Е-Публикации
Технически университет - София

Abstract: This paper presents the structure and operational principle of a low-power AC-DC conversion circuit prototype for wearable battery-free power supply devices. The proposed circuit configuration is intended to use a multilayer piezoelectric module as a source of electrical energy, which converts spontaneous mechanical vibrations into piezoelectric voltage. The electrical energy produced after conversion with a bridge rectifier is used to charge two series-connected low-power supercapacitors. For the proposed prototype, a synchronous step-down low-power DC-DC converter is implemented and tested. The power control system for the converter is realized with PWM and a non-inverting error amplifier with a frequency compensator. As a result of the operation of the converter, a DC output voltage of 1.2V and a maximum output power of 2.4mW is established. The coefficient of overall energy efficiency achieved up to 82% at a power dissipation not greater than 20µW. A printed circuit board is designed and implemented on standard FR-4 material and a flexible substrate to verify the prototype's efficiency.

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