Patent ID: 8217639

Claim:
A power supply device, comprising: a power input unit configured for connecting with an external power source and obtaining power from the external power source; a first interface unit configured for connecting with a power receiving device and outputting power to the power receiving device; a voltage converting unit configured for converting the voltage of the external power source to a predetermined voltage; a detection unit configured for detecting whether the power receiving device needs to be powered, and producing a control signal when the power receiving device needs to be powered, and further configured for controlling the voltage converting unit to provide a communication voltage to the power receiving device to establish a communication connection between the power supply device and the power receiving device according to the control signal; a communication unit configured for obtaining working voltage information from the power receiving device after the communication connection between the power supply device and the power receiving is established, the working voltage information indicating a working voltage to maintain a normal work state of the power receiving device; and a control unit configured for controlling the voltage converting unit to convert the voltage of the external power source to the working voltage of the power receiving device to power the power receiving device.