1THERMAL DESIGN OF POWER MOSFETS OPERATING IN PARALLEL

The objective of this paper is the thermal design analysis of power MOSFETs operating in parallel and which uses phase change immersion cooling. The heat generation (electrical power dissipation) in such devices is a function of the device resistance and the current through the device, both of which are functions of junction temperature of the device. The junction temperature, in turn, depends on the thermal resistance between the junction and the fluid which is a function of the boiling heat transfer coefficient, and the power dissipated. The analysis presented in this paper considers this complex interdependency in the design of heat sinks such that the temperature is below the limit required by reliability consideration. Thermal coupling of MOSFETs minimizes the junction temperature. 2INTRODUCTION Power MOSFETs are used in many electronics applications such as high speed switching devices and to perform other functions involving high power. They dissipate large values of power over a very small area resulting in very high heat flux and the thermal design o