The application discloses a mobile power pack, a power control circuit and an electrical connection device. The power control circuit comprises: a voltage detecting module configured to detect a voltage of an external power source and generate a voltage detection signal indicative of the voltage of the external power source; a control module configured to receive the voltage detection signal and generate a coupling control signal according to the voltage detection signal; a coupling module configured to operably couple a first power source and a second power source, receive the coupling control signal, and in response to the coupling control signal change the way the first power source is coupled with the second power source to control the first power source and the second power source coupled together to output electric energy under different output voltages. The power control circuit of the application can automatically control the coupled power source to output electric energy under different voltage in response to the voltage of the external power source.