Estimation of a maximum bound of uncertain parameter fluctuations with applications to analogue IP-cores

Abstract

In analogue circuits, parameter fluctuations trigger variations in functional behaviour. However, such fluctuations may not result in faulty behaviour and, hence, the circuit may still function satisfactorily. Therefore, it is necessary to estimate a maximum bound of fluctuations that retains satisfactory functional behaviour. A method is presented which integrates design and test and is based on analytical modelling equations to estimate the sensitivity and determine the reliability of analogue circuits in the presence of parameter fluctuations. The proposed method enables two outcomes to be satisfied: (i) during the design process, the designer will need to consider the extent to which changes in circuit parameters will affect behaviour in order to determine the robustness of the design and the range of signatures within the bound which prove satisfactory behaviour; (ii) during operation, parameter fluctuations outside a predefined bound can be used to generate a warning condition.