An autonomous piezoelectric energy harvesting IC based on a synchronous multi-shots technique

This paper presents a fully autonomous integrated circuit (IC) dedicated to piezoelectric harvesters. The IC implements a novel Synchronous Electric Charge Extraction (SECE) technique which optimizes the energy transfer from a highly charged piezoelectric harvester to a low voltage storage element. The system deals with piezoelectric powers in the range of 10 μW to 1mW and handles very high piezoelectric voltage values (>100V) limited by the off-chip components around the IC. The IC has been fabricated in AMS 0.35 μ m3.3V technology and its low power consumption (1 μW @ 5Hz) is particularly suitable for low frequency harvesters. The Multi-Shots SECE (MS-SECE) technique implemented in the IC increases the efficiency by up to 25% compared to a standard SECE technique and allows the use of small off-chip components. An efficiency of 61% has been reached with a 125mm³coupled inductor @ 40V. Moreover, the complete system self-starts and works without any battery.