Analogue fault modelling and simulation for supply current monitoring

Fault simulation of analogue circuits is a very CPU intensive task. This paper describes a technique to increase the speed of fault simulation. The effects of bridging faults within operational amplifiers have been classified according to the externally observable behaviour reducing the number of fault simulations by two thirds. Parameterisable macromodels have been written in which both fault-free specifications and faulty effects can be modelled. The supply current is also modelled. These macromodels have been verified by embedding within a larger circuit, and have been shown to accurately model fault-free and faulty behaviour, and to propagate faulty effects correctly. The macromodels simulate about 7.5 times faster than the full transistor model