65 W GaN flyback integrates 700 V switch and controller

STMicroelectronics has expanded its VIPerGaN family with the VIPerGaN65W, a 65-watt flyback converter that integrates a 700 V GaN power transistor and a quasi-resonant PWM controller in a 5 mm × 6 mm Power QFN package. The device is designed for USB-PD adapters, fast battery chargers, and auxiliary power supplies that require high efficiency in compact form factors.

The controller operates in quasi-resonant mode and maintains zero-voltage switching across the load range. Valley-skipping control improves efficiency at medium to high loads, and a proprietary valley-locking mechanism prevents audible-frequency noise. At light load, frequency foldback reduces switching activity, and the device enters burst mode at no load to limit standby power below 30 mW.

The VIPerGaN65W integrates a gate driver matched to the GaN device parameters, eliminating external components typically required for gate optimization. Additional integration includes a high-voltage startup circuit and a sense FET for accurate current monitoring. These features streamline board design, increase power density, and reduce the bill of materials.

The converter includes line-voltage feedforward to maintain stable output power across supply variations and uses dynamic blanking-time control to limit switching losses. Built-in protection includes input and output overvoltage protection, thermal shutdown, and brown-in/brown-out management.

To support evaluation, ST provides the EVLVIPGAN65WF board, implementing a 24 V / 65 W isolated flyback supply with secondary-side synchronous rectification and universal AC input compatibility from 90 V to 265 V.

The VIPerGaN65W is in production and supplied in a Power QFN package. Pricing begins at $1.19 in quantities of 1,000 units.