Abstract: An operational amplifier with one or more fully-differential amplifier stages has a common-mode control input. A low-frequency feedback control path is coupled between an output of the fully-differential amplifier stages and the common-mode control input to control low-frequency drift of the common-mode voltage of the output of the stages. A high-frequency feed-forward control path couples a pair of inputs of the stages to control high-frequency ripple of a common-mode voltage of the inputs of the stages. One or more of the differential amplifier stages may have a bias input that controls a direct-current (DC) bias voltage of gates of pull-up transistors of the stage that is both DC and capacitively coupled to the gates so that the stage operates with class A bias at DC and with class AB bias at high frequencies.

Abstract: A multi-path subsystem may include a first processing path, a second processing path, a mixed signal return path, and a calibration engine configured to: estimate and cancel a direct current (DC) offset of the mixed signal return path, estimate and cancel a DC offset between the first processing path and the second processing path, estimate and cancel a phase difference between the first processing path and a sum of the second processing path and the mixed signal return path, estimate and cancel a return path gain of the mixed signal return path, and track and correct for a gain difference between the first processing path and the second processing path.

Abstract: A system may include a sensor configured to output a sensor signal indicative of a distance between the sensor and a mechanical member associated with the sensor, a measurement circuit communicatively coupled to the sensor and configured to determine a physical force interaction with the mechanical member based on the sensor signal, and a compensator configured to monitor the sensor signal and to apply a compensation factor to the sensor signal to compensate for changes to properties of the sensor based on at least one of changes in a distance between the sensor and the mechanical member and changes in a temperature associated with the sensor.

Abstract: A system may include a plurality of sensors, a measurement circuit communicatively coupled to the plurality of sensors and configured to measure one or more physical quantities associated with the plurality of sensors, and a predictive optimization subsystem configured to detect an event associated with a first sensor of the plurality of sensors and responsive to the event, execute a predictive action with respect to one or more of the other sensors of the plurality of sensors.

Abstract: A system may include a plurality of actively-driven inductive sensors and a plurality of control circuits, each control circuit of the plurality of control circuits configured to control operation of a respective set of the actively-driven inductive sensors, each control circuit of the plurality of control circuits communicatively coupled to the other control circuits via a connection configured to distribute synchronization information among the plurality of control circuits. Each of the plurality of control circuits may further be configured to configure a schedule for controlling time-division multiplexed operation of its respective set of actively-driven inductive sensors and control time-division multiplexed operation of its respective set of actively-driven inductive sensors based on the schedule and the synchronization information in order to minimize interference among the plurality of actively-driven inductive sensors.

Abstract: A system may include a plurality of actively-driven inductive sensors and a plurality of control circuits, each control circuit of the plurality of control circuits configured to control operation of a respective set of the actively-driven inductive sensors, each control circuit of the plurality of control circuits communicatively coupled to the other control circuits via a connection configured to distribute synchronization information among the plurality of control circuits. Each of the plurality of control circuits may further be configured to configure a schedule for controlling time-division multiplexed operation of its respective set of actively-driven inductive sensors and control time-division multiplexed operation of its respective set of actively-driven inductive sensors based on the schedule and the synchronization information in order to minimize interference among the plurality of actively-driven inductive sensors.

Abstract: A correction unit for use in a sensor system, the sensor system comprising a force sensor configured to output a sensor signal indicative of a temporary mechanical distortion of a material under an applied force, the correction unit configured, based on the sensor signal, to: estimate an effect of the applied force on how the material will return towards an undistorted form upon a substantial reduction or removal of the applied force; and generate a corrected signal based on the estimation.

Abstract: A force sensing system for determining if a user input has occurred, the system comprising: an input channel, to receive an input from at least one force sensor; an activity detection stage, to monitor an activity level of the input from the at least one force sensor and, responsive to an activity level which may be indicative of a user input being reached, to generate an indication that an activity has occurred at the force sensor; and an event detection stage to receive said indication, and to determine if a user input has occurred based on the received input from the at least one force sensor.

Abstract: A system may include a sensor having a variable phase response, a dummy impedance having a known phase response, and a measurement circuit communicatively coupled to the sensor and configured to measure first phase information associated with the sensor, measure second phase information associated with the dummy impedance, and determine a phase response of the measurement circuit based on a comparison of the first phase information to the second phase information.

Abstract: A system may include a sensor configured to output a sensor signal indicative of a distance between the sensor and a mechanical member associated with the sensor, a measurement circuit communicatively coupled to the sensor and configured to determine a physical force interaction with the mechanical member based on the sensor signal, and a compensator configured to monitor the sensor signal and to apply a compensation factor to the sensor signal to compensate for changes to properties of the sensor based on at least one of changes in a distance between the sensor and the mechanical member and changes in a temperature associated with the sensor.

Abstract: A system for detecting displacement of a movable member of an electromagnetic transducer having a magnetic coil-driven linear actuator with a static member and a movable mass mechanically coupled to the static member and having a back electromotive force present across terminals of a coil of the electromagnetic transducer is provided. The system may include a resistive-inductive-capacitive sensor comprising the coil, a driver configured to drive the resistive-inductive-capacitive sensor with a driving signal, a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to measure one or more of phase information and amplitude information associated with the resistive-inductive-capacitive sensor and based on the one or more of phase information and amplitude information, determine a displacement of movable mass, wherein the displacement of the movable mass causes a change in an impedance of the resistive-inductive-capacitive sensor.

Abstract: A method for determining sensor parameters of an actively-driven sensor system may include performing an initialization operation to establish a baseline estimate of the sensor parameters, obtaining as few as three samples of a measured physical quantity versus frequency for the actively-driven sensor system, performing a refinement operation to provide a refined version of the sensor parameters based on the as few as three samples, iteratively repeating the refinement operation until the difference between successive refined versions of the sensor parameters is below a defined threshold, and outputting the refined sensor parameters as updated sensor parameters for the actively-driven sensor system.

Abstract: A force sensing system for determining if a user input has occurred, the system comprising: an input channel, to receive an input from at least one force sensor; an activity detection stage, to monitor an activity level of the input from the at least one force sensor and, responsive to an activity level which may be indicative of a user input being reached, to generate an indication that an activity has occurred at the force sensor; and an event detection stage to receive said indication, and to determine if a user input has occurred based on the received input from the at least one force sensor.

Abstract: A control method for a user interface system may include receiving an input signal, receiving a temperature signal indicative of a temperature, generating a baseline signal based on at least one among the input signal and the temperature signal, calculating an error signal based on a difference of the input signal and the baseline signal, and modifying the baseline signal based on the error signal.

Abstract: A system may include a resistive-inductive-capacitive sensor, a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to at a plurality of periodic intervals, measure phase information associated with the resistive-inductive-capacitive sensor and based on the phase information, determine a displacement of a mechanical member relative to the resistive-inductive-capacitive sensor. The system may also include a driver configured to drive the resistive-inductive-capacitive sensor at a driving frequency and a driving amplitude, wherein at least one of the driving frequency and the driving amplitude varies among the plurality of periodic intervals.

Abstract: A driver system may include a first n-type field-effect transistor coupled at its non-gate terminals between an output of the driver system and a first terminal of a supply voltage and configured to drive the output when the first n-type field-effect transistor is activated, a second n-type field-effect transistor coupled at its non-gate terminals between an output of the driver system and a second terminal of the supply voltage and configured to drive the output when the second n-type field-effect transistor is activated, a high-side capacitor coupled to the output of the driver system, and a low-side capacitor coupled to the second terminal of the supply voltage, wherein the high-side capacitor and the low-side capacitor are configured to track and correct for mismatches between a first resistance of the first n-type field-effect transistor and a second resistance of the second n-type field-effect transistor.

Abstract: A system may include a resistive-inductive-capacitive sensor, a driver configured to drive the resistive-inductive-capacitive sensor at a driving frequency, a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to measure phase information and amplitude associated with the resistive-inductive-capacitive sensor, and a noise detection circuit communicatively coupled to the measurement circuit and configured to determine a presence of external interference in the system based on at least one of the phase information and the amplitude information.

Abstract: A system may include a sensor configured to output a sensor signal indicative of a distance between the sensor and a mechanical member associated with the sensor, a measurement circuit communicatively coupled to the sensor and configured to determine a physical force interaction with the mechanical member based on the sensor signal, and a compensator configured to monitor the sensor signal and to apply a compensation factor to the sensor signal to compensate for changes to properties of the sensor based on at least one of changes in a distance between the sensor and the mechanical member and changes in a temperature associated with the sensor.

Abstract: Embodiments described herein relate to methods and apparatuses for providing a haptic output signal to a haptic actuator. A controller comprises an input configured to receive a force sensor signal from at least one force sensor; and a haptic output module configured to generate a haptic output signal for output to a haptic actuator; wherein the haptic output module is configured to: responsive to determining that the force sensor signal indicates that a force level applied to the at least one force sensor exceeds a first threshold, trigger output of the haptic output signal; and during output of the haptic output signal, adjust the haptic output signal based on the force sensor signal.

Abstract: A system may include a resonant phase sensing system comprising a resistive-inductive-capacitive sensor and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor, and a compensation circuit. The measurement circuit may be configured to use a phase detector to measure phase information associated with the resistive-inductive-capacitive sensor and based on the phase information, determine a displacement of a metal plate relative to the resistive-inductive-capacitive sensor. The compensation circuit may be configured to detect a change in a physical property associated with the resistive-inductive-capacitive sensor other than the displacement and compensate the phase information to correct for the change in the physical property.