A capacitive detection device includes a capacitive sensor having a sense electrode and an auxiliary electrode that are arrangeable in the vicinity of an electric heater member for mutual capacitive coupling. The capacitive detection device has a signal voltage source providing an alternating measurement voltage, a complex impedance measurement circuit for measuring complex sense currents and for determining a complex impedance based on the measured complex sense current, and for electrically connecting the auxiliary electrode either with the reference voltage or with the guard signal. The method includes providing the measurement signal to the sense electrode and electrically connect the auxiliary electrode selectively either to the reference voltage or to the guard voltage; determining capacitance values in the two different connection states of the auxiliary electrode; and calculating a compensated capacitance value as a weighted sum of the two determined capacitance values, wherein the weighting factors are predefined constant values.

A device for closing or opening two or more main switches of corresponding electrical power supply circuits of related electrical devices includes a plate having at least two capacitive touch contact areas, and a control circuit configured to control two or more additional switches so that, in the event that only one of the contact areas is touched, only the corresponding main switch is opened or closed, while in the event of a combined touching of at least two of the contact areas, one of the additional switches is opened or closed.

A touch sensing module includes: a first sensing coil and a second sensing coil, each having inductance varying in response to an applied force touch; a first pad having capacitance varying in response to an applied contact touch, disposed closer to the second sensing coil than to the first sensing coil, and electrically connected to the first sensing coil to constitute a first resonance circuit; and a second pad having capacitance varying in response to the applied contact touch, disposed closer to the first sensing coil than to the second sensing coil, and electrically connected to the second sensing coil to constitute a second resonance circuit.

The present disclosure discloses a driving circuit and a related chip and electronic device. The driving circuit is configured to drive a load and includes: a control unit, configured to generate a first control signal and a second control signal; a first output terminal, coupled to the capacitive touch screen; a mutual capacitive driving circuit, including: a first pull-up unit, configured to selectively pull up the first output terminal coupled to a high voltage level according to the first control signal; a first pull-down unit, configured to selectively couple the first output terminal to a low voltage level according to the second control signal; a first low-pass filter circuit, coupled between the control unit and the first pull-up unit; and a second low-pass filter circuit, coupled between the control unit and the first pull-down unit.

A hover button sensor unit, comprising: a power supply circuit (5-1), a capacitive sensor, a capacitance-to-digital conversion circuit (3), a control module, an acousto-optic feedback control circuit (5-3), and a communication circuit (5-2); The capacitive sensor is a convex structural arrangement of a central electrode (1-1) and a peripheral electrode (1-2). The capacitance-to-digital conversion circuit (3) measures self-capacitance and mutual capacitance of the central electrode (1-1) and the peripheral electrode (1-2) after human finger approaching, to calculate and determine whether a finger enters the area range and its dwell time, so that the control module outputs a control logic signal of the button; detecting the proximity of the human finger to the effective hover trigger area range above a certain central electrode (1-1) by means of the button formed by the sensor unit, providing three-state response to the human finger entering the effective hover trigger area range above a certain central electrode (1-1) by the acousto-optic feedback control circuit (5-3); The above mentioned technical scheme is reasonable in structural design, which can effectively resist various interference, fully utilize a low-cost of capacitance detection and mature CDC chip technology and provide a commercialized technical solution which can be popularized for hygienic sensitivity.

A microcontroller uses a combination of several synchronized PWM outputs to generate a low distortion sine wave by summing the PWM outputs and filtering the summed signal. The sine wave is used as a guard voltage. The unknown impedance is measured by impinging the guard voltage on the sense electrode by a transistor connected in common base configuration and then transferring the sense current through the common base connected transistor to a transimpedance amplifier made out of a second transistor connected in common emitter configuration. The output voltage at the collector of the second transistor is measured by an ADC input of the microcontroller. The microcontroller translates the ADC output values into the unknown impedance to be measured by doing a software demodulation of the ADC output values. A reference impedance can be connected in parallel to the unknown impeder to eliminate gain errors of the signal sensing circuit.

A touch sensing circuit operable to sense a conductor approaching a sensor capacitance by measuring a response signal obtained from the sensor capacitance according to an applied detection signal includes an A/D converter and a Fourier transform device. The A/D converter samples the response signal with a predetermined cycle, followed by conversion to a digital value and outputs as time-series response data. The Fourier transform device calculates, from the time-series response data, a result of transformation at a detection frequency representing the reciprocal of a cycle of the detection signal and outputs it. The touch sensing circuit converts the response signal to the frequency domain, calculates only components (harmonics or others as needed) of a frequency equal to that of the detection signal required for touch sensing, and supplies them for a touch coordinate calculation process in a subsequent stage.

A resonant drive circuit for a capacitive sensor device includes a resonant LC stage, a signal source, and an amplifier stage. The resonant LC stage includes an inductorless floating gyrator circuit electrically connected to a sense capacitor. The inductorless floating gyrator circuit is configured to synthesize a fixed inductance. The resonant LC stage is configured to output a sensed capacitance signal based on the fixed inductance and a change in capacitance of the sense capacitor. The signal source is configured to output a reference signal. The amplifier stage is configured to receive the sensed capacitance signal and the reference signal and output a measured capacitance signal that indicates a difference in one or more of amplitude and phase between the sensed capacitance signal and the reference signal.

A capacitive sensing device includes an antenna electrode for emitting an alternating electric field in response to an alternating voltage caused in the antenna electrode and a control and evaluation circuit configured to maintain the alternating voltage equal to an alternating reference voltage by injecting a current into the antenna electrode and to measure the current. The control and evaluation circuit includes a microcontroller with a digital output for providing a digital signal and a low-pass filter operatively connected to the digital output for generating the alternating reference voltage by low-pass-filtering the digital signal.

One or more embodiments relate to a multi-bias mode current conveyor. Such a current conveyor may include an input terminal, a reference terminal, an output terminal, a first and second cascoded current mirrors, and a biasing circuit. The first cascoded current mirror and a second cascoded current mirror may be arranged as a current conveyor that is configured to provide an output current that a mirror of an input current. The biasing circuit may be configured to provide a bias voltage selectively exhibiting a first voltage level or a second voltage level. The bias voltage may be provided at least partially responsive to a state of the input current. The biasing circuit may be arranged to apply the bias voltage to at least one of the first cascoded current mirror or the second cascoded current mirror.