Mobile power supply device with expanding function

A mobile power supply device, used for charging an electronic host device, allowing at least one external device to communicate with the electronic host device via the mobile power supply device, the mobile power supply device comprising:

• at least one expansion interface;
• at least one transmission interface, used for electrically connecting to the electronic host device;
• a charging control unit, electrically connected to the at least one transmission interface and an external power supply;
• a battery, electrically connected to the charging control unit, wherein the charging control unit is used for controlling the external power supply to charge the battery and for controlling the battery to charge the electronic host device via the at least one transmission interface;
• and
• an expansion control unit, electrically connected to the at least one expansion interface and the at least one transmission interface, wherein the expansion control unit communicates with the at least one external device via the at least one expansion interface and communicates with the electronic host device via the at least one transmission interface, such that the electronic host device communicates with the at least one external device via control of the expansion control unit.