A 2.4μW input power electronic interface circuit for piezoelectric MEMS harvesters

Piezo-electric harvesting systems have proved to be a promising alternative to batteries for supplying portable devices. Recent trends focus on the reduction of the size of piezo-electric transducers through the development of nanostructured materials which exhibit output power levels in the order of few microwatts as well as maximum open voltage sources lower than 2 V. In this paper, we propose a circuit which combines the technique of Synchronous Electric Charge Extraction with negative voltage conversion and a peak detector with a resolution of hundreds of millivolts, and is able to harvest down to 2.4 μW input power. Moreover, the circuit features a start-up phase of about 200 ms, much faster than that with a single storage element, by means of two separate storage elements.