Protection of a speaker using temperature calibration

Patent metadata

Field	Value
Publication number	US-9729986-B2
Application number	US-201314074314-A
Country	US
Kind code	B2
Filing date	Nov 7, 2013
Priority date	Nov 7, 2012
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

In one general aspect, a method can include calculating, at a calibration temperature of a speaker, a calibration parameter through a coil of the speaker in response to a first test signal, and can include sending a second test signal through the coil of the speaker. The method can also include measuring a parameter through the coil of the speaker based on the second test signal, and calculating a temperature change of the coil of the speaker based on the parameter and based on the calibration parameter at the calibration temperature.

First claim

What is claimed is:

1. An apparatus, comprising:
a temperature sensor configured to measure a calibration temperature of a speaker coil;
a test signal generator configured to generate a first test signal through the speaker coil during a calibration time period before an audio signal is generated;
a current detector configured to measure a calibration current at the calibration temperature of the speaker coil based on the first test signal through the speaker coil;
an audio signal generator configured to generate the audio signal; and
a controller configured to trigger sending of a second test signal from the test signal generator through the speaker coil in combination with the audio signal, the current detector configured to calculate a temperature change of the speaker coil during normal operation using a temperature relationship based on the calibration current at the calibration temperature and a temperature coefficient of the speaker coil.

2. The apparatus of claim 1 , wherein the first test signal is a first portion of a test signal produced starting at a first time and the second test signal is a second portion of the test signal produced starting at a second time.

3. The apparatus of claim 1 , wherein the first test signal and the second test signal are produced using a same oscillator.

4. The apparatus of claim 1 , wherein the first test signal is generated in response to initial start up of a computing device.

5. The apparatus of claim 1 , wherein the first test signal is generated in response to a computing device changing from a standby state to an operation state.

6. The apparatus of claim 1 , further comprising:
a parameter measurement module configured to filter the test signal from the audio signal for calculation of the temperature change of the speaker coil.

7. An apparatus, comprising:
a controller configured to calculate, at a calibration temperature of a speaker, a calibration parameter through a coil of the speaker in response to a first test signal applied to the speaker during a calibration time period before an audio signal is generated;
a test signal generator configured to send a second test signal through the coil of the speaker; and
a parameter measurement module configured to measure a parameter through the coil of the speaker based on the second test signal,
the controller configured to calculate a temperature change of the coil of the speaker based on the parameter and based on the calibration parameter at the calibration temperature.

8. The apparatus of claim 7 , wherein the first test signal has a frequency that is a same as a frequency of the second test signal.

9. The apparatus of claim 7 , wherein the first test signal has a triangle waveform.

10. The apparatus of claim 7 , wherein the first test signal has a frequency of approximately 4 Hz.

11. The apparatus of claim 7 , wherein the calculating includes calculating based on a temperature relationship.

12. The apparatus of claim 7 , wherein the calculating includes adding the temperature change of the coil of the speaker to the calibration temperature.

13. The apparatus of claim 7 , wherein the calculating includes calculating based on a serialized process.

14. The apparatus of claim 7 , wherein the measuring is performed during a portion of a measurement cycle.

15. The apparatus of claim 7 , wherein the measuring is performed via a current sense MOSFET device.

16. The apparatus of claim 7 , wherein the parameter is at least one of a current, a resistance, or a voltage.

17. An apparatus, comprising:
a temperature sensor configured to measure a calibration temperature of a speaker coil;
a test signal generator configured to generate a first test signal through the speaker coil in response to initial start up of a computing device;
a current detector configured to measure a calibration current at the calibration temperature of the speaker coil based on the first test signal through the speaker coil;
an audio signal generator configured to generate the audio signal; and
a controller configured to trigger sending of a second test signal from the test signal generator through the speaker coil in combination with the audio signal, the current detector configured to calculate a temperature change of the speaker coil during normal operation using a temperature relationship based on the calibration current at the calibration temperature and a temperature coefficient of the speaker coil.

18. The apparatus of claim 17 , wherein the first test signal is a first portion of a test signal produced starting at a first time and the second test signal is a second portion of the test signal produced starting at a second time.

19. The apparatus of claim 17 , wherein the first test signal and the second test signal are produced using a same oscillator.

20. The apparatus of claim 17 , wherein the first test signal is generated before an audio signal is generated.

Assignees

• Fairchild Semiconductor

Inventors

• Crawley Philip
• Llewellyn William D
• Shushtarian Majid

Classifications

• H04R29/001 Primary

  for loudspeakers (H04R29/007 takes precedence) · CPC title