摘要:
A computer-implemented system, method, and storage device simulate a periodic voltage waveform in a network model of the integrated circuit design. The method then determines resultant current values in each segment of nets of the integrated circuit design resulting from the periodic voltage waveform and performs a Fourier transform of the periodic voltage waveform to generate a frequency domain representation of the periodic voltage waveform. The frequency domain representation comprises multiple Fourier terms, each of the Fourier terms is a frequency that is a multiple of the base frequency. Next, the method performs an AC analysis of the resultant voltage at each frequency of the multiple Fourier terms. The AC analysis provides an electrical current value for each of the frequencies of the Fourier terms for each of the nets. This allows the method to compute a root mean square current through each of the nets based on the AC analysis. Then, the method determines whether the root mean square current for any of the segments of the nets exceeds a current limit, and reports any segment of the nets for which the root mean square current exceeds the current limit.
摘要:
An approach for performing multiple voltage threshold timing analysis for a digital integrated circuit is described. In one embodiment, there is a multiple voltage threshold timing analysis tool for performing a multiple voltage threshold timing analysis of a digital integrated circuit having at least one logic gate loaded by an interconnect circuit. In this embodiment, a characterization data retrieving component is configured to obtain characterization data describing driving behavior of the at least one logic gate. An interconnect circuit model retrieving component is configured to obtain a model of the interconnect circuit. A multiple voltage threshold timing analysis component is configured to derive a sequence of crossing times for the driving point voltage waveform to advance between successive voltage thresholds. The multiple voltage threshold timing analysis component also generates a voltage waveform from the derived sequence of crossing times.
摘要:
This invention relates to computing numerical solutions of linear systems of equations, specifically to implementing preconditioning of the coefficient matrix of such a system. The preconditioning applies to any coefficient matrix, dense or sparse, based on the solutions of a physical problem of unknown functions, commonly referred to as basis or interpolation functions, where the basis function spans more then one mesh element. Examples of such linear systems can result from, as examples, an electromagnetic analysis of printed circuit boards or field scattering in radar applications, fluid mechanics and acoustics. A method and system to compute a preconditioner for a coefficient matrix A that is compatible with the linear system of equations that provides basis function support over at least two mesh elements. Coupling of the preconditioner between partitions of a portioned mesh representation is only through basis functions at the partition boundaries.
摘要:
An accurate method to compute the capacitance at a pin whose capacitance is slew dependant. The method uses existing library characterized data and provides an equation based approach which can easily be integrated in static timing analysis without the added resource needs that an iterative approach would require. An RC/RLC network from slew and output load dependent pin capacitance tables is generated. The resulting linear network which models the pin capacitance is then stitched to the original interconnect network and used to calculate the propagation delay across a gate and corresponding interconnect. The method steps include: a) determining a response of the gate pin capacitance to its input slew and output load; b) synthesizing a linear time-invariant filter that matches the response; c) extending the interconnect model to include the synthesized time-invariant filter; and d) inputting the extended interconnect model into a static timing analysis for determining timing behavior between a gate input and each of its fan-out gates.
摘要:
An approach for performing multiple voltage threshold timing analysis for a digital integrated circuit is described. In one embodiment, there is a multiple voltage threshold timing analysis tool for performing a multiple voltage threshold timing analysis of a digital integrated circuit having at least one logic gate loaded by an interconnect circuit. In this embodiment, a characterization data retrieving component is configured to obtain characterization data describing driving behavior of the at least one logic gate. An interconnect circuit model retrieving component is configured to obtain a model of the interconnect circuit. A multiple voltage threshold timing analysis component is configured to derive a sequence of crossing times for the driving point voltage waveform to advance between successive voltage thresholds. The multiple voltage threshold timing analysis component also generates a voltage waveform from the derived sequence of crossing times.
摘要:
The present invention comprises a system and method for reducing the order of models used to simulate complex electric circuits and linear systems. In particular, the method of the present invention comprises formulating expressions relating the input and output terminals of a complex electric circuit, wherein the expressions comprise a first model of the electric circuit; performing mathematical operations on the first model to reveal correlations between at least two input terminals or between at least two output terminals; and substituting a reduced order second model for the original first model, whereby the reduced order second model eliminates some or all aspects of correlations between input terminals or between output terminals. The system of the present invention comprises a computer system for performing model order reduction.
摘要:
A frequency-domain analysis method computes noise power spectral densities (PSDs) in nonlinear circuits. The method uses harmonic components of the periodic time-varying PSD of cyclostationary noise, i.e., harmonic power spectral densities which are deterministic functions that describe the time-varying second-order statistics of cyclostationary noise. A block-structured matrix equation is used which relates output noise statistics to input noise statistics. By exploiting Toeplitz block structure, an efficient noise calculation method requires O(nN log N) computation time and O(nN) memory, where n is the circuit size and N is the number of significant harmonics in the circuit's steady state. The method successfully treats device noise sources with arbitrarily shaped PSDs (including thermal, shot, and flicker noises), handles noise input correlations and computes correlations between different outputs.
摘要:
A method for optimizing a circuit includes at least a first branch and a second branch includes defining an objective function using a shape of waveforms measured at a timing point in each branch, and optimizing the objective function to minimize a variance of clock skew of the first branch and the second branch across different process voltage temperature values.
摘要:
A computer-implemented system, method, and storage device simulate a periodic voltage waveform in a network model of the integrated circuit design. The method then determines resultant current values in each segment of nets of the integrated circuit design resulting from the periodic voltage waveform and performs a Fourier transform of the periodic voltage waveform to generate a frequency domain representation of the periodic voltage waveform. The frequency domain representation comprises multiple Fourier terms, each of the Fourier terms is a frequency that is a multiple of the base frequency. Next, the method performs an AC analysis of the resultant voltage at each frequency of the multiple Fourier terms. The AC analysis provides an electrical current value for each of the frequencies of the Fourier terms for each of the nets. This allows the method to compute a root mean square current through each of the nets based on the AC analysis. Then, the method determines whether the root mean square current for any of the segments of the nets exceeds a current limit, and reports any segment of the nets for which the root mean square current exceeds the current limit.
摘要:
This invention relates to computing numerical solutions of linear systems of equations, specifically to implementing preconditioning of the coefficient matrix of such a system. The preconditioning applies to any coefficient matrix, dense or sparse, based on the solutions of a physical problem of unknown functions, commonly referred to as basis or interpolation functions, where the basis function spans more then one mesh element. Examples of such linear systems can result from, as examples, an electromagnetic analysis of printed circuit boards or field scattering in radar applications, fluid mechanics and acoustics. A method and system to compute a preconditioner for a coefficient matrix A that is compatible with the linear system of equations that provides basis function support over at least two mesh elements. Coupling of the preconditioner between partitions of a portioned mesh representation is only through basis functions at the partition boundaries.