| 摘要 |
PROBLEM TO BE SOLVED: To provide an operation position detection device capable of increasing the frequency of a scan signal for detecting the operation position of an operation body which operates a capacitance type touch panel.SOLUTION: When a scan signal is applied from a scan signal generation part 32 to a capacity sensor 12 arranged on a touch panel 10, a sensor voltage VM of the capacity sensor 12 rises or lowers in accordance with the level of the scan signal, and converges to a reference voltage Vref. When charging to a capacitor 48 is started by the sensor voltage VM, a switch 60 is switched by a control signal generated by a constant current control part 32, and the capacitor 48 is connected to a constant current source 50 or a constant current source 52 such that discharging from the capacitor 48 is performed. When the voltage Vin of the capacitor 48 changes and matches the reference voltage Vref in accordance with charging/discharging, the switches 60 and 70 are switched by the control signal such that discharging from the capacitor 48 is stopped, and that charging to the capacitor 48 is stopped. |
