Cooperative On-Chip Temperature EstimationUsing Multiple Virtual Sensors

A variety of dynamic thermal management (DTM) schemes have been proposed to address the adverse effects of high temperatures on a chip. These DTM schemes rely on on-chip thermal sensors to get accurate temperature information over a die, and typically assume on-chip thermal sensors give accurate temperature readings. However, on-chip thermal sensors with small footprint and low power consumption, such as popular ring-oscillator (RO) based sensors, have relatively low accuracy. We address the challenging question of how to acquire accurate temperature information of a chip during its runtime using small, low-power on-chip thermal sensors. We propose a novel approach of using multiple virtual thermal sensors to increase the accuracy of temperature readings; the virtual thermal sensors are generated from a small low-power physical thermal sensor by adaptively switching its calibration points on the run. Simulation results show that the RMS error of temperature readings can be reduced by up to 91.1% with the use of four virtual thermal sensors as compared with a single thermal sensor case.