Thermal FEM (Finite Element Method) simulations can be used to predict the thermal behavior of power semiconductors in application. Most power semiconductors are made of silicon. Silicon thermal material properties are significantly temperature dependent. In this paper, validity of a common non-linear silicon material model is verified by transient non-linear thermal FEM simulations of Smart Power Switches and measurements. For verification, over-temperature protection behavior of Smart Power Switches is employed. This protection turns off the switch at a predefined temperature which is used as a temperature reference in the investigation. Power dissipation generated during a thermal overload event of two Smart Power devices is measured and used as an input stimulus to transient thermal FEM simulations. The duration time of the event together with the temperature reference is confronted with simulation results and thus the validity of the silicon model is proved. In addition, the impact of non-linear thermal properties of silicon on the thermal impedance of power semiconductors is shown.

The short circuit robustness of smart power switches has become a major concern in automotive applications over the last years. This is reflected in a new extension to the AEC qualification standard Q100-12, where the basic requirements for short circuit testing of "smart" switches with integrated overcurrent protection are given. This paper describes the practical implementation of a compact test setup for the laboratory measurement of short circuit events with initial peak currents as high as 1000A at supply voltages up to 60V. The AEC standard further requires a low-ohmic test circuit with well-defined impedances. This is usually achieved by arrangement of a large DC power supply with discrete copper bus bars, massive test fixtures and solenoid type air coils to achieve well-defined resistance and inductance values. Our novel approach utilizes a compact printed circuit board arrangement instead, replacing large copper cross sections by short distances and optimized geometries to achieve the same performance at a fraction of the cost and space requirements.To protect the equipment from potential hazard of fire in case of a destructive device failure without sacrificing performance, fast overcurrent detection is required as well as shutdown and removal of energy from the tested device within microseconds. This can be achieved with low-cost offthe-shelf current sensors and surface-mounted MOSFET switches by careful consideration of their specified properties.Representative measurements of industry standard high current smart power switches show that the presented test equipment meets the requirements of Q100-12 for laboratory short circuit measurements.

Reliability stress testing of power semiconductors requires significant development effort for a test apparatus to provide the required functionality. This paper presents a modular test system architecture which focuses on flexibility, reusability and adaptability to future test requirements. Different types of tests for different devices in application circuit configuration can be implemented based on the same modular test system concept. Vital parameters of the device under test (DUT) can be acquired in situ during the running stress test. This enables to collect drift data of this parameters. The control and data acquisition parts of the test system are separated from the actual test circuit. With this physical separation, the same control part can be used for different types of tests. Experimental results of a prototype test system are provided.

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