Design and implementation of reduced power energy efficient binary coded decimal adder

This paper presents a novel architecture for low power energy binary represented decimal addition. The proposed BCD adder uses Binary to Excess Six Converter (BESC) block for constant correction to adjusts binary outputs exceeding 9 to correct decimal values and exploits the inherent advantage of reduced delay and switching, due to elimination of long carry propagation in second stage addition as in conventional design and switching OFF of the BESC block for decimal outputs less than 9. The proposed BESC-BCD adder has been designed using VHDL code and synthesized using Altera Quartus II. Experimental results demonstrates that the proposed decimal adder can lead to significant power savings and delay reduction compared to existing BCD adders which is realised in better power-delay product(PDP) performance. For example the PDP saving of the proposed BESC-BCD adder for a 1 digit and 2 digit addition implementations are 11.6% and 16.05% respectively, compared to the best of the designs used for comparison.