Patent ID: 8907634

Claim:
A charger for a portable electronic device, comprising: a power supply generating a power supply potential; a power supply line and a ground line that are connected to the power supply; a USB connector configured to be connected to a portable electronic device through a USB cable, the USB connector comprising a Vbus terminal, a first data communication terminal, a second data communication terminal and a ground terminal; a switching element provided between the power supply line and the Vbus terminal; a resistor bridge circuit comprising a first resistor, a second resistor, a third resistor and a fourth resistor, a first connection node of the first resistor and the second resistor being connected to the first data communication terminal and a second connection node of the third resistor and the fourth resistor being connected to the second data communication terminal; and a controller comprising a switching control circuit controlling switching of the switching element and a potential setting circuit setting potentials of the first and second connection nodes to a middle potential between the power supply potential and a ground potential in a first mode and setting the potentials of the first and second connection nodes to the power supply potential in a second mode.