Protection of a speaker using temperature calibration
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.
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.