Thermal and Electrical Considerations for MOSFETs in DC-DC Converters for Portable Applications

摘要

The paper considers thermal issues in notebook computers and their influences on the MOSFETs in DC/DC converters with respect to the MOSFET parameters in order to optimize the converter efficiency. Due to the silicon limit - the inherent breakdown voltage of the basis material of MOSFETs - every MOSFET with a higher drain-to-source breakdown voltage has a higher R_((DS)ON) as well. This is valid for MOSFETs made with the same basic technology, package technology and with identical area-specific main parameters such as V_(GSmax), gfs, P_(tot), T_(jmax). This paper discusses how to choose the right MOSFET using the buck converter as an application example. It shows that higher performance of the circuit can be achieved without having a damaging or detrimental influence on the device, if the MOSFET is operated outside of its static safe operation area but still within the specified limits.