Battery charging apparatus

A battery charging apparatus comprising:

• a hybrid power converting unit configured to use a common transformer to separately convert AC power into a first voltage and a second voltage for charging a high voltage battery and an auxiliary battery;
• a high voltage charging unit configured to drop the first voltage output from the hybrid power converting unit and charge the high voltage battery with the dropped first voltage;
• an auxiliary voltage charging unit configured to drop the second voltage output from the hybrid power converting unit or a voltage of the high voltage battery, and charge the auxiliary battery with the dropped second voltage or the dropped voltage of the high voltage battery;
• and
• a switching unit configured to switch an electrical connection between the AC power and the auxiliary voltage charging unit and switch an electrical connection between the high voltage battery and the auxiliary voltage charging unit, such that the second voltage generated by the conversion of the AC power or the voltage of the high voltage battery is selectively input to the auxiliary voltage charging unit,
• wherein, in a first mode, the charging of the high voltage battery and the charging of the auxiliary battery by the AC power are performed by the switching operation of the switching unit, and
• in a second mode, the charging of the high voltage battery by the AC power is stopped and the charging of the auxiliary battery by the voltage of the high voltage battery is performed by the switching operation of the switching unit.