Forward-Zero Cycle Closed-Loop Control of Piezoelectric Resonator DC-DC Converters

Piezoelectric resonator DC-DC converters have been demonstrated with high efficiency and power-density, offering a promising prospect for power converter miniaturization. How-ever, the operation of these converters relies on precise switch timings to achieve zero-voltage-switching and soft-charging of the resonator's parallel capacitance, creating challenges for control at high frequencies. This paper presents a closed-loop control method that regulates voltage through forward-zero cycle modulation. The technique uses a fixed-frequency, requires only one sensing operation per resonant period, and enables a fast transient response.