ST 65W Flayback Converter

ST has added 65 Watt flyback converter in the VIPerGaN series that combines a 700V GaN transistor and quasi-resonant PWM control IC in a single QFN 5×6 package.

VIPerGaN65W is aimed at cost-effective USB-PD chargers, fast battery chargers, and auxiliary power supplies.

The flyback controller of these converters operates in quasi-resonant mode with zero-voltage switching (ZVS) up to the full load.

Valley skipping optimises efficiency at mid-to-high load, with ST’s proprietary valley locking to prevent noise at audio frequencies and thus ensure silent operation. With frequency foldback at light load, the converter enters burst operation at no-load to cut power consumption below 30mW for eco-design compliance.

The integrated gate driver is fine-tuned for the GaN transistor parameters, which saves designers adding external components to optimize switching, helping accelerate time to market, increase power density, and minimizing the bill of materials. High-voltage startup circuitry, and a senseFET for accurate current monitoring, are also integrated.

The device has line-voltage feedforward, which prevents the output power increasing excessively as the supply voltage changes, and dynamic blanking time that limits the operating frequency to minimize switching losses. Input and output overvoltage protection, thermal shutdown, and brown-in and brown-out protection are also built-in.

The EVLVIPGAN65WF evaluation board is available to help explore the VIPerGaN65W features and kick-start customers’ projects. The board implements a 24V/65W isolated flyback converter with secondary-side synchronous rectification, ready to operate with any AC input voltage from 90V to 265 V.

The VIPerGaN65W converter is in production now, in a 5mm x 6mm Power QFN (PQFN) package, and available at the eSTore and distributors from $1.19 for orders of 1000 pieces.