Abstract: Innovative techniques to design and generate haptics waveforms are proposed. The proposed techniques reduce or eliminate audible noises being generated by a haptic actuator during operation. A haptic controller may compose a voltage waveform at a resonant frequency of the haptic actuator and generate a corresponding control signal. Instead of suddenly entering a high impedance state from a driving state, the voltage waveform may include a ramp down portion in which the voltage ramps down continuously but quickly so that the current flowing within the actuator is brought down before entering the high impedance state. In this way, audible noises may be reduced or even eliminated.

Abstract: Innovative techniques to design and generate haptics waveforms are proposed. The proposed techniques reduce or eliminate audible noises being generated by a haptic actuator during operation. A haptic controller may compose a voltage waveform at a resonant frequency of the haptic actuator and generate a corresponding control signal. Instead of suddenly entering a high impedance state from a driving state, the voltage waveform may include a ramp down portion in which the voltage ramps down continuously but quickly so that the current flowing within the actuator is brought down before entering the high impedance state. In this way, audible noises may be reduced or even eliminated.

Abstract: Abstract: In some aspects, a controller may obtain a back electromotive force (BEMF) signal associated with a haptic feedback component, wherein the BEMF signal is generated by movement of the haptic feedback component. The controller may determine a time length for the BEMF signal to cross an amplitude-based window. The controller may determine, based on the time length, a braking amplitude for a control signal to reduce an energy level of the haptic feedback component. The controller may control the control signal according to the braking amplitude. Numerous other aspects are provided.

Abstract: Disclosed are various techniques operating a linear resonant actuator (LRA). In some aspects, a method for operating an LRA includes generating an LRA control signal having a period, the period having an active portion and a high-Z portion according to a duty cycle; detecting, during the high-Z portion of the period, a back electromotive force (BEMF) threshold voltage crossing time and zero voltage crossing time; calculating a period; calculating a BEMF measurement window; calculating a target duty cycle based on the period, the BEMF measurement window, and a margin time; and adjusting the duty cycle of the LRA control signal towards the target duty cycle.

Abstract: Disclosed are various techniques operating a linear resonant actuator (LRA). In some aspects, a method for operating an LRA includes generating an LRA control signal having a period, the period having an active portion and a high-Z portion according to a duty cycle; detecting, during the high-Z portion of the period, a back electromotive force (BEMF) threshold voltage crossing time and zero voltage crossing time; calculating a period; calculating a BEMF measurement window; calculating a target duty cycle based on the period, the BEMF measurement window, and a margin time; and adjusting the duty cycle of the LRA control signal towards the target duty cycle.

Abstract: A synchronous circuit for clock multiplexing and output-enable is implemented using a pair of logic gates and an output block. Select signals and enable signals with the corresponding logic sense are provided as inputs to the pair of logic gates, which generate respective logic outputs. The output block contains synchronizers clocked by respective input signals, and receives the logic outputs also as inputs. The output block provides a selected one of the input signals as an output, the provision of the selected input signal being accomplished in a synchronous fashion. Enabling and disabling of the output are also performed synchronously.

Abstract: Various systems and methods for drift compensation are disclosed. As one example, a system for compensating drift in a control circuit is disclosed that includes at least two control signals. One of the control signals is provided by a circuit that is susceptible to drift. This control signal is provided both to a systems or device under control, and to a detection circuit. The detection circuit is operable to detect a drift in the control signal. In addition, the detection circuit provides another control signal that varies as a function of the drift in the received control signal.

Abstract: Various systems and methods for drift compensation are disclosed. As one example, a system for compensating drift in a control circuit is disclosed that includes at least two control signals. One of the control signals is provided by a circuit that is susceptible to drift. This control signal is provided both to a systems or device under control, and to a detection circuit. The detection circuit is operable to detect a drift in the control signal. In addition, the detection circuit provides another control signal that varies as a function of the drift in the received control signal.