用于非制冷红外探测器片上存储器的低延迟灵敏放大器设计北大核心CSCD

针对非制冷红外探测器片上存储器的高速数据读出,设计了一种用于非制冷红外探测器片上存储器的低延迟灵敏放大器。随着非制冷红外探测器像素阵列的不断加大,对非制冷红外探测器片上存储器的要求也更高,需要一个更高速的存储器进行红外探测器内部数据存储。通过降低灵敏放大器延迟时间是提高数据传输速度的一种可靠方法。本文对传统交叉耦合结构灵敏放大器进行改进,与传统交叉耦合结构灵敏放大器相比,增加了完全互补型的第二级交叉放大电路,并采用NMOS组成的中间阶段进行两级运放的耦合。改进后的新型灵敏放大器能快速有效地放大位线上电压差,同时改善灵敏度低的问题。本论文设计的灵敏放大器采用TSMC 65 nm工艺,在工作电压为5 V、位线电压差为100 mV条件下,仿真结果表明:数据读出延迟仅为25.19 ps,与交叉耦合式灵敏放大器相比,读出延迟降低了37.07%。同时,在全工艺角仿真条件下,环境温度为-45—125℃,新型灵敏放大器延迟仿真最大值仅为39 ps,最小值为17.1 ps。     

一种优化低电压SRAM灵敏放大器时序的4T双复制位线延迟技术

提出一种减少SRAM存取时间的4T双复制位线延迟技术.该技术主要降低灵敏放大器使能信号的时序变化.该设计通过增加另外一根复制位线并提出一种新的4T复制单元,以优化低电压SRAM灵敏放大器的时序.TSMC 65nm工艺仿真结果表明,在0.6V电源电压下,与传统复制位线设计相比,该技术的灵敏放大器使能信号时序的标准偏差降低30.8%,其读周期减少12.3%.除此之外,由于4T复制单元的MOS管数与传统复制单元相比降低1/3,减小了整体面积开销.     

一种容SEU的新型自恢复锁存器

针对单粒子翻转(SEU)的问题,提出了一种容SEU的新型自恢复锁存器。采用1P-2N单元、输入分离的钟控反相器以及C单元,使得锁存器对SEU能够实现自恢复,可用于时钟门控电路。采用高速通路设计和钟控设计,以减小延迟和降低功耗。相比于HLR-CG1,HLR-CG2,TMR,HiPer-CG锁存器,该锁存器的功耗平均下降了44.40%,延迟平均下降了81%,功耗延迟积(PDP)平均下降了94.20%,面积开销平均减少了1.80%。     

低功耗绝热SRAM

文章提出了一种新的绝热电路,并以该绝热电路为驱动,设计了一种低功耗绝热SRAM.由于所提出的绝热电路能以完全绝热的方式回收位线和字线上大开关电容的电荷,因此使该SRAM的功耗大大减小.我们采用0.25μm TSMC工艺,在时钟频率25～200MHz范围内对绝热SRAM进行了能耗和功能的HSPICE仿真,结果显示,与用传统的CMOS电路设计的SRAM相比,可节能80%左右.     

一种高速低功耗多端口寄存器堆的设计

通过使用特殊的存储单元,减小工作电流,设计了一种32×32 bit的1写8读9端口寄存器堆,读操作位线和写操作位线都实现了低摆幅,结合使用自复位地址译码电路、门限时钟和优化的时序控制电路等,实现了高速和低功耗的目标,并用SMIC 0.18μm工艺设计了全定制版图.在1.8V工作电压下用Hspice进行版图后仿真结果显示,写入时间为1.7ns,读取时间为1.32ns,时钟频率为500MHz时,9个端口同时工作的最大功耗为70 mW.     

一种基于改进K-means算法的高能效时钟网络设计

本文针对先进处理器中部件级时钟网络设计面临的时钟网络偏斜难控制、时钟负载重动态功耗大的问题,实现了一种高能效局部时钟网络设计方法,提出了基于考虑负载K-means算法的时钟驱动点位置优化算法TKDLO(Timing driven K-means based Driver Location Optimization),在不影响时序的前提下,实现了局部门控时钟驱动单元的位置优化,降低了时钟网络的偏斜.通过采用不同触发器规模的设计验证,模块级时钟长度可以优化15%以上,时钟偏斜优化30%以上.以访存执行部件的时钟设计为例,本文所提出的局部时钟设计方法,相比于传统CTS的实现方式,在时钟延迟和偏斜方面实现了超过50%的优化,整个设计等效频率提升14%、平均功耗优化28%、最终模块能效提升58.7%;相比于基于触发器聚类的fishbone时钟结构,在15.2%的时钟延迟恶化和5%功耗恶化代价下,使模块的频率提升7.6%,能效优化14.2%.     

一种高速低功耗多端口寄存器堆的设计

通过使用特殊的存储单元,减小工作电流,设计了一种32×32 bit的1写8读9端口寄存器堆,读操作位线和写操作位线都实现了低摆幅,结合使用自复位地址译码电路、门限时钟和优化的时序控制电路等,实现了高速和低功耗的目标,并用SMIC 0.18μm工艺设计了全定制版图.在1.8V工作电压下用Hspice进行版图后仿真结果显示,写入时间为1.7ns,读取时间为1.32ns,时钟频率为500MHz时,9个端口同时工作的最大功耗为70 mW.     

低功耗电流模互连电路设计

芯片长距离互连时,通过传统的插入缓冲器方法减小延迟存在功耗大、占用芯片面积多等问题。针对这些问题,提出了一种电流模互连电路。这一电路在互连线上传输的信号电压摆幅很小,从而能够有效降低互连功耗、减小信号延迟。通过综合使用强、弱两个驱动器作为信号发送器,进一步减小了信号延迟。对于10 mm的片上互连线,延迟为649 ps,功耗为498μW。为了提高电路在制造工艺发生波动时的鲁棒性,电流模互连结构在驱动电路中添加了电流偏置电路。在Hspice中进行的蒙特卡罗仿真结果表明,180 nm工艺技术下,10 mm互连线的延迟和功耗方差均值比分别为7.91%和12.7%,在工艺发生波动时电路能够稳定工作。     

超深亚微米CMOS工艺参数波动的测量电路

分析了超深亚微米工艺参数波动对电路的影响;采用"放大"的思路设计了简单的用于测量超深亚微米工艺门延迟、动态功耗、静态功耗及其波动的电路,并提出了一种用于测量门延迟波动特性曲线的新型电路,该电路采用较短的反相器链可以得到超深亚微米工艺下门延迟波动特性曲线.电路在90nm CMOS工艺下进行了流片制作,得到了90nm CMOS工艺下的单位门延迟波动特性曲线.测得延迟的波动范围为78.6%,动态功耗的波动范围为94.0%,漏电流功耗的波动范围为19.5倍,其中以漏电流功耗的波动性最为严重.     

ASIC后端设计中低功耗时钟树综合方法

以基于Synopsys公司设计流程完成的SMIC 0.18um1p6m工艺的DVBC解调芯片BTV2040S03为例,介绍一种以降低时钟树功耗为主要目的,以反相器构建时钟树的方法.通过完成物理设计动态仿真和功耗分析的数据表明,在保证时序收敛的前提下,相比传统时钟树综合方法,功耗降低了5.7%.     

Design of a low-power 8 × 8-bit parallel multiplier using MOS current mode logic circuit

This paper proposes an 8?×?8 bit parallel multiplier using MOS current mode logic (MCML) for low power consumption. The 8?×?8 bit multiplier is designed with the proposed MCML full adders and the conventional full adders. The proposed multiplier is achieved to reduce the power consumption by 9.4% and the power-delay-product by 11.7% compared with the conventional circuit. The validity and effectiveness are verified through HSPICE simulation. The proposed multiplier is designed with the Samsung 0.35?μm standard CMOS process.     

Variation-Aware Adaptive Voltage Scaling System

Conventional voltage scaling systems require a delay margin to maintain a certain level of robustness across all possible device and wire process variations and temperature fluctuations. This margin is required to cover for a possible change in the critical path due to such variations. Moreover, a slower interconnect delay scaling with voltage compared to logic delay can cause the critical path to change from one operating voltage to another. With technology scaling, both process variation and interconnect delay are growing and demanding more margin to guarantee an error-free operation. Such margin is translated into a voltage overhead and a corresponding energy inefficiency. In this paper, a critical path emulator architecture is shown to track the changing critical path at different process splits by probing the actual transistor and wire conditions. Furthermore, voltage scaling characteristics of the actual critical path is closely tracked by programming logic and interconnect delay lines to achieve the same delay combination as the actual critical path. Compared to conventional open-loop and closed-loop systems, the proposed system is up to 39% and 24% more energy efficient, respectively. A 0.18-mum technology test chip is designed to verify the functionality of the proposed system showing critical path tracking of a 16times16 bit multiplier     

A low-power charge-recycling ROM architecture

This paper describes a newly proposed low-power charge-recycling read-only memory (CR-ROM) architecture. The CR-ROM reduces the power consumption in bit lines, word lines, and precharge lines by recycling the previously used charge. In the proposed CR-ROM, bit-line swing voltage is lowered by the charge recycling between bit lines. When N bit lines recycle their charges, the swing voltage and the power of the bit lines become 1/N and 1/N/sup 2/ compared to the conventional ROMs, respectively. As the number of N increases, the power saving in bit lines becomes salient. Also, power consumption in word lines and precharge lines can be reduced theoretically to half by the proposed charge-recycling techniques. The simulation results show that the CR-ROM consumes 60%/spl sim/85% of the conventional low-power ROMs with 1 K /spl times/ 32 b. A CR-ROM with 32 Kb was implemented in a 0.35-/spl mu/m CMOS process. The power dissipation is 6.60 mW at 100 MHz with 3.3 V and the maximum operating clock frequency is 150 MHz.     

High speed wide fan‐in designs using clock controlled dual keeper domino logic circuits

Clock Controlled Dual keeper Domino logic structures (CCDD_1 and CCDD_2) for achieving a high‐speed performance with low power consumption and a good noise margin are proposed in this paper. The keeper control circuit comprises an additional PMOS keeper transistor controlled by the clock and foot node voltage. This control mechanism offers abrupt conditional control of the keeper circuit and reduces the contention current, leading to high‐speed performance. The keeper transistor arrangement also reduces the loop gain associated with the feedback circuitry. Hence, the circuits offer less delay variability. The design and simulation of various wide fan‐in designs using 180 nm CMOS technology validates the proposed CCDD_1 and CCDD_2 designs, offering an increased speed performance of 7.2% and 8.5%, respectively, over a conventional domino logic structure. The noise gain margin analysis proves good robustness of the CCDD structures when compared with a conventional domino logic circuit configuration. A Monte Carlo simulation for 2,000 runs under statistical process variations demonstrates that the proposed CCDD circuits offer a significantly reduced delay variability factor.     

Low-standby-current and high-speed SAFF with improved conditional-precharge modules

A new low-power and high-speed sense-amplifier-based flip-flop with improved conditional-precharge modules (LSCP-SAFF) is proposed. By employing a modified differential latch with one shared output holder for the 2nd-stage and taking a novel clocked NMOS transistor to improve timing performance, the LSCP-SAFF can achieve a much shorter static CLK-to-Q delay and D-to-Q delay than those of the original conditional-precharge sense-amplifier-based flip-flop (CP-SAFF). Rather than the traditional CP-SAFF, a novel conditional-precharge scheme is adopted in the present study so that the standby power reduction ratio has reached 69%. Post-layout simulation results show that the LSCP-SAFF, compared with the conventional DFF of a modern industrial CMOS standard cell library, suffer from neither timing nor area penalties. Not only so, it has achieved up to 38% of the dynamic power reduction ratio and 42% of power-delay-product (PDP) reduction ratio, respectively. In addition, driven by low swing clock signals, the LSCP-SAFF is superior in both the timing performance and the standby power. Last, the reliability analysis shows that the LSCP-SAFF is less noise sensitive because of its fully differential structure.     

Design methodology for synthesizing clock distribution networksexploiting nonzero localized clock skew

An integrated top-down design methodology is presented in this brief for synthesizing high performance clock distribution networks based on application dependent localized clock skew. The methodology is divided into four phases: (1) determining an optimal clock skew schedule composed of a set of nonzero clock skew values and the related minimum clock path delays; (2) designing the topology of the clock distribution network with delays assigned to each branch based on the circuit hierarchy, the aforementioned clock skew schedule, and minimizing process and environmental delay variations; (3) designing circuit structures to emulate the delay values assigned to the individual branches of the clock tree; and (4) designing the physical layout of the clock distribution network. The clock distribution network synthesis methodology is based on CMOS technology. The clock lines are transformed from distributed resistive capacitive interconnect lines into purely capacitive interconnect lines by partitioning the RC interconnect lines with inverting repeaters. Variations in process parameters are considered during the circuit design of the clock distribution network to guarantee a race-free circuit. Nominal errors of less than 2.5% for the delay of the clock paths and 7% for the clock skew between any two registers belonging to the same global data path as compared with SPICE Level-3 are demonstrated     

基于相位合成的时钟50%占空比调节电路设计

本文介绍了采用纯数字相位合成法设计的高性能时钟50%占空比调节电路PB-DCC(Phase-Blending Duty-Cycle Corrector).相比于传统的占空比调节方式,此电路通过采用SMD(Synchronous Mirror Delay)技术具有较强的抗PVT(Process,Voltage and Temperature)变化的能力,输出时钟和原时钟完全同步和较快的调节速度等特点.经0.13μm CMOS工艺版图实现后HSPICE模拟表明,该占空比调节电路对占空比在10%~90%范围内的400MHz时钟能在4个周期内完成调节,输出时钟占空比为48%~52%.     

A High-Speed Variation-Tolerant Interconnect Technique for Sub-Threshold Circuits Using Capacitive Boosting

This paper describes an interconnect technique for subthreshold circuits to improve global wire delay and reduce the delay variation due to process-voltage-temperature (PVT) fluctuations. By internally boosting the gate voltage of the driver transistors, operating region is shifted from subthreshold region to super-threshold region enhancing performance and improving tolerance to PVT variations. Simulations of a clock distribution network using the proposed driver shows a 66%-76% reduction in 3sigma clock skew value and 84%-88% reduction in clock tree delay compared to using conventional drivers. A 0.4-V test chip has been fabricated in a 0.18-mum 6-metal CMOS process to demonstrate the effectiveness of the proposed scheme. Measurement results show 2.6times faster switching speed and 2.4times less delay sensitivity under temperature variations.     

Dynamics of all-optical clock recovery using two-section index- and gain-coupled DFB lasers

The dynamics of coherent clock recovery (CR) using self-pulsing two-section distributed feedback (TS-DFB) lasers have been investigated. Both simulation and experimental results indicate fast lockup and walk-off of the clock-recovery process on the order of nanoseconds. Phase stability of the recovered clock from a pseudorandom bit sequence (PRBS) signal can be achieved by limiting the detuning between the frequency of free-running self-pulsation and the input bit rate. The simulation results show that all-optical clock recovery using TS-DFB lasers can maintain a better than 5% clock phase stability for large variations in power, bit rate, and optical carrier frequency of the input data and therefore is suitable for applications in optical packet switching.     

Low power dynamic circuit for power efficient bit lines

In this paper, a low power dynamic circuit is presented to reduce the power consumption of bit lines in multi-port memories. Using the proposed circuit, the voltage swing of the pull-down network is lowered to reduce the power consumption of wide fan-in gates employed in memory’s bit lines. Wide fan-in OR gates are designed and simulated using the proposed dynamic circuit in 90 nm CMOS technology. Simulation results show at least 40% reduction of power consumption and 1.2X noise immunity improvement compared to the conventional dynamic circuits at the same delay. Exploiting the proposed dynamic circuit, wide fan-in multiplexers are also designed. The multiplexers are simulated using a 90 nm CMOS model in all process corners. The results show 41% power reduction and 27% speed improvement for the proposed 128-input multiplexer in comparison with the conventional multiplexer at the same noise immunity.