VAD detection microphone and method of operating the same

• US 9,712,923 B2
• Filed: 05/20/2014
• Issued: 07/18/2017
• Est. Priority Date: 05/23/2013
• Status: Active Grant

• Current Assignee: Knowles Electronics Llc (Knowles Corporation)
• Original Assignee: Knowles Electronics Llc (Knowles Corporation)
• Inventors: Thomsen, Henrik, Frst, Claus Erdmann, Deruginsky, Michael, Khamharn, Oddy Nopporn, Nandy, Dibyendu
• Primary Examiner(s): Tsang, Fan
• Assistant Examiner(s): Zhao, Eugene
• Application Number:
  US14/282,101
• Publication Number:
  US 20140348345A1
• Time in Patent Office: 1,155 Days
• Field of Search: 381 26, 381 91- 95, 381111, 700 94
• CPC Class Codes: G06F 1/324 by lowering clock frequency
• CPC Class Codes: G06F 1/325 Power saving in peripheral device
• CPC Class Codes: G10L 15/00 Speech recognition G10L17/00 takes precedence
• 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 1/08 Mouthpieces; Microphones; Attachments therefor
• CPC Class Codes: H04R 17/02 Microphones
• CPC Class Codes: H04R 19/005 using semiconductor materials
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 2201/003 Mems transducers or their use of the electrostatic type H04R19/005
• CPC Class Codes: H04R 3/00 Circuits for transducers , loudspeakers or microphones
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A microphone includes a microelectromechanical system (MEMS) circuit and an integrated circuit. The MEMS circuit is configured to convert a voice signal into an electrical signal, and the integrated circuit is coupled to the MEMS circuit and is configured to receive the electrical signal. The integrated circuit and the MEMS circuit receive a clock signal from an external host. The clock signal is effective to cause the MEMS circuit and integrated circuit to operate in full system operation mode during a first time period and in a voice activity mode of operation during a second time period. The voice activity mode has a first power consumption and the full system operation mode has a second power consumption. The first power consumption is less than the second power consumption. The integrated circuit is configured to generate an interrupt upon the detection of voice activity, and send the interrupt to the host.

Claims

1. A microphone comprising:

a microelectromechanical system (MEMS) circuit configured to convert a voice signal into an electrical signal,

an integrated circuit coupled to the MEMS circuit, the integrated circuit including a voice activity detector that determines whether voice is present in data representative of the electrical signal;

the integrated circuit has a first mode of operation when the data is not provided to an external-device interface of the microphone and a second mode of operation when the data is provided to the external-device interface, the first mode of operation having a first power consumption and the second mode of operation having a second power consumption, the first power consumption being less than the second power consumption,

the integrated circuit configured to provide an interrupt signal to the external-device interface after detection of voice activity in the data;

the integrated circuit includes a buffer in which the data representative of the electrical signal is buffered in order to provide time for the integrated circuit to process the data representative of the electrical signal;

wherein the integrated circuit selectively provides the buffered data to the external-device interface at an overclocked rate after detection of voice activity.

2. The microphone of claim 1, further comprising a local oscillator, the integrated circuit clocked by an internal clock signal based on the local oscillator.

3. The microphone of claim 1, wherein the integrated circuit is configured to provide real-time data to the external-device interface with the buffered data after detecting voice activity.

4. A method in a microphone comprising an acoustic sensor packaged with an integrated circuit, the method comprising:

performing voice activity detection on data obtained from an electrical signal produced in response to acoustic input to the microphone to detect voice activity;

buffering the data while performing voice activity detection;

clocking the microphone with an internal clock signal based on a local oscillator of the microphone;

providing the buffered data at an external-device interface of the microphone after detection of the voice activity; and

compensating for delay attributed to the buffering when providing the buffered data at the external-device interface of the microphone by providing the buffered data at the external-device interface at an overclocked frequency after detection of the voice activity.

5. The method of claim 4, further comprising operating the microphone in a first mode when the buffered data is not provided at the external-device interface, and operating the microphone in a second mode when the buffered data is provided at the external-device interface, a power consumption of the first mode less than a power consumption of the second mode.

6. The method of claim 4, further comprising providing real-time data with the buffered data at the external-device interface after detecting voice activity.

7. The method of claim 6, further comprising providing the buffered data at a first output of the external-device interface and providing the real-time data at a second output of the external-device interface.

8. The method of claim 4, further comprising:

obtaining the data by sampling the electrical signal at a sampling frequency, wherein compensating for delay attributed to buffering comprises clocking the buffered data provided at the external-device interface at a frequency greater than the sampling frequency.

9. The method of claim 4 further comprising:

providing an interrupt signal at the external-device interface upon detecting voice activity,

receiving an external clock signal at the external-device interface in response to providing the interrupt signal, and

clocking the microphone based on the external clock signal received at the external- device interface.

10. The method of claim 9, wherein the clocking the microphone based on the external clock signal includes synchronizing the internal clock signal with the external clock signal.

11. The method of claim 9, further comprising operating the microphone in a first mode when the buffered data is not provided at the external-device interface and operating the microphone in a second mode when the buffered data is provided at the external-device interface, wherein a power consumption of the first mode is lower than a power consumption of the second mode.

12. A microphone comprising:

an acoustic sensor having an output with an electrical signal produced in response to acoustic input at the acoustic sensor;

an integrated circuit packaged with the acoustic sensor, the integrated circuit including a controller coupled to a local oscillator, a voice activity detector, and a buffer,

the integrated circuit clocked by an internal clock signal, the internal clock signal based on an output of the local oscillator,

the output of the acoustic sensor coupled to the buffer and to the voice activity detector, data obtained from the electrical signal buffered at the buffer while the data is processed by the voice activity detector,

the controller providing the buffered data at an external-device interface of the microphone after detection of voice activity,

the buffered data at the external-device interface compensated for delay attributed to buffering, wherein the buffered data is provided at the external-device interface at an overclocked frequency.

13. The microphone of claim 12, the microphone having a first mode of operation when the buffered data is not provided at the external-device interface and a second mode of operation when the buffered data is provided at the external-device interface, a power consumption of the first mode of operation less than a power consumption of the second mode of operation.

14. The microphone of claim 12, the integrated circuit providing real-time data at the external-device interface with the buffered data provided at the external-device interface.

15. The microphone of claim 14, the external-device interface having a first output and a second output, the real-time data provided at the first output and the buffered data provided at the second output.

16. The microphone of claim 12, the buffer having a delay at least as long as a processing delay of the voice activity detector, wherein the buffer delay provides time for the voice activity detector to process the data.

17. The microphone of claim 12, wherein:

the integrated circuit includes an A/D converter coupled to the controller,

an input of the A/D converter coupled to the output of the acoustic sensor, an output of the A/D converter coupled to an input of the buffer and to an input to the voice activity detector,

a clock frequency of the buffer greater than a sampling frequency of the A/D converter when buffered data is provided at the external-device interface.

18. The microphone of claim 17, wherein:

the external-device interface includes an interrupt signal output and an external clock signal input,

the internal clock signal is based on an external clock signal present at the external clock signal input, and

an external clock signal is present at the external-device interface in response to an interrupt signal provided at the interrupt signal output.

19. The microphone of claim 12, wherein the acoustic sensor is a microelectromechanical systems (MEMS) sensor.