| 摘要 |
<p>PURPOSE:To extremely easily attain the on/off of a power source even when a peripheral device is arranged far from a high-order device by making the peripheral device to detect the on/off of the power source of the high-order device to turn on/off its own power source. CONSTITUTION:A detection part 2 contains an inside power source for its own operation. The detection part 2 monitors the voltage of a signal line 5 to respectively output a connection signal when it becomes larger than a first reference voltage and a power source disconnection signal when it becomes lower than a second reference voltage to a power source control circuit 23. The power source control circuit 23 has a power source which is necessary for its own operation inside and when receiving a power source disconnection signal and a power source disconnection signal, it disconnects the connection of an external power source and a peripheral device 2 to make the power source of the peripheral device 2 to be off. Thus, even when the peripheral device is arranged far from the high-order device, the on/off of the power source can extremely easily be executed.</p> |
