Output power protection apparatus and method of operating the same

An output power protection apparatus includes a DC conversion unit (20), an output protection unit (30), a high-voltage battery (50), a low-voltage battery (60), and a control unit (40). The DC conversion unit (20) converts an input DC power into an output DC power. The output protection unit (30) is connected in series to the DC conversion unit (20), and the output protection unit (30) has a plurality of protection circuits (301) connected in parallel to each other. When a short-circuit condition occurs between the high-voltage battery (50) and the low-voltage battery (60) or the low-voltage battery (60) is reversely connected in polarity, the control unit (40) generates a control signal (Sc) to control the protection circuits (301) to disconnect the connection between the low-voltage battery (60) and a low-voltage device (80), and the DC conversion unit (20).