On-Chip Voltage and Temperature Digital Sensor for Security, Reliability, and Portability

The integrated circuits can be exposed to various stresses during run-time due to unexpected environmental conditions or attacks. Ensuring that a circuit is not working out-of-specification via sensing its operating conditions, e.g., temperature and voltage, is highly useful in detecting anomalies. Analog sensors have been used to monitor the operating conditions for a long time, however, weaknesses including lack of portability to thin technology nodes, costly & complex calibration process, and low attack resistance make such sensors inefficient. Digital sensors, via considering the temperature and voltage effects altogether instead of treating each separately, have been demonstrated as a qualified replacement. In this paper, we develop an integrated framework for continuous monitoring of the operating voltage and temperature of each chip. The framework includes an embedded on-chip sensor circuitry along with a Neural Network model that quantifies the temperature and voltage values via processing the data collected by this sensor. The experimental results confirm the high accuracy of the proposed framework in tracking on-chip voltage and temperature variations, i.e., with the average error of 0.014V in a range of 0.65V to 1.4V, and the average error of 3.9°C in a range of -10°C to 150°C, respectively.