900V MOSFETs maximise efficiency in flyback converters

March 10, 2017 // By Graham Prophet
Power-supply designers, according to STMicroelectronics, can meet system demands for higher power and greater efficiency using its 900V MDmesh K5 super-junction MOSFETs, which deliver minimum on-resistance (RDS(ON)) and improved dynamic characteristics.

900V breakdown voltage gives extra safety margin in systems with high bus voltages. This series of switches contains the first 900V MOSFETs with RDS(ON) below 100 mΩ, and claims best RDS(ON) among DPAK devices. Lowest gate charge (Qg) ensures faster switching for greater flexibility where a wide input-voltage range is required. These characteristics permit high efficiency and reliability in all types of flyback converters including standard, quasi-resonant, and active-clamp designs covering power ratings from 35W up to 230W or higher. Low input and output capacitances (Ciss, Coss) enable zero-voltage switching with minimal energy loss in half-bridge LLC resonant converters.


ST’s family of MDmesh K5 super-junction transistors now offers voltage ratings of 800V, 850V, 900V, 950V, 1050V, 1200V, and 1500V. Together with package options including TO-220AB, TO-220FP, TO-247, TO-247 Long Lead, IPAK and I2PAK, as well as D2PAK and DPAK surface-mount power packages, ST’s super-junction devices present designers with a comprehensive portfolio of Very High Voltage (VHV) MOSFETs.


The 900V MDmesh K5 MOSFETs are priced from $0.73 (1000) for the STD4N90K5 in DPAK.


ST; www.st.com/mdmeshk5