Comprehensive analysis on low power step-up conversion

Abstract

Limited information is available on step-up DC-DC converters, many different topologies exist but their optimal implementation is rarely discussed, particularly for low power applications. Recent semiconductor and magnetic technologies, such as GaN MOSFETs and planar transformers have been introduced to the market, promising gain in efficiency and power density, yet the added complexity has not been thoroughly examined. This report, conducted in collaboration with ASML, investigates whether a converter built on these technologies can meet stringent industrial standards for a 24 V to 150 V, 45 W application.
Several candidate topologies have been evaluated, where the flyback resulted in the optimal compromise between efficiency, versatility and design complexity. A flyback converter is then realized as a prototype board and tested against ASML’s established requirements.The prototype achieved 90.4% peak efficiency at 45W and was able to meet all required specifications demonstrating the effectiveness of the chosen topology. These results demonstrated that planar transformers can be an alternative to conventional transformers when low leakage, high switching frequency and low profile are of interest.