Overheat protector for electrodynamic loudspeaker and protection method

Overheat protector for electrodynamic loudspeaker and protection method

  • CN 105,516,874 B
  • Filed: 10/09/2015
  • Issued: 09/24/2021
  • Est. Priority Date: 10/10/2014
  • Status: Active Grant
First Claim
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1. A method of avoiding overheating of a voice coil of an electro-dynamic loudspeaker, comprising the steps of:

  • a) an audio signal is generated and, in response to the audio signal,b) adding a low frequency probe signal to the audio signal to produce a composite loudspeaker drive signal comprising an audio signal component and a probe signal component,c) applying the composite loudspeaker drive signal to a voice coil of an electro-dynamic loudspeaker,d) the level of the detection current component flowing through the voice coil is detected,e) comparing the detected level of the probing current component with a predetermined probing current threshold, wherein the predetermined probing current threshold corresponds to a predetermined voice coil temperature through a known temperature dependence of the voice coil resistance,f) in response to the detection current component falling below a predetermined detection current threshold, attenuating the level of the audio signal,wherein the level of the low frequency detection signal is adjusted depending on the level of the audio signal, and the level of the low frequency detection signal is set to a first fixed level if the level of the audio signal exceeds a predetermined level threshold; and

    setting the level of the low frequency detection signal to a second fixed level if the level of the audio signal component is below a predetermined level threshold, the second fixed level being less than the first fixed level.

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