Differential drive of a sound transducer system
AssigneeRobert Bosch GmbH
InventorsRaik Fiedler, Matthias Landwehr, Ralf Hildebrandt, Franziska Wall
Life of this patent
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Abstract
This invention relates to an apparatus for differentially driving an electrostatic drive unit of a microelectromechanical sound-generating device implemented in a microelectromechanical system (MEMS). The drive unit has a movable element having a first electrode, which is electrostatically drivable by a second electrode and a third electrode of the drive unit.
Claims20
An apparatus for driving an electrostatic drive unit of a sound-generating device, wherein the drive unit has a movable element having a first electrode, which is electrostatically drivable by means of a second electrode and a third electrode of the drive unit, wherein the apparatus comprises:
- a first drive circuit, which is configured to generate a first electrode signal based on a first drive signal and relative to a first reference potential, and to drive the first electrode using the first electrode signal;
- a second drive circuit, which is configured to generate a second electrode signal based on a second drive signal and relative to a second reference potential, which is higher than the first reference potential, and to drive the second electrode using the second electrode signal;
- and
- a third drive circuit, which is configured to generate a third electrode signal based on the second drive signal and relative to a third reference potential, which is lower than the first reference potential, and to drive the third electrode using the third electrode signal,
- wherein the second and third electrode signals are alternating voltage signals of the same phase, which correspond to each other in terms of their waveform, but are shifted with respect to one another by the potential difference between the second reference potential and the third reference potential;
- and
- wherein the first electrode signal is an alternating voltage signal that corresponds to the inverted waveform of the second and third electrode signals in terms of its waveform.
A loudspeaker system comprising:
- a sound-generating device, wherein the sound-generating device is configured to generate sound using one or more drive units, wherein each drive unit comprises a movable element having a first electrode, which is electrostatically drivable by means of a second electrode and a third electrode of the drive unit;
- and
- an apparatus comprising:
- a first drive circuit, which is configured to generate a first electrode signal based on a first drive signal and relative to a first reference potential, and to drive the first electrode using the first electrode signal;
- a second drive circuit, which is configured to generate a second electrode signal based on a second drive signal and relative to a second reference potential, which is higher than the first reference potential, and to drive the second electrode using the second electrode signal;
- and
- a third drive circuit, which is configured to generate a third electrode signal based on the second drive signal and relative to a third reference potential, which is lower than the first reference potential, and to drive the third electrode using the third electrode signal,
- wherein the second and third electrode signals are alternating voltage signals of the same phase, which correspond to each other in terms of their waveform, but are shifted with respect to one another by the potential difference between the second reference potential and the third reference potential;
- and
- wherein the first electrode signal is an alternating voltage signal that corresponds to the inverted waveform of the second and third electrode signals in terms of its waveform.
A method for driving an electrostatic drive unit of a sound-generating device, wherein the drive unit has a movable element having a first electrode, which is electrostatically drivable by means of a second electrode and a third electrode of the drive unit, wherein the method comprises:
- generating a first electrode signal based on a first drive signal and relative to a first reference potential, and to drive the first electrode using the first electrode signal;
- generating a second electrode signal based on a second drive signal and relative to a second reference potential, which is higher than the first reference potential, and to drive the second electrode using the second electrode signal;
- and
- generating a third electrode signal based on the second drive signal and relative to a third reference potential, which is lower than the first reference potential, and to drive the third electrode using the third electrode signal,
- wherein the second and third electrode signals are alternating voltage signals of the same phase, which correspond to each other in terms of their waveform, but are shifted with respect to one another by the potential difference between the second reference potential and the third reference potential;
- and
- wherein the first electrode signal is an alternating voltage signal that corresponds to the inverted waveform of the second and third electrode signals in terms of its waveform.
Dependencies are inferred from the claim text.