An ultra-low power power management unit with −40dB switching-noise-suppression for a 3×3 thermoelectric generator array with 57 maximum end-to-end efficiency

摘要

A high efficiency, dynamically adaptable Power Management Unit (PMU) consuming less than 3μW, for an energy harvesting system based on a thermoelectric generator (TEG) array is presented. A boost converter with a cascaded low drop-out (LDO) voltage regulator comprises the proposed PMU. The design approach allows the PMU to reach maximum power transfer by matching the TEG's dynamic series resistance and simultaneously provide adaptive switching noise rejection. The boost converter's switching frequency (f) is tracked via a background sense-and-control loop which modifies the LDO's power supply rejection (PSR) characteristics to place a notch around the average f. Overall system efficiency is better than 57%, and PSR of −40dB at f are achieved. The total active area is 0.93 mm in 0.5 μm CMOS.