Proximity sensing for user detection and automatic volume regulation with sensor interruption override

• US 8,848,932 B2
• Filed: 10/13/2011
• Issued: 09/30/2014
• Est. Priority Date: 10/13/2011
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Poulsen, Jens Kristian, El-Hage, Mohamad, Broga, Antanas Matthew
• Primary Examiner(s): Paul, Disler
• Application Number:
  US13/272,585
• Publication Number:
  US 20130094668A1
• Time in Patent Office: 1,083 Days
• Field of Search: 381/74, 381104-109, 381/55, 381/58
• US Class Current: 381/58
• CPC Class Codes: H03G 11/002 without controlling loop H03G11/004, H03G11/006, H03G11/008, H03G11/02, H03G11/04, H03G11/06, H03G11/08 take precedence
• CPC Class Codes: H03G 3/301 the gain being continuously variable
• CPC Class Codes: H04R 2420/01 Input selection or mixing for amplifiers or loudspeakers for hearing aids H04R25/43
• CPC Class Codes: H04R 2420/03 Connection circuits to selectively connect loudspeakers or headphones to amplifiers
• CPC Class Codes: H04R 2430/01 Aspects of volume control, not necessarily automatic, in sound systems
• CPC Class Codes: H04R 2430/03 Synergistic effects of band splitting and sub-band processing
• 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 3/12 for distributing signals to two or more loudspeakers specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04R 5/04 Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments combinations of amplifiers H03F3/68; stereophonic systems H04S

Abstract

A mobile device includes at least one speaker and an audio subsystem for providing an audio signal to the at least one speaker for playback by the at least one speaker. The audio subsystem operates by detecting a distance to a user of the mobile device using a proximity sensor and controlling volume output of the at least one speaker based on the distance to the user of the mobile device and the operational status of the proximity sensor. If it is determined that the proximity sensor is functional, the audio subsystem applies a gain factor to the audio signal that varies based on the distance to the user or limits the maximum allowable speaker output based on the distance. A high or low gain setting may be applied for when the user is far away or in close proximity to the mobile device.

Claims

1. An audio subsystem for a mobile device comprising at least one speaker, the audio subsystem comprising:

an audio source for generating an audio signal;

a proximity sensor comprising a detection circuit configured to generate a sensor output signal representing a distance to a user of the mobile device, and a failsafe generator coupled to the detection circuit and configured to generate a sensor status signal indicating an operational status of the proximity sensor; and

a power amplification module configured to process the audio signal received from the audio source into an amplified audio signal for output by the at least one speaker, the power amplification module comprising a gain controller responsive to the sensor output signal and the sensor status signal to determine and apply a gain factor to the audio signal based on the distance to the user of the mobile device and the operational status of the proximity sensor;

wherein the failsafe generator is configured to

monitor an operating parameter of at least one internal signal of the proximity sensor, the operating parameter of the at least one internal signal indicative of the operational status of the proximity sensor;

generate the sensor status signal based on the operating parameter of the at least one internal signal;

monitor the operating parameter of the at least one internal signal over a time interval;

if over the time interval the operating parameter of the at least one internal signal is within an expected range, set the sensor status signal to a default control value for the gain controller to apply variable gain to the audio signal based on the distance to the user; and

if over the time interval the operating parameter of the at least one internal signal is outside the expected range, set the sensor status signal to an override control value for the gain controller to apply fixed gain to the audio signal independently of the distance to the user.

2. The audio subsystem of claim 1, wherein the proximity sensor further comprises

a transmitter for generating a transmission signal;

a transmitting antenna coupled to the transmitter for radiating the transmission signal outwardly from the mobile device; and

a receiving antenna for generating a proximity detection signal having a detection parameter that varies in relation to the transmission signal based on the distance to the user; and

wherein the detection circuit is coupled to the receiving antenna to receive the proximity detection signal and configured to generate the sensor output signal based on the detection parameter of the proximity detection signal.

3. The audio subsystem of claim 2, wherein the transmitter comprises a signal generator for generating a frequency signal, and the failsafe generator is configured to generate the sensor status signal by monitoring a first operating parameter of at least one of the frequency signal and the transmission signal.

4. The audio subsystem of claim 3, wherein the transmitter further comprises a signal modulator coupled to the signal generator for modulating the frequency signal to generate a modulated frequency signal, and wherein the failsafe generator is configured to generate the sensor status signal by monitoring a second operating parameter of at least one of the modulated frequency signal and the transmission signal.

5. The audio subsystem of claim 2, wherein the detection circuit comprises a load detector for generating a load detection signal based on the proximity detection signal to represent an effective loading of the user on the transmitting antenna, and wherein the failsafe generator is configured to generate the sensor status signal based on the effective loading of the user on the transmitting antenna.

6. The audio subsystem of claim 1, wherein the failsafe generator is configured to

monitor the operating parameter of the at least one internal signal over a time interval;

if over the time interval the operating parameter of the at least one internal signal is within an expected range, set the sensor status signal to a default control value for the gain controller to;

(i) apply a first fixed gain to the audio signal, if an output volume of the at least one speaker is less than a maximum volume determined for the distance to the user, and (ii) apply a second fixed gain less than the first fixed gain to the audio signal, if the output volume of the at least one speaker is above the maximum volume determined for the distance to the user; and

if over the time interval the operating parameter of the at least one internal signal is outside the expected range, set the sensor status signal to an override control value for the gain controller to apply a third fixed gain to the audio signal independently of the distance to the user.

7. The audio subsystem of claim 1, further comprising at least one supplemental sensor unit for generating at least one supplemental estimate of the distance to the user, and wherein the failsafe generator is configured to determine the sensor status signal based on the sensor output signal and the at least one supplemental estimate of the distance to the user, and generate the sensor output signal based on a difference between the sensor output signal and the at least one supplemental estimate of the distance to the user;

wherein if the difference between the sensor output signal and the at least one supplemental estimate of the distance to the user exceeds a maximum difference, the failsafe generator is configured to set the sensor status signal to an override control value for the gain controller to apply fixed gain to the audio signal independently of the distance to the user.

8. An audio subsystem for a mobile device comprising at least one speaker, the audio subsystem comprising:

an audio source for generating an audio signal;

a proximity sensor comprising a detection circuit configured to generate a sensor output signal representing a distance to a user of the mobile device, and a failsafe generator coupled to the detection circuit and configured to generate a sensor status signal indicating an operational status of the proximity sensor;

a power amplification module configured to process the audio signal received from the audio source into an amplified audio signal for output by the at least one speaker, the power amplification module comprising a gain controller responsive to the sensor output signal and the sensor status signal to determine and apply a gain factor to the audio signal based on the distance to the user of the mobile device and the operational status of the proximity sensor;

wherein the failsafe generator is configured to

monitor an operating parameter of at least one internal signal of the proximity sensor, the operating parameter of the at least one internal signal indicative of the operational status of the proximity sensor; and

generate the sensor status signal based on the operating parameter of the at least one internal signal; and

wherein the proximity sensor comprises an isolation switch for enabling and disabling the proximity sensor based upon an output volume of the at least one speaker in relation to a maximum volume.

9. A method for controlling volume output in at least one speaker of a mobile device, the method comprising:

a proximity sensor detecting a distance to a user of the mobile device;

monitoring an operational status of the proximity sensor;

providing an audio signal from an audio source;

a) processing the audio signal into an amplified audio signal by determining and applying a gain factor to the audio signal based on the distance to the user of the mobile device and the operational status of the proximity sensor;

b) providing the amplified audio signal to the at least one speaker for output by the at least one speaker;

monitoring an operating parameter of at least one internal signal of the proximity sensor, the operating parameter of the at least one internal signal indicative of the operational status of the proximity sensor;

determining the operational status of the proximity sensor based on the operating parameter of the at least one internal signal; and

,

monitoring the operating parameter of the at least one internal signal over a time interval;

if over the time interval the operating parameter of the at least one internal signal is within an expected range, applying variable gain to the audio signal based on the distance to the user; and

if over the time interval the operating parameter of the at least one internal signal is outside the expected range, applying fixed gain to the audio signal independently of the distance to the user.

10. The method of claim 9, further comprising the proximity sensor:

generating a transmission signal;

radiating the transmission signal outwardly from the mobile device; and

generating a proximity detection signal having a detection parameter that varies in relation to the transmission signal based on the distance to the user, and wherein the method further comprises detecting the distance to the user based on the detection parameter of the proximity detection signal.

11. The method of claim 10, wherein the generating the transmission signal comprises generating a frequency signal, and the method further comprises:

monitoring a first operating parameter of at least one of the frequency signal and the transmission signal; and

determining the operational status of the proximity sensor based on the first operating parameter.

12. The method of claim 11, wherein the generating the transmission signal further comprises modulating the frequency signal to generate a modulated frequency signal, and the method further comprises:

monitoring a second operating parameter of at least one of the modulated frequency signal and the transmission signal; and

determining the operational status of the proximity sensor based on the second operating parameter.

13. The method of claim 10, further comprising:

generating a load detection signal based on the proximity detection signal to represent an effective loading of the user on a transmitting antenna of the proximity sensor; and

determining the operational status of the proximity sensor based on the effective loading of the user on the transmitting antenna.

14. The method of claim 9, further comprising:

monitoring the operating parameter of the at least one internal signal over a time interval;

if over the time interval the operating parameter of the at least one internal signal is within an expected range;

(i) applying a first fixed gain to the audio signal, if an output volume of the at least one speaker is less than a maximum volume determined for the distance to the user, and (ii) applying a second fixed gain less than the first fixed gain to the audio signal, if the output volume of the at least one speaker is above the maximum volume determined for the distance to the user; and

if over the time interval the operating parameter of the at least one internal signal is outside the expected range, applying a third fixed gain to the audio signal independently of the distance to the user.

15. The method of claim 9, further comprising:

generating at least one supplemental estimate of the distance to the user;

determining the operational status of the proximity sensor based on the distance to the user detected by the proximity sensor and the at least one supplemental estimate of the distance to the user;

determining the operational status of the proximity sensor based on a difference between the distance to the user detected by the proximity sensor and the at least one supplemental estimate of the distance to the user; and

,

if the difference between the distance to the user detected by the proximity sensor and the at least one supplemental estimate of the distance to the user exceeds a maximum difference, applying fixed gain to the audio signal independently of the distance to the user.

16. The method of claim 9, further comprising:

determining if an output volume of the at least one speaker exceeds a maximum volume;

enabling the proximity sensor when it is determined that the output volume exceeds the maximum volume; and

disabling the proximity sensor when it is determined that the output volume does not exceed the maximum volume.