An Innovative Heterogeneous SoC Thermal Model for Smartphone System

In conventional smartphone system thermal analysis, system on chip (SoC) was deemed as one single heat source which was an effective way to identify integrated circuit (IC) and skin thermal problem. However, as the heterogeneous computing architecture is getting much more powerful and complex, a sophisticated thermal model of CPU and GPU is required to conduct thermal analysis with their individual and coupling thermal effects. To this end, an innovative dynamic compact thermal model (DCTM) was proposed to enable performance and power optimization under thermal limit. The proposed DCTM could capture their thermal coupling effect and still keep the simplicity of model structure like conventional RC ladder model. Meanwhile, the transient behavior of peripheral ICs, such as power management IC, was also included and could be analyzed simultaneously. To prove the validity of proposed DCTM, a series of experiments was conducted with thermal test vehicle in a real phone enclosure, including multiple-heat-sources SoC and peripheral IC. The validation results showed that it could capture the thermal characteristic of SoC and the peripheral IC in smartphone system with maximum root mean square error less than 1.58°C for all test cases. Moreover, a power budget allocation case study was explored, and the result showed that 8% extra power budget could be obtained if a well allocation strategy is decided.