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OwnerKenichi Matsushimainventor
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Provided are an electrostatic capacitance detection circuit and an electrostatic capacitance detection method with which being capable of detecting minute change in electrostatic capacitance from which offset is removed for detection of approach of an object or the like, at high speed and high resolution while selecting an optimum detection range, with such a simpler configuration as to add a resistor and a capacitor to one input/output port of a general-purpose microcomputer. In the electrostatic capacitance detection circuit and the electrostatic capacitance detection method, a voltage waveform generated by the added capacitor is compared with a threshold voltage while controlling a DC component of the voltage waveform to change in correspondence with the change in electrostatic capacitance and an AC component of the voltage waveform to correspond to a width of a detection range.
An electrostatic capacitance detection device which detects an approach position of an object by means of an electrostatic capacitance, the electrostatic capacitance detection device comprising:
An electrostatic capacitance detection circuit which detects an approach position of an object by means of an electrostatic capacitance, the electrostatic capacitance detection circuit comprising:
An electrostatic capacitance detection circuit which detects an approach position of an object by means of an electrostatic capacitance, the electrostatic capacitance detection circuit comprising:
An electrostatic capacitance detection circuit which detects an approach position of an object by means of an electrostatic capacitance, the electrostatic capacitance detection circuit comprising:
An electrostatic capacitance detection method of detecting one of an electrostatic capacitance and change in electrostatic capacitance, the electrostatic capacitance detection method comprising:
An initialization method of shifting a capacitor from an initialization state before detection to a steady state, which is used in an electrostatic capacitance detection method of detecting one of an electrostatic capacitance and change in electrostatic capacitance, the initialization method comprising a threshold approach step of making a voltage of the capacitor approximate to a threshold voltage of a comparison step by controlling, when the voltage of the capacitor is higher than the threshold voltage of the comparison step, a switch to which a constant voltage source having a voltage lower than the threshold voltage of the comparison step is connected to be continuously turned on until an output of the comparison step is changed, and by controlling, when the voltage of the capacitor is lower than the threshold voltage of the comparison step, a switch to which a constant voltage source having a voltage higher than the threshold voltage is connected to be continuously turned on until an output of the comparison step is changed.
An initialization method of shifting a capacitor from an initialization state before detection to a steady state, which is used in an electrostatic capacitance detection method of detecting one of an electrostatic capacitance and change in electrostatic capacitance, the initialization method comprising a run-up step of repeating, at least once, operations of controlling a first switch to be continuously turned on/off for a number of times which is equal to a number of times the first switch is continuously turned on/off during a CQ conversion step, and of controlling a second switch to be continuously turned on/off for a number of times which is equal to a number of times the second switch is continuously turned on/off during the CQ conversion step.
Dependencies are inferred from the claim text.