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 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 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: In accordance with embodiments of the present disclosure, an apparatus may include a signal path comprising a closed-loop analog pulse width modulator having a forward signal path and a feedback path, a variable resistor coupled to an output of the closed-loop analog pulse width modulator, and a control circuit configured to modify the variable resistor in order to modify an output impedance outside of the feedback path of the closed-loop analog pulse width modulator responsive to a condition for switching between a high output impedance mode and a low output impedance mode of the closed-loop analog pulse width modulator or vice versa.

Abstract: A system may include a resistive-inductive-capacitive sensor, a driver configured to drive the resistive-inductive-capacitive sensor at a driving frequency, and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to determine a measured change in a resonant frequency of the resistive-inductive-capacitive sensor and based on the measured change, modify the driving frequency.

Abstract: In accordance with embodiments of the present disclosure, an apparatus for providing an output signal to an audio transducer may include a control circuit. The control circuit may be configured to predict, based on a magnitude of a signal indicative of the output signal, an occurrence of an event for changing a selectable digital gain and a selectable analog gain and an audio signal path, and responsive to predicting the occurrence of the event, change, at an approximate time in which a zero crossing of the signal indicative of the output signal occurs, the selectable digital gain and the selectable analog gain.

Abstract: A system may include a tactile actuator for providing tactile feedback and a resonant phase sensing system. The resonant phase sensing system may include a resistive-inductive-capacitive sensor and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and the tactile actuator. The resistive-inductive-capacitive sensor may be configured to measure phase information associated with the resistive-inductive-capacitive sensor, based on the phase information, detect an indication of human interaction with the system proximate to the resistive-inductive-capacitive sensor, and trigger the tactile actuator to generate tactile feedback responsive to detecting the indication of human interaction.

Abstract: A system may include a digital modulator configured to modulate an input signal received at an input of the digital modulator to generate a modulated input signal at an output of the digital modulator, a digital gain element having a digital gain and coupled to the digital modulator, an open-loop Class-D amplifier coupled to an output of the digital modulator and configured to amplify the modulated input signal, wherein the open-loop Class-D amplifier is powered from a variable power supply having a variable supply voltage which is variable in response to one or more characteristics of the input signal, and a control circuit configured to control the digital gain to approximately cancel changes in an analog gain of the open-loop Class-D amplifier due to variation in the variable supply voltage in response to the one or more characteristics of the input signal.

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 an array of sensor elements, the array of sensor elements each comprising a first type of passive reactive element, a second type of passive reactive element electrically coupled to the array of sensor elements, a driver configured to drive the array of sensor elements and the second type of passive reactive element, and control circuitry configured to control enabling and disabling of individual sensor elements of the array of sensor elements to ensure no more than one of the array of sensor elements is enabled at a time such that when one of the array of sensor elements is enabled, the one of the array of sensor elements and the second type of passive reactive element together operate as a resonant sensor.

Abstract: A system may include at least one resistive-inductive-capacitive sensor and a control circuit configured to maintain timing parameters for operation of the at least one resistive-inductive-capacitive sensor and vary at least one of the timing parameters to control a spectrum associated with the at least one resistive-inductive-capacitive sensor, wherein the spectrum comprises one of a sensor activity spectrum of the at least one resistive-inductive-capacitive sensor and a current usage spectrum associated with electrical current delivered to the at least one resistive-inductive-capacitive sensor from a source of electrical energy.

Abstract: A system may include a resistive-inductive-capacitive sensor, a driver configured to drive the resistive-inductive-capacitive sensor with a driving signal at a driving frequency, and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to, during a calibration phase of the measurement circuit, measure phase and amplitude information associated with the resistive-inductive-capacitive sensor and based on the phase and amplitude information, determine at least one of a resonant frequency of the resistive-inductive-capacitive sensor and a transfer function of the resistive-inductive-capacitive sensor.

Abstract: A polymorphic playback system is disclosed in which one or more parameters of a signal path of the polymorphic playback system are varied based on one or more characteristics of a playback signal processed by the signal path, wherein the polymorphic playback system may include a lower-latency detection filter, a higher-latency detection filter, and a control subsystem that uses the lower-latency detection filter for detecting the one or more first characteristics of the playback signal and uses the higher-latency detection filter for detecting the one or more second characteristics of the playback signal.

Abstract: A system may include a tactile actuator for providing tactile feedback and a resonant phase sensing system. The resonant phase sensing system may include a resistive-inductive-capacitive sensor and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and the tactile actuator. The resistive-inductive-capacitive sensor may be configured to measure phase information associated with the resistive-inductive-capacitive sensor, based on the phase information, detect an indication of human interaction with the system proximate to the resistive-inductive-capacitive sensor, and trigger the tactile actuator to generate tactile feedback responsive to detecting the indication of human interaction.

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 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 signal processing system may include a modulation stage configured to generate a modulated input signal, an open-loop switched mode driver coupled to the modulation stage and configured to generate an output signal from the modulated input signal, a voltage regulator configured to generate a supply voltage that supplies electrical energy to the open-loop switched mode driver, and a control subsystem configured to, when a magnitude of the modulated input signal falls below a threshold magnitude, control the voltage regulator to control the supply voltage such that the output signal varies non-linearly with the modulated input signal for magnitudes of the modulated input signal below the threshold magnitude.

Abstract: In a signal path comprising an analog path portion configured to operate in a plurality of output impedance modes including a high impedance mode with a first impedance and a low impedance mode with a second impedance, and a digital path portion having a variable digital gain and configured to convert a digital input signal and into an analog signal provided to the analog path portion, a method may include responsive to a condition for switching between the high impedance mode and the low impedance mode or vice versa, transitioning the output impedance continuously or in a series of steps between the first impedance and the second impedance or vice versa and, contemporaneously with transitioning the output impedance, transitioning the variable digital gain continuously or in a series of steps such to maintain a substantially constant overall path gain for the signal path remains substantially constant during transition.

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.