How State Estimation in Integrated Circuits Based on Statistical Tests Can Be Used to Fine-Tune the Control of the Voltage and Frequency Actuators in the Power Management Framework

S. Lesecq, L. Vincent, E. Beigne, and Ph Maurines. Keynote at VARI 2012 the 3rd European Workshop on CMOS Variability, Nice, France. June 2012.
Today mobile computing platforms need ever-increasing computational performances while their energy consumption is drastically limited by battery lifespan. An optimal operating point is obtained thanks to a compromise between performance and power consumption. For distributed architectures (e.g. MultiProcessor System on Chip), the supply voltage and the operating frequency of each processing element are dynamically tuned to reach efficient performance/power consumption trade-offs. To increase the performance of each “actuator”, the physical state (e.g. its current supply voltage and temperature) of the integrated circuit must be monitored to locally adapt the control parameters. During this keynote, we will present a new estimation method based on statistical tests to estimate the supply voltage and the temperature of a local area in an integrated circuit. The raw measurements are acquired form standard ring oscillators buried in the chip and they are fused to estimate the IC physical state. Then we will show how this information might be used to fine-tune the control of the closed-loop actuators in order to ensure for these actuators the appropriate functioning, whatever the physical state in a given range.