Energy-Efficient Reconfigurable Approximate Carry Look-Ahead Adder (Rap-Cla) Using Xilinx

Dalu. Rakesh, Sk. Fairoze


In this paper, we propose a fast yet energy-efficient reconfigurable approximate carry look-ahead adder (RAP-CLA). This adder has the ability of switching between the approximate and exact operating modes making it suitable for both error-resilient and exact applications. The structure, which is more area and power efficient than state-of-the-art reconfigurable approximate adders, is achieved by some modifications to the conventional carry look ahead adder (CLA). The efficacy of the proposed RAP-CLA adder is evaluated by comparing its characteristics to those of two state-of-the-art reconfigurable approximate adders as well as the conventional (exact) CLA. The results reveal that, in the approximate operating mode, the proposed 32-bit adder provides better delay and power reductions compared to those of the exact CLA, respectively, at the cost of low error rate. It also provides lower delay and power consumption, respectively, compared to other approximate adders considered in this work. Finally, the effectiveness of the proposed adder on two image processing applications of smoothing and sharpening is demonstrated. The proposed architecture of this paper analysis the delay and area using Xilinx 14.3.

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