Haptics adaptive duty cycle
AssigneeQUALCOMM Incorporated
InventorsJoshua ZAZZERA, Joseph Dale RUTKOWSKI, Milind SAWANT, Shivaprakash HALAGUR
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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.
Claims32
A method of dynamically adapting a drive duty cycle of a linear resonant actuator (LRA) control signal, the method comprising:
- 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 a BEMF zero voltage crossing time;
- calculating a period;
- calculating a BEMF measurement window;
- calculating a target duty cycle;
- and
- adjusting the duty cycle of the LRA control signal towards the target duty cycle.
An apparatus for dynamically adapting a drive duty cycle of a linear resonant actuator (LRA) control signal, the apparatus comprising:
- a memory;
- and
- at least one processor communicatively coupled to the memory, the at least one processor configured to:
- generate an LRA control signal having a period, the period having an active portion and a high-Z portion according to a duty cycle;
- detect, during the high-Z portion of the period, a back electromotive force (BEMF) threshold voltage crossing time and a BEMF zero voltage crossing time;
- calculate a period;
- calculate a BEMF measurement window;
- calculate a target duty cycle;
- and
- adjust the duty cycle of the LRA control signal towards the target duty cycle.
An apparatus for operating a linear resonant actuator (LRA), the apparatus comprising:
- means for generating an LRA control signal having a period, the period having an active portion and a high-Z portion according to a duty cycle;
- means for detecting, during the high-Z portion of the period, a back electromotive force (BEMF) threshold voltage crossing time and zero voltage crossing time;
- means for calculating a period;
- means for calculating a BEMF measurement window;
- means for calculating a target duty cycle;
- and
- means for adjusting the duty cycle towards the target duty cycle.
A non-transitory computer-readable medium storing computer-executable instructions, the computer-executable instructions comprising:
- at least one instruction instructing an apparatus to generate an LRA control signal having a period, the period having an active portion and a high-Z portion according to a duty cycle;
- at least one instruction instructing the apparatus to detect, during the high-Z portion of the period, a back electromotive force (BEMF) threshold voltage crossing time and zero voltage crossing time;
- at least one instruction instructing the apparatus to calculate a period;
- at least one instruction instructing the apparatus to calculate a BEMF measurement window;
- at least one instruction instructing the apparatus to calculate a target duty cycle;
- and
- at least one instruction instructing the apparatus to adjust the duty cycle towards the target duty cycle.
Dependencies are inferred from the claim text.