Power MOSFET active power cycling for medical system reliability assessment
Abstract High voltage generator is one of the critical subsystems of a medical system. So, a methodology assessing its reliability from component to system is proposed. In this context, N-channel power MOSFETs that are used in high frequency inverter for supplying high voltage transformer is tested. These MOSFETs are subjected to power cycling test in order to reveal thermo-mechanical failure modes and at the same time evaluate their lifetime using DoE. The test is done by using an external current supply to induce self-heating through the component. Heating and cooling phase are controlled by a logic controller. The ON state resistance (RDSON) is monitored during the test as the failure indicator and different imaging methods are used for failure analysis and observed failures mechanism are discussed.