A charging integrated circuit (IC) in a mobile device including battery includes; a switching charger including at least one inductor, a direct charger including at least one capacitor, and a control circuit. The control circuit detects a connection between the mobile device and an external power unit and a disconnection between the mobile device and the external power unit, wherein the switching charger and the direct charger selectively receive an external power signal provided by the external power unit by the connection between the mobile device and an external power unit. Upon detecting the connection between the mobile device and an external power unit, the charging IC activates the direct charger and provides a constant charging current to the battery using the direct charger, and upon detecting the disconnection between the mobile device and an external power unit, the charging IC deactivates the direct charger, activates the switching charger, and maintains a battery voltage associated with the battery using the switching charger.