CNFET Based Low Power Full Adder Circuit for VLSI Applications

2020 ◽  
Vol 10 (3) ◽  
pp. 286-291
Author(s):  
Inamul Hussain ◽  
Saurabh Chaudhury

Background: The Adder is one of the most prominent building blocks in VLSI circuits and systems. Performance of such systems depends mostly on the performance of the adder cell. The scaling down of devices has been the driving force in technological advances. However, in CMOS technology performance of adder cell decreases as technology node scaled down to deep micron regime. Objective: With the growth of research, new device model has been proposed based on carbon nano tube field effect transistor (CNFET). Therefore, there is a need of full adder cell, which performs sufficiently well in CNFET as well as different CMOS technology nodes. Method: A new low power full adder cell has been proposed with a hybrid XOR/XNOR module by using CNFET, which is also compatible for the CMOS technology nodes. The performance of the adder cell is validated with HSPICE simulation in terms of power, delay and power delay product. It is observed that the proposed adder cell performs better than the CMOS, CPL, TGA, 10 T, 14 T, 24 T, HSPC and Hybrid_FA adder cells. The CNFET full adder is designed in 32 nm CNFET model and to appraise its compatibility with Bulk-Si CMOS technology, 90 nm and 32 nm CMOS technology node is used. Conclusion: The proposed adder is very much suitable for both CMOS and CNFET technology based circuits and systems. To validate the result, simulation has been carried out with Synopsis tool. This full adder will definitely dominate other full adder cells at various technology nodes for VLSI applications.

In an electronic processing system, addition of binary numbers is a fundamental operation. A one bit low power hybrid FA(full adder) is shown in showing performance improvisation by analysis and comparing with other conventional adders. 1 bit low power hybrid full adder is considered as a good way for enhancing the speed of the circuit in comparison with other conventional circuits of full adders. In that analysis paper, one bit low power hybrid FA(full adder) is implemented by EDA tool and the simulation is analysis by using generic 90nm CMOS technology at 5 volts and comparison is done at various voltages with other conventional full adders. For comparing 1 bit low power hybrid full adder with other conventional adders at various parameters such as static and dynamic power usage, delay & pdp (power delay product) are taken into consideration to show that 1 bit low power hybrid full adder is most suitable for various low power applications.


VLSI Design ◽  
1996 ◽  
Vol 4 (1) ◽  
pp. 75-81 ◽  
Author(s):  
A. Srivastava ◽  
K. Venkatapathy

In this work, the design and implementation of a low power ternary full adder are presented in CMOS technology. In a ternary full adder design, the basic building blocks, the positive ternary inverter (PTI) and negative ternary inverter (NTI) are developed using a CMOS inverter and pass transistors. In designs of PTI and NTI, W/L ratios of transistors have been varied for their optimum performance. The ternary full adder and its building blocks have been simulated with SPICE 2G.6 using the MOSIS model parameters. The rise and fall times of PTI show an improvement by a factor of 14 and 4, respectively, and that of the NTI by a factor of nearly 4 and 17, respectively over that of earlier designs implemented in depletion-enhancement CMOS (DECMOS) technology. The noise margins improve by a factor of nearly 2 in PTI and NTI, respectively.The ternary full adder has been fabricated in MOSIS two micron n-well CMOS technology. The full adder and its building blocks, NTI and PTI have been tested experimentally for static and dynamic performance, compared with the SPICE simulated behavior, and close agreement is observed.The ternary-valued logic circuits designed in the present work which do not use depletion mode MOSFETS perform better than that implemented earlier in DECMOS technology. The present design is fully compatible with the current CMOS technology, uses fewer components and dissipates power in the microwatt range.


Author(s):  
Sai Venkatramana Prasada G.S ◽  
G. Seshikala ◽  
S. Niranjana

Background: This paper presents the comparative study of power dissipation, delay and power delay product (PDP) of different full adders and multiplier designs. Methods: Full adder is the fundamental operation for any processors, DSP architectures and VLSI systems. Here ten different full adder structures were analyzed for their best performance using a Mentor Graphics tool with 180nm technology. Results: From the analysis result high performance full adder is extracted for further higher level designs. 8T full adder exhibits high speed, low power delay and low power delay product and hence it is considered to construct four different multiplier designs, such as Array multiplier, Baugh Wooley multiplier, Braun multiplier and Wallace Tree multiplier. These different structures of multipliers were designed using 8T full adder and simulated using Mentor Graphics tool in a constant W/L aspect ratio. Conclusion: From the analysis, it is concluded that Wallace Tree multiplier is the high speed multiplier but dissipates comparatively high power. Baugh Wooley multiplier dissipates less power but exhibits more time delay and low PDP.


Author(s):  
Tejaswini M. L ◽  
Aishwarya H ◽  
Akhila M ◽  
B. G. Manasa

The main aim of our work is to achieve low power, high speed design goals. The proposed hybrid adder is designed to meet the requirements of high output swing and minimum power. Performance of hybrid FA in terms of delay, power, and driving capability is largely dependent on the performance of XOR-XNOR circuit. In hybrid FAs maximum power is consumed by XOR-XNOR circuit. In this paper 10T XOR-XNOR is proposed, which provide good driving capabilities and full swing output simultaneously without using any external inverter. The performance of the proposed circuit is measured by simulating it in cadence virtuoso environment using 90-nm CMOS technology. This circuit outperforms its counterparts showing power delay product is reduced than that of available XOR-XNOR modules. Four different full adder designs are proposed utilizing 10T XOR-XNOR, sum and carry modules. The proposed FAs provide improvement in terms of PDP than that of other architectures. To evaluate the performance of proposed full adder circuit, we embedded it in a 4-bit and 8-bit cascaded full adder. Among all FAs two of the proposed FAs provide the best performance for a higher number of bits.


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.


2021 ◽  
Vol 2089 (1) ◽  
pp. 012080
Author(s):  
M. Srinivas ◽  
K.V. Daya Sagar

Abstract Currently, energy consumption in the digital circuit is a key design parameter for emerging mobile products. The principal cause of the power dissipation during idle mode is leakage currents, which are rising dramatically. Sub-threshold leakage is increased by the scaling of threshold voltage when gate current leakage increases because oxide thickness is scaled. With rising demands for mobile devices, leakage energy consumption has received even greater attention. Since a mobile device spends most of its time in standby mode, leakage power savings need to prolong the battery life. That is why low power has become a significant factor in CMOS circuit design. The required design and simulation of an AND gate with the BSIM4 MOS parameter model at 27 0C, supply voltage of 0,70V with CMOS technology of 65nm are the validation of the suitability of the proposed circuit technology. AND simulation. The performance parameters for the two AND input gate are compared with the current MTCMOS and SCCMOS techniques, such as sub-threshold leakage power dissipations in active and standby modes, the dynamic dissipation, and propagation period. The proposed hybrid super cutoff complete stack technique compared to the current MTCMOS technology shows a reduction in sub-threshold dissipation power dissipation by 3. 50x and 1.15x in standby modes and active modes respectively. The hybrid surface-cutting technique also shows savings of 2,50 and 1,04 in power dissipation at the sub-threshold in standby modes and active modes compared with the existing SCCMOS Technique.


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.


2018 ◽  
Vol 7 (2.7) ◽  
pp. 733
Author(s):  
C Priyanka ◽  
N Manoj Kumar ◽  
L Sai Priya ◽  
B Vaishnavi ◽  
M Rama Krishna

Convolution is having extensive area of application in Digital Signal Processing. Convolution supports to evaluate the output of a system with arbitrary input, with information of impulse response of the system.  Linear systems features are totally stated by the systems impulse response, as ruled by the mathematics of convolution. Primary necessity of any application to work fast is that rise in the speed of their basic building block. Multiplier, adder is said to be the important building blocks in the process of convolution. As these blocks consumes plentiful time to obtain the response of the system.  Several methods are designed to progress the speed of the Multiplier and adder, among all GDI (Gate Diffusion Input) is under emphasis because of faster working and low power consumption. In this paper GDI based convolution is implemented using Vedic multiplier and adder in T-SPICE Software which increases the speed and consumes less power compared to CMOS technology. 


Author(s):  
Dan Wang ◽  
Maofeng Yang ◽  
Wu Cheng ◽  
Xuguang Guan ◽  
Zhangming Zhu ◽  
...  
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