Reversible logic gate

This is a simple presentation about Reversible logic gate

1. REVERSIBLE LOGIC GATES Debraj Maji Roll NO.:- 1020133200320020 Reg. NO. :- KNU18001208 Session :- Semester IV

2. CONTENT

3. INTRODUCTION Designing of a complex digital system which dissipates low power is a competitive topic in the research field of hardware design. Heat dissipation in the circuit has become the critical limiting factor. In 1960 Rolf Landauer introduced that Losing One bit of information create heat dissipation of KTln2. According to Moore’s law the numbers of transistors will double every 18 months . In 1973 Bennett said that we can avoid the loss of this energy by using Reversible Logic gate.

4. WHAT IS REVERSIBLE LOGIC GATE? The input vector can be uniquely recovered from the output vector. There is a one-to-one correspondence between its input and output assignments, i.e. not only the outputs can be uniquely determined from the inputs, but also the inputs can be recovered from the outputs Have as many input wires as output wires. There is no fan-out.

5. + 2 2 4 Continue 1 3 1+3=2+2=3+1=4+0=5+(-1)=4

6. Continue A B A.B 1 1 1 1 1 A B A+B 1 1 1 1 1 1 1

7. + +- X Y X+Y X-Y 8 2 3 5 X+Y=8 X-Y=2 Continue

8. Continue Q P U P Q U + U U + =U + U=I x C C(x) x C(x) R Garbage

9. SOME DEFINATION OF REVESIBLE LOGIC GATE Garbage Output : Additional inputs or outputs can be added so as to make the number of inputs and outputs equal whenever necessary. This also refers to the number of outputs which are not used in the synthesis of a given function . Constant Inputs : This refers to the number of inputs that are to be maintain constant at either 0 or 1 in order to synthesize the given logical function. Input + constant input = output + garbage . Quantum Cost : It refers to the cost of the circuit in terms of the cost of a primitive gate

10. Continue Flexibility : Flexibility refers to the universality of a reversible logic gate in realizing more functions . Gate Level : This refers to the number of levels in the circuit which are required to realize the given logic functions . Hardware Complexity : This is refers to the total number of logic operation in a circuit. It means total number of AND, OR and EXOR operation in the circuit

11. SOME REVERSIBLE LOGIC GATES 1. NOT Gate : The Simplest Reversible gate is NOT gate and it is a 1*1 gate. The Reversible 1*1 gate is NOT Gate with zero Quantum Cost A P=A’ NOT GATE A A’ A P 1 1

12. Continue 2. cNOT Gate : C NOT gate is also known as controlled-not gate. It is a 2*2 reversible gate. A B P = A Q = A  B CNOT GATE A P = A B Q = A  B A B P Q 1 1 1 1 1 1 1 1

13. Continue 3 . DOUBLE FEYNMAN Gate : It is a 3*3 Double Feynman gate. The input vector is I (A, B, C) and the output vector is O (P, Q, R). A P = A B C Q = A  B R = A  C DOUBLE FEYNMAN GATE A B C A A  B A  C A B C P Q R 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

14. A B C P = A  B Q = B ’ C  AC ’ R = BC  AC ’ NFT GATE V + V V A B C BC  AC ’ B ’ C  AC ’ A  B Continue 4 . NFT Gate : It is a 3x3 gate and its logic circuit and its quantum implementation is as shown in the figure. It has quantum cost Six. A B C P Q R 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

15. Name Block Diagram Symbol Type Toffoli Gate 3*3 Fredkin gate 3*3 Peres Gate 3*3 TR Gate 3*3 Continue B C Q = B R = AB  C A P = A B C B AB  C A A A B C P = A Q = A’B  AC R = A’C  AB B C A’B  AC A’C  AB A A A B C P = A Q = A  B R = AB  C AB  C A  B A A B C A B C P = A Q = A  B R = AB ’  C AB ’  C A  B A A B C V + V V

16. Continue Name Block Diagram Type TSG Gate 4*4 DKG Gate 4*4 SBV Gate 5*5 BSCL Gate 6*6 A B C D P = B Q = A ’ C+AD ’ S= B  C  D R= (A  B) (C  D)  CD A B C D P = A Q = A ’ C ’  B ’ R= (A ’ C ’  B ’ )  D S= (A ’ C ’  B ’ ).D  (AB  C)

17. APPLICATION Computer security . Transaction processing . Field Programmable Gate Arrays (FPGAs) in CMOS technology . The design of low power arithmetic and data path for digital signal processing (DSP ). Low power CMOS Quantum computer .

18. Continue Nanotechnology. Optical computing . DNA computing . Computer graphics . Communication .

19. CONCLUSION I have presented an approach to the realize the multipurpose binary reversible gates. Such gates can be used in regular circuits realizing Boolean functions. In the same way it is possible to construct multiple-valued reversible gates having similar properties. The proposed asynchronous designs have the applications in digital circuits like a Timer/Counter, building reversible ALU, reversible processor etc. This work forms an important move in building large and complex reversible sequential circuits . reversible logic gates holds a great significance to the realization of the more complex and systematic reversible circuits with reduced power consumption and loss of information bits.

20. REFERENCES