摘要:
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.
摘要:
A method includes powering multiple touch sensors using DC power derived from an AC power signal; monitoring the AC power signal and producing from the AC power signal a trigger signal that occurs repeatedly at a predetermined point in a cycle of the AC power signal; and initiating a scan of the touch sensors when the trigger signal occurs during each cycle of the AC power signal.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A capacitive sensor includes a switching capacitor circuit, a comparator, and a charge dissipation circuit. The switching capacitor circuit reciprocally couples a sensing capacitor in series with a modulation capacitor during a first switching phase and discharges the sensing capacitor during a second switching phase. The comparator is coupled to compare a voltage potential on the modulation capacitor to a reference and to generate a modulation signal in response. The charge dissipation circuit is coupled to the modulation capacitor to selectively discharge the modulation capacitor in response to the modulation signal.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A method and apparatus scan a plurality of scan groups in a capacitive sense array to generate signals corresponding to a mutual capacitance between the electrodes. Each of the plurality of scan groups is formed from a subset of the plurality of electrodes. A processing device identifies a scan group where the generated signal is affected by a presence of a conductive object. The processing device individually scans the subset of the plurality of sense elements in the identified scan group to determine a location of the conductive object.