

Abstract: Two-sided projection-based model reductions have become a necessity for efficient interconnect modeling and simulations in VLSI design. In order to choose the order of the reduced system that can really reflect the essential dynamics of the original interconnect, the element of reduced model of the transfer function can be considered as a stopping criteria to terminate the non-symmetric Lanczos iteration process. Furthermore, the approximate transfer function can also be expressed as the original interconnect model with some additive perturbations. The perturbation matrix only involves at most a rank-2 modification at the previous step of the non-symmetric algorithm. The information of stopping criteria will provide a guideline for the order selection scheme used in the Lanczos model-order reduction algorithm.

Abstract: This invention relates to a method of estimating the signal delay in a VLSI circuit and accurately estimating the delay and conversion time of a transmission signal in the circuit in order to prevent a designer of the VLSI circuit from erroneously judging the logic made by the designed circuit.

Abstract: A method of searching paths that are susceptible to electrostatic discharge (ESD) at the beginning of an integrated circuit (IC) design is disclosed that includes a circuit spreading out algorithm, a matrix closure algorithm, and a supernode algorithm. The found paths are required to satisfy conditions including that (a) they are connected from a gate of a transistor to a source or a drain thereof, and (b) the head node and the tail node of each path are pins of a top level of the IC. ?1/0/1 matrix multiplication is employed by both the circuit spreading out algorithm and the matrix closure algorithm so as to obtain a result of node connections after a plurality of matrix self-multiplications.

Abstract: A method of reducing a MIMO interconnect circuit system in a global Lanczos algorithm is used for estimation of the error margin between the original model and the reduced model of MIMO circuit system. In the algorithm, a projection matrix and then a circuit of declining order system are given. A turbulence system being added to the original system, the transfer function union is completely identical to the reduced system union given in the algorithm. It proves that the union of preceding 2q order of the transfer function of reduced system may be surely corresponding to that of original system. It is deduced from the turbulence system added to the original system that the union of preceding 2q order is equal to that of reduced system. In this invention, the algorithm is the basis of determination of the reduced circuit order in a model reduction algorithm a Krylov subspace.

Abstract: A new method of searching paths that are suffering ESD is proposed in this invention, improving the design flow of a VLSI circuit and reducing the cost of designing the ESD circuits in a whole chip, comprising three parts, the circuit flattening, the closure algorithm, and the supernode algorithm. The objective is to find the paths satisfying the following two constraints: (1) only one edge connected to the gate pin and the source (or drain) pin is allowed; (2) only the head-node and the tail-node in a path could be the pin of top-level circuit. Two algorithms in this invention are the closure algorithm that uses the closure property in the ?1/0/1 matrix multiplication so that the connective property of nodes can be observed after several matrix self-multiplication, and the supernode algorithm.

Abstract: A new method for MIMO RLCG interconnects model order reduction technique using the global Arnoldi algorithm is proposed that is an extension of the standard Arnoldi algorithm for MIMO systems. Under this framework, the input matrix serves as a stacked vector form and the global Arnoldi algorithm will be the standard Arnoldi algorithm applied to a new matrix pair. This new matrix Krylov subspace from the Frobenius orthonormalization process is the union of system moments. By employing the congruence transformation with this matrix Krylov subspace, the one-sided projection method can be used to construct a reduced-order system. Connections of the reduced system and the original RLCG interconnect circuits are developed. The transfer matrix residual error of reduced system is derived analytically. This error information will be a guideline for the order selection scheme. Experimental results demonstrate the feasibility and the effectiveness of the proposed method.

Abstract: A moment computation technique for general lumped R(L)C interconnect circuits with multiple resistor loops is proposed. Using the concept of tearing, a lumped R(L)C network can be partitioned into a spanning tree and several resistor links. The contributions of network moments from each free and the corresponding links can be determined independently. By combining the conventional moment computation algorithms and the reduced ordered binary decision diagram (ROBDD), the proposed method can compute system moments efficiently. Experimental results demonstrate that the proposed method can indeed obtain accurate moments and is more efficient than the conventional approach.

Abstract: A method for low power clock tree synthesis using buffer insertion, removal and resizing for high-speed VLSI design is proposed. A developed tool can be embedded in the existing clock tree synthesis design flow to ensure satisfying both specifying database constrains and clock skew constrains. For a given clock tree netlist, location information of buffers, parameters of wires and buffers' timing and power library are all included. Buffer delay and wire delay of the given clock tree netlist are calculated first. Then, a feasible solution is solved if an input netlist is not feasible for given constrains. Finally, a modified low power clock tree netlist, which satisfies timing specifications, is obtained using the proposed method.

Abstract: Two-sided projection-based model reductions has become a necessity for efficient interconnect modeling and simulations in VLSI design. In order to choose the order of the reduced system that can really reflect the essential dynamics of the original interconnect, the element of reduced model of the transfer function can be considered as a stopping criteria to terminate the non-symmetric Lanczos iteration process. Furthermore, it can be found that the approximate transfer function can also be expressed as the original interconnect model with some additive perturbations. The perturbation matrix only involves at most rank-2 modification at the previous step of the non-symmetric algorithm. The information of stopping criteria will provide a guideline for the order selection scheme used in the Lanczos model-order reduction algorithm.

Abstract: A method for efficiently estimating crosstalk noise of high-speed VLSI interconnects models high-speed VLSI interconnects as lumped RLG coupled frees. An inductive crosstalk noise waveform can be accurately estimated in an efficient manner using a linear time moment computation technique in conjunction with a projection-based order reduction method. Recursive formulas of moment computations for coupled RC trees are derived taking into consideration of both self inductances and mutual inductances. Also, analytical formulas of voltage moments at each node will be derived explicitly. These formulas can be efficiently implemented for use in crosstalk estimations.

Abstract: The adjoint network reduction technique has been shown to reduce 50% of the computational complexity of constructing the congruence transformation matrix. The method was suitable for analyzing the special multi-port driving-point impedance of RLC interconnect circuits. This paper extends this technique for the general circumstances of RLC interconnects. Comparative studies among the conventional methods and the proposed methods are also investigated. Experimental results will demonstrate the accuracy and the efficiency of the proposal method.

Abstract: A method and verification of estimating crosstalk noise in coupled RLC interconnects with distributed line in nanometer integrated circuits is provided. In this invention, nanometer VLSI interconnects are modeled as distributed RLC coupled trees. The efficiency and the accuracy of moment computation of distributed lines can be shown that outperform those of lumped ones. The inductive crosstalk noise waveform can be accurately estimated in an efficient manner using the linear time moment computation technique in conjunction with the projection-based order reduction method. Recursive formulas of moment computations for coupled RC trees are derived with considering both self inductances and mutual inductances. Also, analytical formulas of voltage moments at each node will be derived explicitly. These formulas can be efficiently implemented for crosstalk estimations.

Abstract: A method for low power clock tree synthesis using buffer insertion, removal and resizing for high-speed VLSI design is proposed. The developed tool can be embedded in the existing clock tree synthesis design flow to ensure satisfying both the specifying database constrains and the clock skew constrains. For a given clock tree netlist, the location information of buffers, the parameters of wires and the buffers' timing and power library are all included. The buffer delay and wire delay of the clock tree are calculated first. Then the feasible solution is solved if the input netlist is not feasible for the given constrains. Finally, a modified low power clock tree netlist, which satisfies the timing specifications, is obtained using our proposed method.

Abstract: A new moment computation technique for general lumped R(L)C interconnect circuits with multiple resistor loops is proposed. Using the concept of tearing, a lumped R(L)C network can be partitioned into a spanning tree and several resistor links. The contributions of network moments from each tree and the corresponding links can be determined independently. By combining the conventional moment computation algorithms and the reduced ordered binary decision diagram (ROBDD), the proposed method can compute system moments efficiently. Experimental results have demonstrate that the proposed method can indeed obtain accurate moments and is more efficient than the conventional approach.

Abstract: A method and verification of estimating crosstalk noise in coupled RLC interconnects with distributed line in nanometer integrated circuits is provided. In this invention, nanometer VLSI interconnects are modeled as distributed RLC coupled trees. The efficiency and the accuracy of moment computation of distributed lines can be shown that outperform those of lumped ones. The inductive crosstalk noise waveform can be accurately estimated in an efficient manner using the linear time moment computation technique in conjunction with the projection-based order reduction method. Recursive formulas of moment computations for coupled RC trees are derived with considering both self inductances and mutual inductances. Also, analytical formulas of voltage moments at each node will be derived explicitly. These formulas can be efficiently implemented for crosstalk estimations.

Abstract: A method for efficiently estimating crosstalk noise of high-speed VLSI interconnects is provided. In the invention, high-speed VLSI interconnects are modeled as lumped RLC coupled trees. The inductive crosstalk noise waveform can be accurately estimated in an efficient manner using the linear time moment computation technique in conjunction with the projection-based order reduction method. Recursive formulas of moment computations for coupled RC trees are derived with considering both self inductances and mutual inductances. Also, analytical formulas of voltage moments at each node will be derived explicitly. These formulas can be efficiently implemented for crosstalk estimations.