Systems, methods, and devices improve the sensitivity of capacitive sensors. Devices may include an attenuator configured to receive an input from at least one sense electrode of a capacitive sensing device. The attenuator may be included in a sensing channel of a capacitive sensor. Devices may further include a signal generator coupled to an input of the attenuator. The signal generator may include one or more processors configured to generate a sinusoidal signal based, at least in part, on one or more noise characteristics of a scan sequence associated with one or more transmit electrodes of the capacitive sensing device, and provide the sinusoidal signal to the input of the attenuator.

A switching operation sensing apparatus includes an input operation unit, an oscillation circuit, a frequency digital converter, and a touch detection circuit. The input operation unit includes a first switching member integrally formed with a housing. The oscillation circuit is configured to generate an oscillation signal having a resonant frequency, varying based on a capacitive change or an inductive change, depending on a touch input member in contact with the first switching member during an input operation. The frequency digital converter is configured to convert the oscillation signal into a count value. The touch detection circuit is configured to detect capacitive sensing and inductive sensing based on a slope change of the count value received from the frequency digital converter, and output corresponding touch detection signals of different levels based on the detection.

A method of operating a capacitive sensing device that includes a capacitive sensor having at least one sense electrode, a measurement signal source for providing an alternating electric measurement signal with at least three fixed predefined signal frequencies to the at least one sense electrode, and an impedance measurement circuit for determining an unknown complex impedance of the at least one sense electrode from a response to the provided electric measurement signal. The method includes, for each predefined signal frequency: determining statistical quantities and signal parameters regarding a number of determined momentary values of an unknown complex impedance; eliminating portions up to a predefined hand touch movement lower limit frequency and from a predefined high-frequency limit down to a predefined hand touch movement upper limit frequency; excluding statistical outliers from determined momentary values; and using an eliminated frequency portion for calculating a momentary reference value for the unknown complex impedance.

Provided is a capacitance detection circuit, which has better detection performance. The capacitance detection circuit includes: a first charging and discharging circuit configured to perform charging or discharging on a capacitor to be detected; a second charging and discharging circuit configured to perform charging or discharging on a calibration capacitor; an analog-to-digital conversion circuit configured to continuously sample a voltage difference between the capacitor to be detected and the calibration capacitor in a charging or discharging process to obtain sampled data; and a digital processing circuit configured to detect a capacitance of the capacitor to be detected according to the sampled data.

A capacitance detection circuit, a detection chip, and an electronic device are provided. The circuit includes: a first drive module, a conversion module, a processing module, and a control module. The first drive module is configured to charge a first capacitor to be detected. The conversion module is configured to perform charge conversion processing on the first capacitor to be detected to generate an output voltage. The control module is configured to control a first suppression module of the conversion module to suppress an interference signal with a frequency less than a first frequency or greater than a second frequency when the conversion module generates the output voltage, and the second frequency is greater than the first frequency. The processing module is configured to determine a capacitance change before and after the first capacitor to be detected is affected by an applied electric field based on the output voltage.

A switching operation sensing device is provided. The device includes a touch operation unit that is integrally formed with a housing and includes first and second touch members disposed in different regions; an oscillator circuit configured to generate a first oscillation signal including a variable resonant frequency when the first touch member is touched and a second oscillation signal including a variable resonant frequency when the second touch member is touched; and a touch detector circuit configured to detect whether at least one of the first and second touch members has been touched, and distinguish touch regions based on the first oscillation signal and the second oscillation signal.

A switching operation sensing device is provided. The device includes a touch operation unit that is integrally formed with a housing and includes first and second touch members disposed in different regions; an oscillator circuit configured to generate a first oscillation signal including a variable resonant frequency when the first touch member is touched and a second oscillation signal including a variable resonant frequency when the second touch member is touched; and a touch detector circuit configured to detect whether at least one of the first and second touch members has been touched, and distinguish touch regions based on the first oscillation signal and the second oscillation signal.

A sensing device with a fingerprint sensor is provided. The sensing device includes a touch input pattern included in the fingerprint sensor, an oscillation circuit connected to the touch input pattern and configured to change a capacitance of the oscillation circuit when a touch occurrence is sensed by the touch input pattern and generate an oscillation signal based on the change in the capacitance, and an operation detection circuit configured to detect a touch occurrence based on a frequency included in the oscillation signal input from the oscillation circuit and generate a detection signal.

A switching operation sensing apparatus includes an input operation unit, an oscillation circuit, a frequency digital converter, and a touch detection circuit. The input operation unit includes a first switching member integrally formed with a housing. The oscillation circuit is configured to generate an oscillation signal having a resonant frequency, varying based on a capacitive change or an inductive change, depending on a touch input member in contact with the first switching member during an input operation. The frequency digital converter is configured to convert the oscillation signal into a count value. The touch detection circuit is configured to detect capacitive sensing and inductive sensing based on a slope change of the count value received from the frequency digital converter, and output corresponding touch detection signals of different levels based on the detection.

Electrodes and regions of top plate opposed to electrodes constitute switches that have capacitances varying when the regions of top plate are depressed from top plate toward electrodes. Depression detection circuit calculates the capacitance change amounts of switches indicating changes of the capacitances from a reference value. Depression detection circuit calculates the maximum value and sum of the capacitance change amounts of switches. When the capacitance change amount of at least one switch exceeds threshold and a situation in which the ratio of the maximum value to the sum is equal to or greater than threshold has lasted for the number of repetitions in, depression detection circuit determines that the switch having the maximum value of the capacitance change amount is in a depressed state.