US Patent 7424569 Data transfer control device and electronic equipment

Aspects of the invention can provide a data transfer control device and electronic equipment that can achieve to switch supplying power through a VBUS. The transfer controller can transmit a switching request packet of supplying power through a VBUS to a type-B plug connected side (a type-B device side). In the case when the transfer controller can receive a switching acknowledgment packet of supplying power through the VBUS, the transfer controller can instruct a power supply switching circuit to stop a power supply through the VBUS. A monitoring the voltage level of the VBUS can be stopped before stopping the power supply through the VBUS. A transfer controller can receive the switching request packet of supplying power through the VBUS from the type-A plug connected side (a type-A device side). In the case when the transfer controller acknowledges the switching, the transfer controller can transmit the switching acknowledgment packet of supplying power through the VBUS, and instructs the power supply switching circuit to start supplying power through the VBUS. The monitoring the voltage level of the VBUS can be stopped before starting the power supply through the VBUS. The switching request packet and switching acknowledgment packets can be transmitted using a control transfer.