A Multi-Beam Shared-Inductor Reconfigurable Voltage/SECE Mode Piezoelectric Energy Harvesting Interface Circuit

Area of Science:

• Electrical Engineering
• Biomedical Engineering
• Materials Science

Background:

• Energy harvesting from ambient sources like human motion is crucial for powering autonomous systems.
• Piezoelectric energy harvesters (PEHs) offer a promising solution but face challenges with variable output and impedance matching.
• Existing power management circuits often struggle with low-voltage inputs and efficiency under dynamic conditions.

Purpose of the Study:

• To develop an autonomous, multi-input power management chip for efficient energy harvesting from multi-beam piezoelectric harvesters (PEHs).
• To enable adaptive operation in voltage-mode or synchronous-electrical-charge-extraction-mode (VM-SECE) for optimal energy extraction.
• To enhance robustness against varying PEH characteristics and protect the chip from large input surges.

Main Methods:

• Designed and fabricated a reconfigurable power management chip using a 0.35-μm CMOS process.
• Implemented an adaptive VM-SECE strategy for efficient energy harvesting.
• Integrated an active negative voltage converter for low input voltages (down to 35 mV) and an active voltage doubler for cold-start.
• Tested the chip with commercial single-beam and custom 5-beam PEHs under various conditions.

Main Results:

• The VM-SECE chip harvested 3.28x more power than a full-wave active rectifier (FAR) with shock inputs.
• For a 5-beam PEH under pseudo-walking conditions, the chip achieved 1.59x and 2.38x higher harvested power for 1-beam and 5-beam operations, respectively.
• The chip demonstrated efficient operation across varying PEH impedance, voltage, and frequency.

Conclusions:

• The proposed autonomous power management chip significantly enhances energy harvesting efficiency from multi-beam PEHs.
• Adaptive VM-SECE operation is effective in maximizing power capture from variable and weak human motion sources.
• The chip's design offers a robust and efficient solution for powering autonomous devices using piezoelectric energy harvesting.