Carry Bypass Adder Research Articles

Advancements and Applications of Hardware Adders: Principles, Functions, and Future Challenges

This paper reviews the principles and applications of various types of adders, including Half Adder, Full Adder, Ripple-Carry Adder (RCA), Lookahead Carry Adder (LCA), Carry-Bypass Adder (CBA), and Carry Select Adder (CSA). The basic logic of each adder type is analyzed, emphasizing their performance characteristics, such as area, power consumption, and delay. Applications of adders in fields like image processing, portable electronics, and medical data encryption are discussed, highlighting how different types of adders are tailored to specific performance requirements. Approximate Full Adders (AFA) and low-power, high-speed adders are introduced as solutions for energy-efficient image processing and portable electronic applications, respectively. Challenges in reducing power consumption and improving approximate computing accuracy are addressed, with a focus on novel design approaches such as powerless AND gates, groundless OR gates, and error detection and correction methods. Future expectations for adder optimization are explored, including trends in power reduction, computing efficiency, and improved performance for various application scenarios.

An Optimised Implementation of Adaptive Rns Using Power-Aware CRT

In order to get an efficient comprehensive analysis on Doppler estimation in RADAR; need an enhanced arithmetic formulation procedure for density, power and latency optimisations. Modular adders and multipliers are very crucial components in the performance of residue number system-based applications. The Residue Number System (RNS) is a non-positional number system that allows parallel computations without transfers between digits. However, some operations in RNS require knowledge of the positional characteristic of a number. Among these operations is the conversion from RNS to the positional number system. The methods of reverse conversion for general form moduli based on the Chinese remainder theorem and the mixed-radix conversion are considered, as well as the optimized methods for special form moduli. A modified New CRT-I & New CRT-II with conjugate moduli set is considered to implement adder, multipliers and subtractions with optimised algorithms. This paper mainly deals with the conversion of numbers from binary to RNS as well RNS to binary with the specific modulo {2^n±k} which proves this new method. Modified Radix16 booth encoding algorithm and square carry bypass adder are used in implementation of RNS system to reduce parameter constraints.

Power Efficient Implementation of ECC Using LCSLA Based Dual Field Vedic Multiplier

The Elliptic Curve Cryptographic (ECC) technique is employed for security standards such as Security Key Management (SKM), digital signature, data authentication and so on. The ECC technique is capable of sequential and parallel mode processes through a unified design. It is used for both equally binary fields and prime fields of cryptosystems. The DMM structure has been developed using CSA. This adder requires a greater amount of Full Adder circuits, which occupy more area. To overcome this problem, this paper discusses four different methods, such as DMM-Optimized Carry Look Ahead Adder, DMM-Optimized Carry Bypass Adder, DMM-Look up Table Carry Select Adder, and Dual Field Vedic Multiplier – LCSLA, which is used to increase the performance of the ECC. The parameters like power utilization, time delay information, and hardware area overhead are analyzed and compared with existing methods. Among those four methods, the DVM-LCSLA method gave better results in FPGA and ASIC performances.

High-Speed 16-bit Carry Bypass Adder Design

Adders are one of the most significant blocks in a logical arithmetic unit. These are employed in a wide range of applications, from incrementing the value of a program variable to high-speed applications such as video-encoding, digital-signal. There are various adders with varying propagation delays. As a result, selecting an efficient adder is critical for system performance. This research compares the latency of several 16 bit adders that are available. The delay of logic gates in 180nm technology has been quantitatively modelled utilizing logical effort. The delay is then utilized to calculate the delay of various adders in Virtuoso Cadence while simulating. Virtuoso Cadence was used to perform functional verification on adders. Each adder's route delay has also been determined. Based on this research, a new carry bypass adder has been developed to reduce propagation delay. The suggested carry bypass adder reduces combinational path latency by 7.2 percent and logical effort delay by 29.5 percent, respectively. Keywords: Algorithms for 16-bit adders, logical effort, propagation delay, carry skip adder

Design of Gate Diffusion Input based Wallace Tree Multiplier using Parallel Prefix Adders

Wallace tree multiplier has partial product generation, partial product accumulation, and final addition stages. Usually, the final addition stage of the Wallace tree multiplier is designed with carry bypass adder (CBA). In the proposed work, two GDI (Gate Diffusion Input)-based Wallace tree multipliers are implemented with Kogge-Stone adder (KSA) and Brent-Kung adder (BKA) in the final addition stage respectively. As there is a trade-off between power and area, the number of MOSFETs is increased in the designed GDI-based Wallace tree multipliers using proposed adders as compared to carry bypass adder. The area is represented in terms of the number of MOSFETs are occupied. The proposed implementation though increases the number of MOSFETs, the power dissipation and the delays are predominantly reduced. As a technical contribution, the above parameters are investigated using Tanner V15.23, are compared and tabulated.

Implementation of Low Power High Speed Adder’s using GDI Logic

Addition is a vital arithmetic operation and is the base of other arithmetic operations such as multiplication, subtraction and division. Adder is a digital circuit that does addition of binary numbers. The 1-bit full adder is the basic block of an arithmetic unit. In VLSI, there are many efficient techniques to design digital circuits. Some of the techniques are Pass Transistor logic (PTL), Complementary metal oxide semiconductor (CMOS) and Transmitter gate (TG). There are several adder designs implemented to reduce the power. However, each design undergoes from precise disadvantage. The adder design with good driving capability requires more power and the design with more delay which consumes less power. In this paper 8-bit Carry Increment Adder (CIA), Carry Bypass Adder (CBA), Carry Skip Adder (CSKA), Carry Look Ahead Adder (CLA), Kogge Stone Adder (KSA), Han Carlson Adder (HCA), and Brent Kung Adder (BKA) are implemented using Gate Diffusion Input (GDI) logic. These designs are simulated and implemented using Tanner tool. The result shows that CBA, CLA, and KSA designs using GDI logic are more efficient compared to CMOS logic in view of power consumption, delay, and area (transistors count) respectively.

Variable Latency approach in VLSI adder Implemented to Reduce Area and Power

Objective: The Ultimate aim of the VLSI Design is to improve the efficiency, Reduction of Delay and Power Consumption and to minimize the area. In our proposed approach we had implemented the analysis had been done on the field of Speed, Power consumption, Area and Power delay product (PDP) for a carry skip adder with other adders listed as the parallel prefix adders and others. Methods/Statistical Analysis: The Carry-Skip Adder planned here reduces the time required to propagate the carry by skipping over teams of consecutive adder stages, is understood to be comparable in speed to the carry look-ahead technique whereas it uses less logic space and fewer power. Findings: The adders are basic building blocks of the digital circuits for the Signal processing, Integrating and other process of operation. There are various types of adders are proposed in Literature which are commonly used in VLSI Design. The Simulation results also shows that the proposed adder Architecture is Faster and Area efficient compared to other existing adder architecture. Application/ Improvements: They estimate the performance of proposed design will be better in terms of Logic and route delay by experimental results. Keywords: Adders, Carry Bypass Adder (CBA), Carry Increment Adder (CIA), Carry Look-Ahead Adder (CLA), Carry Skip Adder (CSkA), Han Carlson Adder (HCA), Ripple Carry Adder (RCA)

Multiplication With $m$ :2 and $m$ :3 Compressors—A Comparative Review

Compressors are widely used in multipliers to accumulate and reduce partial products in a parallel manner. This paper conducts a comparative review for high-order m:2 and m:3 compressors within a 16-bit × 16-bit multiplier cell as a benchmark. Furthermore, some of the compressors are slightly modified with the aim of reducing interconnections and logical gates. Four well-known adders are also employed to perform the final addition of partial products. They are ripple-carry adder, carry-lookahead adder (CLA), carry-bypass adder, and carry-select adder. These adders are initially demonstrated by a sequence of unmodified identical blocks. Then, they are simplified in order to decrease hardware components. Their simplification and the use of reduced compressors lead to high speed and considerable power and area savings. Synthesizable structural VHDL code is used to simulate and implement different multipliers. Our investigations show that the design with the reduced m:2 compressors and multilevel CLA is the most efficient multiplier. This paper also includes further comparisons with multipliers containing other structures and arrangements.

DESIGN AND IMPLEMENTATION OF CARRY SKIP ADDER USING AOI AND OAI

Carry-skip adder (CSKA) (another name for it is called as carry-bypass adder) is an adder implementation which helps on the delay of a ripple-carry adder with less effort when it is compared with rest of other adders. The accepted or followed structure of the CSKA consist the different stages containing chain relation of full adders (FAs) (RCA block) and 2:1 multiplexer. The RCA blocks are connected one to one by 2:1 multiplexers, which we can place in further level structures. The configuration of the CSKA (i.e., the number of the FAs per stage) plays a very important role on speed in the adder. Over the period of time, several methods have been proposed to optimize the number of FAs used. Here we are presenting a method based on AND-OR-Invert (AOI) and OR-AND-Invert (OAI) compound gates logic is used to replace the MUX logic being used in traditional design. The presented methodology is about the comparison of power, energy and delay parameters with other existing adders.

VLSI Implementation of High Speed & Low Power Multiplier in FPGA

We known that different multipliers consume most of the power in DSP computations, FIR filters. Hence, it is very important factor for modern DSP systems to built low-power multipliers to minimize the power dissipation. In this paper, we presents high speed & low power Row Column bypass multiplier design methodology that inserts more number of zeros in the multiplicand thereby bypass the number of zero in row & Column as well as reduce power consumption. The bypassing of zero activity of the component used in the process of multiplication, depends on the input bit data. This means if the input bit data is zero, corresponding row and column of adders need not be addition & transfer bit in next row and column adder circuit. If multiplicand having more zeros, higher power reduction can be achieved. At last stage of Row & column bypass multiplier having ripple carry adder which are increase time to generate carry bit to transfer next adder circuit. To reduce this problem by using Carry bypass adder in place of ripple carry adder, then new modification of Row &column multiplier having high speed in comparison to simple row & column bypass multiplier, , the experimental results show that our proposed multiplier reduces power dissipation & High speed overhead on the average for 4x4, 8x8 and 16x16 multiplier.

Area, Delay and Power Comparison of Adder Topologies

Adders form an almost obligatory component of every contemporary integrated circuit. The prerequisite of the adder is that it is primarily fast and secondarily efficient in terms of power consumption and chip area. This paper presents the pertinent choice for selecting the adder topology with the tradeoff between delay, power consumption and area. The adder topology used in this work are ripple carry adder, carry lookahead adder, carry skip adder, carry select adder, carry increment adder, carry save adder and carry bypass adder. The module functionality and performance issues like area, power dissipation and propagation delay are analyzed at 0.12 µm 6metal layer CMOS technology using microwind tool.