Qualcomm Incorporated

Shivaprakash Halagur

Joseph Dale Rutkowski

Joshua Zazzera

Milind Sawant

Liangguo Shen

Nathaniel Jay T Salazar

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.

Braking control of haptic feedback device

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.

Haptics audible noise reduction

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.

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Singapore, Singapore

Shivaprakash Halagur