Research On Memristor Based Logic Circuits

The memristor is a nonlinear resistance element with memory function,whose mathematical model is represented by the ratio of flux to the rate of change of charge amount.The resistance of memristor will change according to the change of the amount of electric charge that flows through itself.The resistance will remains the previous state when no current flow throuth,therefore it has memory characteristics.If a different control voltage is applied at both ends of the memristor,the resistance will be converted between the high impedance state and the low impedance state,which can be used to simulate the switching state of the traditional CMOS transistor,constructing the logic circuit of the memristor,and replacing the transistor to realize the state logic calculation.Based on the theory of memristor state logic proposed by HP Labs,this paper uses a threshold bipolar memristor SPICE model to build a memristor series-parallel circuit to analyze the series-parallel characteristics of memristor.Then,a memristor logic gate circuit is designed by using memristor series-parallel circuit,and the method of realizing logic gate circuit using memristor is explored.Finally,a hardware circuit is constructed to form a binary memristor,which verifies the logic function of the designed logic gate circuit.The main contents of this paper are as follows:(1)The state logic circuit presented by HP Lab can realize arbitrary boolean logic operations based on the state logic of implication operations.This paper studies the realization method of logic gate circuits based on implication operations,analyzes the influence of logic circuits design method of implication operations on the logic gate circuits constructed by threshold type memristor,and introduces and evaluates the design method of logic circuits of implication operations.(2)The characteristics of threshold memristor,mem R_TH,are studied.A series-parallel circuits of memristor is built.Whether or not the equivalent memristor meets the compact hysteresis characteristics is analyzed in the case of series and parallel circuits of memristor with different polarity.The simulation results show that a series of memristor,whether series or parallel connection,even if the polarity is different,its equivalent memristor circuit still meet the tight hysteresis characteristics.(3)The use of memristor's high and low resistance characteristics can be achieved logic gate circuits,and the future can replaces the traditional CMOS transistor circuits for logic calculations in the future.In order to study the characteristic and implementation method of the memristor logic gate circuit,the threshold bipolar memristor is used to construct three basic logic gate circuits,such as AND gate,NOT gate,NOR gate,NAND gate and NOR gate combined the logic gate circuits,then to explore the voltage range that can realize these five boolean functions,and to verify the logic function of the circuits by SPICE simulation.Finally compared with the design method of logic gate based on implication operations to illustrate the necessity of designing logic circuits based on threshold memristor.(4)In order to further verify the correctness of the logic circuits implemented by the thresholdtype memristor,a memristor hardware emulation circuits with memory characteristics is designed.The circuit is used to construct a binary memristor to realize the NOT gate logic circuit,it is proved that the exprimental results of the NOT gate logic circuit are consistent with the simulation results.The experimental results show that the experimental results of the NOT gate logic circuits built using the hardware circuit are consistent with the simulation results,and prove that the logic function of the NOT gate logic circuit is correct.