| 摘要 |
PURPOSE: An electrostatic capacitance switch is provided to prevent the misoperation in strong electrostatic discharge(ESD) from outside by providing a compensation capacitor(Cc). CONSTITUTION: An electrostatic capacitance switch(130) includes an electrostatic capacitance comparator, a first reference capacitor, a second reference capacitor, a first sensing capacitor(Cps), a second sensing capacitor(Cpr) and a compensation capacitor(Cc). The electrostatic capacitance comparator compares the electrostatic capacitances inputted to the inverted terminal and the non-inverted terminal and outputs the signal based on the compared result. One terminal of the first reference capacitor is connected to the inverted terminal and the other terminal is connected to the non-inverted terminal. One terminal of the second reference capacitor is connected to the non-inverted terminal and the other terminal is connected to the ground. One terminal of the first sensing capacitor(Cps) is connected to the terminal of the first reference capacitor and the other terminal is floated to change its electrostatic capacitance when the external object approaches thereto. One terminal of the second sensing capacitor(Cpr) is connected to the terminal of the second reference capacitor and the other terminal is floated to change its electrostatic capacitance with being smaller than that of the first sensing capacitor(Cps). And, the compensation capacitor(Cc) is connected between the first sensing capacitor(Cps) and the second sensing capacitor(Cpr) in serial.
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