text.skipToContent text.skipToNavigation




STMicroelectronics VIPERGAN50 High Voltage Converter

Advanced Offline Quasi-Resonant With E-mode GaN HEMT

The STMicroelectronics VIPERGAN50 is a high voltage converter, designed for medium power quasi-resonant ZVS (Zero Voltage Switching at switch turn-on) flyback converters, capable to provide an output power up to 50 W in wide range.

This device integrates a complete set of features that provide an extremely flexible and easy to use chip and helps to design a highly efficient offline power supply. The ZVS quasi-resonant operation with the dynamic blanking time feature and the valley synchronization function, that turns on the power switch always at the valley of the drain resonance, reduces the switching losses and maximizes the overall efficiency at any input line and load condition. The advanced power management with the low quiescent helps to achieve low stand-by consumptions. The feed-forward compensation minimizes the maximum output peak power variation over the entire input voltage range.

In addition to the above functions, the STMicroelectronics VIPERGAN50 offers protection features that considerably increase end-product’s safety and reliability: the output overvoltage protection, the overtemperature protection (OTP), the overload protection (OLP), the brown-in/out protection, that set the input voltage level to power on and power off the converter and the input overvoltage protection (iOVP), that protects the system in case of an abnormal increase of the input line. All the protections are auto-restart mode.


  • Quasi-resonant (QR) flyback controller
  • 650 V E-mode power GaN transistor
  • Embedded sense FET
  • Dynamic blanking time and adjustable valley synchronization delay functions, to maximize efficiency at any input line and load condition
  • Valley-lock to ensure constant valley skipping
  • Advanced power management for less than 30 mW standby power consumption with adaptive burst-mode
  • Output OVP protection
  • Input voltage feed-forward compensation for mains independent OPP variation
  • Brown-in and brown-out protection
  • Input OVP protection
  • Embedded thermal shutdown
  • Frequency jitter for EMI suppression


  • High efficiency power adapters
  • Fast battery chargers
  • Auxiliary power supply for appliances, industrial, consumers, lighting

VIPERGAN50 Multi-mode Operations

STMicroelectronics — VIPERGAN50 Multi-mode Operations

VIPERGAN50 Typical Schematics: Full Features

STMicroelectronics — VIPERGAN50 Typical Schematics


STMicroelectronics VIPERGAN50 Reference Design

Based on VIPerGaN50 and STUSB4761 for 45W QR USB PD adaptor

The EVLVIPGAN50PD 45 W USB Type-C® Power Delivery 3.0 adapter is a USBPD reference design solution. It is an isolated power supply based on the VIPERGAN50, a new offline high-voltage converter from the VIPerPlus family with a 650 V HEMT Power GaN transistor, designed for quasi-resonant flyback converters, capable of providing an output power up to 50 W in wide range.

STMicroelectronics — VIPERGAN50 Reference Design
EVLVIPGAN50PD Application Note


  • Input voltage range: Universal AC from 90 to 264 VAC with 47 Hz to 63 Hz frequency
  • Output voltage: 5 V, 9 V, 12 V, 15 V, 20 V
  • Output current: 3 A @5 V, 9 V, 12 V, 15 V – 2.25 A @ 20 V
  • Maximum output power: 45 W
  • Efficiency standards: Meet CoC Tier 2 and DoE Level 6 efficiency requirements
  • Peak efficiency: > 92 %
  • Support for USB-PD, Type C output connector
  • Meets IEC55022 Class B conducted EMI
  • Key products: VIPerGaN50, STUSB4761, SRK1001


At the secondary side, to increase the system efficiency, the rectification is based on the SRK1001 adaptive synchronous rectification controller.

Still on the secondary side, the CC/CV regulation loop to drive the power regulation stage and the USB Type-C® PD interface is based on the STUSB4761 controller. This controller offers the benefits of a full hardware USB PD stack allowing robust, deterministic and safe negotiation in line with USB PD standard.

The evaluation board implements a robust adapter protected for output overvoltage, output undervoltage, output over power and output short-circuit. This reference design, based on STMicroelectronics semiconductors, helps designers to develop adapters with a short bill of materials to obtain a cost-effective and fast design.


Featured Products