Piezoelectric devices and methods and circuits for driving same
First Claim
1. A drive circuit for a device comprising a piezoelectric actuator comprising:
- a controller for controlling a drive signal applied to the piezoelectric actuator;
a feedback monitor for obtaining a feedback signal from the piezoelectric actuator while the piezoelectric actuator operates;
wherein the controller is arranged to use the feedback signal to determine capacitance of the piezoelectric actuator and to use the capacitance to customize the drive signal for obtaining a desired waveform for the piezoelectric actuator as the piezoelectric actuator operates in the device.
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Accused Products
Abstract
A drive circuit (18) senses a parameter of a piezoelectric actuator (14) operating in a device (10) and adjusts a drive signal of the piezoelectric actuator in accordance with the parameter. The drive circuit comprises a controller (100) which controls a drive signal applied to the piezoelectric actuator (14); a feedback monitor (122) which obtains a feedback signal from the piezoelectric actuator while the piezoelectric actuator works; and, a processor (116) which uses the feedback signal to determine the parameter of the piezoelectric actuator. In one example mode, the parameter of the piezoelectric actuator which is determined by the piezoelectric actuator drive circuit is the capacitance or dielectric constant of the piezoelectric actuator. In other example modes, the parameter of the piezoelectric actuator which is determined by the piezoelectric actuator drive circuit is impedance or resonant frequency of the piezoelectric actuator.
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Citations
23 Claims
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1. A drive circuit for a device comprising a piezoelectric actuator comprising:
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a controller for controlling a drive signal applied to the piezoelectric actuator; a feedback monitor for obtaining a feedback signal from the piezoelectric actuator while the piezoelectric actuator operates; wherein the controller is arranged to use the feedback signal to determine capacitance of the piezoelectric actuator and to use the capacitance to customize the drive signal for obtaining a desired waveform for the piezoelectric actuator as the piezoelectric actuator operates in the device. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A drive circuit for a device comprising a piezoelectric actuator comprising:
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means for applying a drive signal to the piezoelectric actuator; means for obtaining a feedback signal from the piezoelectric actuator while the piezoelectric actuator operates; means for using the feedback signal to determine capacitance of the piezoelectric actuator and for using the capacitance to customize the drive signal for obtaining a desired waveform for the piezoelectric actuator as the piezoelectric actuator operates in the device. - View Dependent Claims (9)
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10. A piezoelectrically-actuated device comprising:
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a piezoelectric actuator which is responsive to a drive signal for pumping fluid between the inlet and outlet; and a drive circuit comprising; a controller for controlling a drive signal applied to the piezoelectric actuator; a feedback monitor for obtaining a feedback signal from the piezoelectric actuator while the piezoelectric actuator operates; wherein the controller is arranged to use the feedback signal to determine capacitance of the piezoelectric actuator and to use the capacitance to customize the drive signal for obtaining a desired waveform for the piezoelectric actuator as the piezoelectric actuator operates in the device. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method of operating a device that has a piezoelectric actuator, the method comprising:
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applying a drive signal to the piezoelectric actuator; operating the piezoelectric actuator; obtaining a feedback signal from the piezoelectric actuator; using the feedback signal to determine capacitance of the piezoelectric actuator; using the capacitance to customize the drive signal for obtaining a desired waveform for the piezoelectric actuator as the piezoelectric actuator operates in the device. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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Specification