Methods and apparatus for driving a transducer
AssigneeCirrus Logic International Semiconductor Ltd.
InventorsRong HU, Jie SU
Life of this patent
Estimating the term…
Abstract
Embodiments described herein relate to methods and apparatus for driving a haptic transducer with a driving signal. The method comprises estimating, based on a current through the haptic transducer and a terminal voltage across the haptic transducer, a back electromotive force, EMF, voltage representative of a velocity of a mass in the haptic transducer; comparing a phase of a voltage signal derived from the terminal voltage with a phase of the estimated back EMF voltage; and based on the comparison, adjusting a frequency or a phase of an output signal, wherein the driving signal is derived from the output signal, such that a frequency of the driving signal converges to a resonant frequency of the haptic transducer.
Claims19
A method for driving a haptic transducer with a driving signal, the method comprising:
- estimating, based on a current through the haptic transducer and a terminal voltage across the haptic transducer, a back electromotive force, EMF, voltage representative of a velocity of a mass in the haptic transducer;
- comparing a phase of a voltage signal derived from the terminal voltage with a phase of the estimated back EMF voltage;
- and
- based on the comparison, adjusting a frequency or a phase of an output signal, wherein the driving signal is derived from the output signal, such that a frequency of the driving signal converges to a resonant frequency of the haptic transducer.
A resonant frequency tracker for driving a haptic transducer with a driving signal, the resonance-frequency tracker comprising:
- a back electromotive force, EMF, modelling module configured to estimate, based on a current through the haptic transducer and a terminal voltage across the haptic transducer, a back-EMF voltage representative of a velocity of a mass in the haptic transducer;
- and
- a controller configured to:
- receive a voltage signal derived from the terminal voltage;
- compare a phase of the voltage signal with a phase of the estimated back EMF voltage, and
- based on the comparison, adjust a frequency or a phase of an output signal output by the controller, wherein the driving signal is derived from the output of the controller, such that a frequency of the driving signal converges to a resonant frequency of the haptic transducer.
An electronic apparatus comprising:
- a haptic transducer;
- and
- a resonant frequency tracker comprising:
- a back electromotive force, EMF, modelling module configured to estimate, based on a current through the haptic transducer and a terminal voltage across the haptic transducer, a back-EMF voltage representative of a velocity of a mass in the haptic transducer;
- and
- a controller configured to:
- receive a voltage signal derived from the terminal voltage;
- compare a phase of the voltage signal with a phase of the estimated back EMF voltage, and
- based on the comparison, adjust a frequency or a phase of an output signal output by the controller, wherein the driving signal is derived from the output of the controller, such that a frequency of the driving signal converges to a resonant frequency of the haptic transducer.
Dependencies are inferred from the claim text.