基于绝热逻辑的低功耗乘法器电路设计

基于绝热开关理论的能量回收逻辑与传统的静态CMOS逻辑相比,能够大大减少电路的功率消耗。这里介绍了一种使用单相正弦电源时钟的能量回收逻辑,分别用静态CMOS逻辑和这种能量回收逻辑设计,并仿真了一个两位乘法器电路,比较了这两种电路的性能。研究表明,采用能量回收逻辑设计的乘法器显著降低了电路的功率消耗。     

钟控准静态能量回收逻辑电路

钟控准静态能量回收逻辑 (clocked quasi- static energy recovery logic,CQSERL)只在输入信号导致输出状态发生变化的情况下才对电路节点充电 (或者回收 ) ,不需要在每个功率时钟周期循环充电和回收操作 ;CQSERL是单端输入输出逻辑 ,减小了电路实现代价 .设计了 4位 QSERL 串行进位加法器 (RCA)电路 ,和相应的 CMOS电路进行了功耗比较 .功率时钟为 10 MHz时 ,CQSERL 电路功耗是对应 CMOS电路的 35 % .流片实现了一个简单结构的正弦功率时钟产生电路 ,功率时钟的频率和相位与外接系统时钟相同     

Analysis and Design of an Efficient Irreversible Energy Recovery Logic in 0.18-$mu$m CMOS

This paper presents the design and experimental evaluation of a new type of irreversible energy recovery logic (ERL) families called complementary energy path adiabatic logic (CEPAL). It inherits the advantages of quasi-static ERL (QSERL) family, but is with improved driving ability and circuit robustness. The proposed logic style features no hold phase compared to its QSERL counterpart under the same operation conditions; thereupon no feedback keeper is required so that considerable improvements in area and power overheads can be achieved. Moreover, its throughput becomes twice as high as that of QSERL when their frequencies of power clocks (PCs) are identical. Results on the impact of variation on CEPAL are provided. Comparison between CEPAL and other known low-power logic style achieving iso-performance, namely, subthreshold logic is also given. In order to demonstrate workability of the newly developed circuit, an 8-bit shift register, designed in the proposed techniques, has been fabricated in a TSMC 0.18- $mu$m CMOS process. Both simulation and measurement results verify the functionality of such a logic, making it suitable for implementing energy-aware and performance-efficient very-large scale integration (VLSI) circuitry.      

准静态单相能量回收逻辑

提出了一种新的准静态单相能量回收逻辑,其不同于以往的能量回收逻辑,真正实现了单相功率时钟,且不需要任何额外的辅助控制时钟,不但降低了能耗,更大大简化了时钟树的设计.该逻辑还可以达到两相能量回收逻辑所具有的速度.设计了一个8位对数超前进位加法器,并分别用传统的静态CMOS逻辑、钟控CMOS绝热逻辑(典型的单相能量回收逻辑)和准静态单相能量回收逻辑实现.采用128组随机产生的输入测试向量的仿真结果表明:输入频率为10MHz时,准静态能量回收逻辑的能耗仅仅是传统静态CMOS逻辑的45%;当输入频率大于2MHz时,可以获得比时钟控CMOS绝热逻辑更低的能耗.     

准静态单相能量回收逻辑

提出了一种新的准静态单相能量回收逻辑,其不同于以往的能量回收逻辑,真正实现了单相功率时钟,且不需要任何额外的辅助控制时钟,不但降低了能耗,更大大简化了时钟树的设计.该逻辑还可以达到两相能量回收逻辑所具有的速度.设计了一个8位对数超前进位加法器,并分别用传统的静态CMOS逻辑、钟控CMOS绝热逻辑(典型的单相能量回收逻辑)和准静态单相能量回收逻辑实现.采用128组随机产生的输入测试向量的仿真结果表明:输入频率为10MHz时,准静态能量回收逻辑的能耗仅仅是传统静态CMOS逻辑的45%;当输入频率大于2MHz时,可以获得比时钟控CMOS绝热逻辑更低的能耗.     

LSI implementation of a low-power 4×4-bit array two-phase clocked adiabatic static CMOS logic multiplier

As the density and operating speed of complementary metal oxide semiconductor (CMOS) circuits increases, dynamic power dissipation has become a critical concern in the design and development—of personal information systems and large computers. The reduction of supply voltage, node capacitance, and switching activity are common approaches used in conventional CMOS. In adiabatic switching circuits, the current flow through transistors can be significantly reduced by ensuring uniform charge transfer over the entire available time. This paper presents the simulation of this current in two-phase clocked adiabatic static CMOS logic (2PASCL) and conventional CMOS. From the SPICE simulations, at transition frequencies from 1 to 12 MHz, a 4×4-bit array 2PASCL multiplier shows a maximum reduction in power dissipation of 77% relative to that of a static CMOS. The measurement results of a 4×4-bit array 2PASCL multiplier demonstrate a 57% reduction compared to a 4×4-bit array two-phase clocked adiabatic dynamic CMOS logic (2PADCL). These results indicate that 2PASCL technology can be advantageous when applied to low-power digital devices operated at low frequencies, such as radio-frequency identification (RFID) tags, smart cards, and sensors.     

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.     

Clocked CMOS adiabatic logic with integrated single-phasepower-clock supply

The design and experimental evaluation of a clocked adiabatic logic (GAL) is described in this paper. CAL is a dual-rail logic that operates from a single-phase AC power-clock supply. This new low-energy logic makes it possible to integrate all power control circuitry on the chip, resulting in better system efficiency, lower cost, and simpler power distribution. CAL can also be operated from a DC power supply in a nonenergy-recovery mode compatible with standard CMOS logic. In the adiabatic mode, the power-clock supply waveform is generated using an on-chip switching transistor and a small external inductor between the chip and a low-voltage DC supply. Circuit operation and performance are evaluated using a chain of inverters realized in a 1.2 μm CMOS technology. Experimental results show that energy savings are achieved at clock frequencies up to about 40 MHz as compared to the nonadiabatic mode. Since CAL can operate both in adiabatic and nonadiabatic modes, power management strategies may be based upon switching between modes when necessary     

Simultaneous power supply, threshold voltage, and transistor sizeoptimization for low-power operation of CMOS circuits

This paper demonstrates a new approach for minimizing the total of the static and the dynamic power dissipation components in a complementary metal-oxide-semiconductor (CMOS) logic network required to operate at a specified clock frequency. The algorithms presented can be used to design ultralow-power CMOS logic circuits by joint optimization of supply voltage, threshold voltage and device widths. The static, dynamic and short-circuit energy components are considered and an efficient heuristic is developed that delivers over an order of magnitude savings in power over conventional optimization methods     

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.     

Design and application of pipelined dynamic CMOS ternary logic andsimple ternary differential logic

Dynamic CMOS ternary logic circuits that can be used to form a pipelined system with nonoverlapped two-phase clocks are proposed and investigated. The proposed dynamic ternary gates do not dissipate DC power and have full voltage swings. A circuit structure called the simple ternary differential logic (STDL) is also proposed and analyzed, and an optimal procedure is developed. An experimental chip has been fabricated in a 1.2-μm CMOS process and tested. A binary pipelined multiplier has been designed, using the proposed dynamic ternary logic circuits in the interior of the multiplier for coding of radix-2 redundant positive-digit number. The structure has the advantages of higher operating frequency, less latency, and lower device count as compared with the conventional binary parallel pipelined multiplier. The advantages of the circuits over other dynamic ternary logic circuits are shown     

True single-phase adiabatic circuitry

Dynamic logic families that rely on energy recovery to achieve low energy dissipation control the flow of data through gate cascades using multiphase clocks. Consequently, they typically use multiple clock generators and can exhibit increased energy consumption on their clock distribution networks. Moreover, they are not attractive for high-speed design due to their high complexity and clock skew management problems. In this paper, we present TSEL, the first energy-recovering (a.k.a. adiabatic) logic family that operates with a single-phase sinusoidal clocking scheme. We also present SCAL, a source-coupled variant of TSEL with improved supply voltage scalability and energy efficiency. Optimal performance under any operating conditions is achieved in SCAL using a tunable current source in each gate. TSEL and SCAL outperform previous adiabatic logic families in terms of energy efficiency and operating speed. In layout-based simulations with 0.5 μm standard CMOS process parameters, 8-bit carry-lookahead adders (CLAs) in TSEL and SCAL function correctly for operating frequencies exceeding 200 MHz. In comparison with corresponding CLAs in alternative logic styles that operate at minimum supply voltages, CLAs designed in our single-phase adiabatic logic families are more energy efficient across a broad range of operating frequencies. Specifically, for clock rates ranging from 10 to 200 MHz, our andbit SCAL CLAs are 1.5 to 2.5 times more energy efficient than corresponding adders developed in PAL and 2N2P and 2.0 to 5.0 times less dissipative than their purely combinational or pipelined CMOS counterparts     

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。     

Skewed CMOS: noise-tolerant high-performance low-power static circuit family

In this paper, we present a noise-tolerant high-performance static circuit family suitable for low-voltage operation called skewed logic. Skewed logic circuits in comparison with Domino logic have better scalability and are more suitable for low voltage applications because of better noise margins. Skewed logic and its variations have been compared with Domino logic in terms of delay, power, and dynamic noise margin. A design methodology for skewed CMOS pipelined circuits has been developed. To demonstrate the applicability of the proposed logic style, 0.35 /spl mu/m 5.56 ns CMOS 16/spl times/16 bit multipliers have been designed using skewed logic circuits and fabricated through MOSIS. Measurement results show that the multiplier only consumed a power of 195 mW due to its low clock load.     

Improved structure for adiabatic CMOS circuits design

Two adiabatic circuits with complementary structure and operation are proposed in this paper. They employ two-phase sinusoidal power clock. The power consumption of the proposed circuits is comparable to that of some previously reported circuits. The problem of floating output nodes is solved by connecting two MOS transistors to the power clock. In particular, using the proposed architecture more than one stage of gates can be computed simultaneously within a single clock-phase, compared to only one stage is computed in every phase by most other adiabatic logic families. With this feature, the latency of the complex logic circuit is greatly improved and the number of buffers required for a pipelining circuit is also reduced. In this paper, a 2:1 multiplexer and full adder are illustrated and simulated. From the PSPICE simulation results, the effectiveness of the proposed approach and the low power characteristic of the designed circuits are validated.     

A Low Power 16‐Bit RISC Microprocessor Using ECRL Circuits

This paper presents a low power 16‐bit adiabatic reduced instruction set computer (RISC) microprocessor with efficient charge recovery logic (ECRL) registers. The processor consists of registers, a control block, a register file, a program counter, and an arithmetic and logical unit (ALU). Adiabatic circuits based on ECRL are designed using a 0.35 µm CMOS technology. An adiabatic latch based on ECRL is proposed for signal interfaces for the first time, and an efficient four‐phase supply clock generator is designed to provide power for the adiabatic processor. A static CMOS processor with the same architecture is designed to compare the energy consumption of adiabatic and non‐adiabatic microprocessors. Simulation results show that the power consumption of the adiabatic microprocessor is about 1/3 compared to that of the static CMOS microprocessor.     

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     

Monte Carlo optimization of superconducting complementary outputswitching logic circuits

The authors have previously proposed a new superconducting voltage-state logic family called complementary output switching logic (COSL). This logic family has been designed using a Monte Carlo optimization process such that circuits have a high theoretical yield at 5-10 Gb/s clock speeds in spite of existing Josephson process variations. In the present work the Monte Carlo optimization process is described and theoretical yields are calculated for the COSL 2- and 3-bit encoder circuits. The circuit simulations use 5-10-GHz sinusoidal clocks and measured global and local process variations. The 2-bit encoder results are compared to modified variable threshold logic (MVTL) circuits and demonstrate that COSL circuits should have a significantly higher theoretical yield than MVTL at 10 Gb/s. Design rules for optimal COSL circuit layouts are also given, and experimental data are presented for 2-bit encoder circuits operating at multigigahertz clock frequencies. HSPICE is used for all Monte Carlo simulations and the Josephson junction model is given in the Appendix     

A 32×32-b adiabatic register file with supply clock generator

A 32×32-b adiabatic register file with one read port and one write port is designed. A four-phase clock generator is also designed to provide supply clocks for adiabatic circuits. All the word line and bit line charge on the capacitive interconnections is recovered to save energy. Adiabatic circuits are based on efficient charge recovery logic (ECRL) and are integrated using 0.8 μm complimentary metal-oxide-semiconductor (CMOS) technology. Measurement results show that power consumption of the core is significantly reduced by a factor of up to 3.5 compared with a conventional circuit     

NORA: a racefree dynamic CMOS technique for pipelined logic structures

Describes a new dynamic CMOS technique which is fully racefree, yet has high logic flexibility. The circuits operate racefree from two clocks /spl phi/ and /spl phi/~ regardless of their overlap time. In contrast to the critical clock skew specification in the conventional CMOS pipelined circuits, the proposed technique imposes no restriction to the amount of clock skew. The main building blocks of the NORA technique are dynamic CMOS and C/SUP 2/MOS logic functions. Static CMOS functions can also be employed. Logic composition rules to mix dynamic CMOS, C/SUP 2/MOS, and conventional CMOS will be presented. Different from Domino technique, logic inversion is also provided. This means higher logic flexibility and less transistors for the same function. The effects of charge redistribution, noise margin, and leakage in the dynamic CMOS blocks are also analyzed. Experimental results show the feasibility of the principles discussed.