Energy efficient single-ended 6-T SRAM for multimedia applications

Abstract

Image processing and other multimedia applications require large embedded storage. In some of the earlier works approximate memory has been shown as a potential energy-efficient solution for such error-tolerant applications. In this paper, we propose a single ended 6-T (SE6T) SRAM cell which has about 50% less dynamic power compared to conventional 6-T SRAM cell with the same bit error rate(BER). Since image processing applications are tolerant to errors, ultra low voltage power-efficient embedded memories with BER can be used for storage. We show that 1 KB (256x32) SE6T memory consumes 0.45× dynamic power, 0.83× leakage power and takes 0.60× area as compared to conventional 6T SRAM memory for similar peak signal to noise ratio (PSNR). We have also proposed heterogeneous SE6T 1K SRAM memory and show that for a given power budget, PSNR enhances by at least by 14 dB compared to when homogeneous (identically sized bit-cells) SE6T SRAM memory are used. When compared with heterogeneous 6T SRAM memory, the heterogeneous SE6T SRAM memory consumes 0.44× dynamic power, 0.86× leakage power and takes 0.6× area for almost similar PSNR. For a given PSNR, the SE6T memory is cumulatively better in terms of design complexity, area and power when compared with other hybrid and heterogeneous approximate memories.