STMicro Adds 100 W Monolithic GaN Converters to VIPerGaN Family

STMicroelectronics has added two 100 W devices to its VIPerGaN family of monolithic gallium nitride (GaN) converters, doubling the maximum output power available from the product line.

The VIPerGaN100W and VIPerGaN100WB each combine a 700 V GaN power transistor, integrated gate driver, and quasi-resonant flyback controller in a 5 mm x 6 mm QFN package, bringing wide-bandgap efficiency gains to domestic appliances, building automation, smart lighting, and consumer electronics, including USB-C chargers and televisions.

The two converters differ primarily in their current handling. The VIPerGaN100W has a 3.5 A drain current limit, while the VIPerGaN100WB raises that to 4.2 A, allowing it to manage short-term peak loads up to 125 W. That extra headroom is aimed at equipment containing inductive loads such as solenoid valves or motors, including small appliances and air-conditioning units.

The VIPerGaN100W. Image used courtesy of STMicroelectronics

Inside the Package

Both converters operate using a quasi-resonant flyback topology with zero-voltage switching (ZVS), a combination that reduces switching losses while maintaining high efficiency across a range of load conditions. Each device’s core is an integrated 700 V enhancement-mode GaN transistor with an on-resistance of 0.27 milliohms.

GaN transistors can switch faster and with lower losses than their silicon equivalents at this voltage class, but they require precise gate driving to avoid damage. ST addresses this by integrating the gate driver on-die, eliminating the need for designers to fine-tune external gate resistance and inductance and removing one of the more common pain points in discrete GaN power supply design.

The devices are compatible with the universal AC input voltage range from 85 V to 265 V and deliver their full 100 W output from a 185 V supply. At light loads, the converters reduce switching frequency to improve efficiency.

At mid loads, they employ valley-skipping. A proprietary valley-lock function stabilizes the number of valleys skipped, preventing variations at audio frequencies and ensuring silent operation across all load conditions.

Multi-mode operations. Image used courtesy of STMicroelectronics

In standby, burst-mode operation keeps no-load power consumption below 30 mW, an increasingly important specification as energy regulations in the EU and other markets tighten standby power requirements for consumer appliances and electronics.

Integrated protection features cover input overvoltage, output overvoltage, overtemperature, and brown-in/brown-out conditions. Line-voltage feedforward stabilizes output power as the input voltage fluctuates, while dynamic blanking time further minimizes switching losses.

Building on the VIPerGaN Platform

The VIPerGaN100W and VIPerGaN100WB join STMicroelectronics' existing VIPerGaN50 and VIPerGaN65, which deliver 50 W and 65 W, respectively. All devices in the family are pin-to-pin compatible, allowing designers to scale power levels by swapping components without significant changes to their PCB layout.

The GaN transistor's on-resistance decreases across the lineup: 450 milliohms for the VIPerGaN50, 260 milliohms for the VIPerGaN65, and 225 milliohms for the VIPerGaN100 series. That progression reflects the lower conduction losses needed to handle higher power levels efficiently within the same compact package format.

By packaging the power switch, driver, and controller together, the company reduces the external component count and simplifies the design process considerably compared to discrete GaN implementations.

For engineers working on compact power supplies, the single-package approach avoids the layout complexity of discrete GaN solutions that require separate driver ICs and careful high-frequency routing. It also lowers the barrier to GaN adoption for design teams more accustomed to working with traditional silicon flyback controllers, since the integrated driver handles the gate-driving nuances required by GaN transistors.

Reference Design and Availability

To demonstrate the VIPerGaN100W in a practical application, ST has released a reference design, the EVLVIPGAN100WP. It implements a 100 W USB Type-C Power Delivery 3.0 adapter with five output configurations ranging from 5 V/3.0 A to 20 V/5.0 A.

The EVLVIPGAN100PD. Image used courtesy of STMicroelectronics

The design uses secondary-side regulation with optocoupler feedback and achieves a peak efficiency above 92% with a power density of 24 W/in³. Those figures position it competitively against existing 100 W GaN adapter designs on the market, and the reference design serves as a starting point for engineers developing USB-C PD chargers, laptop adapters, or appliance power supplies.

Both converters are available through the ST eStore and authorized distributors. ST provides datasheets for both devices, evaluation board documentation for the EVLVIPGAN100WP, and a detailed application note (AN6333) covering the 100 W USB-PD adapter reference design.

The VIPerGaN100W family arrives as GaN adoption in the consumer and appliance power supply space continues to accelerate. Competing solutions from Power Integrations, Infineon, and others have expanded GaN offerings at similar power levels in recent months, pushing monolithic integration and ease of design as key differentiators alongside efficiency numbers.