DESIGN OF A RELIABLE POWER SUPPLY SYSTEM FOR IOT TERMINALS IN HARSH ENVIRONMENTS

Abstract

To address communication interruptions and low energy efficiency caused by inadequate power-supply dynamic response in Internet of Things (IoT) terminals operating in harsh environments, this study proposes and implements a power supply system based on dynamic voltage regulation via an operational-amplifier (op-amp) adder. The system innovatively modifies the feedback network of a conventional switching power supply: an analog voltage output from the MCU's digital-to-analog converter (DAC) is summed with a fixed reference voltage to dynamically configure the feedback reference potential of a BUCK converter, thereby enabling continuous, high-precision regulation of the output voltage. A software algorithm dynamically computes and outputs the corresponding DAC value according to the real-time sleep, standby, and transmit states of the cellular module, allowing the supply voltage to adaptively switch between a minimum baseline voltage and a maximum allowable voltage. The voltage is lowered in low-power states to save energy, and raised before high-power transmission to optimize power-amplifier efficiency and prevent system crashes caused by line voltage drop. Experimental results show that the system effectively eliminates system restarts caused by power-supply droop and improves overall energy efficiency over a typical duty cycle, significantly enhancing device reliability and endurance under harsh power-supply conditions.