基于FPGA大面阵数字CCD相机驱动电路的设计

介绍了大面阵CCD相机的工作时钟产生电路的设计,利用大规模集成电路FPGA实现了该工作时钟驱动电路,采用了VHDL语言对工作时钟驱动电路进行了硬件描述,并利用Modelsim软件对所设计的工作时钟驱动电路进行了仿真,最后进行了硬件电路调试,实现了整个CCD相机的控制.采用SONY公司的ICX285AL作为传感器.     

基于片上系统的时钟复位设计

从方法优化和电路设计入手,提出了基于片上系统(SOC)的复位方法和时钟复位电路.设计了片外按键复位电路、片内上电电路、晶振控制电路、片内RC低频时钟电路、槽脉冲产生电路、分频延时电路、时钟切换电路及异步复位同步释放电路等电路模块.以上电路模块构成了片上系统的时钟复位电路,形成了特定的电路时钟复位系统.该时钟复位系统将片外按键复位与片内上电复位结合起来,形成多重复位设计,相比单纯按键复位更智能,相比单纯上电复位则更可靠.另外,该时钟复位系统还采用了片内RC振荡时钟电路等一系列电路,借助片内RC时钟实现对芯片的延时复位,进而在保证复位期间寄存器得到正确初始化的同时,还使得芯片能够始终处在稳定的晶振时钟下正常工作.相比传统的时钟复位电路,该时钟复位系统既便捷,又保证了系统初始化和系统工作的可靠性.     

一种适用于NRZ数据的时钟数据恢复电路

提出了一种基于传统电荷泵锁相环结构的时钟数据恢复电路.采用一种适用于NRZ数据的新型鉴频鉴相器电路,以克服传统鉴频鉴相器在恢复NRZ信号时出现错误脉冲的问题,从而准确地恢复出NRZ数据.同时,对其他电路也采用优化的结构,以提高时钟数据恢复电路的性能.设计的电路可在1.1 V超低电压下工作,适合RF ID等需要低电压、低功耗的系统使用.     

用于CDR电路的相位插值选择电路设计

时钟数据恢复电路是高速多通道串行收发系统中接收端的关键电路,其性能的优劣直接影响了整个系统的功能.描述了双环时钟数据恢复电路利用相位正交的参考时钟进行工作的原理,分析了传统的正交时钟产生方案,提出一种新的相位插值-选择方案并给出了CMOS电路实现.在SMIC 0.18 μm CMOS工艺下采用Cadence公司的仿真工具Spectre进行了晶体管级验证,结果显示,利用该电路恢复出来的时钟对数据进行重定时,能较好地消除传输过程中积累的抖动,有效地提高了输入抖动容限.     

一种分析高速时钟网络信号完整性的有效方法

本文基于有耗传输线模型,运用等效源理论首次分析了工作在GHz频率时时钟树电路互连系统对传输信号完整性的影响,对时钟树的'T’型结构引入三端口网络,计算结果表明这是一种有效的分析时钟树电路信号完整性的方法.     

高速时钟电路的EMC设计

能产生射频范围内信号的设备都可能产生电磁干扰(EMI),在高速数字系统中,时钟电路是主要的电磁干扰源,时钟电路的EMC(电磁兼容性)设计好坏直接关系到系统辐射情况和系统的性能.本文讨论了时钟电路中电磁干扰的产生机理和危害,以及降低时钟电路电磁干扰的方法,并采用HYPERLYNX软件来对方法进行验证.     

一种新型的用于高速串行接口电路的单片锁相环电路设计

本文提出了一种新型的适用于USB2.0高速模式480MHz时钟产生的单片锁相环(PLL)电路.该PLL电路由一个鉴频鉴相器电路、一个电荷泵、一个低通滤波器、一个压控振荡器和分频器组成.论文着重对由环型差分对组成的压控振荡器电路进行了优化.电路的设计基于TSMC的0.25(m CMOS混合信号模型,电路的前后仿真结果表明该电路不仅能产生频率为480MHz的时钟信号,并且抖动(jitter)只有2ps rms,锁定时间(lock time)是1.8(s,完全满足USB2.0接口芯片对PLL的要求.     

基于DLL的1.25 G超宽带通信系统时钟生成电路

设计并实现了一个基于延时锁定环(DLL)、用于超宽带(UWB)无线通信系统的1.25GHz时钟生成电路。该时钟生成电路由两个DLL和一个自调谐LC滤波电路组成,输入125MHz的参考时钟,输出1.25GHz的差分时钟和间隔100ps的16相时钟。通过优化电荷泵电路有效地减小了静态相位误差,新式自调谐LC滤波电路的应用消除了工艺偏差对谐振的影响。在1.8V电源电压,SMIC0.18μmCMOS工艺下,该时钟生成电路在各种工作条件下均表现出良好的性能,在标准情况下静态相位误差仅为9ps,最大时钟抖动为10ps。当电感存在30%的工艺偏差时,滤波电路的谐振频率能够自动维持在1.25GHz上。     

高频工作系统中时钟分配电路设计

在25MHz以上频率工作的数字系统中,时钟分配电路设计是一个非常重要的问题.本文介绍了高性能、高速时钟分配电路的简化设计方法,并讨论了与时钟分配设计有关的技术问题.     

时钟低摆幅双边沿低功耗触发器的设计

传统的时钟低摆幅触发器由于工作方式和电路结构不够合理,使得电路的结点电容和开关活动性较大,增加了电路的开关功耗.本文通过改进传统的时钟低摆幅触发器的工作方式和电路结构,设计了一种新型的时钟低摆幅双边沿触发器--反馈保持型时钟低摆幅双边沿触发器(Feedback Keeper Low-swing Clock Double-edge-triggered Flip-flop-FK-LSCDFF).模拟结果表明所设计的触发器具有正确的逻辑功能,跟传统的时钟低摆幅双边沿触发器相比,降低近17%的功耗.     

Modeling and analysis of single-event transient sensitivity of a 65 nm clock tree

The soft error rate (SER) due to heavy-ion irradiation of a clock tree is investigated in this paper. A method for clock tree SER prediction is developed, which employs a dedicated soft error analysis tool to characterize the single-event transient (SET) sensitivities of clock inverters and other commercial tools to calculate the SER through fault-injection simulations. A test circuit including a flip-flop chain and clock tree in a 65 nm CMOS technology is developed through the automatic ASIC design flow. This circuit is analyzed with the developed method to calculate its clock tree SER. In addition, this circuit is implemented in a 65 nm test chip and irradiated by heavy ions to measure its SER resulting from the SETs in the clock tree. The experimental and calculation results of this case study present good correlation, which verifies the effectiveness of the developed method.     

时钟网格与时钟树设计方法对比研究

基于片上偏差对芯片性能的影响,分析对比了时钟树设计与时钟网格设计,重点分析了时钟网格抗OCV影响的优点,并利用实际电路应用两种方法分别进行设计对比,通过结果分析,验证了理论分析的正确性,证明在抗OCV及时序优化时钟网格方法具有很大的优势。     

ASIC后端设计中的时钟树综合

时钟树综合是当今集成电路设计中的重要环节,因此在FFT处理器芯片的版图设计过程中,为了达到良好的布局效果,采用时序驱动布局,同时限制了布局密度;为了使时钟偏移尽可能少,采用了时钟树自动综合和手动修改相结合的优化方法,并提出了关于时钟树约束文件的设置、buffer的选型及手动修改时钟树的策略,最终完成了FFT处理器芯片的时钟树综合并满足了设计要求。     

Design of Thermally Robust Clock Trees Using Dynamically Adaptive Clock Buffers

On-chip temperature gradient has emerged as a major design concern for high-performance integrated circuits for the current and future technology nodes. Clock skew is an undesirable phenomenon for synchronous digital circuits that is exacerbated by the temperature difference between various parts of the clock tree. The main aim of this paper is to provide intelligent solution for minimizing the temperature-dependent clock skew by designing dynamically adaptive circuit elements, particularly the clock buffers. Using an RLC model of the clock tree, we investigate the effect of on-chip temperature gradient on the clock skew for a number of temperature profiles that can arise in practice due to different architectures and applications. As an effective way of mitigating the variable clock skew, we present an adaptive circuit technique that senses the temperature of different parts of the clock tree and adjusts the driving strengths of the corresponding clock buffers dynamically to reduce the clock skew. Simulation results demonstrate that our adaptive technique is capable of reducing the skew by up to 92.4%, leading to much improved clock synchronization and design performance.      

数字电视发端调制器芯片时序优化设计与实现

设计数字集成电路时,关键是要满足时序的约束。时钟树综合是芯片设计后端优化时序过程中至关重要的一环,尤其是在复杂的超大规模高速集成电路设计中,它将直接影响最后的流片。其中时钟偏斜是影响时钟的重要因素。本文以SMIC 0.18μm工艺数字电视发端调制器芯片为例,前端提出新的获得同步分频时钟的方法,后端使用Synopsys的Astro工具来进行手动时钟树综合和时序优化,在满足时序设计要求的同时减小了芯片面积。     

基于异或门自选通的低功耗时钟树综合方案

本文介绍一种降低时钟网络功耗的方法。该方法基于电路中寄存器本身的状态值,在采用异或门进行自选通后构建时钟树结构,从而减少时钟信号额外翻转,降低芯片功耗。将该方法应用于一款基于SMIC0.18μmEflash 2p4m工艺下的非接触式智能卡芯片的物理设计。仿真结果表明,与传统时钟树综合方法相比,芯片功耗降低了10.7%。     

Clock Buffer Polarity Assignment for Power Noise Reduction

Power/ground noise is a major source of VLSI circuit timing variations. This work aims to reduce clock network induced power noise by assigning different signal polarities (opposite switchings) to clock buffers in an existing buffered clock tree. Three assignment algorithms are proposed: 1) partitioning; 2) 2-coloring on minimum spanning tree; and 3) recursive min-matching. A post-processing of clock buffer sizing is performed to achieve desired clock skew. SPICE based experimental results indicate that our techniques could reduce the average peak current and average delay variations by 50% and 51%, respectively.      

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     

单光子探测盖革雪崩焦平面用低抖动多相位时钟电路设计

针对单光子探测盖革雪崩焦平面读出电路应用,基于全局共享延迟锁相环和2维H型时钟树网络,该文设计一款低抖动多相位时钟电路.延迟锁相环采用8相位压控延迟链、双边沿触发型鉴相器和启动-复位模块,引入差分电荷泵结构,减小充放电流失配,降低时钟抖动.采用H时钟树结构,减小大规模电路芯片传输路径不对称引起的相位差异,确保多路分相时...