| 摘要 |
<p>PROBLEM TO BE SOLVED: To promptly restore functional operation of a functional circuit part of a device at re-supply of power even when the functional circuit part of the device is affected by current restriction such as power interruption regarding a bus connection type device to perform required functional operation by receiving power supply from a multipurpose bus such as a USB. SOLUTION: This bus connection type device is constituted so as to be connected with a bus including a signal line and a power supply line and is operated by communicating with an external device via the signal line. It is provided with a functional part at power feeding destination to perform the functional operation by communicating with the external device by receiving the power supply, a power supply control part to perform on/off control of the power supply from the power supply line or a commercial power source to the functional part at power feed destination and a decision means to decide whether the power supply to the functional part at power feed destination is the one from a bus power supply line or the one from the commercial power source. When the power supply from the bus power supply line is turned off in the case of the power supply from the bus power supply line, state information of the functional part at power feed destination is saved in a memory part for saving.</p> |
