Charging device for charging a vehicle battery and method for operating the charging device

A non-transitory, computer-readable storage medium comprising instructions which, when executed by a control unit (452), prompt the control unit to operating a charging device that includes,

• an input connection unit (100) for connecting a single-phase or multiphase AC voltage with n phases, wherein n is greater than or equal to 1, and an input circuit (200) for providing a DC voltage at a two-pole intermediate connection (300),
• an intermediate capacitor (CZ) connected between the positive intermediate connection (310) and the negative intermediate connection (320),
• a bi-directional DC-DC converter (450) connected on the input side to the intermediate connection (300), which is configured to convert the DC voltage applied to the intermediate connection (300) into a charging voltage in a charging mode and to provide it to a high-voltage network (400) connectable to the output side of the DC-DC converter (450),
• wherein the charging device (500) comprises a control unit (452) for controlling the bi-directional DC-DC converter (450), and
• a circuit unit (402) connected on the output side of the DC-DC converter (450) for generating an internal supply voltage for the control unit (452) for the charging device (500), to supply the control unit (452) from the connectable high-voltage network (400)
• by:
• operating (810) the circuit unit (402) for generating an internal supply voltage during a discharge mode.