| 摘要 |
PROBLEM TO BE SOLVED: To allow an IC to switch to a mouse mode such as a USB, PS/2, ADB, PC98 and serial, without restarting a video display device by controlling an IC power source when a USB cable is pulled out from a connection terminal. SOLUTION: After an element 3 ORs signals 1 and 2, an element 4 ANDs the signal of the element 3 and the output signal of an element 1. Consequently, a signal is obtained, which becomes Low only when the USB cable is pulled out from the connection terminal, but becomes Hi in other cases on condition that any mouse cable is connected. This signal is used as the control signal of a power control switch 1 of the mouse IC 101 of the element 2. The mouse IC 101 is powered off for a period wherein no mouse cable is connected and for a certain time after the mouse cable is disconnected when the USB cable is connected and the power source can be turned on in a period wherein any cable is connected.
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