Area Reduction Technique for Digital Circuit Part in Non-Binary Analog-to-Digital Converter

Abstract

We propose an area reduction method of digital circuit part in β-expansion-based analog-to-digital converter (ADC). The digital parts of conventional β-expansion based ADCs use lookup table (LUT) to estimate effective β values, and to convert non-binary digital output from analog part to binary code. Unfortunately, increasing the conversion resolution (bit number) of the ADCs increases the chip area of the LUT. In this work, we estimate the effective β values by Newton's method and directly convert non-binary numbers to binary numbers without LUTs. As a result, when the conversion resolution of the ADCs is increased, the proposed method reduces the increase of the digital part area compared to the conventional LUT-based method.