Study Of Asynchronous Circuits Design Methodology

With the feature sizing shrinking and the increasing in circuits'complexity, synchronous design techniques exhibit increasing disadvantages and limitations in designing manufacturing and application. Asynchronous design method has become the research hot spot in the field of the SOC design. To achieve the final aim of designing an asynchronous system, in this thesis, the combination of asynchronous techniques and synchronous techniques, asynchronous circuits design, and the combination of asynchronous techniques and adiabatic techniques are studied.An improved point-to-point interface design method for Globally Asynchronous Locally Synchronous techniques is introduced. The disadvantages of the common point-to-point interface are analyzed. And a new point-to-point design with unsymmetrical structure for increasing the speed of data communication is introduced, then the theoretical analysis is completed, and also the circuits implementation and layout implementation are achieved. And simulation result of the design implementation based on layout is presented.A new scheme of multi-point connection for Globally Asynchronous Locally Synchronous techniques is introduced. The advantages and disadvantages of common schemes are analyzed. Based on the analysis, a new ring bus scheme is introduced. The new scheme is superior to the common ones both in energy utilizing and time utilizing. And a new solution to null data packages with small hardware addition is presented. The solution makes the new ring scheme become robust.The function and purpose of basic control element in asynchronous are described. And the multi-input control element design is presented. The influence of each part's parameter to the characters of the circuit is analyzed in detail. And the strategy of how to adjust the parameter to fit different requirements is introduced. At last, the simulation result based on the layout is exhibited.The classification and functions of asynchronous arbiter are presented. The advantages and disadvantages of each kind of implementation style of tree arbiter are analyzed. A new design of tree arbiter aimed at the problems of design and applications is introduced. The robust character of the design is analyzed based on theory. The simulation result aimed at the fault condition is exhibited. And the validity of the design is approved. At last, the layout of the design and simulation result is exhibited.The importance of adder design in circuit design and several kinds of improved synchronous adder designs are presented. And the advantages as well the disadvantages of each improved design are analyzed. Also introduced in this thesis are several new designs of adder with asynchronous techniques, with higher speed but less hardware cost. The designs'characters, advantages and disadvantages are analyzed in detail, and the reason why the improved synchronous method can not be directly applied to asynchronous design is described. Then, the comparisons between the asynchronous adders and the synchronous counterpart are exhibited.The characters of asynchronous techniques and adiabatic techniques in low power field is presented. And the collision of them is analyzed. A new design method for low power that combines asynchronous with adiabatic techniques is introduced in this thesis. The new method is not only simple and easy to construct and analyze as the asynchronous design, but also has the character as adiabatic design that consumes lower power than asynchronous design. A hybrid adder is implemented as an example. The comparison of simulation results between the asynchronous adiabatic hybrid adder and the asynchronous adder is exhibited. The comparison improves the validity of the hybrid design method. And the shortage of the method is described in the thesis.