Approximate Carry Look Ahead Adder (CLA)for Error Tolerant Applications

In this paper, we propose power efficient approximate carry look ahead adder(CLA) for error tolerant application. Power dissipation has become a significant issue for integrated circuit. To reduce power consumption, inexact or approximate computing has been considered as a solution where exactness is not required. Here, new approximate CLA is proposed which is based on modified equation of carry propagation. The proposed 32-bit approximate CLA is evaluated and compared with an accurate CLA and existing approximate CLA based on power and delay. The metrics of error are used to evaluate the reability of the proposed approximate design. All circuits have been simulated in cadence virtuoso tool using 45-nm technology.