Design & Implementation of High Dynamic Range Current Measurement System for IoT Applications

Internet-of-Things (IoT) devices have a strict necessity for power consumption to achieve the expected battery life. Therefore, measuring and optimizing the energy consumption of IoT nodes are essential. IoT nodes feature extreme current consumption range over {\mathrm {100}}~\text {dB} between their operating modes. The main focus of this article is to design and implement a low-power and low-cost current measurement circuit, which can be integrated into IoT nodes. A new pass element is introduced for measuring the current consumption. This element is placed in the current path to measure current over a high dynamic range with a constant voltage drop. The introduced pass element consists of a capacitor and analog switches. The current consumption is measured based on the charge and discharge times of the capacitor in the specified period of time. The voltage across the pass element is buffered and fed to a low-power microcontroller. The proper operation of the proposed circuit is verified numerically with simulations and experimental measurements. The implemented current measurement circuit offers a load regulation of 0.23%, a dynamic range of {\mathrm {173.98}}~\text {dB} , and a linearity error of 0.522%. It is expected that the proposed system provides clear information on the power behavior of IoT devices, which can be used for power optimization of IoT networks and self-power test equipment.