A battery charging circuit includes a plurality of unit batteries that are connected in series; a current path forming unit that is connected between the unit batteries and forms a charging current path to one or more unit batteries selected by one or more selection signals; a control unit that senses the charging status of each of the plurality of the unit batteries, and generates the selection signals and controls the duty ratio according to the sensing results; and a charging electricity providing unit that controls the charging voltage provided to the charging current path forming unit according to the duty ratio of the charging control pulse.