Patent ID: 8334844

Claim:
A mouse device, which is provided with a plurality of operation modes, the plurality of operation modes including: a normal operation of converting a movement amount into an electrical signal and outputting the electrical signal; and a low consumption operation in which power consumption is smaller than power consumption in the normal operation, the mouse device comprising light detection means, the light detection means comprising: a p-n junction element for charging a second node in accordance with an amount of incident light; a second constant current circuit for discharging the second node; a depletion type N-channel MOS transistor for discharging a first node with an ON-state current of the depletion type N-channel MOS transistor, the depletion type N-channel MOS transistor including: a gate to which a voltage of a reference power supply terminal is input; and a source to which a voltage of the second node is input; a first P-channel MOS transistor for charging an output terminal with an ON-state current of the first P-channel MOS transistor through a third constant current circuit, the first P-channel MOS transistor including a gate to which a voltage of the first node is input; an N-channel MOS transistor for discharging the output terminal with an ON-state current of the N-channel MOS transistor, the N-channel MOS transistor including a gate to which the voltage of the second node is input; and a second P-channel MOS transistor for charging the first node with an ON-state current of the second P-channel MOS transistor through a first constant current circuit, the second P-channel MOS transistor including a gate to which a voltage of the output terminal is input, the mouse device switching the plurality of operation modes based on an output of the light detection means.