High-accuracy low-power energy metering chip without external crystal

This paper presents an innovative low-power energy metering chip without external crystal clock. By extracting the information of the serial control interface with the external host MCU, the chip is able to calibrate the internal RC clock to achieve active and reactive energy metering accuracy of 0.1% with a dynamic range of5000:1. Also by using interpolation, the chip realizes high — accuracy phase measurement without much power dissipation penalty. The power dissipation of the chip is the lowest compared to all competing products. The chip can be used in both single-phase and poly-phase energy meters. It is currently in production.