A Fast FPGA-Based BCD Adder

Abstract

The binary-coded decimal (BCD) being the more accurate and human-readable representation with ease of conversion is prevailing in the computing and electronic communication. In this paper, a tree-structured parallel BCD addition algorithm is proposed with the reduced time complexity $$O(N(\log _2b)+(N-1))$$ , where N = number of digits and b = number of bits in a digit. BCD adder is more effective with a lookup table (LUT)-based design, due to field programmable gate array (FPGA) technology’s enumerable benefits and applications. A size-minimal and depth-minimal LUT-based BCD adder circuit construction is the main contribution of this paper. The proposed parallel BCD adder gains a radical achievement compared to the existing best known LUT-based BCD adders. The proposed BCD adder is coded in VHDL and implemented in a Virtex-6 platform targeting XC6VLX75T Xilinx FPGA with a $$-3$$ speed grade by using ISE 13.1. The proposed BCD adder provides prominent better performance with 20.0% reduction in area and 41.32% reduction in delay for the post-layout simulation. Since the proposed circuit is improved in both area and delay parameter, it is 53.06% efficient in terms of area-delay product compared to the best known existing BCD adder, which is surely a significant achievement. Moreover, the proposed design consumes 34.28% less power in comparison with existing best known approach at a clock frequency of 200 MHz and a reference voltage of 5 V.