Loudspeaker diaphragm state estimation method and loudspeaker driving circuit using the same

Patent metadata

Field	Value
Publication number	US-10051394-B2
Application number	US-201715800406-A
Country	US
Kind code	B2
Filing date	Nov 1, 2017
Priority date	Nov 17, 2016
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

A loudspeaker diaphragm state estimation method includes: adjusting a weight value of a diaphragm displacement model by adaptive filtering until an error between an estimated value of a driving voltage of a loudspeaker and a measured value of the driving voltage is less than a predetermined threshold; estimating a diaphragm relative displacement of the loudspeaker according to the diaphragm displacement model corresponding to a final determined weight value; determining a diaphragm relative speed at a next moment based on an input current, a product value of a vector determined by an estimated value of a diaphragm relative speed and an estimated value of a diaphragm relative displacement, and a weight value vector obtained at a present moment; and determining an estimated value of the driving voltage using the estimated value of the diaphragm relative speed, the input current, and a DC impedance of the loudspeaker at the present moment.

First claim

What is claimed is:

1. A loudspeaker diaphragm state estimation method, the method comprising:
a) adjusting a weight value of a diaphragm displacement model by adaptive filtering until an error between an estimated value of a driving voltage of a loudspeaker and a measured value of said driving voltage is less than a predetermined threshold;
b) estimating a diaphragm relative displacement of said loudspeaker according to said diaphragm displacement model that corresponds to a final determined weight value;
c) determining a diaphragm relative speed at a next moment based on an input current, a product value of a vector determined by an estimated value of a diaphragm relative speed and an estimated value of a diaphragm relative displacement, and a weight value vector obtained at a present moment; and
d) determining an estimated value of said driving voltage based on said estimated value of said diaphragm relative speed, said input current, and a DC impedance of said loudspeaker obtained at said present moment.

2. The method of claim 1 , wherein adjusting said weight value of said diaphragm displacement model through said adaptive filtering comprises:
a) determining said diaphragm relative speed and said diaphragm relative displacement at said next moment according to said diaphragm displacement model that corresponds to said weight value obtained at said present moment;
b) determining said estimated value of said driving voltage at said present moment;
c) determining said error according to said estimated value of said driving voltage and said measured value of said driving voltage of said loudspeaker at said present moment; and
d) updating said weight value based on historical data of loudspeaker parameters through said adaptive filtering when said error is larger than said predetermined threshold.

3. The method of claim 1 , wherein said diaphragm displacement model is:

{

R
·

i
⁡

(
k
)

+

v
⁡

(
k
)

=

u
⁡

(
k
)

v
⁡

(

k
+
1

)

=

a
·

i
⁡

(
k
)

+

(

1
-
b

)

·

v
⁡

(
k
)

+

c
·

s
⁡

(
k
)

wherein R is said DC impedance of said loudspeaker, i(k) is said input current at moment k, v(k) is said diaphragm speed at moment k, u(k) is said estimated value of said driving voltage at moment k, s(k) is said diaphragm relative displacement, and a, b and c are weight values corresponding to i(k), v(k) and s(k).

4. The method of claim 2 , wherein said adaptive filtering is a least mean square algorithm (LMS).

5. The method of claim 4 , wherein said DC impedance of said loudspeaker is obtained by estimation.

6. The method of claim 1 , further comprising determining a diaphragm absolute displacement based on a predetermined relationship between said diaphragm relative displacement and said diaphragm absolute displacement, wherein said diaphragm relative displacement is obtained by calculation.

7. The method of claim 6 , wherein said predetermined relationship of said diaphragm relative displacement and said diaphragm absolute displacement is a proportion factor that is measured in advance.

8. A loudspeaker driving circuit, comprising a processor configured to perform the method of claim 1 .

Assignees

• Silergy Semiconductor Technology Hangzhou Ltd

Inventors

• Cao Hejinsheng
• Su Xiaotian

Classifications

• H04R29/001 Primary

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

• G01B7/18

  using change in resistance · CPC title

• G01R19/2506

  Arrangements for conditioning or analysing measured signals, e.g. for indicating peak values (G01R19/003 takes precedence); Details concerning sampling, digitizing or waveform capturing (displaying waveforms G01R13/00; analog sampling G01R19/0053) · CPC title

• H04R3/08

  of electromagnetic transducers · CPC title

• H04R3/007

  Protection circuits for transducers · CPC title