scholarly journals CMOS based Power Efficient Digital Comparator with Parallel Prefix Tree Structure

2018 ◽  
Vol 7 (2.7) ◽  
pp. 647
Author(s):  
J Lakshmi Prasanna ◽  
V Sahiti ◽  
E Raghuveera ◽  
M Ravi Kumar

A 128-Bit Digital Comparator is designed with Digital Complementary Metal Oxide Semiconductor (CMOS) logic, with the use of Parallel Prefix Tree Structure [1] technique. The comparison is performed on Most Significant Bit (MSB) to the Least Significant Bit (LSB). The comparison for the lower order bits carried out only when the MSBs are equal. This technique results in Optimized Power consumption and improved speed of operation. To make the circuit regular, the design is made using only CMOS logic gates. Transmission gates were used in the existing design and are replaced with the simple AND gates. This 128-Bit comparator is designed using Cadence TSMC 0.18µm technology and optimized the Power dissipation to 0.28mW and with a Delay of 0.87μs. 

Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 369 ◽  
Author(s):  
Padmanabhan Balasubramanian ◽  
Nikos Mastorakis

Addition is a fundamental operation in microprocessing and digital signal processing hardware, which is physically realized using an adder. The carry-lookahead adder (CLA) and the carry-select adder (CSLA) are two popular high-speed, low-power adder architectures. The speed performance of a CLA architecture can be improved by adopting a hybrid CLA architecture which employs a small-size ripple-carry adder (RCA) to replace a sub-CLA in the least significant bit positions. On the other hand, the power dissipation of a CSLA employing full adders and 2:1 multiplexers can be reduced by utilizing binary-to-excess-1 code (BEC) converters. In the literature, the designs of many CLAs and CSLAs were described separately. It would be useful to have a direct comparison of their performances based on the design metrics. Hence, we implemented homogeneous and hybrid CLAs, and CSLAs with and without the BEC converters by considering 32-bit accurate and approximate additions to facilitate a comparison. For the gate-level implementations, we considered a 32/28 nm complementary metal-oxide-semiconductor (CMOS) process targeting a typical-case process–voltage–temperature (PVT) specification. The results show that the hybrid CLA/RCA architecture is preferable among the CLA and CSLA architectures from the speed and power perspectives to perform accurate and approximate additions.


Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 542 ◽  
Author(s):  
Haifeng Zhang ◽  
Zhaowei Zhang ◽  
Mingyu Gao ◽  
Li Luo ◽  
Shukai Duan ◽  
...  

A memristor is a nanoscale electronic element that displays a threshold property, non-volatility, and variable conductivity. Its composite circuits are promising for the implementation of intelligence computation, especially for logic operations. In this paper, a flexible logic circuit composed of a spintronic memristor and complementary metal-oxide-semiconductor (CMOS) switches is proposed for the implementation of the basic unbalanced ternary logic gates, including the NAND, NOR, AND, and OR gates. Meanwhile, due to the participation of the memristor and CMOS, the proposed circuit has advantages in terms of non-volatility and load capacity. Furthermore, the input and output of the proposed logic are both constant voltages without signal degradation. All these three merits make the proposed circuit capable of realizing the cascaded logic functions. In order to demonstrate the validity and effectiveness of the entire work, series circuit simulations were carried out. The experimental results indicated that the proposed logic circuit has the potential to realize almost all basic ternary logic gates, and even some more complicated cascaded logic functions with a compact circuit construction, high efficiency, and good robustness.


Circuit World ◽  
2019 ◽  
Vol 45 (4) ◽  
pp. 300-310
Author(s):  
Piyush Tankwal ◽  
Vikas Nehra ◽  
Sanjay Prajapati ◽  
Brajesh Kumar Kaushik

Purpose The purpose of this paper is to analyze and compare the characteristics of hybrid conventional complementary metal oxide semiconductor/magnetic tunnel junction (CMOS/MTJ) logic gates based on spin transfer torque (STT) and differential spin Hall effect (DSHE) magnetic random access memory (MRAM). Design/methodology/approach Spintronics technology can be used as an alternative to CMOS technology as it is having comparatively low power dissipation, non-volatility, high density and high endurance. MTJ is the basic spin based device that stores data in form of electron spin instead of charge. Two mechanisms, namely, STT and SHE, are used to switch the magnetization of MTJ. Findings It is observed that the power consumption in DSHE based logic gates is 95.6% less than the STT based gates. DSHE-based write circuit consumes only 5.28 fJ energy per bit. Originality/value This paper describes how the DSHE-MRAM is more effective for implementing logic circuits in comparison to STT-MRAM.


Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 375
Author(s):  
Jianwen Li ◽  
Xuan Guo ◽  
Jian Luan ◽  
Danyu Wu ◽  
Lei Zhou ◽  
...  

A 1 GS/s 12-bit pipelined/successive-approximation-register (pipelined/SAR) hybrid analog-to-digital converter (ADC) is presented in this paper, where the five most significant bits are resolved by two cascading 2.5-bit multiplying digital-to-analog converters, and the eight least significant bits are determined by a two-channel time-interleaved successive-approximation-register (TI-SAR) quantizer. An integrated input buffer and an operational amplifier with improved voltage efficiency at 1.8 V are adopted to achieve high-linearity stably in wide band for 1 GS/s. By designing a 500 MS/s 8-bit SAR quantizer at 1 V, the number of required interleaved channels is minimized to simplify the complexity and an adaptive power/ground is used to compensate the common-mode mismatch between the blocks in different power supply voltages. The offset and gain mismatches due to the TI-SAR quantizer are compensated by a calibration scheme based on virtually-interleaved channels. This ADC is fabricated in a 40 nm complementary metal-oxide-semiconductor (CMOS) technology, and it achieves a signal-to-noise-and-distortion ratio (SNDR) of 58.2 dB and a spurious free dynamic range (SFDR) of 72 dB with a 69 MHz input tone. When the input frequency increases to 1814 MHz in the fourth Nyquist zone, it can maintain an SNDR of 55.3 dB and an SFDR of 64 dB. The differential and integral nonlinearities are −0.94/+0.85 least significant bit (LSB) and −3.4/+3.9 LSB, respectively. The core ADC consumes 94 mW, occupies an active area of 0.47 mm × 0.25 mm. The Walden figure of merit reaches 0.14 pJ/step with a Nyquist input.


2015 ◽  
Vol 24 (03n04) ◽  
pp. 1550008 ◽  
Author(s):  
Bander Saman ◽  
P. Mirdha ◽  
M. Lingalugari ◽  
P. Gogna ◽  
F. C. Jain ◽  
...  

This paper presents the design and modeling of logic gates using two channel spatial wavefunction switched field-effect transistors (SWSFETs) it is also known as a twin-drain MOSFET. In SWSFETs, the channel between source and drain has two or more quantum wells (QWs) layers separated by a high band gap material between them. The gate voltage controls the charge carrier concentration in the two quantum wells layers and it causes the switching of charge carriers from one channel to other channel of the device. The first part of this paper shows the characteristics of n-channel SWSFET model, the second part provides the circuit topology for the SWSFET inverter and universal gates- NAND, AND, NOR,OR, XOR and XOR. The proposed model is based on integration between Berkeley Short-channel IGFET Model (BSIM) and Analog Behavioral Model (ABM), the model is suitable to investigate the gates configuration and transient analysis at circuit level. The results show that all basic two-input logic gates can be implanted by using n-channel SWSFET only, It covers less area compared with CMOS (Complementary metal–oxide–semiconductor) gates. The NAND-NOR can be performed by three SWSFET, moreover the exclusive-NOR “XNOR” can be done by four SWSFET transistors also AND, OR, XOR gates require two additional SWSFET for inverting.


2021 ◽  
Author(s):  
Muhammad Farhan Azmine ◽  
Urmi Debnath ◽  
Yeasir Arafat

<div>Memristor is dubbed as the fourth fundamental electrical component which works primarily as a non-volatile memory element. Memristors can also be used to construct logic gates, and Memristor Ratioed Logic (MRL) is one of these structures. The higher area efficiency and CMOS architecture compatibility of MRL gates have lead researchers to pay attention to its use in digital logic architecture. In this work, binary MRL is integrated with Complementary Metal-Oxide Semiconductor(CMOS) logic elements to develop building blocks of an Arithmetic Logic Unit (ALU). The proposed 1-bit ALU is simulated using LTSpice, which allows the versatility of changing the parameters as per the model used. This work designs and analyses an optimized cascadable 1-bit ALU with with voltage level based binary logic state via simulation. The proposed circuit shows improvement in transistor count and delay over benchmark circuits.</div>


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wenhua Huang ◽  
Juan Ren ◽  
Jinglong Jiang ◽  
J. Cheng

Purpose Quantum-dot Cellular Automata (QCA) is a new nano-scale transistor-less computing model. To address the scaling limitations of complementary-metal-oxide-semiconductor technology, QCA seeks to produce general computation with better results in terms of size, switching speed, energy and fault-tolerant at the nano-scale. Currently, binary information is interpreted in this technology, relying on the distribution of the arrangement of electrons in chemical molecules. Using the coplanar topology in the design of a fault-tolerant digital comparator can improve the comparator’s performance. This paper aims to present the coplanar design of a fault-tolerant digital comparator based on the majority and inverter gate in the QCA. Design/methodology/approach As the digital comparator is one of the essential digital circuits, in the present study, a new fault-tolerant architecture is proposed for a digital comparator based on QCA. The proposed coplanar design is realized using coplanar inverters and majority gates. The QCADesigner 2.0.3 simulator is used to simulate the suggested new fault-tolerant coplanar digital comparator. Findings Four elements, including cell misalignment, cell missing, extra cell and cell dislocation, are evaluated and analyzed in QCADesigner 2.0.3. The outcomes of the study demonstrate that the logical function of the built circuit is accurate. In the presence of a single missed defect, this fault-tolerant digital comparator architecture will achieve 100% fault tolerance. Also, this comparator is above 90% fault-tolerant under single-cell displacement faults and is above 95% fault-tolerant under single-cell missing defects. Originality/value A novel structure for the fault-tolerant digital comparator in the QCA technology was proposed used by coplanar majority and inverter. Also, the performance metrics and obtained results establish that the coplanar design can be used in the QCA circuits to produce optimized and fault-tolerant circuits.


Author(s):  
Pierre-Emmanuel Gaillardon ◽  
Luca Gaetano Amarù ◽  
Shashikanth Bobba ◽  
Michele De Marchi ◽  
Davide Sacchetto ◽  
...  

Nanosystems are large-scale integrated systems exploiting nanoelectronic devices. In this study, we consider double independent gate, vertically stacked nanowire field effect transistors (FETs) with gate-all-around structures and typical diameter of 20 nm. These devices, which we have successfully fabricated and evaluated, control the ambipolar behaviour of the nanostructure by selectively enabling one type of carriers. These transistors work as switches with electrically programmable polarity and thus realize an exclusive or operation. The intrinsic higher expressive power of these FETs, when compared with standard complementary metal oxide semiconductor technology, enables us to realize more efficient logic gates, which we organize as tiles to realize nanowire systems by regular arrays. This article surveys both the technology for double independent gate FETs as well as physical and logic design tools to realize digital systems with this fabrication technology.


2009 ◽  
Vol 6 (suppl_4) ◽  
Author(s):  
Zack Booth Simpson ◽  
Timothy L. Tsai ◽  
Nam Nguyen ◽  
Xi Chen ◽  
Andrew D. Ellington

The power of electronic computation is due in part to the development of modular gate structures that can be coupled to carry out sophisticated logical operations and whose performance can be readily modelled. However, the equivalences between electronic and biochemical operations are far from obvious. In order to help cross between these disciplines, we develop an analogy between complementary metal oxide semiconductor and transcriptional logic gates. We surmise that these transcriptional logic gates might prove to be useful in amorphous computations and model the abilities of immobilized gates to form patterns. Finally, to begin to implement these computations, we design unique hairpin transcriptional gates and then characterize these gates in a binary latch similar to that already demonstrated by Kim et al . (Kim, White & Winfree 2006 Mol. Syst. Biol. 2 , 68 (doi:10.1038/msb4100099)). The hairpin transcriptional gates are uniquely suited to the design of a complementary NAND gate that can serve as an underlying basis of molecular computing that can output matter rather than electronic information.


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