Application of Precision Successive-approximation-register Analog-to-digital Converters for Digital Root-mean-square Calculation

Abstract

The advancement of semiconductor manufacturing processes has allowed for the availability of powerful microcontrollers at lower costs, granting system designers the flexibility to select between analog and digital signal processing techniques. Enabled by recent developments in low-power successive approximation register (SAR) analog-to-digital converter (ADC) technology, a digital approach to root-mean-square (RMS) measurement is proposed. The work begins with an explicit accumulation and averaging approach, and a set of improvements were designed to increase measurement accuracy and reliability. Algorithms are compared using the metrics of error, power efficiency, latency, and digital overhead. High-performing and power-efficient digital RMS measurement methods could be valuable for decentralized instrumentation systems such as smart grids and factory automation where long-lasting handheld and portable solutions are becoming critical.