Sensitivity tuning of a bulk built-in current sensor for optimal transient-fault detection

• A strategy to design BBICS with optimal fault detection sensitivity is proposed.
• An asymmetry in the flipping ability of the sensor’s latch is introduced.
• Low and high threshold voltage transistors are used to increase sensitivity.
• No redesign of the standard cells in CMOS 65-nm is required.

Bulk Built-In Current Sensors (BBICSs) are able to detect anomalous transient currents induced in the bulk of integrated circuits when hit by ionizing particles. This paper presents a new strategy to design BBICSs with optimal transient-fault detection sensitivity while keeping low both area and power overheads. The approach allows increasing the detection sensitivity by setting an asymmetry in the flipping ability of the sensor’s latch. In addition, we introduce a mechanism to tune the delay of the bulk access transistors that improves even more the BBICS detection sensitivity. The proposed design strategy offers a good compromise between fault detection sensitivity and power consumption; moreover it makes feasible the use of several CMOS processes.