The invention provides a charging apparatus and an operating method thereof. The charging apparatus includes a power conversion circuit, a feedback circuit, an identifier control circuit, and a low voltage trickle control circuit. The feedback circuit generates a feedback signal for the power conversion circuit, and the power conversion circuit correspondingly adjusts a charging power according to the feedback signal. The power conversion circuit provides the charging power to charge a battery device. The identifier control circuit determines whether to control the feedback circuit to change the feedback signal according to identifier information of the battery device. The low voltage trickle control circuit determines whether to control the feedback circuit to change the feedback signal according to a voltage of the charging power. When the low voltage trickle control circuit controls the feedback circuit to change the feedback signal, the feedback circuit ignores control of the identifier control circuit.