Rad-Hard Designs by Automated Latching-Delay Assignment and Time-Borrowable D-Flip-Flop

Abstract

As the safety-critical applications (e.g. automotive and medical electronics) emerge, various techniques of radiation hardening by design (RHBD) are proposed to deal with soft errors. Among all RHBD techniques, Built-In Soft-Error Resilience (BISER) is the first one to apply the delayed latching to separate input signals on all flip-flops for error detection. However, the delay values induced by BISER extend the setup time of all flip-flops, and may fail to meet the timing specification of the design. For minimizing such delay impact on the setup time of each flip-flop, we propose the Automated Latching-Delay Assignment (ALDA) to transfer partial values to the CK-Q delay. Later, Time-Borrowable D-Flip-Flop (TBD-FF) as well as a modified design flow is also proposed to realize the delay assignment by ALDA and to complete the design hardening. Experiments show that ALDA together with TBD-FF effectively protects four benchmark circuits against soft errors, and optimally avoids the timing violations caused by the prior delayed-latching solutions.