No abstract

An interval-mathematic approach is presented for frequency-domain simulation and sensitivity analysis of linear analog circuits under parameter variations. With uncertain parameters represented as intervals, bounding frequency-domain responses is formulated as the problem of solving systems of linear interval equations. The formulation is based on a variant of modified nodal analysis, and is particularly amenable to interval analysis. Some characterization of the solution sets of systems of linear interval equations are derived. With these characterizations, an elegant and efficient algorithm is proposed to solve systems of linear interval equations. While the widely used Monte Carlo approach requires many circuit simulations to achieve even moderate accuracy, the computational cost of the proposed approach is about twice that of one circuit simulation. The computed response bounds contain provably, or are usually very close to, the actual response bounds. Further, sensitivity under parameter variations can be computed from the response bounds at minor computational cost. The algorithms are implemented in SPICE3F5, using sparse-matrix techniques and tested on several practical analog circuits.

No abstract

Fault-driven analog and mixed-signal testing calls for rapid fault simulation techniques. A problem that has not been addressed effectively by existing research is that circuit parameters have tolerance ranges. In this paper, we propose representing parameters under variations as intervals, and present an efficient algorithm -based on interval analysis and Householder's formula -to compute the worst-case response bounds of good and faulty linear(ized) circuits under parameter variations. Our approach takes CPU time comparable to one nominal circuit simulation, and always produces correct and conservative results. The algorithm has been implemented into SPICE3F5. Experimental results show an acceptable accuracy.parametric variations which cause the circuit performances to be outside the preset specifications are considered to be faults. As a result, the responses for both good and faulty circuits are bands, called good (vesponse) band and fault (response) band respectively. This is illustrated in Figure 1. Clrcuir Response 1.

No abstract