Control and protection of loudspeakers

• US 10,349,173 B2
• Filed: 07/14/2017
• Issued: 07/09/2019
• Est. Priority Date: 09/24/2012
• Status: Active Grant

• Current Assignee: Cirrus Logic Incorporated
• Original Assignee: Cirrus Logic Incorporated
• Inventors: Risberg, Par Gunnars, Lindahl, Erik, Arvidsson, Marcus, Stahre, Daniel, Toth, Landy
• Primary Examiner(s): Holder, Regina N
• Application Number:
  US15/650,147
• Publication Number:
  US 20170318388A1
• Time in Patent Office: 725 Days
• CPC Class Codes: H04R 3/002 Damping circuit arrangements for transducers, e.g. motional feedback circuits
• CPC Class Codes: H04R 3/007 Protection circuits for transducers

Abstract

A nonlinear control system and a loudspeaker protection system. In particular, a nonlinear control system including a controller, an audio system, and a model is disclosed. The controller is configured to accept one or more input signals, and one or more estimated states produced by the model to produce one or more control signals. The audio system includes one or more transducers configured to accept the control signals to produce a rendered audio stream therefrom. An active loudspeaker with an integrated amplifier is disclosed. A loudspeaker protection system and a quality control system are disclosed. More particularly, a system for clamping the input to a loudspeaker dependent upon a bank of representative models is disclosed.

Claims

1. An active loudspeaker comprising:

a movable membrane configured for production of an audible sound wave;

an enclosure with one or more walls coupled to the movable membrane so as to form a cavity within the enclosure;

a plurality of optical sensors, each being optically coupled to the movable membrane configured to measure one or more states associated with a movement of the movable membrane to produce an optical sensory feedback signal, the plurality of optical sensors comprising an emitter and a detector, both of which are optically coupled to the movable membrane; and

a microcircuit electrically coupled to the plurality of optical sensors and the movable membrane, coupled to and/or embedded within one of the one or more walls of the enclosure, and configured to receive the optical sensory feedback signal and to drive the movement of the movable membrane,

wherein the microcircuit is further configured to compare a plurality of optical feedback signals to determine a presence of a rocking vibration mode of the movable membrane and to reduce a movement of the movable membrane upon detection of the presence of the rocking vibration mode.

2. The active loudspeaker in accordance with claim 1, wherein the plurality of optical sensors and the microcircuit are packaged into a single system on a chip.

3. The active loudspeaker in accordance with claim 1, further comprising a connector coupled to the microcircuit and configured to convey signals between the microcircuit and an external system, and

wherein the microcircuit is further configured to communicate power, an audio stream, and/or configuration data via the connector with the external system.

4. The active loudspeaker in accordance with claim 3, wherein the connector comprises two terminals, through which the power, audio stream, and configuration data are communicated.

5. The active loudspeaker in accordance with claim 1, further comprising a speaker protection system including:

an estimator comprising one or more state estimating models, each state estimating model configured to accept one or more input signals, and to generate one or more estimated states therefrom; and

a loudspeaker protection block configured to accept the one or more input signals and/or delayed versions thereof, and the estimated states and/or signals generated therefrom, and to produce an output signal from a combination thereof.

6. An electronic device, comprising an active loudspeaker as claimed in claim 1.

7. An active loudspeaker, comprising:

a housing;

a membrane actuator, located within the housing, configured for production of an audible sound wave; and

a plurality of optical sensors located within the housing, each being configured to produce a respective optical feedback signal,

wherein the plurality of optical sensors comprise;

an optical source, for directing radiation towards the membrane actuator; and

an optical detector, configured to detect optical radiation from the direction of the membrane actuator,

wherein the active loudspeaker further comprises a control circuit for determining movement of the membrane actuator from the detected optical radiation, and configured to compare a plurality of the optical feedback signals to determine presence of a rocking vibration mode of the membrane actuator and to reduce a movement of the membrane actuator upon detection of the presence of the rocking vibration mode.

8. The active loudspeaker in accordance with claim 7, wherein the control circuit is configured for delivering test signals to the optical source and obtaining feedback signals from the optical detector.

9. The active loudspeaker in accordance with claim 8, wherein the control circuit is provided as an integrated circuit.

10. The active loudspeaker in accordance with claim 8, wherein the control circuit is configured for comparing the determined movement of the membrane actuator with one or more predictive models.

11. The active loudspeaker in accordance with claim 7, further comprising a connector coupled to the control circuit and configured to convey signals between the control circuit and an external system, and

wherein the control circuit is further configured to communicate power, an audio stream, and/or configuration data via the connector with the external system.

12. The active loudspeaker in accordance with claim 11, wherein the connector comprises two terminals, through which the power, audio stream, and/or configuration data are communicated.

13. An electronic device, comprising an active loudspeaker as claimed in claim 7.