Rohm Presents AC/DC Converter ICs with Built-In SiC MOSFET
Device replaces an AC/DC converter IC, two 800V silicon MOSFETs, three Zener diodes, and six resistors
Rohm has announced the availability of AC/DC converter ICs with a built-in 1700V SiC MOSFET, the BM2SCQ12xT-LBZ series. This series is optimised for industrial applications including street lamps, commercial AC systems, and general-purpose AC servos and inverters used in high power equipment.
SiC power semiconductors deliver greater power efficiency, miniaturisation, and higher voltage capability than the existing silicon power devices. In recent years, the growing demand for energy savings has resulted in the adoption of power semiconductors such as SiC in 400VAC industrial applications.
In 2015, Rohm became the first to offer AC/DC converter ICs for driving high voltage, low-loss SiC MOSFETs. This time, it has created the industry's first AC/DC converter ICs with a built-in SiC MOSFET that will further accelerate the adoption of AC/DC converters that use SiC MOSFETs in industrial equipment.
Furthermore, the BM2SCQ12xT-LBZ series integrates a 1700V SiC MOSFET, which is also an industry first. This series enables breakthrough energy savings and facilitates efficient AC/DC converter design by resolving many of the issues encountered by designers using discrete solutions.
Incorporating a SiC MOSFET and control circuitry optimised for auxiliary power supplies for industrial equipment in a single package significantly reduces the number of parts required when compared to the conventional designs, from 12 devices plus heat sink to a single IC that includes AC/DC converter IC, two 800V Si MOSFETs, three Zener diodes, and six resistors.
It also aids to minimising both the component failure risk and the amount of resources required to develop systems using SiC MOSFETs. In addition, this product enables the improvement of power efficiency by 5 percent (and decreasing power loss by 28 percent). These features translate to dramatic reduction in size, improved reliability, and superior power savings in industrial applications.
The BM2SCQ12xT-LBZ series adopts a dedicated package that incorporates a 1700V SiC MOSFET along with the control circuitry (i.e. SiC MOSFET gate drive circuit) optimised for industrial auxiliary power supplies.
The monolithic design reduces the resources required for component selection and reliability evaluation for the clamp and drive circuits while also minimising component failure risk and simplifying the development effort for SiC MOSFET adoption. In addition, overload protection (FB OLP), overvoltage protection (VCC OVP) of the supply voltage pin, and a high accuracy thermal shutdown function (TSD) (achieved through the built-in SiC MOSFETs) are built in, along with the over current protection and secondary overvoltage protection functions.
This enables the incorporation of multiple protection circuits for industrial power supplies that require continuous operation hence leading to a significant improvement in system reliability.
Both internal SiC MOSFET and the built-in gate driver circuit optimised for this SiC MOSFET improve efficiency by as much as 5 percent over conventional Si MOSFETs. according to a Rohm April 2018 study. Also, a quasi-resonant method is adopted for the control circuit that enables operation at higher efficiency and lower noise than conventional PWM systems, minimising the effects of noise in industrial equipment.
