This reference design provides isolated positive and negative voltage rails required for Insulated Gate Bipolar Transistor (IGBT) gate drivers from a single 24-volt DC input supply. Utilizing a Fly-Buck™ control topology, this reference design uses a single transformer for generating power rails for all three arms of the 3-phase inverter. It uses primary-side regulation and can achieve good cross regulation without opto-coupler feedback or an auxiliary winding. The isolated outputs are generated through the coupled windings of the transformer. The voltage rails for all the high-side IGBTs are individually isolated, whereas the voltage rails for all low-side IGBTs are combined.
• Isolated power supply with 24V±20% input range that supports 6 IGBT gate drivers for 3-phase inverter (each arm in half-bridge configuration)
• Low-ripple (<200mV) bias outputs (+15V & -8V) with output power of 2.3W for each IGBT of the 3-phase inverter
• Fly-Buck topology provides easy-to-design multi-output isolated power supply solution with primary side regulation
• Peak efficiency of 82% at balanced full-load
• Output capacitors rated to support up to 6A peak gate drive current