MICROPHONE AND CORRESPONDING DIGITAL INTERFACE

• US 20180308511A1
• Filed: 06/26/2018
• Published: 10/25/2018
• Est. Priority Date: 05/23/2013
• Status: Active Grant

• Current Assignee: Knowles Electronics Llc (Knowles Corporation)
• Original Assignee: Knowles Electronics Llc (Knowles Corporation)
• Inventors: Dai, Weiwen, Popper, Robert A.
• Granted Patent: US 10,332,544 B2
• Time in Patent Office: Days
• CPC Class Codes: G10L 25/78 Detection of presence or absence of voice signals switching of direction of transmission by voice frequency in two-way loud-speaking telephone systems H04M9/10
• CPC Class Codes: H04R 2410/00 Microphones
• CPC Class Codes: H04R 2499/11 Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones

Abstract

A microphone apparatus including a MEMS transducer, an acoustic activity detector, a local oscillator, and an external-device interface standardized for compatibility with devices from different manufacturers is disclosed. The microphone apparatus has a first mode of operation during which the apparatus is clocked by the internal clock signal when the acoustic activity detector processes digital data for acoustic activity, and a second mode of operation during which the microphone apparatus is clocked by an external clock signal received at the external-device interface after voice activity is detected by the acoustic activity detector.

Claims

1. A method in a microphone apparatus, the method comprising:

producing an analog signal using a microelectromechanical system (MEMS) transducer;

converting the analog signal to digital data using an analog-to-digital convertor;

determining whether acoustic activity exists within the digital data using an acoustic activity detector;

upon the detection of acoustic activity, providing an indication of acoustic activity at an external-device interface of the microphone apparatus, the external-device interface standardized for compatibility with a plurality of devices from different manufacturers;

before detecting voice activity, operating the microphone apparatus in a first mode while determining whether acoustic activity exists by clocking at least a portion of the microphone apparatus with an internal clock signal based on a local oscillator; and

after detecting voice activity, operating the microphone in a second mode using an external clock signal received at the external-device interface.

2. The method of claim 1, operating the microphone apparatus in the second mode including providing output data at the external-device interface using the external clock signal.

3. The method of claim 2, further comprising receiving the external clock signal at the external-device interface in response to providing the indication of acoustic activity at the external-device interface, wherein output data provided at the external-device interface in the second mode is synchronized with the external clock signal.

4. The method of claim 3, further comprising transitioning the microphone apparatus from operating in the second mode to operating in the first mode after acoustic activity is no longer detected, wherein the first mode has lower power consumption than the second mode.

5. The method of claim 4, further comprising buffering data representing the analog signal during acoustic activity detection, at least some of the output data based on the buffered data.

6. The method of claim 4, wherein the indication of acoustic activity is provided at a select contact of the external-device interface, the external clock signal is received at a clock contact of the external-device interface, and the output data is provided at a data contact of the external device interface.

7. A microphone apparatus comprising:

a MEMS transducer configured to produce an analog signal in response to acoustic input;

an analog-to-digital converter coupled to the transducer and configured to convert the analog signal to digital data; and

an acoustic activity detector configured to determine presence of acoustic activity by performing acoustic activity detection on the digital data;

before acoustic activity is detected, the microphone apparatus is configured to operate in a first mode by performing voice activity detection using an internal clock signal generated from a local oscillator of the microphone apparatus; and

after acoustic activity is detected, the microphone apparatus is configured to operate in a second mode using an external clock signal received at an external-device interface of the microphone apparatus,

the external-device interface standardized for compatibility with devices from different manufacturers.

8. The apparatus of claim 7, wherein the microphone apparatus is configured to receive the external clock signal in response to providing a signal on the external-device interface after detecting voice activity and to provide output data on the external-device interface using the external clock signal.

9. The apparatus of claim 8, wherein in the second mode, the microphone apparatus is configured to provide output data on the external-device interface for a specified time after determining that acoustic activity is no longer present before discontinuing providing the output data on the external-device interface.

10. The apparatus of claim 7, wherein the microphone apparatus is configured to transition from operating in the second mode to operating in the first mode when the external clock signal is no longer received on the external-device interface.

11. The apparatus of claim 8, wherein the microphone apparatus is configured to buffer data representing the analog signal during acoustic activity detection, wherein the output data includes buffered data.

12. The apparatus of claim 8,

the external-device interface including a clock contact, a data contact, and a select contact,

the microphone configured to provide the signal on the select contact after detecting voice activity, receive the external clock signal on the clock contact, and provide the output data on the data contact.

13. The apparatus of claim 7, wherein the external-device interface is compatible with at least one of a PDM protocol, an I²S protocol, or an I²C protocol.

14. A microphone apparatus comprising:

a MEMS transducer configured to generate an analog signal in response to an acoustic input;

an analog-to-digital converter coupled to the MEMS transducer, the analog-to-digital converter configured to generate digital data representative of the analog signal;

an acoustic activity detector coupled to the analog-to-digital converter;

a controller coupled to the analog-to-digital converter,

a local oscillator configured to generate an internal clock signal;

an external-device interface standardized for compatibility with devices from different manufacturers, the external-device interface coupled to the controller,

the microphone having a first mode of operation during which the microphone apparatus is clocked by the internal clock signal when the acoustic activity detector processes the digital data for acoustic activity;

the microphone having a second mode of operation during which the microphone apparatus is clocked by an external clock signal received at the external-device interface after voice activity is detected by the acoustic activity detector.

15. The apparatus of claim 14, wherein, after acoustic activity has been detected, the controller is configured to provide an indication on the external-device interface, and the external clock signal is received at the external-device interface in response to providing the indication.

16. The apparatus of claim 15, wherein the microphone apparatus provides output data, representing the analog signal, at the external-device interface using the external clock signal during the second mode of operation.

17. The apparatus of claim 15, wherein the microphone apparatus transitions from the second mode of operation to the first mode of operation in the absence of the external clock signal on the external-device interface.

18. The apparatus of claim 16, further comprising a buffer coupled to the analog-to-digital converter, wherein data representing the analog signal is buffered in the buffer during acoustic activity detection, and the output data includes buffered data.

19. The apparatus of claim 18, wherein the interface is compatible with at least one of a PDM protocol, an I²S protocol, or an I²C protocol.