An energy harvesting wireless sensor node for IoT systems featuring a near-threshold voltage IA-32 microcontroller in 14nm tri-gate CMOS

A wireless sensor node (WSN) integrates a 0.79mm 2 near-threshold voltage (NTV) 32-bit Intel Architecture (IA) microcontroller (MCU) in 14nm tri-gate CMOS, along with solar cell, energy harvester, flash memory, sensors and Bluetooth Low Energy (BLE) radio, to enable always-on always-sensing (AOAS) and advanced edge computing capabilities in Internet-of-Things (IoT) systems. The MCU features four independent voltage-frequency islands (VFI), a low-leakage SRAM array, an on-die oscillator clock source capable of operating at sub-threshold voltage, power gating and multiple active/sleep states, managed by an integrated power management unit (PMU). The MCU operates across a wide frequency (voltage) range of 297MHz (1V) to 0.5MHz (308mV), and achieves a peak energy efficiency of 17pJ/cycle at an optimum supply voltage (VOPT) of 370mV, operating at 3.5MHz. The WSN, powered by a solar cell, demonstrates sustained MHz AOAS operation, consuming only 360µW.