Patent ID: 8225114

Claim:
A portable electronic apparatus, connected to a power supply device via a transmission line, the power supply device comprising a USB connector, and the USB connector having a first pin used for providing a charge power, a second pin used for delivering data, a third pin used for delivering data, a fourth pin used as an identification judgment, and a fifth pin coupled to a grounding terminal, the portable electronic apparatus comprising: a designated connector, comprising a first terminal corresponding to the first pin of the USB connector, a second terminal corresponding to the second pin of the USB connector, a third terminal corresponding to the third pin of the USB connector, a fourth terminal corresponding to the fourth pin of the USB connector, and a fifth terminal corresponding to the fifth pin of the USB connector; a charge control circuit, coupled to the designated connector, for receiving the charge power from the first pin of the USB connector via the first terminal of the designated connector; and a judgment circuit, coupled to the designated connector and the charge control circuit, the judgment circuit comprising: a first determining unit, used for pulling down a voltage level of the third terminal and detecting the voltage level of the third terminal so as to generate a third determining result under a condition that the power supply device is connected to the portable electronic apparatus, a voltage level of the first terminal is logic high, a voltage level of the fourth terminal is logic high, and the voltage level of the third terminal is logic high after pulling up a voltage level of the second terminal; wherein the judgment circuit determines a type of the power supply device according to at least the third determining result.