Fast and accurate thermal analysis of smartphone with dynamic power management using reduced order modeling

Abstract

Power saving techniques and associated thermal management are inevitable for present day smartphones. Smartphones employ thermal feedback (temperature at key locations) based dynamic power management strategies to maintain the system temperature in the desired range. It is challenging to simulate the thermal behavior of such a system as running a computational fluid dynamics system with control logic consumes significant time and computation resources. An efficient transient thermal model for smartphone simulation based on Linear Time Invariant (LTI) system is proposed in this paper. State space model developed based on LTI system can be used for transient thermal simulations with similar accuracy as full 3D transient CFD model but a significantly faster run time. The model generation process starts with computation fluid dynamics (CFD) results of a smartphone model. A state model is created which is very efficient and runs orders of magnitude faster. Extracted state space model can be used to check different variations of power control logics for a given smart phone design without the need to perform Full CFD analysis. In this paper, case study has been conducted to compare results from state space model with full CFD model for specific control logic.