Flexible DC Triboelectric Generator with Associated Conditioning Circuit

This paper reports the design, fabrication, and testing of a direct current (DC) Triboelectric Generator (DC-TEG) based on flexible materials and topology. It offers a direct powering solution integrated within a single-substrate device topology with the prime advantages of high-output, low-cost, flexible, and compact design. This is in contrast with conventional DC-TEG topologies involving a mechanical rectifier, electrostatic breakdown, or dynamic Schottky junctions. The DC-TEG generates a unidirectional current with a substantially high peak to average ratio, which is inefficient in charging loads. It is integrated with a dc-dc converter which supplies regulated dc within the operation range of the driven load. Conventional dc converters either involve bulky inductors or a network of diodes and capacitors, which incur substantial voltage drop. In this work, we integrate the proposed DC-TEG device with a novel switched capacitor architecture involving active diodes as a replacement for standard diodes. The conditioned output charges the load capacitors to their saturation voltage of 5V within 2s of operation, the charging time being fairly independent of the load capacitor value. This proposed harvesting system shows promising applications as self-powered electronics, powering low-power IoT nodes for battery-less operation.