Design Methodology for a Very High Frequency Resonant Boost Converter

This paper introduces a design methodology for a resonant boost converter topology that is suitable for operation at very high frequencies. The topology we examine features a low parts count and fast transient response, but suffers from higher device stresses compared to other topologies that use a larger number of passive components. A numerical design procedure is developed for this topology that does not rely on time-domain simulation sweeps across parameters. This allows the optimal converter design to be found for a particular main semiconductor switch. If an integrated power process is used where the designer has control over layout of the semiconductor switch, the optimal combination of converter design and semiconductor layout can be found. To validate the proposed converter topology and design approach, a 75-MHz prototype converter is designed and experimentally demonstrated. The performance of the prototype closely matches that predicted by the design procedure, and the converter achieves good efficiency over a wide input voltage range

Design methodology for a very high frequency resonant boost converter

This document introduces a design methodology for a resonant boost converter topology that is suitable for operation at very high frequencies. The topology we examine features a low parts count and fast transient response but suffers from higher device stresses compared to other topologies that use a larger number of passive components. A numerical design procedure is developed for this topology that does not rely on time-domain simulation sweeps across parameters. This allows the optimal converter design to be found for a particular main semiconductor switch. If an integrated power process is used where the designer has control over layout of the semiconductor switch, the optimal combination of converter design and semiconductor layout can be found. To validate the proposed converter topology and design approach, a 75 MHz prototype converter is designed and experimentally demonstrated. The performance of the prototype closely matches that predicted by the design procedure, and achieves good efficiency over a wide input voltage range

Hydrogel-Inducing Graphene-Oxide-Derived Core–Shell Fiber Composite for Antibacterial Wound Dressing

The study reveals the polymer–crosslinker interactions and functionality of hydrophilic nanofibers for antibacterial wound coatings. Coaxial electrospinning leverages a drug encapsulation protocol for a core–shell fiber composite with a core derived from polyvinyl alcohol and polyethylene glycol with amorphous silica (PVA-PEG-SiO2), and a shell originating from polyvinyl alcohol and graphene oxide (PVA-GO). Crosslinking with GO and SiO2 initiates the hydrogel transition for the fiber composite upon contact with moisture, which aims to optimize the drug release. The effect of hydrogel-inducing additives on the drug kinetics is evaluated in the case of chlorhexidine digluconate (CHX) encapsulation in the core of core–shell fiber composite PVA-PEG-SiO2-1x-CHX@PVA-GO. The release rate is assessed with the zero, first-order, Higuchi, and Korsmeyer–Peppas kinetic models, where the inclusion of crosslinking silica provides a longer degradation and release rate. CHX medicated core–shell composite provides sustainable antibacterial activity against Staphylococcus aureus