Diagnosis of Soft Spot Short Defects in Analog Circuits Considering the Thermal Behaviour of the Chip

The paper deals with fault diagnosis of nonlinear analogue integrated circuits. Soft spot short defects are analysed taking into account variations of the circuit parameters due to physical imperfections as well as self-heating of the chip. A method enabling to detect, locate and estimate the value of a spot defect has been developed. For this purpose an appropriate objective function was minimized using an optimization procedure based on the Fibonacci method. The proposed approach exploits DC measurements in the test phase, performed at a limited number of accessible points. For illustration three numerical examples are given.

High Temperature Digital and Analogue Integrated Circuits in Silicon Carbide

Silicon Carbide devices are capable of operating as a semiconductor at high temperatures and this capability is being exploited today in discrete power components, bringing system advantages such as reduced cooling requirements [1]. Therefore there is an emerging need for control ICs mounted on the same modules and being capable of operating at the same temperatures. In addition, several application areas are pushing electronics to higher temperatures, particularly sensors and interface devices required for aero engines and in deep hydrocarbon and geothermal drilling. This paper discusses a developing CMOS manufacturing process using a 4H SiC substrate, which has been used to fabricate a range of simple logic and analogue circuits and is intended for power control and mixed signal sensor interface applications [2]. Test circuits have been found to operate at up to 400°C. The introduction of a floating capacitor structure to the process allows the use of switched capacitor techniques in mixed signal circuits operating over an extended temperature range.

Evolutionary algorithms for global parametric fault diagnosis in analogue integrated circuits

Evolutionary algorithms for global parametric fault diagnosis in analogue integrated circuitsAn evolutionary method for analogue integrated circuits diagnosis is presented in this paper. The method allows for global parametric faults localization at the prototype stage of life of an analogue integrated circuit. The presented method is based on the circuit under test response base and the advanced features classification. A classifier is built with the use of evolutionary algorithms, such as differential evolution and gene expression programming. As the proposed diagnosis method might be applied at the production phase there is a method for shortening the diagnosis time suggested. An evolutionary approach has been verified with the use of several exemplary circuits - an oscillator, a band-pass filter and two operational amplifiers. A comparison of the presented algorithm and two classical methods - the linear classifier and the nearest neighborhood method - proves that the heuristic approach allows for acquiring significantly better results.