The Memristor Based Combinational Logic Circuit

Moore's law is being challenged by the limitations of transistors in physical materials,energy consumption,performance,and economics.One of the many ideas proposed to continue Moore's law is the search for smaller devices to replace CMOS transistors.Chua came up with the definition of the memristor 50 years ago,but it wasn't until 2008 that the first memristor was discovered.Memristor is a nano memory device with two(or more)different resistance states,RON and ROFF(corresponding to binary logic states of "1" and "0").Based on the nonvolatile and binary characteristics of memristor,a new type of nonvolatile memory can be designed,a new type of logic operation circuit can be developed,and a new type of computer architecture integrating storage and operation can be realized.This paper mainly studies the design of memristor basic logic gate and combined logic circuit.The main contents are as follows:(1)Based on the basic theory of memristor,the linear drift model for HP memristor and the general model are studied.Through the LTSPICE simulation,the characteristics of different theoretical models in the practical circuits are tested,and optimal memristor model is found for combinational logic circuit design.(2)This paper studies the Material Implication(IMPLY),gives the basic gate circuits based on the IMPLY and the method to solve the fanout problem,and construct the XOR/NXOR gate based on it.This paper studies the Memristor Aided Logic(MAGIC)and gives the basic gate circuit based on the MAGIC.This paper studies Memristor Ratioed Logic(MRL),designs an XOR gate based on the basic gate circuit of MRL,and designs a simple 1-bit half-adder according to the XOR gate.Through these design ideas,the theory is laid for the design of later combinational logic circuit.(3)Based on MRL,a new type of NOT,NOR,"A and not B" MRL gate is designed.A single MRL gate circuit needs at least 2 memristors and 2 CMOS transistors,while the new MRL gate circuit requires only 1 memristor and 1 NMOS.In order to compare the advantages and disadvantages of the two methods,two one-bit numerical comparators are designed respectively based on the two kinds of MRL gates.After comparative analysis,it is found that the new MRL circuit can significantly reduce the number of memristors and CMOS.Furthermore,a new multi-function logic module is designed based on the new MRL.The multi-function module uses only 5 memristors and 1 NMOS transistor to realize the functions of XOR and AND.Compared with other XOR circuits,the new multi-function module proposed in this paper can save more memristors and CMOS devices than traditional XOR gates.(4)The new MRL method is used to design 3:8encoder,8:3decoder,4:1multiplexer and 2 bit multiplier.The new multi-function module is used to design 1 bits full adder,4 bit numerical comparator and 2 bit multiplier.The performance of the MRL circuits are compared and analyzed by LTSPICE simulation.The results show that the logic circuits designed in this paper have low power consumption,small delay and few components.