EVLVIPGAN50WF 15 V / 50 W QR flyback converter based on VIPERGAN50W

The EVLVIPGAN50WF evaluation board implements a 15 V / 50 W SSR isolated flyback converter developed for general-purpose applications, operating from 90 to 265 VAC.

The reference design is built around the VIPERGAN50W, a new advanced offline high-voltage converter by STMicroelectronics with the following features:

- 700 V PowerGaN with embedded senseFET (Si) and HV startup;

- QR operation with dynamic blanking time and adjustable valley synchronization delay functions, to maximize efficiency at any input line and load conditions;

- Valley-lock to ensure constant valley skipping;

- Input voltage feedforward compensation for mains-independent OPP intervention;

- Adaptive burst mode for advanced power management in light load conditions;

- Frequency jittering for EMI suppression.

Enhanced system reliability is ensured by the built-in soft-start function and by the following set of protections:

- Input OVP (settable);

- Brown-in and brown-out (settable);

- Output OVP (settable);

- Output overload;

- OCP LEB;

- Embedded thermal shutdown.

The EVLVIPGAN50WF is composed of a main board and a daughter board, with schematics shown in Figure 1 and Figure 2 respectively.

The main board contains a diode bridge for double wave rectification, an input pi filter for EMI, a flyback transformer, the VIPERGAN50W and all the related components needed for polarization and feature setting on the primary side. On the secondary side, it contains the output capacitors and the output rectifier, realized by a Power MOSFET driven by a synchronous rectifier for efficiency optimization.