Abstract
Due to the advance in CMOS technology and design complexity, more power is dissipated in smaller die area, thus the thermal density of modern VLSI systems is becoming a critical issue. High die temperature can not only degrade circuit performance but also leads to thermal runaway. Therefore, continuous monitoring of die temperature is crucial. This thesis proposes an on-line digital thermal/power monitoring system. The proposed system includes a digital programmable temperature sensor, digital programmable dc-dc buck converter, and a fully digital thermal/power controller/interface. With the pulse frequency modulation (PFM) control technique and digitalized control circuits, the proposed buck converter can tightly regulate the output voltage and is robust to the process variation. The output voltage range is from 0.8V to 1.8V with the maximum output current of 300mA. With the proposed digital interface and a high accurate 0.12°C to -0.34°C, high conversion rate temperature sensor, the proposed architecture is very suitable for on-line thermal/power monitoring. In addition, the proposed temperature sensor is integrated into an on-line thermal monitoring scheme to verify its performance. Simulation shows that the circuit is under continuous monitoring of the proposed temperature sensor. If the die temperature reaches a certain limit, the on-line thermal monitoring will invoke supply voltage scaling to decrease the circuit power dissipation, thus the die temperature will decrease to a constant stable value.