Departamento de Física
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/785
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3 resultados
Resultados da Pesquisa
- Evaluating the Reliability of Different Voting Schemes for Fault Tolerant Approximate Systems(2023-06-20) BALEN, T. R.; GONZALEZ, C. J.; OLIVEIRA, I. F. V.; DA ROSA JR. L. S.; SOARES, R. I.; SCHVITTZ, R. B.; ADDED, N.; MACCHIONE, E. L. A.; AGUIAR, V. A. P.; Marcilei Aparecida Guazzelli; MEDINA, N. H.; BUTZEN, P. F.© 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.This work presents a study on the reliability of voters for approximate fault tolerant systems in the context of single event effects and electromagnetic interference. A first case study analyses different topologies of single-bit majority voters for logic circuits employing fault injection by simulation. In these simulations, an analysis is first performed to identify the critical diffusion areas of the physical implementation according to the voter input vector. Additionally, as a second case study, practical heavy ion experiments on different architectures of software-based approximate voters for mixed-signal applications are also presented, and the cross section of each voter is evaluated. The system comprising the voters was irradiated in two distinct experiments with an 16O ion beam, producing an effective LET at the active region of 5.5 MeV/mg/cm 2 . As a complementary study, a conducted electromagnetic interference injection was also performed, considering two distinct voting schemes. Results of the case-studies allow identifying the most tolerant voter architectures (among the studied ones) for approximate computing applications under single event effects and electromagnetic interference.
- Testing a Fault Tolerant Mixed-Signal Design Under TID and Heavy Ions(2021-01-05) GONZALEZ, C. J.; MACHADO, D. N.; VAZ, R. G.; VILAS BOAS, A. C.; GONLALEZ, O. L.; PUCHNER, H.; ADDED, N.; MACCHIONE, E. L. A.; AGUIAR, V. A. P.; KASTENSMIDT, F. L.; MEDINA, N. H.; Marcilei Aparecida Guazzelli; BALEN, T. R.© 2021, Brazilian Microelectronics Society. All rights reserved.— This work presents results of three distinct radiation tests performed upon a fault tolerant data acquisition system comprising a design diversity redundancy technique. The first and second experiments are Total Ionizing Dose (TID) essays, comprising gamma and X-ray irradiations. The last experiment considers single event effects, in which two heavy ion irradiation campaigns are carried out. The case study system comprises three analog-to-digital converters and two software-based vot-ers, besides additional software and hardware resources used for controlling, monitoring and memory manage-ment. The applied Diversity Triple Modular Redundancy (DTMR) technique, comprises different levels of diversity (temporal and architectural). The circuit was designed in a programmable System-on-Chip (PSoC), fabricated in a 130nm CMOS technology process. Results show that the technique may increase the lifetime of the system under TID if comparing with a non-redundant implementation. Considering the heavy ions experiments the system was proved effective to tolerate 100% of the observed errors originated in the converters, while errors in the processing unit present a higher criticality. Critical errors occur-ring in one of the voters were also observed. A second heavy ion campaign was then carried out to investigate the voters reliability, comparing the the dynamic cross section of three different software-based voter schemes im-plemented in the considered PSoC.
- Failure Mechanism and Sampling Frequency Dependency on TID Response of SAR ADCs(2021) GONZALEZ, C. J.; COSTA, B. L.; MACHADO, D. N.; VAZ, R. G.; BOAS, A. C. V.; GONÇALEZ, O. L.; PUCHNER, H.; KASTENSMIDT, F. L.; MEDINA, N. H.; Marcilei Aparecida Guazzelli; BALEN, T. R.© 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.This paper describes the main failure mechanism of charge redistribution Successive Approximation Register (SAR) Analog-to-Digital Converters (ADCs) under radiation. Results of two different radiation experiments (gamma and X-ray) each considering two identical 130nm, 8-bit SAR ADCs, operating with distinct sampling rates, showed that lower sampling frequencies cause the converters to fail at lower accumulated dose, while increasing the sampling frequency increases the converters robustness to radiation. A SPICE model of a SAR ADC is used to simulate radiation induced leakage effects, considering the same technology node and operating conditions of the tested converters. A very good agreement between simulation results and gamma irradiation experimental data allows us to explain the main failure mechanism, which is related to leakage in switches connected to the programmable capacitor array of the internal DAC of the converter.