An algorithm for simulating power/ground networks using Padeapproximants and its symbolic implementation

摘要

This paper presents an event-driven algorithm and its symbolicnimplementation for the analysis of power and ground (P/G) bus networks.nThe algorithm uses frequency-domain techniques and moment matchingnapproaches based on Pade approximants to estimate the transfer functionnat each node in the P/G network. Afterwards, the transient waveforms arenextracted for each node. The process requires repetitive simulation of anlinear and time-variant (from one time event to the next) circuit modelnfor the P/G network which is the reason a symbolic implementation wasnproduced. The P/G network is modeled by a hierarchical combination ofnmesh and tree structures that are composed of a collection ofnRC-Π-segments and pulldown (or pullup) switches. The switches arensymbolically represented by Boolean variables and a compiled symbolicncode is generated only once for each P/G network. The transientnwaveforms are then produced by repetitive evaluation of the symbolicnoutput. The results show that the symbolic implementation is an order ofnmagnitude faster, with reasonably good accuracy, than using antraditional analog circuit simulator like SPICE