Analysis of Circuit Configurations Suitable for Self-Supplied AC-DC Converters Using Thin-Film Piezoelectric Generators and Multilayer Energy Storage Supercapacitors

The improvement of microelectronic technologies and the practical application of some new materials has resulted in the realization of various highly efficient thin-film energy harvesters in the last few years. Self-powered supplies intended to work with thin-film harvesters have been developed. This type of power supply with integrated various thin-film harvesters has proven to be very suitable for providing electrical energy for wearable electronic sensor systems, with practical applications for implementing personalized medicine through continuously monitoring an individual’s state of health. The application of wearable electronics in medicine will become increasingly important in the next few years, as it can support timely decision-making, especially in high-risk patients. This paper presents a review and comparative analysis of the optimal circuit configurations used to design power supply devices with discrete and integrated components, obtaining electrical power from various thin-film piezoelectric generators, and storing electrical energy in low-power multilayer supercapacitors. Based on an analysis of the principle of operation of the selected circuit configurations, analytical expressions for the basic static and dynamic parameters have been obtained, taking into account the peculiarities of their integration with the biomedical signal processing system. Advantages and weaknesses are analyzed through simulation testing for each configuration, as the prospects for improvement are outlined. Also, for each group of circuit configurations, the key parameters and characteristics of recent high-impact papers, especially those focusing on low-power applications, are presented and analyzed in tabular form. As a result of the analysis of the various circuit configurations, some analytical recommendations have been defined regarding the optimal selection of passive and active elements, which can contribute to a better understanding of the design principles of battery-free power supplies converting electrical energy from some specific recently developed thin-film energy harvesters.