Design and Analysis of Energy-Efficient Single-Pulse Piezoelectric Energy Harvester and Power Management IC for Battery-Free Wireless Remote Switch Applications

Abstract

This paper presents a piezoelectric-based power management solution for battery-free wireless remote switches (BWSs). The proposed BWS IC, including a piezoelectric (PE) energy harvester and a buck converter, can collect the energy generated by a single PE-button press, and then supply that energy to a wireless transmitter to send a message. By combining a rectifier using the synchronized switch harvesting on inductor technique and a 6:1 series–parallel switched-capacitor converter, the proposed PE energy harvester can maximize the collected amount of energy, while supplying it at a low output voltage. In addition, by employing a switching-based start-up scheme and a variable ON-time pulse-frequency modulation scheme, the proposed buck converter can reduce the loss associated with charging the output capacitor during start-up, and then deliver the largest possible energy to the load, while maintaining low voltage ripples and high-power efficiency. A prototype BWS IC fabricated with high-voltage 250-nm CMOS technology was shown to be capable of harvesting a total energy of $246~\mu \text{J}$ from a single button-pressing of a 300-mm2 lead magnesium niobate-lead titanate PE disc. More than $200~\mu \text{J}$ was delivered to the load, sufficient to transmit a 4-B-long message via a 2.4-GHz wireless USB channel over a 10-m distance.