Optimized control circuit for a microelectromechanical sound generator and a sound generation system

Patent metadata

Field	Value
Publication number	US-2025132742-A1
Application number	US-202418887599-A
Country	US
Kind code	A1
Filing date	Sep 17, 2024
Priority date	Oct 18, 2023
Publication date	Apr 24, 2025
Grant date	—

Abstract

A control circuit for a microelectromechanical sound generator with a first center connector, a second center connector, a first external connector, and a second external connector. The control circuit includes a differential amplifier which comprises a first output connector coupled to the first external connector and a second output connector coupled to the second external connector and is configured to control the first external connector and the second external connector with a differential signal that corresponds to an input signal. The control circuit includes a first voltage generator circuit, which is configured to provide the first center connector with a predetermined first DC voltage in relation to a common-mode voltage of the differential amplifier, and a second voltage generator circuit, which is configured to provide the second center connector with a predetermined second DC voltage in relation to the common-mode voltage of the differential amplifier.

First claim

What is claimed is:

1 . A control circuit for a microelectromechanical sound generator with a first center connector, a second center connector, a first external connector and a second external connector, the control circuit comprising:
a differential amplifier which includes a first output connector coupled to the first external connector and a second output connector coupled to the second external connector, the differential amplifier being configured to control the first external connector and the second external connector with a differential signal that corresponds to an input signal; a first voltage generator circuit configured to provide the first center connector with a predetermined first DC voltage in relation to a common-mode voltage of the differential amplifier; and a second voltage generator circuit configured to provide the second center connector with a predetermined second DC voltage in relation to the common-mode voltage of the differential amplifier.

2 . The control circuit according to claim 1 , wherein the control circuit is configured to set a supply voltage for the differential amplifier as a function of a maximum amplitude of the input signal.

3 . The control circuit according to claim 1 , further comprising:
a level converter configured to adjust a common-mode signal level of the input signal, wherein the level converter is coupled to or integrated in the differential amplifier to provide an adjusted input signal.

4 . The control circuit according to claim 3 , wherein the control circuit is configured to receive a supply voltage for the level converter as a function of a maximum amplitude of the input signal.

5 . The control circuit according to claim 1 , wherein the control circuit is configured to receive an electrical voltage between a reference potential and a predetermined positive supply voltage as a supply voltage for the differential amplifier.

6 . The control circuit according to claim 1 , wherein the control circuit is configured to receive an electrical voltage between a predetermined negative supply voltage and a predetermined positive supply voltage as a supply voltage for the differential amplifier.

7 . The control circuit according to claim 1 , wherein the differential amplifier is a class G amplifier or a class H amplifier.

8 . The control circuit according to claim 1 , wherein:
the first voltage generator circuit provides the predetermined first DC voltage in relation to the common-mode voltage of the differential amplifier via a first buffer circuit, wherein the first buffer circuit uses two supply voltages, a voltage difference of the two supply voltages being kept constant by a first potential-free charge pump, using a first comparator which compares two currents, a first current of the two currents being proportional to the voltage difference and a second current of the two currents being proportional to a reference voltage; and/or the second voltage generator circuit provides the predetermined second DC voltage in relation to the common-mode voltage of the differential amplifier via a second buffer circuit, wherein the second buffer circuit uses two supply voltages, a voltage difference of the two supply voltages being kept constant by a second potential-free charge pump, by using a second comparator which compares two currents, a first current of the two currents being proportional to the voltage difference, and a second current of the two currents being proportional to a reference voltage.

9 . The control circuit according to claim 3 , further comprising:
a signal processing device configured to receive a digital audio signal, convert the digital audio signal into an analog audio signal, and provide the analog audio signal as the input signal to the level converter or the differential amplifier, wherein the signal processing device is further configured to ascertain a maximum amplitude of the input signal using the digital input signal.

10 . A microelectromechanical sound generator, comprising:
a first center connector, a second center connector, a first external connector, and a second external connector; wherein the first external connector is disposed on a first substrate of the microelectromechanical sound generator and the second external connector is disposed on the first substrate; and wherein the first center connector is disposed on a second substrate of the microelectromechanical sound generator and the second center connector is disposed on the second substrate.

11 . The microelectromechanical sound generator according to claim 10 , wherein:
the first substrate is configured to reduce a parasitic capacitance between the first external connector and the first substrate and a parasitic capacitance between the second external connector and the first substrate; and/or wherein the second substrate is configured to increase a parasitic capacitance between the first center connector and the second substrate and a parasitic capacitance between the second center connector and the second substrate.

12 . The microelectromechanical sound generator according to claim 10 , wherein:
the first substrate is static and the second substrate is movable; or the first substrate is movable and the second substrate is static.

13 . A sound generation system, comprising:
a microelectromechanical sound generator, including:
a first center connector, a second center connector, a first external connector, and a second external connector,
wherein the first external connector is disposed on a first substrate of the microelectromechanical sound generator and the second external connector is disposed on the first substrate, and
wherein the first center connector is disposed on a second substrate of the microelectromechanical sound generator and the second center connector is disposed on the second substrate; and
a control circuit, including:
a differential amplifier which includes a first output connector coupled to the first external connector and a second output connector coupled to the second external connector, the differential amplifier being configured to control the first external connector and the second external connector with a differential signal that corresponds to an input signal,
a first voltage generator circuit configured to provide the first center connector with a predetermined first DC voltage in relation to a common-mode voltage of the differential amplifier, and
a second voltage generator circuit configured to provide the second center connector with a predetermined second DC voltage in relation to the common-mode voltage of the differential amplifier.

Assignees

• Bosch Gmbh Robert

Inventors

• De Sandre Guido
• Fiedler Raik

Classifications

• H04R2201/003

  Mems transducers or their use · CPC title

• H04R2430/00

  Signal processing covered by H04R, not provided for in its groups · CPC title

• H04R19/005

  using semiconductor materials · CPC title

• H04R3/00 Primary

  Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F) · CPC title

• H04R3/06

  of electrostatic transducers · CPC title