Energy Efficient Approximate 4:2 Compressors for Error Tolerant Applications

In many real-life applications such as image/video processing, the error present in the output will not impact the output visual information. Approximation at the hardware level is one of the promising techniques to design energy-efficient circuits. This paper proposes an approximate 4:2 compressor design to reduce partial products in the multiplier design. The proposed approximate 4:2 compressor design consumes on an average 56% less energy compared with the existing designs from the literature, respectively. This paper proposes two variants of the approximate multiplier designs, where design1 uses only proposed approximate 4:2 compressors and multiplier design2's lower half of the multiplier is designed using proposed approximate 4:2 compressor and higher half of the multiplier is designed using existing accurate compressors to reduce the error rate and improve the output image visual quality.