Abstract: Apparatuses and method of driving a shield electrode and electrodes of a matrix are described. One apparatus includes a plurality of electrodes disposed as a matrix below a touch surface, a shield electrode, and a capacitance-sensing circuit. The capacitance-sensing circuit measures capacitances of the plurality of electrodes to detect a conductive object in contact with the touch surface or above the touch surface. The capacitance-sensing circuit measures a self-capacitance of a first electrode of the plurality of electrodes while driving the shield electrode with a shield signal, the shield signal being the same electrical potential as the plurality of electrodes. The capacitance-sensing circuit drives a second electrode of the plurality of electrodes as a barrier electrode to increase a detection distance from the touch surface to detect a conductive object above the touch surface.

Abstract: Apparatuses and methods of frequency selection algorithms and frequency set selection are described. One method monitors a signal on the electrodes of a sense network, determine a first group of noise metrics of noise in the signal, determine a second group of noise metrics. The method switches from a first operating frequency in a first set to a second operating frequency in the first frequency set based on the first group of noise metrics and switches from the first operating frequency in the first set to a third operating frequency in a second frequency set based on the second group of noise metrics.

Abstract: A capacitance sensing module includes a timer circuit configured to generate a repetitive trigger signal, a low power oscillator block configured to generate a clock signal having a higher frequency than the repetitive trigger signal, a sensing block coupled with the timer circuit and the oscillator block and configured to, in response to the repetitive trigger signal, detect a presence of a conductive object at a capacitive sensor button by applying an excitation signal based on the clock signal to the capacitive sensor button, and a wake logic block coupled with the sensing block and configured to transition a processing unit from a low power consumption state to a high power consumption state in response to the sensing block detecting the presence of the conductive object at the capacitive sensor button.

Abstract: Apparatuses and methods of driving barrier electrodes of a capacitive-sense array with an excitation signal are described. One apparatus includes a capacitance-sensing circuit coupled to a capacitive-sense array including multiple electrodes. The capacitance-sensing circuit includes multiple sensing channels. The capacitance-sensing circuit is operative to measure signals on a first subset of the multiple electrodes using the multiple sensing channels. Each of the sensing channels is selectively coupled to one of the first subset of electrodes. The capacitance-sensing circuit is further operative to drive a barrier electrode of the multiple electrodes with an excitation signal while measuring the signals on the first subset. The excitation signal is greater in magnitude than the measured signals. The barrier electrode is adjacent to an edge electrode of the first subset that is coupled to one of the sensing channels.

Abstract: A method for compensating for panel capacitance the associated current is proposed, wherein the mutual capacitances of a capacitance sensing array are selectively coupled to drive voltages and to a self capacitance under test.

Abstract: Apparatuses and methods of high-voltage capacitance-sensing circuits are described. One apparatus includes a capacitance-sensing circuit coupled to a capacitive-sense array of electrodes. The capacitance-sensing circuit includes a self-capacitance sensing channel, a first voltage source (e.g., a low-voltage drive source) to drive a reference voltage, and a second voltage source (e.g., high-voltage drive source) to drive a sensing voltage. The sensing voltage is greater in magnitude than the reference voltage. The capacitance-sensing circuit also includes 1) a first set of switches to selectively couple the self-capacitance sensing channel or the second voltage source to a sensing electrode of the capacitance-sensing array; and 2) a second set of switches to selectively couple the first voltage source or the second voltage source to a shielding electrode of the capacitance-sensing array.

Abstract: An integration circuit including a first capacitor is operatively coupled to a comparator. The comparator is configured to compare a first capacitor voltage of the first capacitor to a reference voltage and produce a first comparator output based on the comparison. A current generator is operatively coupled with the integration circuit and configured to balance charge on the first capacitor. A control unit is operatively coupled to the comparator and the current generator and configured to balance charge on the first capacitor by sensing the first comparator output and controlling the current generator based on the first comparator output.

Abstract: A capacitance sensing system can filter noise that presents in a subset of electrodes in the proximity of a sense object (i.e., finger). A capacitance sensing system can include a sense network comprising a plurality of electrodes for generating sense values; a noise listening circuit configured to detect noise on a plurality of the electrodes; and a filtering circuit that enables a filtering for localized noise events when detected noise values are above one level, and disables the filtering for localized noise events when detected noise values are below the one level.

Abstract: Apparatuses and methods of driving barrier electrodes of a capacitive-sense array with an excitation signal are described. One apparatus includes a capacitance-sensing circuit coupled to a capacitive-sense array including multiple electrodes. The capacitance-sensing circuit includes multiple sensing channels. The capacitance-sensing circuit is operative to measure signals on a first subset of the multiple electrodes using the multiple sensing channels. Each of the sensing channels is selectively coupled to one of the first subset of electrodes. The capacitance-sensing circuit is further operative to drive a barrier electrode of the multiple electrodes with an excitation signal while measuring the signals on the first subset. The excitation signal is greater in magnitude than the measured signals. The barrier electrode is adjacent to an edge electrode of the first subset that is coupled to one of the sensing channels.

Abstract: Methods and apparatus include receiving a current set of measurements of a touch sense array using a first functional block of a processing device and processing the current set of measurements using a second functional block to render a touch map corresponding to the touch sense array. The methods and apparatus include performing the next set of measurements using the first functional block. Performing the next set of measurements and processing the current set of measurement are performed substantially concurrently.

Abstract: A processing device scans, during a first operation, a first plurality of electrodes along a first axis in a capacitive sense array to generate a first plurality of signals corresponding to a mutual capacitance at electrode intersections of the capacitive sense array. During a second operation, the processing device scans a second plurality of electrodes along a second axis in the capacitive sense array to generate a second plurality of signals corresponding to the mutual capacitance at the electrode intersections of the capacitive sense array, wherein the second operation occurs during a different period of time than the first operation. The processing device determines a first coordinate of a conductive object proximate to the capacitive sense array based on the first plurality of signals and a second coordinate of the conductive object based on the second plurality of signals.

Abstract: A method for improving noise immunity of capacitive sensing circuit associated with a touch sense array is disclosed. The capacitive sensing circuit receives a response signal from a touch sense array. The capacitive sensing circuit measures a noise component of the response signal. When a level of noise of the noise component within a passband of the capacitive sensing circuit is greater than a threshold, the capacitive sensing circuit changes at least one parameter of capacitive sensing circuit to move the passband substantially outside the frequency spectrum of the noise component.

Abstract: A processing device configured to induce, during a listening scan of a sense array, an injected touch to produce similar data as would be present during a touch scan of the sense array with a conductive object at a known location on the sense array. The processing device is further configured to compute, using the data, an estimate of a noise metric based on the injected touch.

Abstract: A capacitive sensor may include a transmit electrode and a receive electrode capacitively coupled with the transmit electrode. A capacitance sensing circuit senses a capacitance between the transmit and receive electrodes by applying a signal to the transmit electrode and rectifying a current waveform induced at the receive electrode. A compensation circuit reduces the effect of a mutual and parasitic capacitances of the transmit and receive electrode pair by adding a compensation current to the rectified current.

Abstract: A method for compensating for panel capacitance the associated current is proposed, wherein the mutual capacitances of a capacitance sensing array are selectively coupled to drive voltages and to a self capacitance under test.

Abstract: A method and apparatus for scanning a first set of electrodes of a capacitive sense array using a first sensing mode to identify a presence of an object in proximity to the capacitive sense array, where scanning using the first sensing mode identifies objects not in physical contact with the capacitive sense array. The first set of electrodes is scanned using a second sensing mode to determine a location of the object in relation to the capacitive sense array, where rescanning using the second sensing mode determines locations of objects in physical contact with the capacitive sense array.

Abstract: A capacitance sensing system may include a first selection circuit that couples N electrodes of a first electrode set to a capacitance sense circuit; and a second selection circuit that couples M electrodes of a second electrode set, substantially simultaneously, to a signal generator circuit as a group to induce current in the N electrodes by mutual capacitance between the M and N electrodes; wherein N is at least one, and M>N.

Abstract: An apparatus for and a method of sensing capacitance of one or more sensor elements in multiple capacitance sensing modes, including a self-capacitance sensing mode and a mutual capacitance sensing mode.

Abstract: An integration circuit including a first capacitor is operatively coupled to a comparator. The comparator is configured to compare a first capacitor voltage of the first capacitor to a reference voltage and produce a first comparator output based on the comparison. A current generator is operatively coupled with the integration circuit and configured to balance charge on the first capacitor. A control unit is operatively coupled to the comparator and the current generator and configured to balance charge on the first capacitor by sensing the first comparator output and controlling the current generator based on the first comparator output.

Abstract: A capacitive sensor may include a transmit electrode and a receive electrode capacitively coupled with the transmit electrode. A capacitance sensing circuit senses a capacitance between the transmit and receive electrodes by applying a signal to the transmit electrode and rectifying a signal induced at the receive electrode. A compensation circuit reduces the effect of a mutual and parasitic capacitances of the transmit and receive electrode pair by adding a compensation signal to the rectified signal.