Event Driven Time-logging System based on Continuous Operation of Real Time Clock towards Perpetual Electronics

Abstract

This paper presents a novel time logging system using a real time clock (RTC) powered by a vibrational energy harvester to record the time of events when piezoelectric PVDF film as an event-driven sensor is activated. The power-management circuit normally remains in the sleep mode to cut power supply to the micro-processor and the ferroelectric random access memory. On the other hand, the RTC alone is powered by a battery to keep the time by seamless operation, which lowers the standby power consumption as small as 231 nW. As the PVDF film generates power, the developed power management circuit can supply load current upwards of 8 mA at 3.3 Vdc for external circuit to record the time of events with the energy consumption of 467 μJ.