Probability aware fault-injection approach for SER estimation

Abstract

The Soft-Error Rate (SER) estimation is used to predict how electronic systems will respond to the transient electrical pulses induced by the ionizing radiation. SER estimation by radiation test is an accurate method, but it is expensive and requires the real device. Traditional simulation methods incorporate logical, temporal and electrical masking effects while injecting faults at the output of the device's functional elements. Nevertheless, they do not consider the probability of the ionizing radiation to produce a transient fault at the output of each class of functional element. On the other hand, studies in the stochastic computing domain deal with a probabilistic faultinjection approach. Since many concomitant faults among the elements may occur, the fault probability of each element is treated independently. This leads to the use of one Pseudo-Random Number Generator (PRNG) and a probability comparator for each functional element. However, the analysis of a single fault is usually enough for SER estimation. In this context, this work presents a different approach for probability-aware faultinjection, in which a weighted distribution of faults is defined considering the relative fault probability of each functional element. This approach enables the use of just one PRNG and a decoder for the entire device, instead of a pair 'PRNGcomparator' per element, leading to a significant reduction in logic blocks consumption. For the example analyzed in this study, the use of relative fault probability decreases the number of logic blocks from 875 (adopting independent fault probability) to 495.

Soft-Error Vulnerability Estimation Approach Based on the SET Susceptibility of Each Gate

“…Finally, our proposed approach can also be adapted for an emulation-based fault-injection platform, as the one introduced in [25]. In this case, the emulation would replace the simulation framework, used in Step 7, while keeping the other steps.…”

“…Instead of using the RandomPkg from the OSVVM, we decided to use Linear-Feedback Shift Registers (LFSR) to generate the pseudo-random sequence. Contrarily to the RandomPkg functions, the LFSR structures are synthesisable, which is interesting for an emulation-based SET injection approach, as proposed in [25].…”