US 6,636,839 B1Granted

Method for determining the steady state behavior of a circuit using an iterative technique

AssigneeCadence Design Systems, Inc.

InventorsRicardo Telichevesky, Kenneth S. Kundert, Jacob K. White

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Abstract

An efficient method for determining the periodic steady state response of a circuit driven by a periodic signal, the method including the steps of 1) using a shooting method to form a non-linear system of equations for initial conditions of the circuit that directly result in the periodic steady state response; 2) solving the non-linear system via a Newton iterative method, where each iteration of the Newton method involves solution of a respective linear system of equations; and 3) for each iteration of the Newton method, solving the respective linear system of equations associated with the iteration of the Newton method via an iterative technique. The iterative technique may be a matrix-implicit application of a Krylov subspace technique, resulting in a computational cost that grows approximately in a linear fashion with the number of nodes in the circuit.

Claims12

Dependent claims

In a circuit simulation tool, a method for determining a periodic steady state output response of a circuit driven by a periodic input signal, the periodic steady state output response covering a plurality of timepoints that span a period of the periodic input signal, the plurality of timepoints including a last timepoint, the method comprising:

using a finite-difference method to form a non-linear system of equations for the periodic steady state output response of the circuit;
solving the non-linear system of equations via a Newton iterative method to produce the periodic steady state output response of the circuit, each iteration of the Newton method associated with a respective linear system of equations;
for each iteration of the Newton method, using a matrix-implicit iterative technique to solve for nodal voltages of the circuit at a particular one of the timepoints, the nodal voltages satisfying the respective linear system of equations associated with the iteration of the Newton method, wherein use of the matrix-implicit iterative technique avoids computation of a matrix to produce a solution of the respective linear system of equations;
and
providing the periodic steady state output response to the circuit simulation tool.

2 more elements

Dependencies are inferred from the claim text.