Soft fault diagnosis in linear circuits: Test selection and non-iterative identification procedure

Abstract

The paper deals with the diagnosis of soft faults in linear electronic circuits. Circuits containing operational amplifiers operating at low frequencies are considered. A method for identifying single and double faults in the AC domain is proposed. The method is non-iterative and relies on certain relations derived from the modified nodal description of the circuit. An essential part of the paper is a procedure enabling the selection of measurement nodes and test frequencies. The algorithm considers the AC sensitivities, the measurement accuracy, and the diagnostic method applied. The effectiveness of both methods was verified on several electronic circuits. The simulation and laboratory tests were done. Considering parameter tolerances and measurement uncertainties leads to determining intervals of parameter values covering the actual faults.