Würth Elektronik presents technically mature circuit templates for developers in its reference designs. Release RD002 is currently available for free download: 6 W unipolar isolated auxiliary supply for SiC MOSFETs and IGBT gate drivers. It explains the setup of a 27 x 14 x 14 mm small board with adjustable output voltage.
The reference design delivers a unipolar output voltage of 15V to 20V at 6W of power. It can be employed in battery chargers, solar system inverters, AC motors or switch-mode power supplies with SiC MOSFETs, and more.
An isolated low-power auxiliary power supply, commonly with a flyback, push-pull, or half-bridge topology, supplies the gate drive voltage level and power needed to turn the SiC transistor on and off and galvanic isolation between the high-voltage and low-voltage sides. Isolation is required not only to fulfil the relevant safety standards but also to lessen electrical interference due to coupling between the primary and secondary sides of the converter and, thus, to enhance EMC and the stability of the gate driver control. The transformer in the auxiliary power supply (WE-750318114) performs this main task. The reference design offers the circuitry and components and displays different layout variants.
"As developers, we don't have to keep reinventing the wheel, and that includes circuit technology," says Falco Eleazar, application engineer at Würth Elektronik eiSos. "Thanks to our reference designs, you save a lot of time and can be sure that the components featured are also reliably available from stock."