Abstract: A capacitance sensing device includes a transmit (TX) generator for generating a sequence of receive (RX) signals by applying each TX signal pattern in a sequence of TX signal patterns to a set of sensor electrodes. For each TX signal pattern in the sequence of TX signal patterns, and for each subset of three or more contiguous sensor electrodes of the set of sensor electrodes, the TX generator applies to the subset one of a first excitation signal and a second excitation signal. The plurality of subsets includes at least half of the sensor electrodes in the set of sensor electrodes. The capacitance sensing device also includes a sequencer circuit coupled with the TX generator. For each TX signal pattern in the sequence of TX signal patterns, the sequencer circuit determines a next subsequent TX signal pattern in the sequence based on a circular rotation of the TX signal pattern. The capacitance sensing device also includes a processing block coupled with the TX generator.

Abstract: One or more circuits and/or methods are provided. In an example, a circuit includes a first sampling capacitor connected to a first battery terminal for connecting to a battery, an excitation circuit connected to the first battery terminal and configured to generate a first excitation signal, and a measurement circuit connected to the first sampling capacitor and configured to measure charge transferred to the first sampling capacitor by the first excitation signal to generate a charge transfer measurement and to determine a first impedance measurement across the first battery terminal and a second battery terminal for connecting to the battery based on the charge transfer measurement.

Abstract: Technology directed to capacitive touch-sensing channels, including a capacitive-sensing converter based on a sigma-delta modulator, is described. One sigma-delta modulator includes a comparator, a first integrator coupled to receive an incoming signal from the input node and to provide a first output signal, a second integrator, coupled in parallel to the first integrator, to receive the incoming signal and to provide a second output signal, and switching circuitry. The switching circuitry is configured to selectively couple the first integrator between the input node and the comparator to provide the first output signal to the comparator or selectively couple the second integrator between the input node and the comparator to provide the second output signal to the comparator.

Abstract: Apparatus and methods of impedance sensing are described. One method includes performing a first digital conversion of an attribute of a sensor electrode and performing a second digital conversion of the attribute of the sensor electrode. The second digital conversion differs by at least one characteristic from the first digital conversion. The method further includes calculating a resistance of the sensor electrode from a first and second digital value of the first and second digital conversions, respectively; and calculating a capacitance of the sensor electrode from the first and second digital value of the first and second digital conversions, respectively.

Abstract: Apparatus and methods of impedance sensing are described. One method includes performing a first digital conversion of an attribute of a sensor electrode and performing a second digital conversion of the attribute of the sensor electrode. The second digital conversion differs by at least one characteristic from the first digital conversion. The method further includes calculating a resistance of the sensor electrode from a first and second digital value of the first and second digital conversions, respectively; and calculating a capacitance of the sensor electrode from the first and second digital value of the first and second digital conversions, respectively.

Abstract: A fingerprint sensor-compatible overlay material which uses anisotropic conductive material to enable accurate imaging of a fingerprint through an overlay is disclosed. The anisotropic conductive material has increased conductivity in a direction orthogonal to the fingerprint sensor, increasing the capacitive coupling of the fingerprint to the sensor surface, allowing the fingerprint sensor to accurately image the fingerprint through the overlay. Methods for forming a fingerprint sensor-compatible overlay are also disclosed.

Abstract: A capacitance-sensing circuit may include a channel input associated with measuring a capacitance of a unit cell of a capacitive sense array. The capacitance-sensing circuit may also include a capacitive hardware baseliner that is coupled to the channel input. The capacitive hardware baseliner generates a baseline current based on a time constant of the channel input associated with the measuring of the capacitance of the element of the capacitive sense array using the programmable baseline resistor. The capacitive hardware baseliner provides the baseline current at the channel input to provide a charge for a sense capacitor. A change in the charge of the sense capacitor is provided by the baseline current indicating a presence of a tough object proximate to the element.

Abstract: Apparatus and methods of impedance sensing are described. One method includes performing a first digital conversion of an attribute of a sensor electrode and performing a second digital conversion of the attribute of the sensor electrode. The second digital conversion differs by at least one characteristic from the first digital conversion. The method further includes calculating a resistance of the sensor electrode from a first and second digital value of the first and second digital conversions, respectively; and calculating a capacitance of the sensor electrode from the first and second digital value of the first and second digital conversions, respectively.

Abstract: Embodiments described herein provide capacitive sensor devices and methods for operating capacitive sensor devices. A first number of electrodes on the capacitive sensor array is activated. A signal is received from each of the first number of electrodes with a second number of receiver circuits on a controller associated with the capacitive sensor array. The first number is greater than the second number. It is determined if an object is proximate the capacitive sensor array based on the signals received from the first number of electrodes.

Abstract: A capacitance-sensing circuit may include a channel input associated with measuring a capacitance of a unit cell of a capacitive sense array. The capacitance-sensing circuit may also include a capacitive hardware baseliner that is coupled to the channel input. The capacitive hardware baseliner generates a baseline current based on a time constant of the channel input associated with the measuring of the capacitance of the element of the capacitive sense array using the programmable baseline resistor. The capacitive hardware baseliner provides the baseline current at the channel input to provide a charge for a sense capacitor. A change in the charge of the sense capacitor is provided by the baseline current indicating a presence of a tough object proximate to the element.

Abstract: Technology directed to capacitive touch-sensing channels, including a capacitive-sensing converter based on a sigma-delta modulator, is described. One sigma-delta modulator includes a comparator, a first integrator coupled to receive an incoming signal from the input node and to provide a first output signal, a second integrator, coupled in parallel to the first integrator, to receive the incoming signal and to provide a second output signal, and switching circuitry. The switching circuitry is configured to selectively couple the first integrator between the input node and the comparator to provide the first output signal to the comparator or selectively couple the second integrator between the input node and the comparator to provide the second output signal to the comparator.

Abstract: A capacitance-sensing circuit may include a channel input associated with measuring a capacitance of a unit cell of a capacitive sense array. The capacitance-sensing circuit may also include a capacitive hardware baseliner that is coupled to the channel input. The capacitive hardware baseliner includes a programmable baseline resistor, and a buffer with an input coupled to the programmable baseline resistor and an output coupled to the channel input. The capacitive hardware baseliner generates a baseline current based on a time constant of the channel input associated with the measuring of the capacitance of the element of the capacitive sense array using the programmable baseline resistor. The capacitive hardware baseliner provides the baseline current at the channel input to provide a charge for a sense capacitor. A change in the charge of the sense capacitor is provided by the baseline current indicating a presence of a touch object proximate to the element.

Abstract: A fingerprint sensor-compatible overlay material which uses anisotropic conductive material to enable accurate imaging of a fingerprint through an overlay is disclosed. The anisotropic conductive material has increased conductivity in a direction orthogonal to the fingerprint sensor, increasing the capacitive coupling of the fingerprint to the sensor surface, allowing the fingerprint sensor to accurately image the fingerprint through the overlay. Methods for forming a fingerprint sensor-compatible overlay are also disclosed.

Abstract: A fingerprint sensor-compatible overlay material which uses anisotropic conductive material to enable accurate imaging of a fingerprint through an overlay is disclosed. The anisotropic conductive material has increased conductivity in a direction orthogonal to the fingerprint sensor, increasing the capacitive coupling of the fingerprint to the sensor surface, allowing the fingerprint sensor to accurately image the fingerprint through the overlay. Methods for forming a fingerprint sensor-compatible overlay are also disclosed.

Abstract: A method for detecting fingerprint spoof objects includes detecting a presence of the object at a fingerprint sensor and, in response to detecting the presence of the object, measuring a set of physical properties of the object based on one or more signals from a set of electrodes of the fingerprint sensor. The set of physical properties includes at least one of a subdermal compliance of the object and a surface adhesiveness of the object. The method further includes distinguishing the object as an actual finger or a spoof based on the one or more physical properties.

Abstract: Techniques for multi-phase scanning based on pseudo-random sequences in capacitive fingerprint applications are described herein. In an example embodiment, a method performed by a processing device comprises: receiving measurements that are representative of a portion of a finger on a capacitive fingerprint sensor array, where the measurements are obtained from sensor elements of the capacitive fingerprint sensor array that are scanned in a multi-phase mode based on an excitation vector generated from a pseudo-random sequence; and generating a fingerprint image for the portion of the finger based on the measurements.

Abstract: The sensing circuit includes including first input of a first electrode, a first set of inputs of a first set of two or more electrodes forming a first intersection and a second intersection, and a second set of inputs of a second set of two or more electrodes forming the second intersection and a third intersection. The sensing circuit includes a scan control circuit, coupled to the touch panel of electrodes, to concurrently select the sets of electrodes via a multiplexer. The touch sensing circuit includes an analog front end configured to generate digital values representative of mutual capacitances of a first and second unit cell, wherein the first unit cell comprises the first and second intersections and the second unit cell comprises the second and third intersections, and a channel engine configured to generate capacitance values corresponding to the unit cells.

Abstract: Fingerprint detection circuits with common mode noise rejection are described. The Fingerprint detection circuit includes a half-bridge circuit coupled to a receive (RX) electrode of an array of fingerprint detection electrodes and to a buried capacitance that is unalterable by the presence of a conductive object on the array. The fingerprint detection circuit may also include a listener electrode configured to enable common mode noise rejection through a differential input stage of a low noise amplifier (LNA).

Abstract: A capacitance-sensing circuit may include a plurality of channel inputs associated with measuring a capacitance of a unit cell of a capacitive sense array. The capacitance-sensing circuit may also include a baseliner component that is coupled to the plurality of channel inputs. The baseliner component may generate a baseline compensation signal using a capacitive circuit and may provide the baseline compensation signal to each of the plurality of channel inputs of the capacitive sense array.

Abstract: A fingerprint sensor-compatible overlay material which uses anisotropic conductive material to enable accurate imaging of a fingerprint through an overlay is disclosed. The anisotropic conductive material has increased conductivity in a direction orthogonal to the fingerprint sensor, increasing the capacitive coupling of the fingerprint to the sensor surface, allowing the fingerprint sensor to accurately image the fingerprint through the overlay. Methods for forming a fingerprint sensor-compatible overlay are also disclosed.