A method of controlling charging includes: receiving an input voltage; receiving by a control unit a detected voltage related to the input voltage; outputting a conducting voltage from the control unit when the detected voltage falls within an operation range; outputting an operating voltage to a detection pin of a charging unit according to the conducting voltage; outputting a charging current from the charging unit according to the input voltage when the detection pin receives the operating voltage; and not outputting the conducting voltage from the control unit when the detected voltage falls outside the operation range.