scholarly journals Design of low power 8-bit gate-diffusion input (GDI) full adder using variable body bias (VBB) technique in 90nm technology

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):  
Woo Wei Kai ◽  
Nabihah binti Ahmad ◽  
Mohamad Hairol Bin Jabbar

The static power consumption is an important parameter concern in IC design due to t for a higher integration numbers of transistor to achieve greater performance in a single chip. Leakage current is the main issues for static power dissipation in standby mode as the size of transistor been scale. Therefore, the subthreshold leakage current rises due to threshold voltage scaling and gate leakage current increases due to scale down of oxide thickness. In this paper, a Variable Body Biasing (VBB) technique was applied to reduce static power consumption in VLSI design. The VBB technique used a DC bias at body terminal to control the threshold voltage efficiently. The Synopsys Custom Designer EDA tools in 90nm MOSFET technology was used to design a 1-bit full adder with VBB technique in full custom methodology. The simulation of 1-bit full adder was carried out with operation voltage   supply was compared in conventional technique and VBB technique. The results achieved the reduction in term of peak power,   and average power,   in static CMOS 1-bit full adder compared with conventional bias and VBB technique.


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):  
Diksha Siddhamshittiwar

Static power reduction is a challenge in deep submicron VLSI circuits. In this paper 28T full adder circuit, 14T full adder circuit and 32 bit power gated BCD adder using the full adders respectively were designed and their average power was compared. In existing work a conventional full adder is designed using 28T and the same is used to design 32 bit BCD adder. In the proposed architecture 14T transmission gate based power gated full adder is used for the design of 32 bit BCD adder. The leakage supremacy dissipated during standby mode in all deep submicron CMOS devices is reduced using efficient power gating and multi-channel technique. Simulation results were obtained using Tanner EDA and TSMC_180nm library file is used for the design of 28T full adder, 14T full adder and power gated BCD adder and a significant power reduction is achieved in the proposed architecture.


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.


2013 ◽  
Vol 7 (3) ◽  
pp. 1155-1165
Author(s):  
Dayadi Lakshmaiah ◽  
Dr. M.V. Subramanyam ◽  
Dr. K.Sathya Prasad

This paper process a novel design for low power 1-bit CMOS full adder using XNOR and MUX, with reduced number of transistors using GDI cell. The circuits were simulated with supply voltage scaling from 1.2V to 0.6V &0.6V to 0.3V. To achieve the desired performance of power delay product, area, capacitance the transistors with low threshold voltage were used at critical paths and high threshold voltage at non critical paths. The results show the efficiency of the proposed technique in terms of power consumption, delay and area.


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.


2019 ◽  
Vol 8 (2) ◽  
pp. 4253-4263

In this research paper, CMOS and FinFET based hybrid Full Adders operating at low voltages with low power dissipation are proposed. The proposed CMOS based circuit is compared with few existing hybrid full adders in terms of average power dissipation and power-delay-product (PDP). The designed CMOS based hybrid adder achieves lower power dissipation and low PDP compared to other hybrid adders over a voltage range of 0.6V to 1V. The proposed CMOS implementation of hybrid full adder fails at 0.5V to produce full swing output. To solve this full swing problem, the proposed hybrid full adder is implemented using FinFETs which produce full output voltage, lower power and low PDP comparing with CMOS implementation. The circuits are designed with HSPICE tool in 32nm predictive technology model (PTM).


Author(s):  
Madabhushi Sai Meghana

In this project, novel circuits for FULL ADDER are proposed using new XOR or XNOR gates. The conventional design of XOR or XNOR gates shows that the not gate in the schematic has drawbacks. So by investigating advanced XOR or XNOR gates we proposed the schematic design. The proposed schematics are optimized in terms of speed, delay, power and power delay product. We developed six novel hybrid full adder schematics based on exploring new XOR or XNOR gates. Each designed schematics have their specifications of energy consumption, delay, power delay product. To simulate the performance of the proposed designs, we use mentor graphics, tanner tool. The simulation yields a 45-nm CMOS innovation model that focuses on the proposed plans having best speed and power other than the plan of any full adder. The proposed Full Adders has 2-28% increment in consumption of energy and power delay product compared to other design schematics. The proposed hybrid full adders are investigated with voltage 1.8V, speed ,size of transistors, area, power consumption and delay.


Author(s):  
S.C. Wagaj ◽  
◽  
S.C. Patil ◽  

In this paper it has been demonstrated that a shielded channel made by varying the side gate length in silicon-on-nothing junctionless transistor not only improves the short channel effect but also improve the performance of CMOS circuits of this device. The proposed device shielded channel dual gate stack silicon on nothing junctionless transistor (SCDGSSONJLT) drain induced barrier lowering (DIBL), cut-off frequency and subthreshold slope are improved by 20%, 39% and 20% respectively over the single material gate silicon on insulator junctionless transistor (SMG SOI JLT). The proposed device CMOS inverter fall time Tf (pS) and noise margin improves by 50% and 10% compare to shielded channel silicon on insulator junctionless transistor (SCSOIJLT). It has been observed that circuit simulation of CMOS inverter, NAND and NOR of proposed device. The static power dissipation in the case of proposed SCDGSSONJLT device are reduced by 45%, 81% and 83% respectively over the SMGSOIJLT. Thus, significant improvement in DIBL, cut-off frequency, propagation delay and static power dissipation at low power supply voltage shows that the proposed device is more suitable for low power CMOS circuits.


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.


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