In the drive to continue increasing energy efficiency in switching power-conversion systems such as PFC and switching power supplies, Toshiba’s Superjunction MOSFETs and wide-bandgap silicon-carbide (SiC) diodes have become favoured solutions for energy-conscious designers. Both technologies have allowed smaller die sizes in relation to key parameters such as MOSFET on-resistance and diode reverse voltage, enabling designers also to reduce circuit size and increase current density. As market adoption of these device technologies continues to grow, new demands are coming to the fore, such as improved noise performance.

Reducing electromagnetic noise emission is desirable in high-end power supplies for equipment such as LCD TVs, LED lighting, medical power supplies, notebook power adapters and power supplies for tablets. Resonant switching topologies, such as the LLC converter with zero-voltage switching, are popular for these types of applications for their inherently low electromagnetic emissions. Primary-side switching in an LLC circuit is often now handled by superjunction transistors to achieve a compact and energy-efficient power supply.

This white paper discusses how Toshiba is optimizing power conversion performance with Superjunction MOSFETs and SiC diodes.