A study of the maximum theoretical power dissipation of tablets under natural convection conditions

This study determines the limits of natural convection cooling for ideal handheld devices of various sizes based on simulations. Four popular tables were tested to determine the surface temperature rise under heavy computational and graphics loads. The thermal performance of each tablet based on hot spot temperature is measured against the performance of an ideal tablet of the same size and a figure of merit for the efficiency of heat dissipation is calculated to see how well they perform against the ideal tablet. The factors affecting the maximum possible power dissipation are the available surface area and surface finishes, selection of the outer shell materials, thermal interface materials, heat spreaders and air gaps. In most cases, the limiting factor in the thermal design of these devices is not the temperatures of the internal components but the temperature of the external surfaces since these are in direct contact with the skin of the user. This study presents a method for analyzing the efficiency of the thermal design of these devices.