Cluster-based distributed active current timer for hardware Trojan detection

With the globalization of integrated circuit (IC) design and fabrication, there is a growing concern on the devastating impact of subverted chip supply. This paper presents a current sensing circuit that converts the current activity on local power grid to a timing pulse to detect if an IC is Trojan-infected. This new approach increases the Trojan detection sensitivity by combining the switching activity and path sensitization abnormalities into a single side-channel signal that can be easily monitored by existing scan test structure. One main advantage of the proposed regional Trojan detector is that the current comparator threshold can be calibrated against the quiescent current noise floor to reduce the impacts of process variations. Experiments are performed on a Trojan-infected benchmark circuit to demonstrate the feasibility of the proposed technique.