A capacitance detection circuit, a touch control chip and an electronic device can effectively extract a capacitance change without increasing costs of a circuit. The capacitance detection circuit includes: a CCA circuit, a first input end and a second input end of the CCA circuit are connected to a capacitance to be measured and a cancellation capacitance, respectively, a third input end of the CCA circuit is connected to a coding voltage, and a first output end and a second output end of the CCA circuit output a first current and a second current, respectively, where the cancellation capacitance is smaller than an initial value of the capacitance to be measured; a PGA circuit, two input ends of the PGA circuit are connected to two output ends of the CCA circuit, respectively.

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 transform is used to transform raw sensor data from the time domain to the frequency or sequency domain. The transformed data falls into several signal bins. The transformed data in at least one of the signal bins is analyzed to determine whether a touch event or release event has occurred.

A sensor switch including a first sensor electrode and a second sensor electrode at least partially surrounding the first sensor electrode. An evaluation and control circuit of the sensor switch is configured to generate a switch output signal if a first sensor electrode attenuation signal indicates a high signal attenuation, a second sensor electrode attenuation signal indicates a low signal attenuation, and a cross-coupling signal from the first to the second electrode indicates a low cross-coupling.

A capacitance detection device detecting a capacitance between a detection electrode and a detection target close to the detection electrode has: a first voltage output circuit that outputs a first alternating current voltage to be supplied to a shield electrode placed close to the detection electrode; a second voltage output circuit that outputs a second alternating current voltage with substantially the same frequency as the first alternating current voltage; and an operational amplifier that amplifies the difference in voltage between an inverting input terminal connected to the detection electrode and a non-inverting input terminal to which the second alternating current voltage is applied, and outputs the amplified difference in voltage. With the detection target close to the detection electrode, the second voltage output circuit outputs the second alternating current voltage adjusted so that an output voltage from the operational amplifier has a smaller amplitude than the first alternating current voltage.

Provided is a system that includes: a plurality of touch sensors sharing a signal medium, each touch sensor in the plurality being configured to output set of frequencies on the signal medium responsive to being touched, each touch sensor in the plurality being configured to output a different set of frequencies; an analog to digital converter electrically coupled to the signal medium and configured to receive the sets of frequencies from the touch sensors and convert the sets of frequencies to digital representations of the sets of frequencies in the time domain; a processor communicatively coupled to the analog to digital converter and configured to execute a fast Fourier transform of the digital representations from the time domain into digital representations in the frequency domain; and an address decoder operative to transform the digital representations in the frequency domain into identifiers of touch sensors among the plurality of touch sensors.

A sensor switch including a first sensor electrode and a second sensor electrode at least partially surrounding the first sensor electrode. An evaluation and control circuit of the sensor switch is configured to generate a switch output signal if a first sensor electrode attenuation signal indicates a high signal attenuation, a second sensor electrode attenuation signal indicates a low signal attenuation, and a cross-coupling signal from the first to the second electrode indicates a low cross-coupling.

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 transform is used to transform raw sensor data from the time domain to the frequency or sequency domain. The transformed data falls into several signal bins. The transformed data in at least one of the signal bins is analyzed to determine whether a touch event or release event has occurred.

An ON/OFF detection device is configured to detect ON/OFF of an input unit using a load sensor, and includes a threshold setting unit, a comparison unit, and an ON/OFF determination unit. The threshold setting unit is configured to set a threshold value with respect to a previous detection value of the load sensor. The comparison unit is configured to compare the threshold value and a current detection value. The ON/OFF determination unit is configured to determine ON/OFF of the input unit based on a comparison result. When a previous determination result of the ON/OFF determination unit is ON, the threshold setting unit is configured to set the threshold value to be lower than the previous detection value. When the previous determination result of the ON/OFF determination unit is OFF, the threshold setting unit is configured to set the threshold value to be higher than the previous detection value.