Improving the energy efficiency of reversible logic circuits by the combined use of adiabatic styles

One of the most prominent issues in fully adiabatic circuits is the breaking reversibility problem; i.e., non-adiabatic energy dissipation in the last stage adiabatic gates whose outputs are connected to external circuits. In this paper, we show that the breaking reversibility problem can result in significant energy dissipation. Subsequently, we propose an efficient technique to address the breaking reversibility problem, which is applicable to the usual fully adiabatic logic such as 2LAL, SCRL, and RERL. Detailed SPICE simulations are used to evaluate the proposed technique. The experimental results show that the proposed technique can considerably reduce (e.g., about 74% for RERL, 35% for 2LAL, and 17% for SCRL) the energy dissipation arising from the breaking reversibility problem.     

绝热开关的工作特性及其能耗分析

本文对绝热充电原理以及绝热开关的工作特性进行了详细讨论,建立了绝热开关的能耗计算模型。ＰＳＰＩＣＥ模拟证明了所提出的计算模型的正确性。文章最后对包括输入激励在内的整个绝热开关的能耗进行了综合分析,它是分析复杂绝热电路的基础并为在设计能量恢复型电路时合理选取在关参数提供了理论依据。     

Adiabatic dynamic logic

With adiabatic techniques for capacitor charging, theory suggests that it should be possible to build gates with arbitrarily small energy dissipation. In practice, the complexity of adiabatic approaches has made them impractical. We describe a new CMOS logic family-adiabatic dynamic logic (ADL)-that is the result of combining adiabatic theory with conventional CMOS dynamic logic. ADL gates are simple, general, readily cascadable, and may be fabricated in a standard CMOS process. A chain of 1000 ADL inverters has been constructed in 0.9 μm CMOS and successfully tested at 250 MHz. This result, together with comprehensive circuit simulation, suggest that ADL offers an order of magnitude reduction in power consumption over conventional CMOS circuitry     

Adiabatic differential voltage switch logic

To diminish the trapped charges in internal nodes of the complex logic adiabatic gate, adiabatic differential voltage switch logic (ADVSL) using capacitance coupling technique is presented. An adiabatic system, based on a relatively small number of complex ADVSL gates, reduces not only dissipation loss, but also the gate count greatly.     

Performance analysis of a complete adiabatic logic system driven by the proposed power clock generator

We analyze the energy performance of a complete adiabatic circuit/system including the Power Clock Generator （PCG） at the 90 nm CMOS technology node. The energy performance in terms of the conversion efficiency of the PCG is extensively carried out under the variations of supply voltage, process comer and the driver transistor＇s width. We propose an energy-efficient singe cycle control circuit based on the two-stage comparator for the synchronous charge recovery sinusoidal power clock generator （PCG）. The proposed PCG is used to drive the 4-bit adiabatic Ripple Carry Adder （RCA） and their simulation results are compared with the adiabatic RCA driven by the reported PCG. We have also simulated the logically equivalent static CMOS RCA circuit to compare the energy saving of adiabatic and non-adiabatic logic circuits. In the clock frequency range from 25 MHz to 1GHz, the proposed PCG gives a maximum conversion efficiency of 56.48%. This research work shows how the design of an efficient PCG increases the energy saving of adiabatic logic.     

采用三相电源的互补传输管绝热逻辑电路

提出了一种由三相电源驱动的新绝热逻辑电路--complementary pass-transistor adiabatic logic(CPAL).电路由CPL电路完成相应的逻辑运算,由互补传输门对输出负载进行绝热驱动,电路的整体功耗较小.指出选取合适的输出驱动管的器件尺寸可进一步减小CPAL电路的总能耗.设计了仅由一个电感和简单控制电路组成的三相功率时钟产生电路.为了验证提出的CPAL电路和时钟产生电路,设计了8bit全加器进行模拟试验.采用MOSIS的0.25μm CMOS工艺,在50～200MHz频率范围内,CPAL全加器的功耗仅为PFAL电路和2N-2N2P电路的50%和35%.     

Low-power interface circuits between adiabatic and standard CMOS circuits

The clocking schemes and signal waveforms of adiabatic circuits are different from those of standard CMOS circuits. This paper investigates the design approaches of low-power interface circuits in terms of energy dissipation. Several low-power interface circuits that convert signals between adiabatic logic and standard CMOS circuits are presented. All interface circuits and their layouts are implemented using TSMC 0.18 μm CMOS technology. The function verifications and energy loss tests for all interfaces are carried out using the net-list extracted from the layout. Full parasitic extraction is done. An adiabatic 8-bit carry look-ahead adder embedded in a static CMOS circuits is used to verify the proposed interfaces. The proposed interface circuits attain large energy savings over a wide range of frequencies, as compared with the previously reported circuits.     

Adiabatic Logic Circuits: A Review

The current status of research and development in the field of adiabatic electronic devices for the production of information is reviewed. The adiabatic property means that the power supply regains most of the energy expended on computing. A design philosophy of universal adiabatic logic gates is framed. The gates are categorized according to adiabatic rank, the principle of operation, the method used to satisfy the thermal-equilibrium conditions, the information-storage technique, and the mode of operation. For adiabatic-gate drivers, existing design concepts are categorized and described. Promising avenues of development are outlined.     

采用交流能源的低功耗CPL电路

从改变CM O S电路中能量转换模式的观点出发,研究CPL电路在采用交流能源后的低功耗特性。在此基础上提出了一种仅由nM O S构成的低功耗绝热电路——nM O S Com p lem en tary Pass-trans istor A d iabaticLog ic(nCPAL)。该电路利用nM O S管自举原理对负载进行全绝热驱动,从而减小了电路整体功耗和芯片面积。nCPAL能耗几乎与工作频率无关,对负载的敏感程度也较低。采用TSM C的0.25μm CM O S工艺,设计了一个8-b it超前进位加法器和功率时钟产生器。版图后仿真表明,在50~200 MH z频率范围内,nCPAL全加器的功耗仅为PAL-2N电路和2N-2N 2P电路的50%和35%。研究表明nCAPL适合于在VLS I设计中对功率要求较高的应用场合。     

Reversible energy recovery logic circuit without non-adiabaticenergy loss

The authors propose a reversible energy recovery logic (RERL) circuit for ultra-low-energy consumption, which consumes only adiabatic energy loss and leakage current loss by completely eliminating non-adiabatic energy loss. It is a dual-rail adiabatic circuit using the concept of reversible logic with a new eight-phase clocking scheme. Simulation results show that at low-speed operation, the RERL consumes much less energy than the complementary static CMOS circuit and other adiabatic logic circuits     

Design and Evaluation of Adiabatic Arithmetic Units

Adiabatic design is an attractive approach to reducingenergy consumption in VLSI circuits after exhausting the potentialof conventional energy-saving techniques. Despite the plethoraof adiabatic logic architectures that have been proposed in recentyears, several practical considerations in the design of nontrivialadiabatic circuits remain largely unexplored. Moreover, it isstill unclear whether adiabatic circuits of significant sizeand complexity can achieve substantial savings in energy dissipationover corresponding conventional designs. We recently designedseveral low-power arithmetic units using a dual-rail adiabaticlogic design style. We also designed static CMOS versions ofthese units and compared their energy dissipation with theircorresponding adiabatic designs. In this paper we describe ourimplementations, discuss architecture and logic-level issuesrelated to our adiabatic designs, and present the findings ofour empirical comparison. Our results suggest that adiabaticlogic can be used for the implementation of relatively complexVLSI circuits that dissipate significantly less energy than theircorresponding CMOS designs.     

Dynamic GaAs capacitively coupled domino logic (CCDL)

Dynamic capacitively coupled domino logic (CCDL) has been proposed as a practical means of implementing low-power and high-speed complex gates. The CCDL gate delay characteristics obtained from an analytical model and from test circuits implemented in a 1-μm GaAs E/D process are presented. In addition, the feasibility of using CCDL gates to implement practical circuits is demonstrated by the experimental characterization of a 4-b carry-lookahead adder. The adder has a critical delay of 1.1 ns and a power dissipation of 96 mW. A comparison of the dynamic CCDL adder with conventional static designs indicates the advantages of dynamic CCDL gates in reducing power dissipation and increasing speed, making such gates suitable for VLSI implementations     

A balanced power analysis attack resilient adiabatic logic using single charge sharing transistor

The existing Power Analysis Attacks (PAA) resilient adiabatic logic designs exhibit variations in current peaks, have asymmetric structures and suffer from Non-Adiabatic Losses (NAL) during the evaluation phase of the power-clock. However, asymmetric structure and variations in current peaks make the circuit susceptible to PAA. In this paper, we present a novel PAA resilient adiabatic logic which has a symmetric structure, completely removes NAL from the evaluation phase of the power-clock and exhibits minimal variations in current peaks for gates as well as in an 8-bit Montgomery multiplier. The proposed logic has been compared with three existing secure adiabatic logic designs for operating frequencies ranging from 1 MHz to 100 MHz and power-clock scaling ranging from 1.8 V to 0.6 V. Simulation results of the gates show that our proposed logic exhibits the lowest Normalized Energy Deviation (NED) and Normalized Standard Deviation (NSD) at the frequencies mentioned above. In addition, all the 2-input gates using proposed logic dissipate average energy within 0.3% of each other and thus, lowest value of standard deviation at all the simulated frequencies. The simulation results for the 8-bit Montgomery multiplier show that proposed logic exhibits the least value of NED and NSD at all the simulated frequencies and under power-supply scaling.     

Energy-efficiency bounds for deep submicron VLSI systems in the presence of noise

In this paper, we present an algorithm for computing the bounds on energy-efficiency of digital very large scale integration (VLSI) systems in the presence of deep submicron noise. The proposed algorithm is based on a soft-decision channel model of noisy VLSI systems and employs information-theoretic arguments. Bounds on energy-efficiency are computed for multimodule systems, static gates, dynamic circuits and noise-tolerant dynamic circuits in 0.25-/spl mu/m CMOS technology. As the complexity of the proposed algorithm grows linearly with the size of the system, it is suitable for computing the bounds on energy-efficiency for complex VLSI systems. A key result presented is that noise-tolerant dynamic circuits offer the best trade off between energy-efficiency and noise-immunity when compared to static and domino circuits. Furthermore, employing a 16-bit noise-tolerant Manchester adder in a CDMA receiver, we demonstrate a 31.2%-51.4% energy reduction over conventional systems when operating in the presence of noise. In addition, we compute the lower bounds on energy dissipation for this CDMA receiver and show that these lower bounds are 2.8/spl times/ below the actual energy consumed, and that noise-tolerance reduces the gap between the lower bounds and actual energy dissipation by a factor of 1.9/spl times/.     

Power Consumption of Asymptotically Adiabatic Static Logic Gates

A computer simulation is conducted of power consumption in the 1n–1p type of asymptotically adiabatic static logic gate. The increase is estimated in dissipation due to violation of any single condition of thermodynamic reversibility. The dissipation characteristics obtained are compared with those of quasi-adiabatic gates of the 2n–2n2p and the efficient charge-recovery logic (ECRL) type.     

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.     

Investigating the influence of adiabatic load on the 4-phase adiabatic system design

This paper investigates the power-clock generation using Step Charging Circuits (SCC). In particular, the impact of the adiabatic load on the energy dissipation of the 4-phase Power-Clock Generator (PCG) and on the overall adiabatic system is investigated. The adiabatic implementations are compared with their conventional CMOS counterparts based on energy dissipation, the number of transistors and operation time. The simulation results show that the area (number of transistors) influences the energy dissipation of SCC. Operation time affects the energy dissipation of the controller and degrades the energy benefits obtained in the energy dissipation of SCC and adiabatic core. Lastly, the impact of a number of steps on the energy efficiency of the 4-phase PCG is investigated. We compare the energy efficiency of the 4-phase PCG using 2-step, 3-step and 4-step charging circuit with the energy efficiency of the existing 4-phase PCG with and without resonant inductors.     

Full-Swing Gate Diffusion Input logic—Case-study of low-power CLA adder design

Full Swing Gate Diffusion Input (FS-GDI) methodology is presented. The proposed methodology is applied to a 40 nm Carry Look Ahead Adder (CLA). The CLA is implemented mainly using GDI full-swing F1 and F2 gates, which are the counterparts of standard CMOS NAND and NOR gates. A 16-bit GDI CLA was designed in a 40 nm low power TSMC process. The CLA, implemented according to the proposed methodology, presents full functionality and robustness under global and local process variations at wide range of supply voltages. Simulation results show 2× area reduction, 5× improvement in dynamic energy dissipation and 4× decrease in leakage, with a slight (24%) degradation in performance, when compared to the CMOS CLA. Advanced design metrics of GDI cells, such as minimum energy point (MEP) operation and minimum leakage vector (MLV), are discussed.     

New Light Weight Threshold Voltage Defined Camouflaged Gates for Trustworthy Designs

The outsourcing of the IC fabrication process introduces the security vulnerabilities into the design. An attacker can exploit them to extract the functionality using image processing-based reverse engineering and can also mount the various attacks such as hardware Trojan, piracy, overbuilding, etc. Various dummy contacts and Threshold Voltage Defined (TVD) logic-based layout camouflaging techniques are presented that can deceive the attacker into incorrectly interpreting the functionality of the camouflaged gate. The existing dummy contact-based techniques require large overhead and provide poor security whereas, the TVD logic-based camouflaging techniques increase the security at the cost of large area and energy overhead. Therefore, in this paper, new light weight TVD static and dynamic logic (TVD-SL and TVD-DL) based camouflaged gates are proposed. The proposed TVD-SL/DL gates have same physical structure and provide the functionality of several standard gates by implanting different threshold voltages during manufacturing. Further, various simplified TVD-SL/DL gates are also proposed to achieve the overhead and security trade-off. To evaluate the efficacy, the proposed TVD logic gates are implemented using 32nm PTM library and simulated using the HSPICE simulator. The simulation results show that the proposed TVD-SL-based gates on an average reduce 35.49%, 59.18% and 72.05% whereas the proposed TVD-DL reduces 54.84%, 84.18% and 82.30% area, power and delay respectively over the existing. Further, on an average, the proposed TVD-DL-based camouflaged gates require 56% less power over the standard gates. Due to the low-cost and high energy efficiency, the proposed logic gates are best suited for the development of secure and portable devices for the Internet of Things applications.     

QSERL: quasi-static energy recovery logic

A new quasi-static energy recovery logic family (QSERL) using the principle of adiabatic switching is proposed in this paper. Most of the previously proposed adiabatic logic styles are dynamic and require complex clocking schemes. The proposed QSERL uses two complementary sinusoidal supply clocks and resembles the behavior of static CMOS. Thus, switching activity is significantly lower than dynamic logic. In addition, QSERL circuits can be directly derived from static CMOS circuits. A high-efficiency clock generation circuitry, which generates two complementary sinusoidal clocks compatible to QSERL, is also presented in this paper. The adiabatic clock circuitry locks the frequency of clock signals, which makes it possible to integrate adiabatic modules into a VLSI system. We have designed an 8×8 carry-save multiplier using QSERL logic and two phase sinusoidal clocks. SPICE simulation shows that the QSERL multiplier can save 34% of energy over static CMOS multiplier at 100 MHz