Thermal Modeling and Design on Smartphones with Heat Pipe Cooling Technique

Abstract

While the performance of smartphones becomes much higher, the application processor consumes considerable power. Thus, it is hard to meet thermal constraints by using conventional cooling techniques. Fortunately, since heat pipes can efficiently transfer the thermal energy from hot regions to cool regions, temperatures in hot regions can be reduced greatly. Hence, in the past three years, the heat pipe cooling techniques have been applied to smartphones by industries. However, although the time-consuming commercial simulation tools, such as ANSYS Fluent, can provide accurate thermal maps, they may lead to inefficiency during design stages. Besides, the compact thermal model for bended heat pipes is still underdeveloped. Therefore, efficient thermal simulation for smartphones with bended heat pipes should be developed for the design stage. Furthermore, the routing of bended heat pipe should be optimized to obtain more thermal energy transfer. This work presents a compact thermal model for bended heat pipes and an efficient thermal simulator for smartphones. Moreover, with inconsistent maze routing and dynamic thermal weight assignment, a thermal-driven routing algorithm is proposed for optimizing the design of bended heat pipe. Compared with ANSYS Fluent, the thermal simulation with bended heat pipe thermal model can achieve at least three orders of magnitude speedup with only 3.58% maximum error for all chips. The proposed heat pipe routing algorithm can reduce at least 10.86% of the maximum temperatures for application processors.