a b s t r a c tIn this paper, we propose the development of superconductive combinational logic circuits. One of the difficulties in designing superconductive single-flux-quantum (SFQ) digital circuits can be attributed to the fundamental nature of the SFQ circuits, in which all logic gates have latching functions and are based on sequential logic. The design of ultralow-power superconductive digital circuits can be facilitated by the development of superconductive combinational logic circuits in which the output is a function of only the present input. This is because superconductive combinational logic circuits do not require determination of the timing adjustment and clocking scheme. Moreover, semiconductor design tools can be used to design digital circuits because CMOS logic gates are based on combinational logic. The proposed superconductive combinational logic circuits comprise a magnetically coupled SQUID array. By adjusting the circuit parameters and coupling strengths between neighboring SQUIDs, fundamental combinational logic gates, including the AND, OR, and NOT gates, can be built. We have verified the accuracy of the operations of the fundamental logic gates by analog circuit simulations.
This paper presents the implementation of a 4-bit Arithmetic Logic Unit (ALU) using Complementary Energy Path Adiabatic Logic (CEPAL). This static adiabatic logic has proved its advantage through the minimization of the 1/2CVdd2 energy dissipation occurring every cycle. Firstly, the performance characteristics of CEPAL 4-to-1 multiplexer and full adder are compared against the conventional static CMOS logic counterpart to identify its adiabatic power advantage. Finally, A 4-bit Arithmetic Logic Unit (ALU) is implemented with both the technologies and comparisons have been made. The analysis is carried out using the industry standard EDA design environment using 250 nm technology libraries from Tanner. The results prove that the CEPAL 4-bit ALU is 55% more power efficient than the CMOS 4-bit ALU at 100MHz and at 2.5V operating voltage.
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