The trend in power converter is towards increasing power densities. To achieve this goal, it is necessary to reduce power losses, overall system size, and weight by increasing the switching frequency. High reliability is also very important for todays switched-mode power supplies (SMPS). The zero-voltage-switching (ZVS) or zero-current-switching (ZCS) topologies that allow for hight frequency switching while minimizing the switching losses are of interest. The ZVS topology operating at high frequency can improve the efficiency as well as reduce the size of the application. It also reduces the stress on power switches and therefore improves the reliability. LLC resonant half-bridge converters are becoming a popular topology because they can provide these benefits. It has become widely accepted for applications from high-end servers to flat-panel display power supplies, but the ZVS bridge require a MOSFET with fast reverse-recovery body diode for better reliability. This application note discusses potential failure mode and mechanism in LLC resonant converters and provides a simple and cost-effective solution to prevent failures. — Article Quote
The topics discussed inside the application note including the abstract, introduction, LLC Resonant High-Bridge Converter, Failure modes in LLC resonant converter, overload failure mode, short-circuit failure mode, Power MOSFET failure mechanism, body diode reverse recovery dv/dt, solution, experimental results at short circuit, and conclusion.
Source : Won-suk Choi and Sungmo Young (Faichild Semiconductor)
Find more details about the MOSFET failure modes in LLC resonance converter from the FAIRCHILD SEMICONDUCTOR by downloading the pdf document from the following source:
Analysis of MOSFET Failure Modes in LLC Resonance Converter Application Notes DOWNLOAD