Threshold Voltage Control to Improve Energy Utilization Efficiency of a Power Management Circuit for Energy Harvesting Applications

Abstract

This work presents a design approach that improves power management circuit (PMC) for energy harvesting applications so that more of the harvested energy can be utilized by the wireless sensor nodes (WSNs) to perform useful tasks. The proposed method is widely applicable to different circuits by setting an appropriate threshold voltage at the energy flow control interface of the circuit. Experimental results show that with a threshold voltage difference of around 20 mV, the energy output from the PMC can differ by more than 5%. This difference is significant over a long period of time as more tasks can be performed by the WSN with the extra energy.

Energy Harvesting in Smart Cities

“…Apart from the energy-aware approaches that make efficient use of the harvested energy before the capacitor voltage reaches the turn-off threshold, the turn-on threshold also requires attention. An improper choice on turn-on threshold voltage reduces the energy transfer from the DC-DC converter to the energy storage capacitor [65]. If the selected turn-on threshold voltage is very close to the maximum output voltage of the DC-DC converter, the energy transfer efficiency will reduce.…”

“…This process is undesirable for energy harvesting which usually has low power as it would make even less energy to be accumulated in the capacitor. Therefore, by setting the turn-on threshold lower than the voltage region where the DC-DC converter starts to regulate its output voltage, the harvested energy from the energy harvester can be transferred to the energy storage capacitor at higher efficiencies [65].…”

Energy Harvesting Powered Wireless Sensor Nodes With Energy Efficient Network Joining Strategies

“…The EAI keeps the wireless sensor node disconnected from the capacitor so that energy can be accumulated [20]. Once the capacitor voltage reaches 3.15 V, the EAI connects the node to the capacitor, which subsequently turns on the node [21]. The node stays active until the voltage drops to 2.25 V, and then the EAI disconnects the node from the capacitor again to allow the capacitor to be recharged to 3.15 V.…”