8 research outputs found
Recommended from our members
Design and Evaluation of Radiation-Hardened Standard Cell Flip-Flops
Use of a standard non-rad-hard digital cell library in the rad-hard design can be a cost-effective solution for space applications. In this paper we demonstrate how a standard non-rad-hard flip-flop, as one of the most vulnerable digital cells, can be converted into a rad-hard flip-flop without modifying its internal structure. We present five variants of a Triple Modular Redundancy (TMR) flip-flop: baseline TMR flip-flop, latch-based TMR flip-flop, True-Single Phase Clock (TSPC) TMR flip-flop, scannable TMR flip-flop and self-correcting TMR flip-flop. For all variants, the multi-bit upsets have been addressed by applying special placement constraints, while the Single Event Transient (SET) mitigation was achieved through the usage of customized SET filters and selection of optimal inverter sizes for the clock and reset trees. The proposed flip-flop variants feature differing performance, thus enabling to choose the optimal solution for every sensitive node in the circuit, according to the predefined design constraints. Several flip-flop designs have been validated on IHP’s 130nm BiCMOS process, by irradiation of custom-designed shift registers. It has been shown that the proposed TMR flip-flops are robust to soft errors with a threshold Linear Energy Transfer (LET) from ( 32.4 (MeV⋅cm2/mg) ) to ( 62.5 (MeV⋅cm2/mg) ), depending on the variant
INVESTIGATING THE EFFECTS OF SINGLE-EVENT UPSETS IN STATIC AND DYNAMIC REGISTERS
Radiation-induced single-event upsets (SEUs) pose a serious threat to the reliability of registers. The existing SEU analyses for static CMOS registers focus on the circuit-level impact and may underestimate the pertinent SEU information provided through node analysis. This thesis proposes SEU node analysis to evaluate the sensitivity of static registers and apply the obtained node information to improve the robustness of the register through selective node hardening (SNH) technique. Unlike previous hardening techniques such as the Triple Modular Redundancy (TMR) and the Dual Interlocked Cell (DICE) latch, the SNH method does not introduce larger area overhead. Moreover, this thesis also explores the impact of SEUs in dynamic flip-flops, which are appealing for the design of high-performance microprocessors. Previous work either uses the approaches for static flip-flops to evaluate SEU effects in dynamic flip-flops or overlook the SEU injected during the precharge phase. In this thesis, possible SEU sensitive nodes in dynamic flip-flops are re-examined and their window of vulnerability (WOV) is extended. Simulation results for SEU analysis in non-hardened dynamic flip-flops reveal that the last 55.3 % of the precharge time and a 100% evaluation time are affected by SEUs
Design for prognostics and security in field programmable gate arrays (FPGAs).
There is an evolutionary progression of Field Programmable Gate Arrays (FPGAs)
toward more complex and high power density architectures such as Systems-on-
Chip (SoC) and Adaptive Compute Acceleration Platforms (ACAP). Primarily, this is
attributable to the continual transistor miniaturisation and more innovative and
efficient IC manufacturing processes. Concurrently, degradation mechanism of Bias
Temperature Instability (BTI) has become more pronounced with respect to its
ageing impact. It could weaken the reliability of VLSI devices, FPGAs in particular
due to their run-time reconfigurability. At the same time, vulnerability of FPGAs to
device-level attacks in the increasing cyber and hardware threat environment is also
quadrupling as the susceptible reliability realm opens door for the rogue elements to
intervene. Insertion of highly stealthy and malicious circuitry, called hardware
Trojans, in FPGAs is one of such malicious interventions. On the one hand where
such attacks/interventions adversely affect the security ambit of these devices, they
also undermine their reliability substantially. Hitherto, the security and reliability are
treated as two separate entities impacting the FPGA health. This has resulted in
fragmented solutions that do not reflect the true state of the FPGA operational and
functional readiness, thereby making them even more prone to hardware attacks.
The recent episodes of Spectre and Meltdown vulnerabilities are some of the key
examples. This research addresses these concerns by adopting an integrated
approach and investigating the FPGA security and reliability as two inter-dependent
entities with an additional dimension of health estimation/ prognostics. The design
and implementation of a small footprint frequency and threshold voltage-shift
detection sensor, a novel hardware Trojan, and an online transistor dynamic scaling
circuitry present a viable FPGA security scheme that helps build a strong
microarchitectural level defence against unscrupulous hardware attacks. Augmented
with an efficient Kernel-based learning technique for FPGA health
estimation/prognostics, the optimal integrated solution proves to be more
dependable and trustworthy than the prevalent disjointed approach.Samie, Mohammad (Associate)PhD in Transport System
Radiation Tolerant Electronics, Volume II
Research on radiation tolerant electronics has increased rapidly over the last few years, resulting in many interesting approaches to model radiation effects and design radiation hardened integrated circuits and embedded systems. This research is strongly driven by the growing need for radiation hardened electronics for space applications, high-energy physics experiments such as those on the large hadron collider at CERN, and many terrestrial nuclear applications, including nuclear energy and safety management. With the progressive scaling of integrated circuit technologies and the growing complexity of electronic systems, their ionizing radiation susceptibility has raised many exciting challenges, which are expected to drive research in the coming decade.After the success of the first Special Issue on Radiation Tolerant Electronics, the current Special Issue features thirteen articles highlighting recent breakthroughs in radiation tolerant integrated circuit design, fault tolerance in FPGAs, radiation effects in semiconductor materials and advanced IC technologies and modelling of radiation effects
Reliability-energy-performance optimisation in combinational circuits in presence of soft errors
PhD ThesisThe reliability metric has a direct relationship to the amount of value produced
by a circuit, similar to the performance metric. With advances in CMOS
technology, digital circuits become increasingly more susceptible to soft errors.
Therefore, it is imperative to be able to assess and improve the level of reliability
of these circuits. A framework for evaluating and improving the reliability of
combinational circuits is proposed, and an interplay between the metrics of
reliability, energy and performance is explored.
Reliability evaluation is divided into two levels of characterisation: stochastic
fault model (SFM) of the component library and a design-specific critical vector
model (CVM). The SFM captures the properties of components with regard to
the interference which causes error. The CVM is derived from a limited number
of simulation runs on the specific design at the design time and producing
the reliability metric. The idea is to move the high-complexity problem of the
stochastic characterisation of components to the generic part of the design
process, and to do it just once for a large number of specific designs. The
method is demonstrated on a range of circuits with various structures.
A three-way trade-off between reliability, energy, and performance has
been discovered; this trade-off facilitates optimisations of circuits and their
operating conditions.
A technique for improving the reliability of a circuit is proposed, based on
adding a slow stage at the primary output. Slow stages have the ability to
absorb narrow glitches from prior stages, thus reducing the error probability.
Such stages, or filters, suppress most of the glitches generated in prior stages
and prevent them from arriving at the primary output of the circuit. Two filter
solutions have been developed and analysed. The results show a dramatic
improvement in reliability at the expense of minor performance and energy
penalties.
To alleviate the problem of the time-consuming analogue simulations involved in the proposed method, a simplification technique is proposed. This
technique exploits the equivalence between the properties of the gates within
a path and the equivalence between paths. On the basis of these equivalences,
it is possible to reduce the number of simulation runs. The effectiveness of
the proposed technique is evaluated by applying it to different circuits with
a representative variety of path topologies. The results show a significant
decrease in the time taken to estimate reliability at the expense of a minor
decrease in the accuracy of estimation. The simplification technique enables
the use of the proposed method in applications with complex circuits.Ministry of Education and Scientific Research in Liby
Soft error resilient and energy efficient dual modular TSPC flip-flop
by Shubhanshu Gupta and Joycee Meki
Bowdoin Orient v.132, no.1-24 (2002-2003)
https://digitalcommons.bowdoin.edu/bowdoinorient-2000s/1003/thumbnail.jp