Entwicklung, Untersuchung und Vergleich von Selbsttestverfahren für integrierte Sensoren in der Betriebsphase

Abstract

Today and more and more in the near future, analogue circuits will place great importance on integration. Technological progresses in the field of microelectronic systems make it possible to integrate both sensors and actuators directly into the circuitry production process. The development of suitable self test methods becomes necessary, if the sensor will act in security relevant or life preserving systems. In the case of an incorrect measurement, an unwanted or uncontrolled system reaction could arise. This reaction can be suppressed, if the system is monitored during the operation phase. The function control should be done during the whole operation time. The aim of this dissertation and the previous works were to improve known methods and to develop new solutions; that can provide a statement to the function of the system during the operation phase. This dissertation contains the following topics: It presents which kind of defects that occurs to an erroneous system function of the considered system. To simulate this kind of defects some error modeling concepts was developed, of which some are presented. A summary about analogue and digital test methods and how they can complement each other is given. It is described how a temperature measurement system could be tested and demonstrates new test methods and solutions developed for sensor systems which are not available for direct stimulation. One test method use the limited dynamic of system itself to make a time based correlation between following measurement values. The result of this correlation can be used as test criteria. Another new test method uses properties of a researched amplifier circuit structure to make a test during the operation phase. Furthermore it is described if and how an observation of the supply current is an adequate test criterion. Therefore a new current sensor was developed, which allows a temperature independent measurement.