Fault Analysis and Parameter Tuning in Analog Circuits

Abstract

<p>This thesis addresses itself to the two principal problems of computer-aided-testing in analog circuits, namely, fault analysis and postproduction tuning.</p> <p>A unified approach to fault location in large analog circuits is introduced. The approach closely meets the goals of practical criteria for fault analysis. Network decomposition and logical analysis are incorporated to identify faulty subnetworks. Necessary and almost sufficient testing conditions for locating fault-free subnetworks are derived. These conditions are based on invoking KCL and topological relations between subnetworks. The application of the approach to practical linear and nonlinear networks is presented. Further fault analysis is carried out to identify faulty elements or regions inside the faulty subnetwork. Deterministic and approximate methods are introduced for that respect. The approximate method utilizes an estimation criterion, namely, the least-one objective function to predict the most likely faulty elements. The deterministic methods verify the existence of faults by examining the consistency of algebraic equations or by matching the subnetwork response using faulty models of the subnetwork elements. A number of network examples are considered to illustrate the application of the introduced methods.</p> <p>The deviation in the response of a manufactured circuit can often be compensated by adjusting specified tunable elements. A number of aspects of the postproduction tuning problem are studied. In particular, the relevant fundamental concepts and definitions are given, the tuning algorithms either functional or deterministic are reviewed and new techniques for choosing tunable parameters and critical response points are introduced. Two new functional tuning techniques are presented. The application of the new techniques in tuning a microwave network example is illustrated. A comparison and evaluation of four different tuning techniques are given by testing them in tuning an active filter example.</p>