THERMAL 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.