Inrush current solution with bypass SCR

Based on an analog control circuit with only discrete components, it provides a compact and reliable alternative to using relays to bypass inrush current limiting resistors in power converters.
Its drive circuit automatically synchronizes with the AC line. Operating in pulse mode, it allows low gate drive consumption and no SCR reverse losses. Additionally, the 50 mA SCR TN5015H-6G provides better immunity to electrical fast transients (EFTs).
The power supply of the circuit can be generated by the secondary winding of the PFC or the auxiliary power supply used to drive the transistors and power the system MCU. When supplying 12 V unregulated power, no adjustments are required, just 5 wires need to be connected and the board can be easily implemented on an existing PFC or flyback converter.
It is suitable for peak currents up to 5 A (application temperature 60°C ambient temperature)