The Waveform Relaxation (WR) method is an iterative method for analyzing nonlinear dynamical systems in the time domain. The method, at each iteration, decomposes the system into several dynamical subsystems each of which is analyzed for the entire given time interval. Sufficient conditions for convergence of the WR method are proposed and examples in MOS digital integrated circuits are given to show that these conditions are very mild in practice. Theoretical and computational studies show the method to be efficient and reliable.

The Waveform Relaxation Method for Time-Domain Analysis of Large Scale Integrated Circuits

With the rapid developments in very large-scale integration (VLSI) technology, design and computer-aided design (CAD) techniques, at both the chip and package level, the operating frequencies are fast reaching the vicinity of gigahertz and switching times are getting to the subnanosecond levels. The ever increasing quest for high-speed applications is placing higher demands on interconnect performance and highlighted the previously negligible effects of interconnects such as ringing, signal delay, distortion, reflections, and crosstalk. In this review paper various high-speed interconnect effects are briefly discussed. In addition, recent advances in transmission line macromodeling techniques are presented. Also, simulation of high-speed interconnects using model-reduction-based algorithms is discussed in detail.

/pdf/simulation-of-high-speed-interconnects-4k5dt3lsur.pdf

Simulation of high-speed interconnects

The Ptolemy project studies heterogeneous modeling and design of concurrent systems. Th is on embedded systems , particularly those that mix technologies, including for example analog a digital electronics, hardware and software, and electronics and mechanical devices (including M microelectromechanical systems). The focus is also on systems that are complex in the sense t mix widely different operations, such as signal processing, feedback control, sequential decision ing, and user interfaces. Modelingis the act of representing a system or subsystem formally. A model might be mathe cal, in which case it can be viewed as a set of assertions about properties of the system such as tionality or physical dimensions. A model can also be constructive, in which case it defin computational procedure that mimics a set of properties of the system. Constructive models ar used to describe behavior of a system in response to stimulus from outside the system. Cons models are also called executable models. Designis the act of defining a system or subsystem. Usually this involves defining one or m models of the system and refining the models until the desired functionality is obtained within a constraints. Design and modeling are obviously closely coupled. In some circumstances, models m immutable, in the sense that they describe subsystems, constraints, or behaviors that are ex imposed on a design. For instance, they may describe a mechanical system that is not under des must be controlled by an electronic system that is under design. Executable models are sometimes called simulations, an appropriate term when the executab model is clearly distinct from the system it models. However, in many electronic systems, a mode starts as a simulation mutates into a software implementation of the system. The distinction be the model and the system itself becomes blurred in this case. This is particularly true for emb software.

/pdf/overview-of-the-ptolemy-project-105cn2y1j9.pdf

Overview of the Ptolemy project

https://ipstconf.org/papers/Proc_IPST2005/05IPST139.pdf

On a new approach for the simulation of transients in power systems

DELIGHT.SPICE is the union of the DELIGHT interactive optimization-based computer-aided-design system and the SPICE circuit analysis program. With the DELIGHT.SPICE tool, circuit designers can take advantage of recent powerful optimization algorithms and a methodology that emphasizes designer intuition and man-machine interaction. Designer and computer are complementary in adjusting parameters of electronic circuits automatically to improve their performance criteria and to study complex tradeoffs between multiple competing objectives, while simultaneously satisfying multiple-constraint specifications. The optimization runs much more efficiently than previously because the SPICE program used has been enhanced to perform DC, AC, and transient sensitivity computation. Industrial analog and digital circuits have been redesigned using this tool, yielding substantial improvement in circuit performance. >

DELIGHT.SPICE: an optimization-based system for the design of integrated circuits

The nodal method has been widely used for formulating circuit equations in computer-aided network analysis and design programs. However, several limitations exist in this method including the inability to process voltage sources and current-dependent circuit elements in a simple and efficient manner. A modified nodal analysis (MNA) method is proposed here which retains the simplicity and other advantages of nodal analysis while removing its limitations. A simple and effective pivoting scheme is also given. Numerical examples are used to compare the MNA method with the tableau method. Favorable results are observed for the MNA method in terms of the dimension, number of nonzeros, and fill-ins for comparable circuit matrices.

https://cseweb.ucsd.edu/classes/fa04/cse245/Reading/MNA.pdf

Chung-Wen Ho

Papers

The modified nodal approach to network analysis