Circuit and System Designs of Ultra-Low Power Sensor Nodes With Illustration in a Miniaturized GNSS Logger for Position Tracking: Part II—Data Communication, Energy Harvesting, Power Management, and Digital Circuits

A Wide Load Current and Voltage Range Switched Capacitor DC–DC Converter with Load Dependent Configurability for Dynamic Voltage Implementation in Miniature Sensors

“…RSI provides a differential input voltage (V H −V L ) to each SC stage, which can be configured with 2-bit control signals A n and B n . Through RSI, the next stage's high input V H(n) can be connected to the previous stage's high V H(n−1) or intermediate power supply (first stage output 1 2 V BAT ) or the previous stage's output V S(n−1) . Likewise, the next stage's low input V L(n) can be connected to the previous stage's low input V L(n−1) or ground node V SS or the previous stage's output V S(n−1) .…”

“…With the recent advancements in low power circuit design, packaging and battery technologies, the volumes of computing systems have been significantly reduced. With such a trend, numerous mm-scale miniature sensors have been demonstrated over the last decade [1][2][3]. These miniature sensors have been drawing attention since they can make traditional sensor systems more effective and energy-efficient.…”

“…However, the biggest concern for such miniature systems is the operation lifetime. Therefore, optimizing the use of energy stored in a battery is a key design goal for battery powered miniature sensor systems [1].…”

“…Miniature sensor systems are typically designed to spend most of their time in standby mode to minimize power consumption and maximize battery lifetime [1,2] but are periodically activated for short periods of time to perform their designated functions. During standby mode, the current consumption of such systems is on the order of sub-microamperes.…”

A High-Voltage Energy-Harvesting Interface for Irregular Kinetic Energy Harvesting in IoT Systems with 1365% Improvement Using All-NMOS Power Switches and Ultra-low Quiescent Current Controller

“…Kinetic energy harvesting has been drawing significant attention in recent years since it can potentially extend battery lifetime or even facilitate energy autonomy for battery-operated IoT systems or portable/wearable electronics [1,2,3]. For kinetic energy harvesting, energy harvesters with periodic excitations, such as cantilever-based piezoelectric energy harvesters, are widely studied since they generate regular periodic energy input, which allows the optimization of the harvesting interface circuit at the resonant frequency.…”