50-W GaN flyback converter delivers high efficiency

STMicroelectronics has released its VIPerGaN50 50-W gallium-nitride (GaN) flyback converter with an integrated 650-V GaN power transistor, delivering miniaturization and high energy efficiency to a range of consumer and industrial applications. These include power adapters, USB-PD chargers, and power supplies for home appliances, air conditioners, LED-lighting equipment, and smart meters.

Click for a larger image. (Source: STMicroelectronics)

The VIPerGaN50 is the first device in the VIPerPlus series to offer up to 50 W in a wide 9 V to 23 V operating voltage range. It is also ST’s first VIPer device with a GaN transistor. “The VIPerGaN50 helps designers leverage GaN wide-bandgap technology to meet increasingly stringent eco-design codes that target global energy savings and net-zero carbon emissions,” said STMicroelectronics.

With its single-switch topology and high integration, which includes  built-in current-sensing and protection circuitry, the VIPerGaN50 also is housed in a compact 5 × 6-mm package. In addition, minimal additional external components are needed to design an advanced, high-efficiency switched-mode power supply (SMPS), and thanks to the speed of the integrated GaN transistor it allows for a high switching frequency with a small and lightweight flyback transformer, said the company.

VIPerGaN50 typical configuration with full features. Click for a larger image. (Source: STMicroelectronics)

The converter operates in multiple modes to optimize efficiency at all line and load conditions. At heavy load, quasi-resonant (QR) operation with zero-voltage switching minimizes turn-on losses and electromagnetic emissions (EMI), while at reduced load, valley skipping limits switching losses and leverages ST’s proprietary valley lock to prevent audible noise.

Multi-mode operation of VIPerGaN50. Click for a larger image. (Source: STMicroelectronics)

ST said the frequency foldback with zero-voltage switching ensures the highest possible efficiency at light load. It also uses adaptive burst mode operation to minimize losses at very low load. Advanced power management features reduce standby power to below 30 mW.

In addition to the built-in protection circuitry, including output over-voltage protection, brown-in and brown-out protection, and input over-voltage protection, input-voltage feedforward compensation is also included to minimize output peak-power variation, as well as embedded thermal shutdown and frequency jittering to minimize EMI.

The VIPerGaN50 is priced from $2.30 for orders of 1000 pieces. The device is in a free-sample program and can be ordered at the ST eSTore. STMicroelectronics is exhibiting at APEC 2022 in booth #502.