Research Of Ternary Combinational Circuit Based On CNFET

A value of two signals(0, 1) is widely applied in the integrated circuit area, but it carries a little of information and increases the wiring area circuit. If use multiple valued logic circuit, we could reduce the area of circuit wiring and strengthen the ability of processing information in the area of digital circuit system. Multiple valued logic circuit carrys amount of information in each wiring, and has a small number of input and output pins and high density of information, so it not only improves the utilization circuit ratio of space and time, but also reduces production costs of integrated circuits. The multiple valued logic circuit mostly adopts two value elements,the circuit structure is complicated, high power consumption, so exploring the multiple valued logic low power circuit design is particularly important. Through research on the carbon nanotube field effect transistor(Carbon Nanotube Field Effect Transistor, CNFET) and the multiple valued logic circuit, the paper which uses the ternary logic as representative and uses combinational logic circuits as a goal, proposes a design method of three valued combinational logic circuit based on CNFET. Multiple-valued logic circuit improves information density and using CNFET model device reduce the power consumption of the circuit in the scheme. So it achieves the design goal of high information density and low power consumption of combinational logic circuit. The thesis contains the following parts:1 、 Switch-signal theory and design of ternary literal operation circuit: through researching on the switch-signal theory,we design the ternary gate circuits and operation circuits,which lay the foundation for designing further ternary combinational logic circuit.2、Design of ternary codec based on CNFET: through analysing the existing codec types and the structure of CNFET, we design the CNFET ternary codec with characteristics of switch signal theory and literal operation circuit which based on multiple valued logic circuits: 1T-2B codec, 2T-3B codec.3、Design of magnitude ternary comparator based on CNFET: according to the multi valued logic circuit design ideas and the working principle of the comparator, we design a two bit ternary numeric comparator with codec. Then combined with the multiple comparison principle, we design multi-bits ternary comparator based on the CNFET.4、Design of ternary SAR ADC based on CNFET: through analysing the ternary principle of successive comparator, the ternary capacitor array and multi beam decoder circuit, we eventually realize the ternary successive comparison of ADC which has ternary sampling and output.In order to verify the designed circuits, we use HSPICE to simulate their logic function. Then we analyze the power and speed of different combination circuit and ADC, and verify the characteristics of high speed and low power circuit.