Reduce Leakage Power Consumption Research Articles

Design of Enhanced Reversible 9T SRAM Design for the Reduction in Sub-threshold Leakage Current with14nm FinFET Technology

Power dissipation is considered one of the important issues in low power Very-large-scale integration (VLSI) circuit design and is related to the threshold voltage. Generally, the sub-threshold leakage current and the leakage power dissipation are increased by reducing the threshold voltage. The overall performance of the circuit completely depends on this leakage power dissipation because this leakage and power consumption causes the components that are functioning by the battery for a long period to be washed-out rapidly. In this research, the reversible logic gate-based 9T static random access memory (SRAM) is designed in 14nm FinFET technology to reduce leakage power consumption in memory related applications. The Schmitt-trigger (ST)-based 9T SRAM cell is designed to attain high read-write stability and low power consumption using a single bit line structure. The reversible logic gates of Feynman (FG) and Fredkin gate (FRG) are combined to develop a row and column decoder in an SRAM design to diminish the leakage power. Moreover, the transistor stacking effect is applied to the proposed memory design to reduce the leakage power in active mode. The proposed reversible logic and transistor stacking based SRAM design is implemented in Tanner EDA Tool version 16.0. It also performs both read and write operations using the proposed circuit. The performance measures of read access time (RAT), write access time (WAT), read, write, and static power by varying supply voltage and temperature, delay and stability analysis (read/write static noise margin) are examined and compared with existing SRAM designs.

Enhanced Quasi-Static Energy Recovery and Modified Clock Gating for the Wallace Tree Multiplier with Reversible Adders

High-speed, low-power digital circuits are essential in many digital applications. The objective of the paper is to design high-speed low-power multipliers with reversible gates. The realization of a multiplier with an efficient clocking system is also presented to reduce leakage power consumption. The existing reversible configurations do not possess an effective clocking system for reducing power in an idle state. In this work, a modified clock gating (MCG) and Enhanced Quasi-Static Energy Recovery Logic (EQSERL) are designed to generate a clock pulse. The EQSERL reduces the dynamic state in the circuit and it is designed with reduced complexity. This process effectively reduces leakage power consumption in the circuit. The conventional clock gating circuit is modified for connecting it with the EQSERL. This MCG circuit reduces unwanted power consumption. The conventional Wallace tree multiplier (WTM) involves full adder and half adder circuits. In this proposed work, a square root carry select adder (SQRT CSLA) with a reversible binary to excess-1 converter (BEC) and a ripple carry adder is presented. The reversible gates such as the Feynman gate, the Toffoli gate, and the dual key gate are employed. Finally, the proposed architecture is tested with different clocking circuits using Synopsys tools and the performance metrics like delay and power are observed.

Design of Efficient Complex Gate using 45nm Technology

In this paper, we designed complex gate which is having very good performance in terms of delay. This is achieved by increasing threshold voltage. The reduced delay and its percentage variation with respect to threshold voltage is shown below in the result analysis. Increasing of threshold voltage not only reduces delay but indirectly reduces leakage power consumption. Now-a-days Efficient Complex Gate using 45nm technology is preferable because of its delay and power.

Analysing the Role of Last Level Caches in Controlling Chip Temperature

Dynamic Thermal Management (DTM) has become a major concern for the chip-designers, as it becomes a challenging task in recent power densed high performance Chip Multi-Processors (CMPs), due to integration of more on-chip components to meet ever increasing demand of processing power. The increased chip temperature incorporates severe circuit errors along with significant increment in leakage power consumption. Traditional DTM techniques apply DVFS or task migration to reduce core temperature, as cores are considered as the hottest on-chip components. Additionally, to commensurate high data demand of these high performance cores, large on-chip Last Level Caches (LLCs) are attached, which are the principal contributors to the on-chip leakage power consumption and occupy the largest on-chip area. As power consumption reduction plays the pivotal role in temperature reduction, hence, this work dynamically shrinks the cache size not only to reduce leakage power consumption, but also, to create on-chip thermal buffers for reducing average chip temperature by exploiting the heat transfer physics. Cache resizing decisions are taken based upon the generated cache hotspots and/or the access patterns, during process execution. Simulation results of the proposed thermal management method are compared with an existing DVFS based method (at cores) and a prior drowsy cache based technique to show its effectiveness.

Thermal energy aware proportionate scheduler for multiprocessor systems

As per Moore’s law, the power consumption and heat solidity of the multiprocessor systems are increasing proportionately. High temperature increases the leakage power consumption of the processor and thus probably escort to thermal runaway. Efficiently managing the energy consumption of the multiprocessor systems in order to increase the battery lifetime is a major challenge in multiprocessor platforms. This article presents Thermal Energy aware proportionate scheduler (TEAPS) to reduce leakage power consumption. Simulation experiment illustrate that TEAPS reduces 16% of energy consumption with respect to Mixed Proportionate Fair (PFAIR-M) and 36% of energy consumption with respect to Proportionate Fair (PFAIR) Schedulers on the system consisting of 20 processors under full load condition.

An Exploration of Applying Gate-Length-Biasing Techniques to Deeply-Scaled FinFETs Operating in Multiple Voltage Regimes

With the aggressive downscaling of process technologies and the importance of battery-powered systems, reducing leakage power consumption has become a crucial design challenge for IC designers. In addition, the traditional bulk CMOS technologies face significant challenges related to short-channel effects and process variations. FinFET devices have attracted a lot of attention as an alternative to bulk CMOS in sub-32nm technology nodes. This paper presents a device-circuit cross-layer framework to utilize fine-grained gate-length biased FinFETs for circuit leakage power reduction in near- and super-threshold ( $V_T$ ) operation regimes. The impacts of cell-level and transistor-level Gate-Length Biasing (GLB) on circuit speed and leakage power are studied using a 7 nm FinFET technology.

Sleep signal controlled footless domino circuit for low leakage current

PurposeThis paper aims to propose a new sleep signal controlled footless domino circuit for reducing the subthreshold and gate oxide leakage currents.Design/methodology/approachIn the proposed circuit, a P channel MOSFET (PMOS) sleep switch transistor is inserted between the power supply and the output node. The sleep transistor, the source of the pull-down network, and the source of the N channel MOSFET (NMOS) transistor of the output inverter are controlled by this additional sleep signal to place the footless domino circuit in a low leakage state.FindingsThe authors simulate the proposed circuit by using HSPICE in 45-nm CMOS technology for OR and AND logic gates such as OR2, OR4, OR8, AND2 and AND4 at 25°C and 110°C. The proposed circuit reduces leakage power consumption as compared to the existing circuits.Originality/valueThe proposed circuit significantly reduces the total leakage power consumption up to 99.41 and 99.51 per cent as compared to the standard dual-threshold voltage footless domino circuits at 25°C and 110°C, respectively, and up to 93.79 and 97.98 per cent as compared to the sleep control techniques at 25°C and 110°C, respectively. Similarly, the proposed circuit reduces the active power consumption up to 26.76 and 86.25 per cent as compared to the standard dual-threshold voltage and sleep control techniques footless domino circuits at 25°C and 110°C, respectively.

Minimum Implant Area-Aware Placement and Threshold Voltage Refinement

Threshold voltage assignment is a very effective technique to reduce leakage power consumption in modern integrated circuit design. As feature size continues to decrease, the layout constraints [called minimum implant area (MinIA) constraints] on the implant area, which determines the threshold voltage of a device, are becoming increasingly difficult to satisfy. It is necessary to take these constraints into consideration during the placement stage. In this paper, we propose to resolve the MinIA constraint violations of a given placement by performing simultaneous detailed placement and threshold voltage refinement. We first present an optimal and efficient mixed integer-linear programming (MILP)-based algorithm to handle intrarow MinIA constraints. We then extend the MILP-based algorithm to handle both inter-row and intrarow MinIA constraints. Both of our algorithms guarantee to fix all MinIA constraint violations. Experimental results demonstrate that our algorithms only perturb the original placement and threshold voltage assignment solutions minimally to eliminate all violations and are fast in practice.

Architecture and data migration methodology for L1 cache design with hybrid SRAM and volatile STT-RAM configuration

Spin-Transfer Torque RAM (STT-RAM) has the advantages of circuit density and ignorable leakage power. However, it suffers from the bad write latency and poor write power consumption. Therefore, it is difficult to replace entire SRAM with STT-RAM in the L1 cache, but we can relax the retention time of STT-RAM cell to improve its write performance and replace some of the SRAM capacity to reduce leakage power. In this paper, we propose a locality-aware approach for L1 cache design with hybrid SRAM and volatile STT-RAM configuration. Based on the principle of cache locality, data block is mapped to SRAM firstly to reduce write latency and write energy, and is moved to volatile STT-RAM to reduce leakage power consumption. After a time period when there is no access of a data block in the volatile STT-RAM, we then stop its refresh operations to further reduce power consumption. Experimental results show that in comparison with the SRAM only L1 cache configuration, our hybrid cache configuration and data migration methodology reduce energy consumption by about 15–20%, with only nearly to 5% of latency overhead. Also when comparing to the STT-RAM only L1 cache configuration, we reduce memory access latency nearly to 20% with close or even better energy consumption.

Low Power Consumption Low Noise Amplifier for 1-10GHz Application

In this paper low power consumption amplifier is presented. Low power consumption amplifier is versatile demanded in modern technology, modern technology want such type of amplifier which gives low power consumption with less reflection, in this paper presented series and shunt feedback topology with pole zero compensation method for designing of low power consumption amplifier, Today the demand of integrated circuits are increasing day by day with increase in the number of elements in it. However, power and reflection should be less. The scaling of the components increase, increase its number, for the similar area of an chip reduces its sub-threshold voltage with its increase in the leakage power consumption.. The Power consumption is based on the number of elements and routing of components and its process fabrication. In this paper developed method to reduce leakage power consumption with reduction of reflection. Here design low power dissipation amplifier using compensation and feedback technique

Read Performance: The Newest Barrier in Scaled STT-RAM

Spin-torque transfer RAM (STT-RAM), a promising alternative to static RAM (SRAM) for reducing leakage power consumption, has been widely studied to mitigate the impact of its asymmetrically long write latency. However, physical effects of technology scaling down to 45 nm and below, in particular, process variation, introduce the previously unreported and alarming trends in read performance and reliability due to reduced sensing margins and increasing error rates. In this brief, we study the scaling trends of STT-RAM from 65 down to 22 nm as they pertain to read performance, including a 50% increase in sensing versus peripheral circuit delay ratio and a more than 80% increase in uncorrectable read error rates. Through differential sensing, we show how 22 nm can return to sense delay ratio levels at 65 nm and uncorrectable read errors can be reduced by an order of magnitude. Through a case study of a multilevel STT-RAM cache, we show how a reconfigurable cache cell can create an extreme access mode (X-mode) based on differential sensing improve to outperform the state-of-the-art STT-RAM caching techniques in both raw performance and performance per watt by more than 10% while still reducing energy consumption over SRAM caches by more than 1/3.

A New Approach for Gate-Level Delay-Insensitive Asynchronous Logic

We present a new approach for gate-level delay-insensitive asynchronous logic. The new approach uses only conventional synchronous synthesis and computer-aided design tools, as well as conventional standard cell libraries. This new design approach is highly suitable for very low voltage operation compared with traditional static CMOS design. An auto-sleep mode together with supply voltage control logic reduces leakage power consumption. Several benchmark circuits are implemented using IBM 130nm technology to show that the new asynchronous logic approach is robust even when operating in the sub-threshold regime. The layout for each benchmark is generated using Cadence's automatic placement and routing tool. Hspice simulations for both asynchronous and synchronous versions of the benchmark circuits enabled comparison of the delay, area and leakage current. Monte Carlo simulations are performed for each benchmark circuit to demonstrate delay insensitivity for very low supply voltages with substantial threshold voltage ($$V_{T}$$VT) variations.

Evaluation of Leakage Reduction Alternatives for Deep Submicron Dynamic Nonuniform Cache Architecture Caches

Wire delays and leakage energy consumption are both growing problems in designing large on-chip caches. Nonuniform cache architecture (NUCA) is a wire-delay aware design paradigm based on the sub-banking of a cache, which allows the banks closer to the controller to be accessed with reduced latencies with respect to the other banks. This feature is leveraged by dynamic NUCA (D-NUCA) caches via a migration mechanism which speeds up frequently used data access, further reducing the effect wire delays have on performance. To reduce leakage power consumption of static random access memory caches, various micro-architectural techniques have been proposed. In this brief, we compare the benefits and limits of the application of some of these techniques to a D-NUCA cache memory, and propose a novel hybrid scheme based on the Drowsy and Way Adaptable techniques. Such a scheme allows further improvement in leakage reduction and limits the impact of process variation on the effectiveness of the Drowsy technique.

C1C

Spin-Transfer Torque RAM (STT-RAM), a promising alternative to SRAM for reducing leakage power consumption, has been widely studied to mitigate the impact of its asymmetrically long write latency. Recently, STT-RAM has been proposed for L1 caches by relaxing the data retention time to improve write performance and dynamic energy. However, as the technology scales down from 65nm to 22nm, the performance of the read operation scales poorly due to reduced sense margins and sense amplifier delays. In this article, we leverage a dual-mode STT memory cell to design a configurable L1 cache architecture termed C1C to mitigate read performance barriers with technology scaling. Guided by application access characteristics discovered through novel compiler analyses, the proposed cache adaptively switches between a high performance and a low-power access mode. Our evaluation demonstrates that the proposed cache with compiler guidance outperforms a state-of-the-art STT-RAM cache design by 9% with high dynamic energy efficiency, leading to significant performance/watt improvements over several competing approaches.

Stochastically power‐minimum scheduling of real‐time multicore systems with leakage power awareness

The proposed scheduling scheme minimises the mean power consumption of real-time tasks with probabilistic computation amounts on multicore processors. To reduce leakage power consumption of idle cores, the scheme activates a part of available cores while turning off the power of unused cores, and determines the instant speed of activated cores so that the expected power consumption of real-time tasks would be minimised.

Leakage Power Analysis of Domino XOR Gate

Two new XOR gates are proposed. First proposed circuits adopt hybrid transistor topology in the pull-down network with all transistors being low threshold voltages. A second proposed circuit adopts hybrid topology with dual threshold voltage transistors. Simulation parameters are measured at 25°C and 110°C. First proposed circuit reduces leakage power consumption up to 50% at 25°C and 58% at 110°C as compared to standard N-type domino XOR gate. It also reduces active mode power consumption by 14% as compared to standard N-type domino XOR gate. Similarly, second proposed circuit reduces leakage power consumption up to 73% at 25°C and 90% at 110°C as compared to standard N-type domino XOR gate. It also reduces active mode power consumption by 39% as compared to standard N-type domino XOR gate.

Galeorstack- A Novel Leakage Reduction Technique for Low Power VLSI Design

power consumption plays a significant role in current CMOS technology. International Technology Roadmap for semiconductors reports that leakage power consumption dominates the total chip power consumption as technology advances to nano scale. Most of the battery operated applications such as cell phones, Laptops etc requires a longer battery life, which can be made possible by controlling leakage current flowing through the CMOS gate. This paper presents leakage current mechanisms and different leakage reduction techniques to reduce leakage power consumption. We propose a novel leakage reduction technique named Galeorstack which can achieve better leakage reduction by maintaining exact logic state than the other techniques discussed in this paper. The proposed technique has been verified and compared with the other techniques for NOR and EXOR logic circuits and implemented using standard cells of 90nm CMOS process from CADENCE TOOLS. GaleorStack technique would be the best choice to the designer for the low leakage and less delay while achieving exact logic state.

Energy Efficient Scheduling of Real-Time Tasks on Multicore Processors

Multicore processors deliver a higher throughput at lower power consumption than unicore processors. In the near future, they will thus be widely used in mobile real-time systems. There have been many research on energy-efficient scheduling of real-time tasks using DVS. These approaches must be modified for multicore processors, however, since normally all the cores in a chip must run at the same performance level. Thus, blindly adopting existing DVS algorithms that do not consider the restriction will result in a waste of energy. This article suggests Dynamic Repartitioning algorithm based on existing partitioning approaches of multiprocessor systems. The algorithm dynamically balances the task loads of multiple cores to optimize power consumption during execution. We also suggest Dynamic Core Scaling algorithm, which adjusts the number of active cores to reduce leakage power consumption under low load conditions. Simulation results show that Dynamic Repartitioning can produce energy savings of about 8 percent even with the best energy-efficient partitioning algorithm. The results also show that Dynamic Core Scaling can reduce energy consumption by about 26 percent under low load conditions.

A functionality-directed clustering technique for low-power MTCMOS design—computation of simultaneously discharging current

Multithreshold CMOS (MTCMOS) is a circuit style that can effectively reduce leakage power consumption. Sleep transistor sizing is the key issue when a MTCMOS circuit is designed. If the size of sleep transistor is large enough, the circuit performance can surely be maintained but the area and dynamic power consumption of the sleep transistor may increase. On the other hand, if the sleep transistor size is too small, there will be significant performance degradation because of the increased resistance to ground. Previous approaches [Kao et al. 1998; Anis et al. 2002] to designing sleep transistor size are based mainly on mutually-exclusive discharge patterns. However, these approaches considered only the topology of a circuit (i.e., interconnections of nodes in the circuit-graph saving the functionality of node). We observed that any two possible simultaneously switching gates may not discharge at the same time in terms of functionality. Thus, we propose an algorithm to determine how to cluster cells to share sleep transistors, while taking both topology and functionality into consideration. Moreover, one placement refinement algorithm that takes clustering information into account will be presented. At the logic level, the results show that the proposed clustering method can achieve an average of 22% reduction in terms of the number of unit-size sleep transistors as compared to a method that does not consider functionality. At the physical level, two placement results are discussed. The first is produced by a traditional placement tool plus topology check (functionality check) for insertion of sleep transistors. It shows that the functionality check algorithm produces 9% less chip area as compared with the topology check algorithm. The second result is produced by a placement refinement algorithm where the initial placement is done in the first placement experiment. It shows that the placement refinement algorithm achieves 5% more reduction in area at the expense of 4% increase in wire length. Totally, around 14% reduction is achieved by utilizing the clustering information.

A single-V/sub t/ low-leakage gated-ground cache for deep submicron

We propose a novel integrated circuit and architectural level technique to reduce leakage power consumption in high-performance cache memories using single V/sub t/ (transistor threshold voltage) process. We utilize the concept of gated-ground (nMOS transistor inserted between ground line and SRAM cell) to achieve a reduction in leakage energy without significantly affecting performance. Experimental results on gated-ground caches show that data is retained (DRG-Cache) even if the memory is put in the standby mode of operation. Data is restored when the gated-ground transistor is turned on. Turning off the gated-ground transistor in turn gives a large reduction in leakage power. This technique requires no extra circuitry; the row decoder itself can be used to control the gated-ground transistor. The technique is applicable to data and instruction caches as well as different levels of cache hierarchy, such as the L1, L2, or L3 caches. We fabricated a test chip in TSMC 0.25-μm technology to show the data retention capability and the cell stability of the DRG-Cache. Our simulation results on 100-nm and 70-nm processes (Berkeley Predictive Technology Model) show 16.5% and 27% reduction in consumed energy in L1 cache and 50% and 47% reduction in L2 cache, respectively, with less than 5% impact on execution time and within 4% increase in area overhead.