Considerable research has considered the design of low-power and high-speed devices.Designing integrated circuits with low-power consumption is an important issue due to the rapid growth of high-speed devices.Embedded...Considerable research has considered the design of low-power and high-speed devices.Designing integrated circuits with low-power consumption is an important issue due to the rapid growth of high-speed devices.Embedded static random-access memory(SRAM)units are necessary components in fast mobile computing.Traditional SRAM cells are more energyconsuming and with lower performances.The major constraints in SRAM cells are their reliability and low power.The objectives of the proposed method are to provide a high read stability,low energy consumption,and better writing abilities.A transmission gate-based multi-threshold single-ended Schmitt trigger(ST)9T SRAM cell in a bit-interleaving structure without a write-back scheme is proposed.Herein,an ST inverter with a single bit-line design is used to attain the high read stability.A negative assist technique is applied to alter the trip voltage of the single-ended ST inverter.The multithreshold complementary metal oxide semiconductor(MTCMOS)technique is adopted to reduce the leakage power in the proposed single-ended TGST 9T SRAM cell.The proposed system uses a combination of standard and ST inverters,which results in a large read stability.Compared with the previous ST 9T,ST 11T,11T,10T,and 7T SRAM cells,the proposed cell is implemented in Cadence Virtuoso ADE with 45-nm CMOS technology and consumes 35.80%,42.09%,31.60%,12.54%,and 31.60%less energy for read operations and 73.59%,93.95%,92.76%,89.23%,and 85.78%less energy for write operations,respectively.展开更多
The use of Internet of Things(IoT)applications become dominant in many systems.Its on-chip data processing and computations are also increasing consistently.The battery enabled and low leakage memory system at subthre...The use of Internet of Things(IoT)applications become dominant in many systems.Its on-chip data processing and computations are also increasing consistently.The battery enabled and low leakage memory system at subthreshold regime is a critical requirement for these IoT applications.The cache memory designed on Static Random-Access Memory(SRAM)cell with features such as low power,high speed,and process tolerance are highly important for the IoT memory system.Therefore,a process tolerant SRAM cell with low power,improved delay and better stability is presented in this research paper.The proposed cell comprises 11 transistors designed with symmetric approach for write operations and single ended circuit for read operations that exhibits an average dynamic power saving of 43.55%and 47.75%for write and 35.59%and 36.56%for read operations compared to 6 T and 8 T SRAM cells.The cell shows an improved write delay of 26.46%and 37.16%over 6 T and 8T and read delay is lowered by 50.64%and 72.90%against 6 T and 10 T cells.The symmetric design used in core latch to improve the write noise margin(WNM)by 17.78%and 6.67%whereas the single ended separate read circuit improves the Read Static Noise Margin(RSNM)by 1.88x and 0.33x compared to 6 T and 8T cells.The read power delay product and write power delay product are lower by 1.94x,1.39x and 0.17x,2.02x than 6 T and 8 T cells respectively.The lower variability from 5000 samples validates the robustness of the proposed cell.The simulations are carried out in Cadence virtuoso simulator tool with Generic Process Design Kit(GPDK)45 nm technology file in this work.展开更多
In advanced technologies, single event upset reversal(SEUR) due to charge sharing can make the upset state of SRAM cells recover to their initial state, which can reduce the soft error for SRAMs in radiation environme...In advanced technologies, single event upset reversal(SEUR) due to charge sharing can make the upset state of SRAM cells recover to their initial state, which can reduce the soft error for SRAMs in radiation environments. By using the full 3D TCAD simulations, this paper presents a new kind of SEUR triggered by the charge collection of the Off-PMOS and the delayed charge collection of the On-NMOS in commercial 40-nm 6 T SRAM cells. The simulation results show that the proposed SEUR can not occur at normal incidence,but can present easily at angular incidence. It is also found that the width of SET induced by this SEUR remains the same after linear energy transfer(LET) increases to a certain value. In addition, through analyzing the effect of the spacing, the adjacent transistors, the drain area, and some other dependent parameters on this new kind of SEUR, some methods are proposed to strengthen the recovery ability of SRAM cells.展开更多
Low power supply operation with leakage power reduction is the prime concern in modern nano-scale CMOS memory devices. In the present scenario, low leakage memory architecture becomes more challenging, as it has 30% o...Low power supply operation with leakage power reduction is the prime concern in modern nano-scale CMOS memory devices. In the present scenario, low leakage memory architecture becomes more challenging, as it has 30% of the total chip power consumption. Since, the SRAM cell is low in density and most of memory processing data remain stable during the data holding operation, the stored memory data are more affected by the leakage phenomena in the circuit while the device parameters are scaled down. In this survey, origins of leakage currents in a short-channel device and various leakage control techniques for ultra-low power SRAM design are discussed. A classification of these approaches made based on their key design and functions, such as biasing technique, power gating and multi-threshold techniques. Based on our survey, we summarize the merits and demerits and challenges of these techniques. This comprehensive study will be helpful to extend the further research for future implementations.展开更多
Due to continuous scaling of CMOS, stability is a prime concerned for CMOS SRAM memory cells. As scaling will increase the packing density but at the same time it is affecting the stability which leads to write failur...Due to continuous scaling of CMOS, stability is a prime concerned for CMOS SRAM memory cells. As scaling will increase the packing density but at the same time it is affecting the stability which leads to write failures and read disturbs of the conventional 6T SRAM cell. To increase the stability of the cell various SRAM cell topologies has been introduced, 8T SRAM is one of them but it has its limitation like read disturbance. In this paper we have analyzed a novel PP based 9T SRAM at 45 nm technology. Cell which has 33% increased SVNM (Static Voltage Noise Margin) from 6T and also 22%.reduced leakage power. N curve analysis has been done to find the various stability factors. As compared to the 10T SRAM cell it is more area efficient.展开更多
This paper proposes a novel loadless 4T SRAM cell composed of nMOS transistors. The SRAM cell is based on 32nm silicon-on-insulator （SO1） technology node. It consists of two access transistors and two pull-down tran...This paper proposes a novel loadless 4T SRAM cell composed of nMOS transistors. The SRAM cell is based on 32nm silicon-on-insulator （SO1） technology node. It consists of two access transistors and two pull-down transistors. The pull-down transistors have larger channel length than the access transistors. Due to the significant short channel effect of small-size MOS transistors, the access transistors have much larger leakage current than the pull-down transistors,enabling the SRAM cell to maintain logic ＂1＂ while in standby. The storage node voltages of the cell are fed back to the back-gates of the access transistors,enabling the stable ＂read＂ operation of the cell. The use of back-gate feedback also helps to im- prove the static noise margin （SNM） of the cell. The proposed SRAM cell has smaller area than conventional bulk 6T SRAM cells and 4T SRAM cells. The speed and power dissipation of the SRAM cell are simulated and discussed. The SRAM cell can operate with a 0. 5V supply voltage.展开更多
In this work, a novel memristive SRAM cell is designed using seven transistors and one memristor（7T1M）. In this 7T1 M SRAM cell, the non-volatile functionality is achieved by adding a single memristor and a transist...In this work, a novel memristive SRAM cell is designed using seven transistors and one memristor（7T1M）. In this 7T1 M SRAM cell, the non-volatile functionality is achieved by adding a single memristor and a transistor to the design of a volatile SRAM cell. The designing of the 7T1 M SRAM cell also introduces VCTRL which allows bidirectional current flowing through the memristor, instead of relying on complementary input sources which would require more design components. In this article, memristive SRAM cells available from the literature are simulated using the same simulation environment for a fair comparison. Simulations show that the7T1 M SRAM cell has the least power consumption against other memristive SRAM cells in the literature. The7T1 M SRAM cell operates with an average switching speed of 176.21 ns and an average power consumption of2.9665μW. The 7T1 M SRAM cell has an energy-delay-area product value of 1.61, which is the lowest among the memristive SRAM cells available in the literature.展开更多
Power dissipation, speed and stability are the most important parameters for multiple-valued SRAM design. To reduce the power consumption and further improve the performance of the ternary SRAM cell, we propose a low ...Power dissipation, speed and stability are the most important parameters for multiple-valued SRAM design. To reduce the power consumption and further improve the performance of the ternary SRAM cell, we propose a low standby-power fast ternary SRAM cell based on carbon nanotube field effect transistors(CNFETs).The performance is simulated in terms of three criteria including standby-power, delay(write and read) and stability(RSNM). Compared to the novel ternary SRAM cell, our results show that the average standby-power, write and read delay of the proposed cell are reduced by 78.1%, 39.6% and 58.2%, respectively. In addition, the RSNM under process variations is 2.01× and 1.95× of the conventional and novel ternary SRAM cells, respectively.展开更多
建立了单粒子多位翻转的测试方法和数据处理方法,在此基础上开展了体硅90nm SRAM重离子单粒子多位翻转的实验研究。通过分析单粒子多位翻转百分比、均值、尺寸等参数随线性能量转移(linear energy transfer,LET)的变化关系,表明了纳米...建立了单粒子多位翻转的测试方法和数据处理方法,在此基础上开展了体硅90nm SRAM重离子单粒子多位翻转的实验研究。通过分析单粒子多位翻转百分比、均值、尺寸等参数随线性能量转移(linear energy transfer,LET)的变化关系,表明了纳米尺度下器件单粒子多位翻转的严重性,指出了单粒子多位翻转对现有重离子单粒子效应实验方法和预估方法带来的影响。构建了包含多个存储单元的全三维器件模型,数值模拟研究了不同阱接触布放位置对单粒子多位翻转电荷收集的影响机制,表明阱电势扰动触发多单元双极放大机制是导致单粒子多位翻转的主要因素,减小阱接触与存储单元之间的距离是降低单粒子多位翻转的有效方法。展开更多
为提升SRAM型FPGA电路块存储器和配置存储器抗单粒子翻转性能,本文提出一种脉冲屏蔽SRAM单元结构。该结构通过在标准的六管单元中加入延迟结构,增大单元对单粒子事件响应时间,实现对粒子入射产生的脉冲电流屏蔽作用。以64k SRAM作为验...为提升SRAM型FPGA电路块存储器和配置存储器抗单粒子翻转性能,本文提出一种脉冲屏蔽SRAM单元结构。该结构通过在标准的六管单元中加入延迟结构,增大单元对单粒子事件响应时间,实现对粒子入射产生的脉冲电流屏蔽作用。以64k SRAM作为验证电路进行单粒子翻转性能对比,电路的抗单粒子翻转阈值由采用标准六管单元的抗单粒子翻转阈值大于25 Me V·cm2·mg-1提升至大于45 Me V·cm2·mg-1,加固单元面积较标准六管单元增大约21.3%。30万门级抗辐照FPGA电路通过脉冲屏蔽单元结合抗辐照SOI工艺实现,其抗辐照指标分别为:抗单粒子翻转阈值大于37.3 Me V·cm2·mg-1,抗单粒子锁定阈值大于99.8 Me V·cm2·mg-1,抗电离总剂量能力大于200 krad(Si)。展开更多
文摘Considerable research has considered the design of low-power and high-speed devices.Designing integrated circuits with low-power consumption is an important issue due to the rapid growth of high-speed devices.Embedded static random-access memory(SRAM)units are necessary components in fast mobile computing.Traditional SRAM cells are more energyconsuming and with lower performances.The major constraints in SRAM cells are their reliability and low power.The objectives of the proposed method are to provide a high read stability,low energy consumption,and better writing abilities.A transmission gate-based multi-threshold single-ended Schmitt trigger(ST)9T SRAM cell in a bit-interleaving structure without a write-back scheme is proposed.Herein,an ST inverter with a single bit-line design is used to attain the high read stability.A negative assist technique is applied to alter the trip voltage of the single-ended ST inverter.The multithreshold complementary metal oxide semiconductor(MTCMOS)technique is adopted to reduce the leakage power in the proposed single-ended TGST 9T SRAM cell.The proposed system uses a combination of standard and ST inverters,which results in a large read stability.Compared with the previous ST 9T,ST 11T,11T,10T,and 7T SRAM cells,the proposed cell is implemented in Cadence Virtuoso ADE with 45-nm CMOS technology and consumes 35.80%,42.09%,31.60%,12.54%,and 31.60%less energy for read operations and 73.59%,93.95%,92.76%,89.23%,and 85.78%less energy for write operations,respectively.
文摘The use of Internet of Things(IoT)applications become dominant in many systems.Its on-chip data processing and computations are also increasing consistently.The battery enabled and low leakage memory system at subthreshold regime is a critical requirement for these IoT applications.The cache memory designed on Static Random-Access Memory(SRAM)cell with features such as low power,high speed,and process tolerance are highly important for the IoT memory system.Therefore,a process tolerant SRAM cell with low power,improved delay and better stability is presented in this research paper.The proposed cell comprises 11 transistors designed with symmetric approach for write operations and single ended circuit for read operations that exhibits an average dynamic power saving of 43.55%and 47.75%for write and 35.59%and 36.56%for read operations compared to 6 T and 8 T SRAM cells.The cell shows an improved write delay of 26.46%and 37.16%over 6 T and 8T and read delay is lowered by 50.64%and 72.90%against 6 T and 10 T cells.The symmetric design used in core latch to improve the write noise margin(WNM)by 17.78%and 6.67%whereas the single ended separate read circuit improves the Read Static Noise Margin(RSNM)by 1.88x and 0.33x compared to 6 T and 8T cells.The read power delay product and write power delay product are lower by 1.94x,1.39x and 0.17x,2.02x than 6 T and 8 T cells respectively.The lower variability from 5000 samples validates the robustness of the proposed cell.The simulations are carried out in Cadence virtuoso simulator tool with Generic Process Design Kit(GPDK)45 nm technology file in this work.
基金Supported by National Natural Science Foundation of China(Nos.61176030 and 61373032)Specialized Research Fund for the Doctor Program of Higher Education of China(No.20124307110016)
文摘In advanced technologies, single event upset reversal(SEUR) due to charge sharing can make the upset state of SRAM cells recover to their initial state, which can reduce the soft error for SRAMs in radiation environments. By using the full 3D TCAD simulations, this paper presents a new kind of SEUR triggered by the charge collection of the Off-PMOS and the delayed charge collection of the On-NMOS in commercial 40-nm 6 T SRAM cells. The simulation results show that the proposed SEUR can not occur at normal incidence,but can present easily at angular incidence. It is also found that the width of SET induced by this SEUR remains the same after linear energy transfer(LET) increases to a certain value. In addition, through analyzing the effect of the spacing, the adjacent transistors, the drain area, and some other dependent parameters on this new kind of SEUR, some methods are proposed to strengthen the recovery ability of SRAM cells.
文摘Low power supply operation with leakage power reduction is the prime concern in modern nano-scale CMOS memory devices. In the present scenario, low leakage memory architecture becomes more challenging, as it has 30% of the total chip power consumption. Since, the SRAM cell is low in density and most of memory processing data remain stable during the data holding operation, the stored memory data are more affected by the leakage phenomena in the circuit while the device parameters are scaled down. In this survey, origins of leakage currents in a short-channel device and various leakage control techniques for ultra-low power SRAM design are discussed. A classification of these approaches made based on their key design and functions, such as biasing technique, power gating and multi-threshold techniques. Based on our survey, we summarize the merits and demerits and challenges of these techniques. This comprehensive study will be helpful to extend the further research for future implementations.
文摘Due to continuous scaling of CMOS, stability is a prime concerned for CMOS SRAM memory cells. As scaling will increase the packing density but at the same time it is affecting the stability which leads to write failures and read disturbs of the conventional 6T SRAM cell. To increase the stability of the cell various SRAM cell topologies has been introduced, 8T SRAM is one of them but it has its limitation like read disturbance. In this paper we have analyzed a novel PP based 9T SRAM at 45 nm technology. Cell which has 33% increased SVNM (Static Voltage Noise Margin) from 6T and also 22%.reduced leakage power. N curve analysis has been done to find the various stability factors. As compared to the 10T SRAM cell it is more area efficient.
文摘This paper proposes a novel loadless 4T SRAM cell composed of nMOS transistors. The SRAM cell is based on 32nm silicon-on-insulator （SO1） technology node. It consists of two access transistors and two pull-down transistors. The pull-down transistors have larger channel length than the access transistors. Due to the significant short channel effect of small-size MOS transistors, the access transistors have much larger leakage current than the pull-down transistors,enabling the SRAM cell to maintain logic ＂1＂ while in standby. The storage node voltages of the cell are fed back to the back-gates of the access transistors,enabling the stable ＂read＂ operation of the cell. The use of back-gate feedback also helps to im- prove the static noise margin （SNM） of the cell. The proposed SRAM cell has smaller area than conventional bulk 6T SRAM cells and 4T SRAM cells. The speed and power dissipation of the SRAM cell are simulated and discussed. The SRAM cell can operate with a 0. 5V supply voltage.
文摘In this work, a novel memristive SRAM cell is designed using seven transistors and one memristor（7T1M）. In this 7T1 M SRAM cell, the non-volatile functionality is achieved by adding a single memristor and a transistor to the design of a volatile SRAM cell. The designing of the 7T1 M SRAM cell also introduces VCTRL which allows bidirectional current flowing through the memristor, instead of relying on complementary input sources which would require more design components. In this article, memristive SRAM cells available from the literature are simulated using the same simulation environment for a fair comparison. Simulations show that the7T1 M SRAM cell has the least power consumption against other memristive SRAM cells in the literature. The7T1 M SRAM cell operates with an average switching speed of 176.21 ns and an average power consumption of2.9665μW. The 7T1 M SRAM cell has an energy-delay-area product value of 1.61, which is the lowest among the memristive SRAM cells available in the literature.
基金supported by the National Natural Science Foundation of China(Nos.61474068,61234002,61404076)the S&T Plan of Zhejiang Provincial Science and Technology Department(No.2016C31078)the K.C.Wong Magna Fund in Ningbo University,China
文摘Power dissipation, speed and stability are the most important parameters for multiple-valued SRAM design. To reduce the power consumption and further improve the performance of the ternary SRAM cell, we propose a low standby-power fast ternary SRAM cell based on carbon nanotube field effect transistors(CNFETs).The performance is simulated in terms of three criteria including standby-power, delay(write and read) and stability(RSNM). Compared to the novel ternary SRAM cell, our results show that the average standby-power, write and read delay of the proposed cell are reduced by 78.1%, 39.6% and 58.2%, respectively. In addition, the RSNM under process variations is 2.01× and 1.95× of the conventional and novel ternary SRAM cells, respectively.
文摘建立了单粒子多位翻转的测试方法和数据处理方法,在此基础上开展了体硅90nm SRAM重离子单粒子多位翻转的实验研究。通过分析单粒子多位翻转百分比、均值、尺寸等参数随线性能量转移(linear energy transfer,LET)的变化关系,表明了纳米尺度下器件单粒子多位翻转的严重性,指出了单粒子多位翻转对现有重离子单粒子效应实验方法和预估方法带来的影响。构建了包含多个存储单元的全三维器件模型,数值模拟研究了不同阱接触布放位置对单粒子多位翻转电荷收集的影响机制,表明阱电势扰动触发多单元双极放大机制是导致单粒子多位翻转的主要因素,减小阱接触与存储单元之间的距离是降低单粒子多位翻转的有效方法。
文摘为提升SRAM型FPGA电路块存储器和配置存储器抗单粒子翻转性能,本文提出一种脉冲屏蔽SRAM单元结构。该结构通过在标准的六管单元中加入延迟结构,增大单元对单粒子事件响应时间,实现对粒子入射产生的脉冲电流屏蔽作用。以64k SRAM作为验证电路进行单粒子翻转性能对比,电路的抗单粒子翻转阈值由采用标准六管单元的抗单粒子翻转阈值大于25 Me V·cm2·mg-1提升至大于45 Me V·cm2·mg-1,加固单元面积较标准六管单元增大约21.3%。30万门级抗辐照FPGA电路通过脉冲屏蔽单元结合抗辐照SOI工艺实现,其抗辐照指标分别为:抗单粒子翻转阈值大于37.3 Me V·cm2·mg-1,抗单粒子锁定阈值大于99.8 Me V·cm2·mg-1,抗电离总剂量能力大于200 krad(Si)。
