Analog Circuit Test Point Selection Incorporating Discretization-Based Fuzzification and Extended Fault Dictionary to Handle Component Tolerances

Abstract

Analog circuit test point selection aims to find the least number of test points that can isolate all the fault modes (including the fault-free case). The fault dictionary, which uses the integer-valued codes to represent the diagnosability of a specific test point, is very popular and saves computation efforts. However, the classical fault dictionary has a limited ability to handle the component tolerances and continuous-valued monitoring variables. To solve the problem, the approach of clustering-based discretization (CBD) is used to abstract the information of data samples distribution. We also develop a new fault dictionary construction technique called extended fault dictionary (EFD). An element of EFD is a set containing either a single integer code or multiple integer codes. The fault isolation rules are redefined, and a novel entropy measure is created in line with CBD of the continuous values. The practical test point selection procedures are presented, which avoids the likelihood to include a redundant test point. Finally, two application studies of circuit test point election are presented, showing that the proposed method provides an effective implementation option for the engineering practice of circuit diagnosis.