Area-sharing cyclic structure MRF cirucits design in ultra-low supply voltage

Abstract

Feedback structure is an efficient topology for noise-reducing in analog circuit while the cyclic circuit has been widely used in digital circuit only to establish sequential circuits due to its data-keeping property. The Markov Random Field (MRF) based circuit is proposed with feedback structure from the point of energy, which has high noise-immune property in ultra-low supply voltage. However the MRF-based elements have complex structures which have almost 20 times area compared to traditional units. In this paper we propose area-sharing feedback NAND path based on the MRF circuit which not only can reduce about 60% of area and complex for MRF element but also has 3dB performance of noise tolerant improvement compared to traditional CMOS NAND. Then we provide area-sharing feedback NOR-NAND path for multifunction calculating with the case study of half adder and 8-bits ripple carry adder, which has about at least 4 dB for output bits performance improvement compared to CMOS half adder and 84.2% energy saving at the 0.25V supply voltage compared to original MRF adder.