Power adapter device with input power detection

A method comprising:

• receiving an alternating current (AC) input voltage for a power adapter device at a rectifier bridge of the power adapter device;
• determining, by a power delivery integrated circuit (PD IC) of the power adapter device, a direct current (DC) voltage across a sub-coil in a secondary side of a transformer;
• based on the DC voltage, determining a voltage level of the AC input voltage;
• and
• storing, by the PD IC, the determined voltage level of the AC input voltage.

A power adapter device comprising:

• a rectifier bridge including input terminals to receive an alternating current (AC) input voltage for the power adapter device;
• a transformer including a primary side coupled to one of a plurality of output terminals of the rectifier bridge, and a secondary side including a secondary side coil and a sub-coil;
• a power delivery integrated circuit (PD IC) coupled to the sub-coil of the transformer, the PD IC to:
• detect the AC input voltage;
• in response to the detection of the AC input voltage, disable a power factor correction of the power adapter device and direct current (DC) voltage output of the power adapter device;
• determine a DC voltage across the sub-coil of the transformer;
• based on the DC voltage, determine a voltage level of the AC input voltage;
• and
• store the determined voltage level of the AC input voltage.