Circuits and methods for battery charging are disclosed. In one embodiment, the battery charging circuit comprises an AC to DC converter, a charging control switch, and a charger controller. The AC to DC converter provides a charging power to a battery pack. The charging control switch is coupled between the AC to DC converter and the battery pack. The charging control switch transfers the charging power to the battery pack. The charger controller detects a battery status of the battery pack and controls the charging control switch to charge the battery pack in a continuous charging mode or a pulse charging mode according to the battery status. The charger controller also controls the AC to DC converter to regulate the charging power according to the battery status.