Switching mode power supply with single power line detection circuit

A switching mode power supply with single power line detection circuit, comprising:

• a power conversion circuit receiving an AC input voltage from an input side and converting said AC input voltage into a DC output voltage;
• a safety capacitor connected across said input side;
• a control unit coupled to said power conversion circuit to control an operation of said power conversion circuit;
• a detection circuit coupled to said safety capacitor, said power conversion circuit and said control unit;
• wherein said power conversion circuit further includes:
• an input rectification and filtering unit coupled to said safety capacitor and performs full-wave rectification and filtering on said AC input voltage to generate an input voltage;
• a transformer conversion circuit coupled to said input rectification and filtering unit, and is controlled by said control unit to transform said input voltage to generate said DC output voltage;
• an auxiliary winding unit coupled to said transformer conversion circuit to generate a DC supply voltage for said control unit;
• and
• wherein said control unit determines whether said switching mode power supply is in a single power line connection state based on a waveform of a voltage signal or a current signal detected by said detection circuit.