scholarly journals Performance Analysis of High Speed Hybrid CMOS Full Adder Circuits for Low Voltage VLSI Design

VLSI Design ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Subodh Wairya ◽  
Rajendra Kumar Nagaria ◽  
Sudarshan Tiwari

This paper presents a comparative study of high-speed and low-voltage full adder circuits. Our approach is based on hybrid design full adder circuits combined in a single unit. A high performance adder cell using an XOR-XNOR (3T) design style is discussed. This paper also discusses a high-speed conventional full adder design combined with MOSCAP Majority function circuit in one unit to implement a hybrid full adder circuit. Moreover, it presents low-power Majority-function-based 1-bit full addersthat use MOS capacitors (MOSCAP) in its structure. This technique helps in reducing power consumption, propagation delay, and area of digital circuits while maintaining low complexity of logic design. Simulation results illustrate the superiority of the designed adder circuits over the conventional CMOS, TG, and hybrid adder circuits in terms of power, delay, power delay product (PDP), and energy delay product (EDP). Postlayout simulation results illustrate the superiority of the newly designed majority adder circuits against the reported conventional adder circuits. The design is implemented on UMC 0.18 m process models in Cadence Virtuoso Schematic Composer at 1.8 V single-ended supply voltage, and simulations are carried out on Spectre S.

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.


Author(s):  
P.A. Gowri Sankar ◽  
G. Sathiyabama

The continuous scaling down of metal-oxide-semiconductor field effect transistors (MOSFETs) led to the considerable impact in the analog-digital mixed signal integrated circuit design for system-on-chips (SoCs) application. SoCs trends force ADCs to be integrated on the chip with other digital circuits. These trends present new challenges in ADC circuit design based on existing CMOS technology. In this paper, we have designed and analyzed a 3-bit high speed, low-voltage and low-power flash ADC at 32nm CNFET technology for SoC applications. The proposed ADC utilizes the Threshold Inverter Quantization (TIQ) technique that uses two cascaded carbon nanotube field effect transistor (CNFET) inverters as a comparator. The TIQ technique proposed has been developed for better implementation in SoC applications. The performance of the proposed ADC is studied using two different types of encoders such as ROM and Fat tree encoders. The proposed ADCs circuits are simulated using Synopsys HSPICE with standard 32nm CNFET model at 0.9 input supply voltage. The simulation results show that the proposed 3 bit TIQ technique based flash ADC with fat tree encoder operates up to 8 giga samples per second (GSPS) with 35.88µW power consumption. From the simulation results, we observed that the proposed TIQ flash ADC achieves high speed, small size, low power consumption, and low voltage operation compared to other low power CMOS technology based flash ADCs. The proposed method is sensitive to process, temperature and power supply voltage variations and their impact on the ADC performance is also investigated.


Author(s):  
Basavoju Harish ◽  
M. S. S. Rukmini

In the field of bio medical engineering high performance CPU for digital signal processing plays a significant role. Frequency efficient circuit is a paramount requirement for the portable digital devices employing various digital processors. In this work a novel high speed one-bit 10T full adder with complemented output was described. The circuit was constructed with XOR gates which were built using two CMOS transistors. The XOR gate was constructed using 2T multiplexer circuit style. It was observed that power consumption of the designed circuit at 180nm with supply voltage 1.8V is 183.6 uW and delay was 1.809 ps whereas power consumption at 90nm with supply voltage 1.2V is 25.74 uW and delay was 8.245 ps. The observed Power Delay Product (PDP) in 180nm (at supply voltage 1.8V) is 0.33 and in 90nm (at supply voltage 1.2V) is 0.212. The work was extended by implementing a 32-bit Ripple Carry Adder (RCA) and was found that the delay at 180nm is 93.7ps and at 90nm is 198ps. The results were drawn at 180nm and also 90nm technology using CAD tool. The results say that the present work offered significant enhancement in speed and PDP compared with existing designs.


2013 ◽  
Vol 284-287 ◽  
pp. 2580-2589
Author(s):  
G. Ramana Murthy ◽  
C. Senthilpari ◽  
P. Velrajkumar ◽  
T.S. Lim

This paper presents a 1-bit full adder by using as few as six transistors per bit in its design. It is designed with a combination of multiplexing control input and Boolean identities. The proposed design features lower operating voltage, higher computing speed and lower energy consumption due to the efficient operation of 6-transistor adder cell. The design adopts Multiplexing with Control input technique to alleviate the threshold voltage loss problem commonly encountered in pass transistor logic design. The proposed design successfully embeds the buffering circuit in the full adder design and the transistor count is minimized. The improved buffering helps the design operate under lower supply voltage compared with existing works. It also enhances the speed performance of the cascaded operation significantly while maintaining the performance edge in energy consumption. For performance comparison, the proposed full adder is evaluated along with four existing full adders via extensive BSIM4 simulation. The simulation results, 180nm process models, indicate that the proposed design has lowest energy consumption per addition along with the performance edge in both speed and energy consumption makes it suitable for low power and high speed embedded processor applications.


2021 ◽  
Vol 13 (4) ◽  
pp. 449-456
Author(s):  
Nikolae V. Masalsky ◽  

The applicability of the architecture of a nanoscale surrounding gate field-effect transistor with a combined cylindrical working area for low-voltage applications is discussed. At the same time, the licensed TCAD Sentaurus instrument and technological modeling system is used as a tool. The transistor architecture under consideration involves combining the working zones of n-channel and p-channel transistors with one common gate. At the same time, the efficiency of suppressing short-channel effects is maintained and a high level of transistor current is provided in the strong inversion mode. Based on this architecture, a TCAD model of the NAND gate has been developed, the design of which contains two independent surrounding gates one combined working area. The use of the proposed gate architecture makes it possible to reduce the number of required transistor structures per gate by three times. This leads to a decrease in the switched capacity and power dissipation. From the simulation results, the gate geometric parameters with a working area length of 25 nm and a diameter of 8.5 nm, which can function at control voltages of 0.5 V in the frequency range up to 20 GHz with high gain, are determined. The switching time delay is 0.81 ps. The TCAD model of a half-adder is developed in the basis 2NAND. According to the simulation results, the efficiency of the prototype, which performs binary code addition operations with a delay of 4.2 ps at a supply voltage of 0.5 V and a frequency of 20 GHz, is shown. The obtained results create a theoretical basis for the synthesis of low-voltage complex functional blocks with high performance and minimal occupied area, which meets modern requirements for digital applications.


In the application of digital signal process multipliers play a vital role. With advances in technology, several researchers have tried and try to design multipliers which supply high speed, low power consumption, regularity of layout and thus less space or maybe combination of them in one multiplier factor. Thus, Compact VLSI design for four bit multiplier factor is planned during this paper that is appropriate for low power and high speed applications. Multiplier factor with high performance is achieved through the novel style of hybrid single bit full adder and Dadda algorithmic rule. The important path delay and power consumption of the planned multiplier factor square measure reduced by 65.9% and 24.5% severally when put next with existing multipliers. The planned multiplier factor is synthesized exploitation CADENCE five.1.0 EDA tool and simulated exploitation spectre virtuoso.


Author(s):  
Haroon Rasheed S ◽  
Mohan Das S ◽  
Samba Sivudu Gaddam

This paper presents an energy efficient 1-bit full adder designed with a low voltage and high performance internal logic cells which leads to have abridged Power Delay Product (PDP). The customized XNOR and XOR gates, a necessary entity, are also presented. The simulations for the designed circuits performed in cadence virtuoso tool with 45-nm CMOS technology at a supply voltage of 0.9 Volts. The proposed 1-bit adder cell is compared with various trendy adders based on speed, power consumption and energy (PDP). The proposed adder schemes with modified internal entity cells achieve significant savings in terms of delay and energy consumption and which are more than 77% and 40.47% respectively when compared with conventional “C-CMOS” 1-bit full adder and other counter parts.


2015 ◽  
Vol 37 ◽  
pp. 285 ◽  
Author(s):  
Milad Jalalian Abbasi Morad ◽  
Seyyed Reza Talebiyan ◽  
Ebrahim Pakniyat

This paper, presents a new design for 1-bit full adder cell using hybrid-CMOS logic style. Using a novel structure for implementation of the proposed full adder caused it has better performance in terms of propagation delay and power-delay product (PDP) compared to its counterparts. According to the simulation results, the propagation delay of the proposed full adder is 22.8% less than the propagation delay of next fastest full adder, and the power-delay product of the proposed full adder is 22.7% less than the next best PDP. HSpice simulations using 65nm technology with a power supply of 1.2V was utilized to evaluate the performance of the circuits.


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.


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