Recent demand on more advanced functionalities in mobile devices has led to a drastic increase in power consumption of the device. Therefore, heat dissipation has become a major concern. To effectively overcome the thermal barrier based on the surface temperature of mobile devices, we propose a surface temperature-aware thermal management (STaTM) technique to be incorporated into a mobile application processor (AP), which plays a key role in the heat management of the mobile device. The proposed STaTM enables the AP to maximize the energy efficiency using accuracy-enhanced rapid surface temperature estimation. Experimental results show that the proposed solution achieves an average performance improvement of 14.2% when compared to conventional thermal management techniques.

When there is an impending heavy workload under low battery conditions, mobile device such as smartphones can autonomously reset or even shut down to prevent damage caused by sudden voltage drops. Recently, the occurrence probability of sudden voltage drop under low battery conditions has increased with the use of high-performance 64-bit CPU cores, which adversely affects the user experiences. To overcome this problem, we propose a cost-effective sudden-voltage-drop protection (SVDP) technique to minimize unstable states, thus enhancing customer satisfaction. Programmable low-battery-state-aware logic for sudden voltage drop detection and performance tuning to maintain system stability via clock frequency control is incorporated in power management integrated circuit (PMIC) and application processor (AP). Experimental results show that the proposed technique significantly reduces the failure rate due to sudden voltage drops under low battery conditions.