A new cycle test system emulating inductive switching waveforms

Cycle life testing of smart power switches requires significant hardware effort to provide the required ohmic-inductive load patterns. A new reliability test system for research purposes is therefore introduced that generates arbitrary current waveforms to emulate inductive switching behavior. This allows flexible cycle stress testing of integrated power switches under arbitrary application conditions. The current drivers of the proposed "ARCTIS" test system are protected from thermal overload in case of failure of a stressed device using a combination of case temperature sensing and a thermal equivalent circuit. Therefore the power MOSFETs in the output stage may be utilized to the limits of their dynamical safe operating area. All devices under test are continuously monitored for short circuit and open load failures. The respective waveforms and failure events are digitally recorded by the PXI-based control system to obtain a statistical basis for the evaluation of cycle life time.