Low-Power Hybrid 1-Bit Full-Adder Circuit for Energy Efficient Arithmetic Applications

2016 ◽  
Vol 26 (01) ◽  
pp. 1750014 ◽  
Author(s):  
M. C. Parameshwara ◽  
H. C. Srinivasaiah

A novel “16 transistor” (16T) 1-bit Full adder (FA) circuit based on CMOS transmission-gate (TG) and pass transistor logics (PTL) is presented. This 1-bit FA circuit with TG and PTL structure is derived based on carry dependent sum implementation approach. The design metrics (DMs) such as power, delay, power-delay-product (PDP), and transistor-count (TC) for this 1-bit FA are compared against eight other standard and state-of-the-art 1-bit FA circuits reported till date. All the comparisons are done at post layout level with respect to the DMs under consideration. The proposed 1-bit FA dissipates an average power of 2.118[Formula: see text][Formula: see text]W, with a delay of 606 ps, with an area of 33.1[Formula: see text][Formula: see text]m2, resulting in a PDP of 1.28 fJ. This power and hence the PDP is the lowest of all, ever reported till date. In this comparative study a common test bench with a supply voltage [Formula: see text][Formula: see text]V, input signal frequency [Formula: see text][Formula: see text]MHz is used. This 1-bit FA is designed and implemented using Cadences' 90[Formula: see text]nm “generic-process-design-kit” (GPDK).

Author(s):  
M. Naga Gowtham Et.al

In this paper, a hybrid 1-bit adder and 1-bit Subtractor designs are implemented. The hybrid adder circuit is constructed using CMOS (complementary metal oxide semiconductor) logic along with pass transistor logic. The design can be extended 16 and 32 bits lately. The proposed full adder circuit is compared with the existing conventional adders in terms of power, delay and area in order to obtain a better circuit that serves the present day needs of people. The existing 1-bit hybrid adder uses EXNOR logic combined with the transmission gate logic. For a supply voltage of 1.8V the average power consumption (4.1563 µW) which is extremely low with moderately low delay (224 ps) resulting because of the deliberate incorporation of very weak CMOS inverters coupled with strong transmission gates. At 1.2V supply the power and delay were recorded to be 1.17664 µW and 91.3 ps. The design was implemented using 1-bit which can also be extended into a 32-bit design later. The designed implementation offers a better performance in terms of power and speed compared to the existing full adder design styles. The circuits were implemented in DSCH2 and Microwind tools respectively. The parameters such as power, delay, layout area and speed of the proposed circuit design is compared with pass transistor logic, adiabatic logic, transmission gate adder and so on. The circuit is also designed with a decrease in transistors in order to get the better results. Full Subtractor, a combinational digital circuit which performs 1-bit subtraction with borrow in is designed as a part of this project. The main aim behind this part of the project is to design a 1-bit full Subtractor using CMOS technology with reduced number of transistors and hence the efficiency in terms of area, power and speed have been calculated is designed using 8,10,15and 16 transistors. The parameters were calculated in each case and the results have been tabulated.


Author(s):  
M. Naga Gowtham, P.S Hari Krishna Reddy, K Jeevitha, K Hari Kishore, E Raghuveera, Shaik Razia

In this paper, a hybrid 1-bit adder and 1-bit Subtractor designs are implemented. The hybrid adder circuit is constructed using CMOS (complementary metal oxide semiconductor) logic along with pass transistor logic. The design can be extended 16 and 32 bits lately. The proposed full adder circuit is compared with the existing conventional adders in terms of power, delay and area in order to obtain a better circuit that serves the present day needs of people. The existing 1-bit hybrid adder uses EXNOR logic combined with the transmission gate logic. For a supply voltage of 1.8V the average power consumption (4.1563 µW) which is extremely low with moderately low delay (224 ps) resulting because of the deliberate incorporation of very weak CMOS inverters coupled with strong transmission gates. At 1.2V supply the power and delay were recorded to be 1.17664 µW and 91.3 ps. The design was implemented using 1-bit which can also be extended into a 32-bit design later. The designed implementation offers a better performance in terms of power and speed compared to the existing full adder design styles. The circuits were implemented in DSCH2 and Microwind tools respectively. The parameters such as power, delay, layout area and speed of the proposed circuit design is compared with pass transistor logic, adiabatic logic, transmission gate adder and so on. The circuit is also designed with a decrease in transistors in order to get the better results. Full Subtractor, a combinational digital circuit which performs 1-bit subtraction with borrow in is designed as a part of this project. The main aim behind this part of the project is to design a 1-bit full Subtractor using CMOS technology with reduced number of transistors and hence the efficiency in terms of area, power and speed have been calculated is designed using 8,10,15and 16 transistors. The parameters were calculated in each case and the results have been tabulated.


2016 ◽  
Vol 62 (4) ◽  
pp. 329-334 ◽  
Author(s):  
Raushan Kumar ◽  
Sahadev Roy ◽  
C.T. Bhunia

Abstract In this paper, we proposed an efficient full adder circuit using 16 transistors. The proposed high-speed adder circuit is able to operate at very low voltage and maintain the proper output voltage swing and also balance the power consumption and speed. Proposed design is based on CMOS mixed threshold voltage logic (MTVL) and implemented in 180nm CMOS technology. In the proposed technique the most time-consuming and power consuming XOR gates and multiplexer are designed using MTVL scheme. The maximum average power consumed by the proposed circuit is 6.94μW at 1.8V supply voltage and frequency of 500 MHz, which is less than other conventional methods. Power, delay, and area are optimized by using pass transistor logic and verified using the SPICE simulation tool at desired broad frequency range. It is also observed that the proposed design may be successfully utilized in many cases, especially whenever the lowest power consumption and delay are aimed.


2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
Candy Goyal ◽  
Jagpal Singh Ubhi ◽  
Balwinder Raj

In this paper, an effective and reliable sleep circuit is proposed, which not only reduces leakage power but also shows significant reduction in ground bounce noise (GBN) in approximate full adder (FA) circuits. Four 1-bit approximate FA circuits are modified using proposed sleep circuit which uses one NMOS and one PMOS transistor. The design metrics such as average power, delay, power delay product (PDP), leakage power, and GBN are compared with nine other 1-bit FA circuits reported till date. All the comparisons are done using post-layout netlist at 45nm technology. The modified designs achieve reduction in leakage power and GBN up to 60% and 80%, respectively, as compared to the best reported approximate FA circuits. The modified approximate FA also achieves 83% reduction in leakage power as compared to conventional FA. Finally, application level metrics such as peak signal to noise ratio (PSNR) are considered to measure the performance of all the proposed approximate FAs.


2017 ◽  
Vol 7 (1.1) ◽  
pp. 660
Author(s):  
Venkata Rao Tirumalasetty ◽  
C V. Mohan Krishna ◽  
K Sai Sree Tanmaie ◽  
T Lakshmi Naveena ◽  
Ch Jonathan

In this paper, the design of hybrid 1-bit full adder circuit using both pass transistor and CMOS logic was implemented. Performance pa-rameters such as power, delay, and PDP were compared with the existing designs such as complementary pass-transistor logic, transmis-sion gate adder. At 0.4V supply at 22nm technology, the average power consumption is 1. 525 uW was found to be extremely low with moderately low delay 90. 25 ps and PDP found to be 0.137 fJ. The present implementation has very good improvement in terms of delay, power and power delay product when compared to the existing hybrid 1-bit full adders. Also the number of transistors has been reduced to 13 where as the existiing hybrid full adder circuit has 16 transistors. The proposed circuit was implemented using mentor graphics tool in 45nm, 32nm and 22nm technologies with different supply voltages.  


Author(s):  
Woo Wei Kai ◽  
Nabihah Ahmad ◽  
Mohamad Hairol Jabbar

In digital system, the full adders are fundamental circuits that are used for arithmetic operations. Adder operation can be used to implement and perform calculation of the multipliers, subtraction, comparators, and address operation in an Arithmetic Logic Unit (ALU). The subthreshold leakage current increasing as proportional with the scaling down of oxide thickness and transistor in short channel sizes. In this paper, a Gate-diffusion Input (GDI) circuit design technique allow minimization the number of transistor while maintaining low complexity of logic design and low power realization of Variable Body Biasing (VBB) technique to reduce the static power consumption. The Silterra 90nm process design kit (PDK) was used to design 8-bit full adder with VBB technique in full custom methodology by using Synopsys Electronic Design Automation (EDA) tools. The simulation of 8-bit full adder was compared within a conventional bias technique and VBB technique with operating voltage of  supply. The result showed the reduction of VBB technique in term of peak power,  and average power,   compare with conventional bias technique. Moreover, the Power Delay Product (PDP) showed 1.29pJ in VBB technique compare with conventional bias mode 1.67pJ. The area size of 8-Bit full adder was 10μm×23μm.


Author(s):  
M. C. Parameshwara

This paper proposes six novel approximate 1-bit full adders (AFAs) for inexact computing. The six novel AFAs namely AFA1, AFA2, AFA3, AFA4, AFA5, and AFA6 are derived from state-of-the-art exact 1-bit full adder (EFA) architectures. The performance of these AFAs is compared with reported AFAs (RAAs) in terms of design metrics (DMs) and peak-signal-to-noise-ratio (PSNR). The DMs under consideration are power, delay, power-delay-product (PDP), energy-delay-product (EDP), and area. For a fair comparison, the EFAs and proposed AFAs along with RAAs are described in Verilog, simulated, and synthesized using Cadences’ RC tool, using generic 180 nm standard cell library. The unconstrained synthesis results show that: among all the proposed AFAs, the AFA1 and AFA2 are found to be energy-efficient adders with high PSNR. The AFA1 has a total [Formula: see text][Formula: see text][Formula: see text]W, [Formula: see text][Formula: see text]ps, [Formula: see text][Formula: see text]fJ, [Formula: see text][Formula: see text]Js, [Formula: see text][Formula: see text][Formula: see text]m2, and [Formula: see text][Formula: see text]dB. And the AFA2 has the total [Formula: see text][Formula: see text][Formula: see text]W, [Formula: see text][Formula: see text]ps, [Formula: see text][Formula: see text]fJ, [Formula: see text][Formula: see text]Js, [Formula: see text][Formula: see text][Formula: see text]m2, and [Formula: see text][Formula: see text]dB.


Author(s):  
T. Suguna ◽  
M. Janaki Rani

In VLSI, power optimization is the main criteria for all the portable mobile applications and developments because of its impact on system performance. The performance of an adder has significant impact on overall performance of a digital system. Adiabatic logic (AL), a new emerging research domain for optimizing the power in VLSI circuits with high switching activity is discussed, in this paper, for implementing the adder circuits. Various adiabatic logic styles full adder designs are reviewed and multiplexer based hybrid full adder topology is designed and implemented with ECRL and 2PASCL AL styles. Moreover in this paper, 32 bit adders such as Ripple Carry Adder (RCA), Carry Select Adder (CSLA), Carry Save Adder (CSA), Carry Skip Adder (CSKA) and Brent Kung Adder (BKA) are realised using proposed ECRL and 2PASCL adiabatic full adders. All the adders are implemented and simulated using TANNER EDA tool 22nm technology, parameters like power, area, delay and power delay product (PDP) of all the adders are observed at different operating frequencies, with supply voltage of 0.95 v and load capacitance of 0.5 pF. The observed parameters are compared with the existing adiabatic full adder designs and concluded that the proposed adiabatic full adders have the advantages of less power, delay and transistor count. In conclusion ECRL full adder is 31% faster, has equal PDP and less area than 2PASCL full adder. At 1000MHz ECRL 32 bit carry save adder is having less delay among all the 32 bit adder and 65% less PDP than 2PASCL adder and it is concluded that ECRL 32 bit carry save adder can be selected for implementation of circuits that can be used in portable mobile applications.


2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
‘Aqilah binti Abdul Tahrim ◽  
Huei Chaeng Chin ◽  
Cheng Siong Lim ◽  
Michael Loong Peng Tan

The scaling process of the conventional 2D-planar metal-oxide semiconductor field-effect transistor (MOSFET) is now approaching its limit as technology has reached below 20 nm process technology. A new nonplanar device architecture called FinFET was invented to overcome the problem by allowing transistors to be scaled down into sub-20 nm region. In this work, the FinFET structure is implemented in 1-bit full adder transistors to investigate its performance and energy efficiency in the subthreshold region for cell designs of Complementary MOS (CMOS), Complementary Pass-Transistor Logic (CPL), Transmission Gate (TG), and Hybrid CMOS (HCMOS). The performance of 1-bit FinFET-based full adder in 16-nm technology is benchmarked against conventional MOSFET-based full adder. The Predictive Technology Model (PTM) and Berkeley Shortchannel IGFET Model-Common Multi-Gate (BSIM-CMG) 16 nm low power libraries are used. Propagation delay, average power dissipation, power-delay-product (PDP), and energy-delay-product (EDP) are analysed based on all four types of full adder cell designs of both FETs. The 1-bit FinFET-based full adder shows a great reduction in all four metric performances. A reduction in propagation delay, PDP, and EDP is evident in the 1-bit FinFET-based full adder of CPL, giving the best overall performance due to its high-speed performance and good current driving capabilities.


Author(s):  
Bilal N Md ◽  
Bhaskara Rao K ◽  
Mohan Das S

This This paper presents energy efficient GDI based 1-bit full adder cells with low power consumption and lesser delay with full swing modified basic logic gates to have reduced Power Delay Product (PDP). The various full adders are effectively realized by means of full swing OR, AND and XOR gates with the noteworthy enhancement in their performance. The simulations for the designed circuits performed in cadence virtuoso tool with 45-nm CMOS technologies at a supply voltage of 1 Volts. The proposed 1-bit adder cells are compared with various basic adders based on speed, power consumption and energy (PDP). The proposed adder schemes with full swing basic cells achieve significant savings in terms of delay and energy consumption and which are more than 41% and 32% respectively in comparison to conventional “C-CMOS” 1-bit full adder and other existing adders.


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