| 摘要 |
A device for detecting key input is provided to realize a power switch not using a microprocessor in a vehicle information device and reduce the number of operation keys by utilizing the power key as the other function key after power is turned on. A charger(100) outputs a voltage value by being charged and discharged according to switching the operation key. A switch(200) selects a path having a big or small time constant as a charging/discharging path of the charger. A flip-flop(300) is togged by the voltage value output from the charger and controls a switching operation of the switch by an output value. A gate device is connected between the charger and the flip-flop in serial, and has a hysteresis characteristic. A key input detector(400) detects an output voltage value at another end of the switch. The charger includes the first, second, and third resistors, and a condenser.
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