The Research On Negative Differential Resistance Characteristic Circuit

Nowadays,resonant tunneling diode(RTD)has attracted wide attention due to its high frequency,high speed and low power consumption.Its unique I-V characteristic curve makes it very advantageous in circuit design.Using its negative differential resistance(NDR),RTD has many applications in the fields of oscillator,logic circuit,wireless communication and neural network.Firstly,the RTD modeling is studied,and the influence of each parameter on the characteristic curve of the model is analyzed.In view of the local hysteretic characteristics of RTD in the negative resistance region,this paper utilizes the NDR negative resistance characteristics of RTD and its unstable working characteristics in the negative resistance region,and then constructs a RTD switching unit circuit with hysteretic characteristics.The characteristics of high and low resistance state,hysteresis and threshold voltage of the circuit are analyzed.Compared with the local hysteresis characteristic of RTD,the hysteresis curve of RTD switching unit circuit has a wider range,which makes it more convenient to use in the design of multi-valued logic circuit,and the threshold voltage which can be controlled makes it more flexible to use.In addition,the hysteresis curve of RTD switching unit circuit is very similar to that of complementary switching memristor,but due to the limitation of negative resistance network,the hysteresis curve can only be generated under positive voltage.Then,in order to improve the circuit of RTD switch unit,this paper further improves the original NDR negative resistance network structure,uses symmetrical structure to build a bidirectional NDR negative resistance network,and designs a memristor based on NDR negative resistance characteristics.Based on this,a memristor based on the negative resistance characteristic of NDR is designed.By using different NDR negative resistance networks,several kinds of negative resistance characteristic memristors with different hysteresis curves are built,which have adjustable threshold voltage and rich resistance characteristics,and are very suitable for digital circuit design.In addition,the actual circuit of R-HBT-NDR structure memristor is built,and the feasibility of the design is proved by experiments.Finally,in this paper introduces the design methods of RTD and memristor's basic logic gates respectively.Through the similar properties of RTD and memristor,combined with their design methods,an improved logic gate design method based on memristor is proposed.It is different from the "substantial implication" state logic circuit design proposed by HP Labs.It uses level input and output compatible with current digital circuit design.Based on this,a binary programmable logic circuit of memristor is designed.Through different control signals,the circuit can produce different logic functions.