6 W Bipolar isolated auxiliary supply for SiC-Mosfet and IGBT gate driver

RD001

This reference design presents an auxiliary power supply providing a positive and a negative output voltage rail with a combined total output power of 6 W. The optimized design is for driving high-voltage SiC-MOSFET and IGBT discrete devices as well as power modules in high-power converters, and can be easily integrated in the gate driver system. Three design variants with different bipolar output voltage levels provide for different SiC-MOSFETs and IGBT device requirements. In addition to the compact size and high efficiency, one of the main features of the design is the extremely low interwinding capacitance of the WE-AGDT transformers down to 7 pF, which helps to achieve high CMTI rating (Common-Mode Transient Immunity). A high CMTI enables faster switching transitions without compromising the functionality of the system, helping to achieve smaller system size and higher efficiency of the high power converter, as demanded by trending applications in areas like e-mobility, renewable energy and industrial automation.

Key Features

• Extremely compact (27 x 14 x 14 mm)

• Input voltage range: 9 to 18 V

• Bipolar output voltages:

• 4 kV primary-secondary Isolation

• WE-AGDT transformer with only 7 pF interwinding capacitance

• PSR Flyback topology with LT8302 (ADI Power by Linear)

• Two BoM variants: Standard and AEC-Q component qualification

• Two PCB Layout variants: single sided and double sided

Typical Applications

• Battery charging stations

• Industrial drives: AC motor inverter

• Renewable energy: Solar inverters

• Power factor corrector (PFC) stage

• Switch-mode power supplies with SiC MOSFETs