Device and method for filtering the resonance peak in a power supply circuit of at least one loudspeaker

Patent metadata

Field	Value
Publication number	US-10212515-B2
Application number	US-201515127884-A
Country	US
Kind code	B2
Filing date	Mar 3, 2015
Priority date	Mar 4, 2014
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

The present invention relates to an acoustic signal supply circuit of at least one loudspeaker (HP) incorporating a filtering device of the resonance peak of said at least one loudspeaker (HP) occurring at a given frequency, characterized in that the filtering device of the resonance peak of said at least one loudspeaker (HP) is incorporated either into the first instrumentation ground circuit or in the feedback loop, this filtering device being purely electrical in the form an impedance incorporated in the first instrumentation ground circuit or in the feedback loop, the impedance parameters being predetermined as a function of the resonance peak to be filtered of said at least one loudspeaker (HP).

First claim

The invention claimed is:

1. An acoustic signal supply circuit of at least one loudspeaker incorporating a filtering device of the resonance peak of said at least one loudspeaker occurring at a given frequency of the supply current of said at least one loudspeaker, said circuit comprising at least one non-inverting converter arranged upstream of said at least one loudspeaker having a positive supply terminal connected to the input power circuit and a negative supply terminal, said circuit comprising also, at the output of said at least one loudspeaker, a first instrumentation ground circuit bypassing a feedback loop connecting a point in the circuit downstream of the loudspeaker to the negative supply terminal of the non-inverting converter, the filtering device of the resonance peak of said at least one loudspeaker being purely electrical in the form of an impedance incorporated either in the first instrumentation ground circuit or in the feedback loop, the impedance parameters being predetermined as a function of the resonance peak to be filtered of said at least one loudspeaker, characterized in that:
when the impedance is incorporated into the first instrumentation ground circuit, this impedance is in the form of a dead resistor coupled with a first parallel impedance called RLC comprising at least one first resistor, at least one first inductor and least one first capacitor arranged in parallel to each other, the first parallel RLC impedance being arranged in series with the dead resistor in said first instrumentation ground circuit, and
when the impedance is incorporated into the feedback loop, this impedance as the second impedance comprises a second resistor coupled in parallel with at least one second inductor and at least one second capacitor, said at least one second inductor and said at least one second capacitor being arranged in series.

2. The circuit according to the preceding claim, wherein, when the impedance is incorporated into the first instrumentation ground circuit, the values of said at least one first capacitor, said at least one first resistor and said at least one first inductor are calculated according to the parameters of the at least one loudspeaker, namely the f m :M m ratio representative of mitigation and the k m :M m ratio representative of the square of the resonance angular frequency of the at least one loudspeaker according to the following equations:
f m /M m =1/ R b ·C b
k m /M m =1/ L b ·C b .

3. The circuit according to claim 1 , wherein the first parallel RLC impedance comprises n first inductors and n first capacitors, n being greater than or equal to one.

4. The circuit according to claim 1 , wherein, when the value of said at least one second inductor exceeds a value of 50 mH, said at least one second inductor is in the form of artificial chokes provided with gyrating means.

5. A method of current control of an acoustic signal supply circuit of at least one loudspeaker incorporating a filtering device of the resonance peak of said at least one loudspeaker according to claim 1 , in which method a correction step of the resonance peak by the filtering device is carried out, said correction step being carried out downstream of said at least one loudspeaker.

6. A control method according to the preceding claim, wherein the overall resonance factor of the loudspeaker and of the filtering device is set to a Butterworth filter.

7. A control method according to claim 5 , wherein temperature variations of said at least one loudspeaker are taken into account by the filtering device by variation corresponding to the parameters of the impedance of said device.

Assignees

• Whylot Sas
• Univ Maine
• Centre Nat Rech Scient

Inventors

• Gaviot Etienne
• Erza Mehran
• Polet Frédéric
• Camberlain Lionel
• Ravaud Romain

Classifications

• H04R3/002

  Damping circuit arrangements for transducers, e.g. motional feedback circuits · CPC title

• H03H7/01

  Frequency selective two-port networks · CPC title

• H04R3/007 Primary

  Protection circuits for transducers · CPC title

• H04R3/02 Primary

  for preventing acoustic reaction {, i.e. acoustic oscillatory feedback (specially adapted for hearing aids H04R25/453)} · CPC title

• H04R3/08 Primary

  of electromagnetic transducers · CPC title