Source device and power control method of source device

A source device that is connected to a sink device to supply power to the sink device, the source device comprising:

• one or more memories that store processor-executable instructions,
• one or more hardware processors configured to execute the processor-executable instructions to cause the one or more hardware processors to:
• perform negotiation with the sink device on the basis of a predetermined power standard;
• perform control of supplying power to the sink device on the basis of a first power information determined by the negotiation;
• detect power required by the sink device;
• receive an input of the first power information, wherein the first power information has been determined by the negotiation, and the first power information includes a voltage value and a current value of power;
• receive an input of a second power information, wherein the second power information includes a voltage value and a current value of power detected;
• generate a third power information, wherein the third power information includes a voltage value and a current value on the basis of both the inputs of the first power information and the second power information and on the basis of the predetermined power standard;
• perform negotiation with the sink device again on the basis of the third power information generated;
• and
• when a current value of the second power information gets greater than a set threshold value while a power determined being supplied to the sink device as a result of the negotiation, change the third power information by setting the current value of the first power information determined by the negotiation to be lowered by a predetermined current value in the third power information, and perform negotiation with the sink device again on the basis of the third power information changed.