基于SOC的低功耗管理模块设计

功耗是片上系统(SOC)设计中的关键指标之一。对于SOC芯片的低功耗设计,可以采用多种设计方法进行优化。本文设计的低功耗管理模块是通过管理工作时钟的方式对SOC的功耗进行动态调节,能够有效地降低SOC芯片的功耗。     

SOC技术及系统级低功耗设计

介绍了SOC设计中的IP核可复用技术、软硬件协同设计技术、SOC验证技术、可测性设计技术以及低功耗设计技术。对SOC低功耗设计中的瞬态功耗优化、平均功耗优化以及功耗的物理来源、电容充放电功耗、短路功耗、静电漏电功耗进行了分析。并对典型SOC设计中采取降低芯片和封装电容、降低电源电压,达到降低功耗的技术进行了研究。最后对系统级功耗设计中的电源系统低功耗设计、工作系统低功耗设计进行了探讨。     

SOC时代低功耗设计的研究与进展

在片上系统(SOC)时代,芯片内核的超高功耗密度以及移动应用市场对低功耗的无止境需求,使低功耗设计变得日益重要.文章全面系统地介绍了低功耗设计的相关内容,包括背景、原理和不同层次的功耗优化技术,着重介绍了面向SOC的系统级功耗优化技术.通过对已有研究成果按设计抽象层次和系统功能的分析,指出了其优化的全局性不够充分.提出了基于软硬件协同设计的系统功耗优化思路和设计流程,展望了SOC低功耗设计的发展方向.     

多媒体SOC芯片的低功耗设计

从集成电路功耗原理出发,分析了CMOS电路功耗的来源,从集成电路设计的系统级、算法级、架构级、电路/门级以及工艺/器件级五个抽象层次出发,整理、总结了当前主要的低功耗设计方法,并在实际的移动多媒体处理应用SOC芯片设计中,平衡产品成本、设计复杂度、设计环境等多种因素,确定并应用了适合设计对象的低功耗设计方法的组合.通过对于样片功耗的测试分析,低功耗设计方法(组合)取得了预期的效果,实现了较低的动态功耗与很低的静态功耗.     

百万门级系统芯片低功耗技术研究

针对超大规模集成电路低功耗设计技术市场需求的迅速增大,提出了一种新的百万门级系统芯片低功耗设计流程,重点分析了芯片系统级、电路级、逻辑级与物理级四个不同的层次的低功耗设计方法,包括系统构架、时钟与功耗管理算法等低功耗关键技术。以某新型雷达SoC低功耗设计为例,采用SMIC 0.18 μm 1P6M CMOS工艺进行设计,版图尺寸为7.825 mm×7.820 mm,规模约为200万门。实验结果表明,在100 MHz工作频率下,采用新的低功耗设计流程后,前端设计阶段功耗降低了42.79%,后端设计阶段功耗降低了12.77%,芯片总功耗仅为350 mW。样品电路通过了用户某新型相控阵雷达系统的应用验证,满足小型化和低功耗的要求。     

SoC低功耗设计及其技术实现

文章根据低功耗设计理论和方法,分别从系统级、模块级及RTL级三个层次上考虑一款SoC芯片功耗设计。在系统级采用工作模式管理方式,在模块级采用软件管理的方式,RTL级采用门控方式,三种方式的应用大大降低芯片了的功耗。仿真分析表明,该芯片的低功耗设计策略取得了预期的效果,实现了较低的动态功耗与很低的静态功耗。该SoC采用0．18μm CMOS工艺库实现,面积为7．8mm×7．8mm,工作频率为80Mnz,平均功耗为454．268mW。     

通用视频输出控制器IP核的低功耗设计

随着芯片的集成度越来越高,芯片的功耗成为芯片设计中越来越重要的优化参数。设计了一种可应用于视频处理芯片、多媒体手持设备、嵌入式SoC等系统中的视频输出控制器。设计中通过多种工艺无关的低功耗设计技术优化控制器的动态功耗。首先分析各子模块的工作频率,降低低速子模块的工作时钟,然后通过添加门控时钟单元降低时钟的翻转次数。应用Design Compiler[1]进行工程的功耗分析,结果表明设计中使用的低功耗设计方法有效降低了模块的动态功耗。     

一种500MHz高性能锁相环的设计

随着专用集成芯片（ASIC）和系统芯片（SOC）的飞速发展，芯片内部生成可变频率的稳定时钟变得至关重要，设计一个高性能锁相环正是适应了这样的需求。本文在传统锁相环结构的基础上设计了一种高速、低功耗、低噪声的高性能嵌入式混合信号锁相环结构。它可以在片内产生多分组高频稳定时钟信号，从而为先进的专用集成芯片（ASIC）和系统芯片（SOC）的实现提供最基础且最重要的可应用时钟产生电路。模拟结果表明：该锁相环可稳定输出500 MHz时钟信号，稳定时间小于700ns，在1．8V电源下的功耗小于18mW，噪声小于180mV。     

一种低功耗时钟芯片的设计与实现

本文讨论了一种低功耗时钟芯片的设计与实现。通过分析CMOS电路功耗产生原因,给出了详细的低功耗实现方案。流片后测试表明该芯片工作电流0.17mA,满足低功耗要求。     

一种自动化瞬时功耗分析方法

随着IC设计的规模更大,要求速度更快,以及便携式设备的广泛需求,芯片功耗的问题越来越凸显出来。对于纳米尺寸的芯片来说,功耗管理是一个主要的挑战。因此,在芯片的设计阶段功耗分析是贯穿于整个设计流程的重要步骤。在整个设计流程中需要对功耗进行分析并依据分析结果进行低功耗设计,这些技术可以保证芯片的每一部分都能高效、可靠、正确地工作。选择合适的低功耗手段,必须以细致的功耗预估为前提。这样才能保证找到芯片工作时的功耗极值点,这些数值的分析对降低芯片功耗、优化电路设计提供有力支持。     

A 1-V, 1.2-mA fully integrated SoC for digital hearing aids

Both power and size are very important design issues for hearing aids. This paper proposes a fully integrated low-power SoC for today׳s digital hearing aids. The SoC integrates all the audio processing elements on single chip, including the analog front-end, digital signal processing (DSP) platform and class-D amplifier. Also, the low-dropout voltage regulators and internal clock generator are both integrated to minimize the system overall size. The 24-bit DSP platform comprises an application-specific instruction-set processor and several dedicated accelerators to achieve a trade-off between flexibility and power efficiency. Three critical hearing-aid algorithms (wide dynamic range compression, noise reduction and feedback cancellation) are performed by the low-power accelerators. The proposed SoC has been fabricated in SMIC 130 nm CMOS technology. The measurement results show that the analog front-end has up to 88 dB signal-to-noise ratio. And the DSP platform consumes about 0.86 mA current at 8 MHz clock frequency when executing the three algorithms. The total current consumption of SoC is only 1.2 mA at 1 V supply. In addition, the acoustic test results indicate that the SoC is one promising candidate for hearing-aid manufacturers.     

SoC设计中的低功耗策略

低功耗设计已经成为片上系统(SoC)设计的主题.当今的设计已经从过去的性能、面积二维目标转变为性能、面积和功耗的三维目标.本文深入探讨了片上系统设计中的低功耗设计策略,在晶体管和逻辑门级、寄存器传输级和系统结构级各设计抽象层次上阐述了低功耗设计所面临的问题,并给出了各级的低功耗优化策略.     

A new successive approximation architecture for low-power low-cost CMOS A/D converter

A new 6-bit 250 MS/s analog-to-digital converter (ADC) is proposed for low-power low-cost CMOS integrated systems. This design is based on an improved successive approximation ADC with a mixed-mode subtracter that minimizes the overall power consumption and system complexity. The experimental results indicate that this ADC works up to 250 MS/s with power consumption less than 30 mW at 3.3 V. Moreover, the operating voltage is scaled down to 0.8 V using a slight adjustment. The ADC occupies only 0.1 mm/sup 2/ with the TSMC 0.35-/spl mu/m single poly quadruple metal (SPQM) CMOS technology. This design is suitable for standard CMOS technology with low-power low-cost VLSI implementation. It is well applied when embedded into system-on-chip (SoC) circuit designs.     

基于CCopt引擎的SMIC 40nm低功耗工艺Cortex A9的时钟树实现

随着市场智能手机平台和平板电脑对芯片性能和上市时间要求的不断提升,后端工程师面临的设计压力会越来越大。传统的数字实现流程在满足当今SoC设计的功耗、频率与面积要求方面正在达到极限。那如何在很短的时间内迅速实现芯片功耗、频率与面积的提升变的尤为重要。本文基于SMIC 40nm低功耗工艺的ARM Cortex A9物理设计的实际情况,详细阐述了如何使用cadence最新的时钟同步优化技术,又称为CCopt技术来实现统一的时钟树综合和物理优化。根据实现的结果来看,CCopt引擎很好的实现了目标。实现8%的设计频率提升,并实现了时钟树功率与面积降低。Cadence最新的CCopt引擎对实现复杂芯片物理设计、缩短设计周期、提升芯片性能带来了很大的优势。     

Power consumption reduction in systems on Chip (SoCs)

Systems on Chip are becoming extremely complex integrated circuits, containing tens or hundreds of analog,rf and digital blocks. For most applications, they have to present extremely low power consumption. It is the case, for instance, in ad hoc networks for which 100 or 1000 SoC nodes have to sense their environment, do some processing and send by radio some information to adjacent nodes in a multi-hop fashion to reach finally a base station. The design of such SoC nodes, to achieve the required extremely low power consumption, has to performed first at the system level, including low power communication protocols and data routing through the network, node wake-up strategies, low-power software and operating systems, innovative solutions for the sensor part, flexible or reconfigurable and very low power digital processing, low-power networks on chip for the communication between embedded processors and memories, as well as low powerrf front-ends. In addition, due to the impressive technology pace, new problems have to be solved for the design of SoCs, such as the interconnect delays, reliability and the dramatic increase of the static power. Some techniques, considered as the most efficient, of dynamic as well as static power reduction are described. It is however shown that the design of SoCs in 130 nm and below will impact dramatically the design methodologies, mainly due the static power increase. Finally, if today most SoCs are powered by batteries, alternative sources of energy are reviewed.     

基于数字IP的NoC低功耗方法研究

为了设计实现高性能的片上系统SoC,针对基于分层星型连接集成数字IP核的片上网络,提出了低振幅信号发送、基于Mux-Tree的轮转法调度程序,部分激活的交叉单元和串行链路编码等不同的低功耗方法,并分别在每一个开放系统互连层得到应用实现,实验数据证明获得了功耗最经济的片上网络.     

基于ARCA3 CPU的嵌入式SoC的FPGA原型验证

基于FPGA的验证是SoC功能验证的有效途径,建立一个基于FPGA的原型验证系统已成为SoC验证的重要方法.ARCA3是一种高性能、低功耗,国产的嵌入式微处理器.在ARCA3和AMBA架构上集成存储器控制器等IP核和外设,构建一个嵌入式SoC,并在FPGA上实现SoC的原型验证系统和软硬件协同验证环境.在FPGA原型机上运行Bootloader和操作系统,验证整个系统硬件的可操作性和软硬件之间的交互.基于FPGA的原型验证系统的实现可以快速验证基于ARCA3的各种抽象层次的IP核和开发基于ARCA3的软件应用.     

90-nm process-variation adaptive embedded SRAM modules with power-line-floating write technique

The power consumption of a low-power system-on-a-chip (SoC) has a large impact on the battery life of mobile appliances. General SoCs have large on-chip SRAMs, which consume a large proportion of the whole LSI power. To achieve a low-power SoC, we have developed embedded SRAM modules, which use some low-power SRAM techniques. One technique involves expanding the write margin; another is a power-line-floating write technique, which enables low-voltage write operation. The power-line-floating write technique makes it possible to lower the minimum operating supply voltage by 100 mV. The other techniques involve using a process-variation-adaptive write replica circuit and reducing leakage current. These techniques reduce active power during write operations by 18% and reduce active leakage of the word-line driver by 64%. The prototype SRAM modules achieve 0.8-V operation, and a 512-kb SRAM module achieves 48.4-/spl mu/A active leakage and 7.8-/spl mu/A standby leakage with worst-leakage devices.     

一种共源共栅自偏置带隙基准源设计

在分析带隙基准理论的基础上,针对SoC芯片的1.2V数字电路供电,设计一个低功耗低温度系数、高电源抑制比的带隙基准源。电路由一个与绝对温度成正比(PTAT)电流源和一个绝对温度相补(CTAT)电流源叠加构成,采用低压共源共栅自偏置结构来减少镜像失配和工艺误差对电路的影响。在SMIC0.13μm混合信号CMOS工艺下,电源电压为2.5V时,使用Cadence Spectre对电路进行模拟,结果表明可实现1.2V输出电压,电源抑制比在低频段为-86dB、高频段为-53dB,温度系数为12×10-6/℃、功耗为0.57mW。带隙电压基准源的版图面积为75μm×86μm。     

Low-power design for embedded processors

Minimization of power consumption in portable and battery powered embedded systems has become an important aspect of processor and system design. Opportunities for power optimization and tradeoffs emphasizing low power are available across the entire design hierarchy. A review of low-power techniques applied at many levels of the design hierarchy is presented, and an example of low-power processor architecture is described along with some of the design decisions made in implementation of the architecture