Novel radiation hardened latch design considering process, voltage and temperature variations for nanoscale CMOS technology

As CMOS technology is scaled down, the supply voltage and gate capacitance are reduced, which results in the reduction of charge storing capacity at each node and increase of the susceptibility to external noise in radiation environments. The traditional error tolerant circuit design methods provide very limited protection against the environment noise for storage cells such as latches and memories. In this paper, a novel hardened latch design is proposed and compared with the previous hardened latch designs using 32 nm technology node. Extensive simulation results using HSPICE are reported to show that the proposed hardened latch design achieves 15× improvement of critical charge (Qcrit) with comparable cost in terms of speed and power compared to the most up to date hardened latch design. Moreover, PVT variations have great impact on the reliability of hardened circuit. The proposed latch circuit is also evaluated with the presence of PVT variations and demonstrates higher robustness than other considered robust latch under severe PVT variation condition.     

Low cost and highly reliable hardened latch design for nanoscale CMOS technology

With technology node shrinking, the susceptibility of a single chip to soft errors increases. Hence, the critical charge (Qcrit) of circuit decreases and this decrease is expected to continue with further technology scaling. In this paper previous hardened latch circuits are analyzed and it is found that previous designs offer limited protection against soft error especially for soft error caused by high energy particles and not all the nodes are under soft error protection. Therefore, in this paper we propose a low cost hardened latch design in 45 nm CMOS technology with full protection for all internal nodes as well as output node against soft error. Moreover, the proposed hardened approach is technology independent. Compared to previous hardened latch designs, the proposed design reduces cost in terms of power delay product (PDP) 59% on average.     

一种低开销加固锁存器的设计

针对单粒子翻转问题,设计了一种低开销的加固锁存器。在输出级使用钟控C单元,以屏蔽锁存器内部节点的瞬态故障;在输出节点所在的反馈环上使用C单元,屏蔽输出节点上瞬态故障对电路的影响;采用了从输入节点到输出节点的高速通路设计,延迟开销大幅降低。HSPICE仿真结果表明,相比于FERST,SEUI,HLR,Iso-DICE锁存器,该锁存器的面积平均下降23.20%,延迟平均下降55.14%,功耗平均下降42.62%。PVT分析表明,该锁存器的性能参数受PVT变化的影响很小,性能稳定。     

Low cost and highly reliable radiation hardened latch design in 65 nm CMOS technology

As a consequence of technology scaling down, gate capacitances and stored charge in sensitive nodes are decreasing rapidly, which makes CMOS circuits more vulnerable to radiation induced soft errors. In this paper, a low cost and highly reliable radiation hardened latch is proposed using 65 nm CMOS commercial technology. The proposed latch can fully tolerate the single event upset (SEU) when particles strike on any one of its single node. Furthermore, it can efficiently mask the input single event transient (SET). A set of HSPICE post-layout simulations are done to evaluate the proposed latch circuit and previous latch circuits designed in the literatures, and the comparison results among the latches of type 4 show that the proposed latch reduces at least 39% power consumption and 67.6% power delay product. Moreover, the proposed latch has a second lowest area overhead and a comparable ability of the single event multiple upsets (SEMUs) tolerance among the latches of type 4. Finally, the impacts of process, supply voltage and temperature variations on our proposed latch and previous latches are investigated.     

一种新型抗多节点翻转加固锁存器

在纳米锁存器中,由电荷共享效应导致的多节点翻转(MNU)正急剧增加,成为主要的可靠性问题之一。尽管现有的辐射加固锁存器能够对MNU进行较好的容错,但是这些加固锁存器只依赖于传统的冗余技术进行加固,需要非常大的硬件开销。基于辐射翻转机制(瞬态脉冲翻转极性)设计了一种新型抗MNU锁存器。该锁存器可有效减少需保护的节点数(敏感节点数)和晶体管数,因此可减少电路的硬件开销。由于至少存在2个节点可以保存正确的值,因此任何单节点翻转(SNU)和MNU都可以被恢复容错。基于TSMC 65 nm CMOS工艺进行仿真,结果显示,设计的加固锁存器的电路面积、传播延迟和动态功耗分别为19.44μm²,16.96 ps和0.91μW。与现有的辐射加固锁存器相比,设计的锁存器具有较小的硬件开销功耗-延迟-面积乘积(PDAP)值,仅为300.02。     

一种低开销的抗SEU锁存器

随着微电子技术的不断进步,集成电路工艺尺寸不断缩小,工作电压不断降低,节点的临界电荷越来越小,空间辐射引起的单粒子效应逐渐成为影响芯片可靠性的重要因素之一。针对辐射环境中高能粒子对锁存器的影响,提出了一种低开销的抗SEU锁存器(LOHL)。该结构基于C单元的双模冗余,实现对单粒子翻转的防护,从而降低软错误发生的概率。Spice模拟结果显示,与其他相关文献中加固锁存器相比,LOHL在电路面积、延迟和延迟-功耗积上有优势。     

An advanced SEU tolerant latch based on error detection

This paper proposes a latch that can mitigate SEUs via an error detection circuit.The error detection circuit is hardened by a C-element and a stacked PMOS.In the hold state,a particle strikes the latch or the error detection circuit may cause a fault logic state of the circuit.The error detection circuit can detect the upset node in the latch and the fault output will be corrected.The upset node in the error detection circuit can be corrected by the Celement.The power dissipation and propagation delay of the proposed latch are analyzed by HSPICE simulations.The proposed latch consumes about 77.5％ less energy and 33.1％ less propagation delay than the triple modular redundancy (TMR) latch.Simulation results demonstrate that the proposed latch can mitigate SEU effectively.     

一种低功耗低延迟的容忍DNU锁存器设计

随着集成电路器件特征尺寸的进一步减小,锁存器内部节点之间的距离越来越短.由于内部节点间的电荷共享效应,器件在空间辐射环境中频繁发生单粒子翻转(SEU),受影响节点由单节点扩展到双节点.文章提出了一种新型的锁存器加固结构,利用C单元固有的保持属性,实现对单节点翻转(SNU)和双节点翻转(DNU)的完全容忍.HSPICE仿...     

一种自恢复容SEU锁存器的设计

随着集成电路工艺水平的不断提高、器件尺寸的不断缩小以及电源的不断降低,传统的锁存器越发容易受到由辐射效应引起的软错误影响。为了增强锁存器的可靠性,提出了一种适用于低功耗电路的自恢复SEU加固锁存器。该锁存器由传输门、反馈冗余单元和保护门C单元构成。反馈冗余单元由六个内部节点构成,每个节点均由一个NMOS管和一个PMOS管驱动,从而构成自恢复容SEU的结构。在45 nm工艺下,使用Hspice仿真工具进行仿真,结果表明,与现有的加固方案FERST[1]结构相比,在具备相同面积开销和单粒子翻转容忍能力的情况下,提出的锁存器不仅适用于时钟门控电路,而且节省了61.38%的功耗-延迟积开销。     

40 nm CMOS工艺下的低功耗容软错误锁存器

为了降低集成电路的软错误率,该文基于时间冗余的方法提出一种低功耗容忍软错误锁存器。该锁存器不但可以过滤上游组合逻辑传播过来的SET脉冲,而且对SEU完全免疫。其输出节点不会因为高能粒子轰击而进入高阻态,所以该锁存器能够适用于门控时钟电路。SPICE仿真结果表明,与同类的加固锁存器相比,该文结构仅仅增加13.4%的平均延时,使得可以过滤的SET脉冲宽度平均增加了44.3%,并且功耗平均降低了48.5%,功耗延时积(PDP)平均降低了46.0%,晶体管数目平均减少了9.1%。     

A novel radiation hardened by design latch

Due to aggressive technology scaling, radiation-induced soft errors have become a serious reliability concern in VLSI chip design. This paper presents a novel radiation hardened by design latch with high single-event-upset (SEU) immunity. The proposed latch can effectively mitigate SEU by internal dual interlocked scheme. The propagation delay, power dissipation and power delay product of the presented latch are evaluated by detailed SPICE simulations. Compared with previous SEU-hardening solutions such as TMR-Latch, the presented latch is more area efficient, delay and power efficient. Fault injection simulations also demonstrate the robustness of the presented latch even under high energy particle strikes.     

一种新型的抗辐射加固锁存器

Due to aggressive technology scaling, radiation-induced soft errors have become a serious reliability concern in VLSI chip design. This paper presents a novel radiation hardened by design latch with high single-eventupset （SEU） immunity. The proposed latch can effectively mitigate SEU by internal dual interlocked scheme. The propagation delay, power dissipation and power delay product of the presented latch are evaluated by detailed SPICE simulations. Compared with previous SEU-hardening solutions such as TMR-Latch, the presented latch is more area efficient, delay and power efficient. Fault injection simulations also demonstrate the robustness of the presented latch even under high energy particle strikes.     

High performance energy efficient radiation hardened latch for low voltage applications

Energy efficiency is considered to be the most critical design parameter for IoT and other ultra low power applications. However, energy efficient circuits show a lesser immunity against soft error, because of the smaller device node capacitances in nanoscale technologies and near-threshold voltage operation. Due to these reasons, the tolerance of the sequential circuits to SEUs is an important consideration in nanoscale near threshold CMOS design. This paper presents an energy efficient SEU tolerant latch. The proposed latch improves the SEU tolerance by using a clocked Muller- C and memory elements based restorer circuit. The parasitic extracted simulations using STMicroelectronics 65 nm CMOS technology show that by employing the proposed latch, an average improvement of ∼40% in energy delay product (EDP), is obtained over the recently reported latch. Moreover, the proposed latch is also validated in a TCAD calibrated PTM 32 nm framework and PTM 22 nm CMOS technology nodes. In 32 nm and 22 nm technologies, the proposed latch improves the EDP ∼12% and 59% over existing latches respectively.     

Single event double node upset tolerance in MOS/spintronic sequential and combinational logic circuits

Spin-transfer torque random access memory (STT-RAM) is an emerging storage technology that is considered widely thanks to its attractive features such as low power consumption, nonvolatility, scalability and high density. STT-RAMs are comprised of a hybrid design of CMOS and spintronic units. Magnetic tunnel junction (MTJ) as the basic element of such hybrid technology is inherently robust against radiation induced faults. However, the peripheral CMOS component for sensing the resistance of the MTJs are prone to be affected by energetic particles. This paper proposes low power, nonvolatile and radiation hardened latch and lookup table circuits based on hybrid CMOS/MTJ technology for the next generation integrated circuit devices. Simulation results revealed that, the proposed circuits are fully robust against single event upsets (SEU) and also single event double node upsets (SEDU) that are of the main reliability challenging issues in current sub-nanometer CMOS technologies.     

A low power-delay-product and robust Isolated-DICE based SEU-tolerant latch circuit design

Soft-error interference is a crucial design challenge in the advanced CMOS VLSI circuit designs. In this paper, we proposed a SEU Isolating DICE latch (Iso-DICE) design by combing the new proposed soft-error isolating technique and the inter-latching technique used in the DICE (Calin et al., 1996 [1]) design. To further enhance SEU-tolerance of DICE design, we keep the storage node pairs having the ability to recover the SEU fault occurring in each other pair but also avoid the storage node to be affected by each other. To mitigate the interference effect between dual storage node pairs, we use the isolation mechanism to resist high energy particle strikes instead of the original interlocking design method. Through isolating the output nodes and the internal circuit nodes, the Iso-DICE latch can possess more superior SEU-tolerance as compared with the DICE design (Calin et al., 1996 [1]). As compared with the FERST design (Fazeli, 2009 [2]) which performs with the same superior SEU-tolerance, the proposed Iso-DICE latch consumes 50% less power with only 45% of power delay product in TSMC 90 nm CMOS technology. Under 22 nm PTM model, the proposed Iso-DICE latch can also perform with 11% power delay product saving as compared with the FERST design (Fazeli, 2009 [2]) that performs with the same superior SEU-tolerance.     

An SEU resilient,SET filterable and cost effective latch in presence of PVT variations

This paper presents a single event upset (SEU) resilient, single event transient (SET) filterable and cost effective latch (referred to as RFEL) using 45 nm CMOS commercial technology. By means of triple mutual feedback CMOS structures, one of which is an input-split Schmitt trigger, and two of which are Muller C-elements, the internal nodes and output node of the latch are self-recoverable from single event upset regardless of the energy of a striking particle. The latch filters a much wider spectrum of single event transient on account of hysteresis property of the embedded input-split Schmitt trigger, and temporal redundancy in the grouped inputs of the Muller C-element at output stage. The latch performs with lower overheads regarding area, power, and delay than most of the single event upset and single event transient simultaneously tolerated latches as well. Simulation results show that the area-power-delay-pulse product of the latch is 65.58% saving on average, and Monte Carlo simulation results demonstrate the equivalent or even less sensitivity of the latch to process, and temperature variations, compared with the previous radiation hardened latches.     

一种低开销的三点翻转自恢复锁存器设计

随着集成电路特征尺寸的不断缩减,在恶劣辐射环境下,纳米级CMOS集成电路中单粒子三点翻转的几率日益增高,严重影响可靠性。为了实现单粒子三点翻转自恢复,该文提出一种低开销的三点翻转自恢复锁存器(LC-TNURL)。该锁存器由7个C单元和7个钟控C单元组成,具有对称的环状交叉互锁结构。利用C单元的阻塞特性和交叉互锁连接方式,任意3个内部节点发生翻转后,瞬态脉冲在锁存器内部传播,经过C单元多级阻塞后会逐级消失,确保LC-TNURL锁存器能够自行恢复到正确逻辑状态。详细的HSPICE仿真表明,与其他三点翻转加固锁存器(TNU-Latch, LCTNUT, TNUTL, TNURL)相比,LC-TNURL锁存器的功耗平均降低了31.9%,延迟平均降低了87.8%,功耗延迟积平均降低了92.3%,面积开销平均增加了15.4%。相对于参考文献中提出的锁存器,LC-TNURL锁存器的PVT波动敏感性最低,具有较高的可靠性。     

Radiation Hardened by Design Latches — A Review and SEU Fault Simulations

There are many Radiation Hardened by Design (RHBD) architectures presented in the literature to mitigate Single Event Upset (SEU) in a storage element, a latch. Nevertheless, the design of a SEU hardened latch is being continuously improved with respect to reliability, performance, power consumption and area overhead. SEU mitigating techniques by design focus on reducing criticality of sensitive nodes in a latch. Sensitive node(s) in a latch could be an active and/or a high impedance node(s). In this paper, we have classified previously presented SEU hardened by design latch architectures and reviewed SEU mechanisms in selected RHBD latch architectures on Complementary Metal Oxide Semiconductor (CMOS) technology models. Simulation studies using latest fault simulation model have been carried out. Simulation results have revealed some interesting observations described in this paper. Our findings, based on analyses, will provide valuable design inputs for futuristic RHBD latches with advanced technology nodes.     

基于C单元反馈回路的容SEU锁存器设计

随着电子技术的不断发展,集成电路的特征尺寸不断缩小,导致电路对宇宙高能粒子引发的单粒子翻转愈发敏感。提出了一种对单粒子翻转完全免疫的抗辐射加固锁存器。该锁存器利用具有过滤功能的C单元构建反馈回路,并在锁存器末端使用钟控C单元来阻塞传播至输出端的软错误。HSPICE仿真结果显示,在与TMR锁存器同等可靠性的情况下,该锁存器面积下降50%,延迟下降92%,功耗下降47%,功耗延迟积下降96%。     

一种新型低功耗抗软错误锁存器

该文提出一种新型的C单元的连接方法,将距离输出节点比较远的P型和N型晶体管的栅端与C单元的输出节点相连接,利用晶体管自身的反馈机制形成反馈路径,实现了自恢复功能,因此大幅降低动态消耗和硬件开销;采用点加强型C单元作为输出级电路并进行优化,使得电路抵御单粒子翻转的能力更强;基于上述改进,搭建出一个新的抗软错误锁存器,将输入信号经过传输门以后接传到输出端,以降低输入信号传到输出节点的延迟,利用节点之间的反馈比较机制进一步提升各个电路节点的临界电荷量。在22 nm的先进工艺下进行仿真,实验结果表明,提出的新型锁存器电路不仅具有优秀的抗软错误能力,并且在功耗延迟积方面比现有的锁存器电路性能提升了26.74%~97.50%。