On-chip reconfigurable monitor circuit for process variation and temperature estimation

This paper proposes a monitor circuit that can estimate process variation and temperature by circuit reconfiguration. The circuit topology of the temperature monitoring is crafted such that the oscillation frequency is determined by the amount of leakage current which has an exponential dependency to temperature. The voltage dependence of this circuit is small in the configuration for temperature measurement, and the temperature dependence is small in the configuration for process variation estimation. A test chip fabricated in a 65 nm CMOS process demonstrates the temperature estimation capability with accuracy within −0.3 °C to 0.4 °C over a temperature range of 10 ° C to 100 °C, as well as the ability for estimating process variations.