4-to-2 carry save adder using limited switching dynamic logic

摘要

A 4-to-2 carry save adder using limited switching dynamic logic (LSDL) to reduce power consumption while reducing the delay of outputting the sum and carry bits. The 4-to-2 carry save adder may include a first LSDL circuit configured to output a sum bit. The carry save adder may further include a second LSDL circuit configured to output a carry bit. Both the first and second LSDL circuits use a carry generated in the current stage that was previously generated in the previous stage (next lower order bit position). Since the carry is generated in the current stage and not in the previous stage, the delay in outputting the sum and carry bits is reduced and hence the performance of carry save adders is improved. Further, since LSDL circuits were used in the carry save adder, power consumption was reduced while using a small amount of area.