Autonomous Self-Powered Bias-Flip Rectifier with On-Chip Flip Switch Timing Controller for Piezoelectric Energy Harvesting

Abstract

This paper presents an autonomous bias-flip rectifier (BFR) integrated with an on-chip flip switch timing controller (FSTC) designed for piezoelectric energy harvesting. The proposed FSTC utilizes a pulse-width modulation (PWM)-based feedback loop that automatically calibrates the switch control pulse width, thereby eliminating the need for post-fabrication trimming and allowing the circuit to adapt to component variations. Implemented in a 0.18-μm CMOS process, the circuit achieves fully autonomous operation and can successfully cold-start from a piezoelectric harvester’s open-circuit voltage of 2 V. Measurement results confirm that the FSTC effectively optimizes the bias-flip timing, thereby maximizing the harvested power. Compared to an ideal full-bridge rectifier (FBR), the proposed BFR achieves up to 3.2× higher output power. These results demonstrate the effectiveness of the proposed on-chip automatic calibration architecture in realizing high-efficiency and cost-effective vibration energy harvesting systems.