IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-ISSN: 2278-2834,p- ISSN: 2278-8735.Volume 11, Issue 2, Ver. III (Mar-Apr .2016), PP 33-39 www.iosrjournals.org DOI: 10.9790/2834-1102033339 www.iosrjournals.org 33 | Page Performance Analysis and Hardware Implementation of Digital Circuit Design Using Reversible Logic Ms. Sahyadri J. V. 1 ,Mr.Kotresh E. Marali 2 1 P.G. Student 2 Assistant Professor ECE Department SDM College of Engineering and Technology, Dharwad Abstract: Reversible logic approach of designing is gaining its attention by researchers due to its characteristics of dissipating less power. Reversible logic technology do not erase information hence no heat dissipation. In this paper,various reversible combinational and sequential circuits are proposed such as Multifunction Generator, 4-bit Full/Subtractor, 4-bit Fast carry chain adder and 4-bit asynchronous counter by the proposed reversible T-flip flop.The proposed circuits hasbeen designed for low power, less area and high speed based on the designs, also multifunction generator with zero garbage output can be seen. The power, speed and area parameters for the circuit have been indicated, and compared with their conventional non- reversible counterparts. The comparative statistical study proves that circuits employing Reversible logic thus are more efficient. The designs presented in this paper were simulated using Xilinx 14.2 software. Key Terms: Low Power, Less Area,High Speed, Reversible design. I. Introduction Reversible logic is widely used in low power VLSI applications. Landauer showed that combinational logic circuits dissipate heat of the order of KT In2 joules [1] for every bit of information that is lost. As Reversible circuits are capable of back-computation andthere is no loss of information,we find reduction in dissipated power with higher speed and higher density. Any circuit is said to be reversible if there exists a unique output for each input i.e., number of inputs must be equal to number of outputs, making it logically reversible. And an operation is said to be physically reversible if it converts no energy to heat and produces noentropy. A logic circuit is said to be reversible, if there is one-to-one correspondence between inputs and outputs with no loss of information. This permits the system to run backwards and while doing so, any intermediate design stage can be comprehensively examined. The fan-out of reversible logic circuit has to be one and only one. In any reversible design garbage outputs and number of reversible gates are two of the importantdesign parameters which must be as minimum as possible. To evidence this multifunction generator[2]which is able to change its function in an expected, controllable and required way, is been proposed with no zero garbage outputs, less number of reversible gates using reversible logic. Secondly in any digital system, adder and subtractorblock, flip-flop or Counterare the most essential one. And an integration of these blocks becomes essential sometimes thus; full adder/subtractor isused in most digital systems. In the present day consequence, technology scaling is believedto be at its greater summits and further scaling leads to lots ofcomplexities. Hence, there is a need for a low power circuits with optimized area and high speeds. Reversible logic is one of the answers forthe above problem which is evolving as a performance substitute for conventional logic. Thus to substantiate, a new 4-bit reversible full adder/subtractor,4-bit fast carry chain adder[3] and 4-bit asynchronous ripple counter[4]is proposed using reversible logic that are performance efficient with respect to power, area and speed[1]. II. Reversible Logic A Boolean logic is supposed to be reversible if, the following conditions are encountered [5] 1. Condition 1 A reversible logic gate must have some features such as equal number of input and output signals, one to one mapping between inputs and outputs that has been entitled as “ Bi-jective Conditions” 2. Condition 2 From the total number of input combinations, half of its input combinations must have an output equal to 1, entitled as “Balance Conditions”. 3. Condition 3 By inversing output, we must be able to reproduce mapped input entitled as “Inversing Conditions”. The important design constraints for reversible logic circuits are stated below [5]