US Patent 9148050 AC/DC converting circuit

An AC/DC converting circuit and a starting method thereof are provided. An AC detection or a rectified AC voltage detection is disabled when the AC voltage or the rectified AC voltage not up to a start-up voltage is detected, so as to shorten a recovery time of a voltage of a power supply terminal of an AC/DC power conversion controller, and further shorten a starting time of the AC/DC converting circuit.