Abstract: A charging relay device of the embodiments has a power receiving unit, a power transmitting unit and a communication protocol converting unit. The power receiving unit is capable of receiving power according to first standard. The power transmitting unit is capable of transmitting power according to second standard that is different from the first standard. The communication protocol converting unit converts a communication protocol complying with the first standard into a communication protocol complying with the first standard.

Abstract: A semiconductor device in an embodiment includes an arithmetic unit and a determining unit. The arithmetic unit detects an output current outputted to a charging target device or calculates output power outputted to the charging target device. The determining unit determines, according to the output current or the output power, whether a battery of the charging target device is fully charged.