AC/DC converter controller drives SiC MOSFETs

June 29, 2015 // By Graham Prophet
Enabling the use of silicon carbide MOSFETs to achieve greater energy savings and miniaturisation in industrial applications, Rohm has developed an AC/DC converter control IC designed specifically for SiC MOSFET drive in industrial equipment.

BD7682FJ-LB allows SiC MOSFETs to be applied in an AC/DC converter AC/DC converter design, which – the company says – has proved challenging when using discrete configurations due to the large number of components required. Compared to silicon MOSFETs used in conventional AC/DC converters, SiC MOSFETs enable AC/DC converters with power efficiency improved by up to 6%. Components used for heat dissipation are not required (50W class power supplies), leading to greater compactness. BD7682FJ-LB includes multiple protection functions that enable support for high voltages up to 690 VAC, suiting them for general industrial equipment.

The BD7682FJ-LB integrates a gate drive circuit optimised for SiC MOSFET drive by including analogue design techniques plus SiC power semiconductor development expertise. A quasi-resonant system delivers lower noise and higher efficiency vs. conventional PWM methods. Employing SiC MOSFETs in AC/DC converters eliminates the need for components used for heat dissipation, contributing to smaller, lighter AC/DC converter designs. Higher switching frequencies (i.e. 120kHz) are also featured.

Protection circuits enable high voltage operation in AC/DC converters up to 690VAC – for general 400VAC industrial applications. In addition to overvoltage protection for the supply voltage pin and brown in/out (undervoltage) countermeasure for the input voltage pin, overcurrent and secondary overvoltage protection functions are included, enabling continuous operation in industrial equipment while improving reliability considerably.

Rohm Semiconductor;