CN109546979A - A kind of current detection circuit of loudspeaker - Google Patents
A kind of current detection circuit of loudspeaker Download PDFInfo
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- CN109546979A CN109546979A CN201910035711.5A CN201910035711A CN109546979A CN 109546979 A CN109546979 A CN 109546979A CN 201910035711 A CN201910035711 A CN 201910035711A CN 109546979 A CN109546979 A CN 109546979A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
- H03F3/217—Class D power amplifiers; Switching amplifiers
- H03F3/2175—Class D power amplifiers; Switching amplifiers using analogue-digital or digital-analogue conversion
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
- H03F3/217—Class D power amplifiers; Switching amplifiers
- H03F3/2178—Class D power amplifiers; Switching amplifiers using more than one switch or switching amplifier in parallel or in series
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Abstract
The present invention discloses a kind of current detection circuit of loudspeaker, including the first detection resistance, the second detection resistance, sampling selection circuit, input selection circuit and processing circuit；One end of first detection resistance is connected with the first input end of the input selection circuit；One end of second detection resistance is connected with the second input terminal of the input selection circuit；The output end of the sampling selection circuit is connected with the switch control terminal of the input selection circuit；The input selection circuit is connected with the processing circuit.The present invention is by increasing sampling selection circuit and input selection circuit, the different half periods are according to the potential difference of the output stage VOP of D-type audio power amplifier and output stage VON, sample the voltage at corresponding detection resistance both ends, and the electric current of loudspeaker is obtained by processing, so as to realize the detection for loudspeaker electric current, and without cutting top distortion function to D-type audio power amplifier addition is anti-, it ensure that the performance of D-type audio power amplifier.
Description
Technical field
The present invention relates to technical field of current detection more particularly to a kind of current detection circuits of loudspeaker.
Background technique
Currently, D-type audio power amplifier is widely used due to having the advantages that high-efficient, small and performance of generating heat is good
In the portable devices such as Baffle Box of Bluetooth and mobile phone.
But due to portable device pursuit is small and exquisite, internal loudspeaker cavity is smaller, so biggish in broadcast sound volume
When music, when especially big supper bass song, it is excessively high that loudspeaker cavity may be displaced excessive or loudspeaker temperature because of vibrating diaphragm
Reason and damage, so generally can give D-type audio power amplifier design current detection circuit, so as to according to loudspeaker electric current
Size control D-type audio power amplifier output electric current size, and then protect loudspeaker will not because vibrating diaphragm be displaced it is excessive or
Loudspeaker temperature is excessively high and damages.But when larger due to the output power of D-type audio power amplifier, it may occur that top phenomenon is cut,
The current potential of its output stage VOP or the current potential of output stage VON may be continuous height occur in several pulse-width modulation frequencies
Level or low level, general electric current detecting method is difficult accurate detection and goes out loudspeaker electric current at this time, so usually requiring that D assonance
Frequency power amplifier cuts top distortion function plus anti-, i.e., actively limits the output power of D-type audio power amplifier, make its output
Top is not cut.
But top distortion function is cut plus anti-in D-type audio power amplifier, D-type audio power amplifier will be reduced
Output power, without playing the performance of D-type audio power amplifier to greatest extent.
Summary of the invention
In view of this, the embodiment of the present invention provides a kind of current detection circuit of loudspeaker, when solving to detect loudspeaker electric current,
The problem of sacrificing the performance of D-type audio power amplifier.
To achieve the above object, the embodiment of the present invention provides the following technical solutions:
A kind of current detection circuit of loudspeaker, suitable for the loudspeaker being connected with D-type audio power amplifier, the loudspeaker
Current detection circuit includes: the first detection resistance, the second detection resistance, sampling selection circuit, input selection circuit and processing electricity
Road；Wherein:
One end of first detection resistance is connected with the first input end of the input selection circuit, and tie point is as institute
The first input end for stating the current detection circuit of loudspeaker, the low side NMOS with the output stage VON of the D-type audio power amplifier
The source electrode of transistor is connected；
One end of second detection resistance is connected with the second input terminal of the input selection circuit, and tie point is as institute
The second input terminal for stating the current detection circuit of loudspeaker, the low side NMOS with the output stage VOP of the D-type audio power amplifier
The source electrode of transistor is connected；
The other end and the input selection circuit of the other end of first detection resistance, second detection resistance
Third input terminal, be grounded；
First output end of the input selection circuit is connected with the first input end of the processing circuit；The input choosing
The second output terminal for selecting circuit is connected with the second input terminal of the processing circuit；
The output end of the processing circuit is the output end of the current detection circuit of the loudspeaker；
It is described sampling selection circuit three input terminals respectively with sampling clock, the output stage VOP and the output stage
VON is connected；
The output end of the sampling selection circuit is connected with the switch control terminal of the input selection circuit；
The sampling selection circuit is used to be located at positive half cycle when the potential difference of the output stage VOP and output stage VON
When the phase, first input end and the first output end formation access, third input terminal and second for controlling the input selection circuit are defeated
Outlet forms access；And when the potential difference of the output stage VOP and the output stage VON are located at negative half-cycle, described in control
The third input terminal of input selection circuit and the first output end form access, the second input terminal and second output terminal and form access.
Optionally, the input selection circuit, comprising: first switch, second switch, third switch, the 4th switch and control
Molding block；Wherein:
First input end of the first end of the first switch as the input selection circuit；The of the second switch
Second input terminal of the one end as the input selection circuit；The first of the first end of the third switch and the 4th switch
End is connected, third input terminal of the tie point as the input selection circuit；
The second end of the first switch is connected with the second end that third switchs, and tie point is as the input selection circuit
The first output end；The second end of the second switch is connected with the second end of the 4th switch, and tie point is selected as the input
Select the second output terminal of circuit；
The control terminal of the first switch is connected with the control terminal of the 4th switch, and the first of tie point and the control module
Output end is connected；The control terminal of the second switch is connected with the control terminal that third switchs, tie point and the control module
Second output terminal is connected；
Switch control terminal of the input terminal of the control module as the input selection circuit.
Optionally, the processing circuit, comprising: active power filtering amplifying circuit and conversion module；Wherein:
First input end of the first input end of the active power filtering amplifying circuit as the processing circuit；It is described active
Second input terminal of second input terminal of filter amplification circuit as the processing circuit；
First output end of the active power filtering amplifying circuit is connected with the first input end of the conversion module, described to have
The second output terminal of source filter amplification circuit is connected with the second input terminal of the conversion module；
Output end of the output end of the conversion module as the processing circuit.
Optionally, the active power filtering amplifying circuit, comprising: operational amplifier, the first input resistance, the second input resistance
And first filter branch and the second filter branch；Wherein:
The first end of the operational amplifier is connected with the input terminal of first filter branch, tie point and described first
One end of input resistance is connected；First input of the other end of first input resistance as the active power filtering amplifying circuit
End；
The second end of the operational amplifier is connected with the input terminal of second filter branch, tie point and described second
One end of input resistance is connected；Second input of the other end of second input resistance as the active power filtering amplifying circuit
End；
The third end of the operational amplifier is connected with the output end of first filter branch, has described in tie point conduct
First output end of source filter amplification circuit；
4th end of the operational amplifier is connected with the output end of second filter branch, has described in tie point conduct
The second output terminal of source filter amplification circuit.
Optionally, first filter branch, comprising: first capacitor and the first feedback resistance；Wherein:
The first capacitor is in parallel with first feedback resistance, and the one end being connected in parallel is as first filter branch
Input terminal, output end of the other end being connected in parallel as first filter branch.
Optionally, second filter branch, comprising: the second capacitor and the second feedback resistance；Wherein:
Second capacitor is in parallel with second feedback resistance, and the one end being connected in parallel is as second filter branch
Input terminal, output end of the other end being connected in parallel as second filter branch.
Optionally, the conversion module is Integrated Derivative analog-digital converter.
Optionally, the resistance value of first detection resistance and the second detection resistance is equal.
Optionally, the frequency of the sampling clock is the current potential of the output stage VOP and the current potential of the output stage VON
256 times of pulse-width modulation frequency.
Optionally, the resistance value of first input resistance and the second input resistance is identical.
Compared with the existing technology, the present invention is by increasing sampling selection circuit and input selection circuit, according to D class audio frequency function
The potential difference of the output stage VOP and output stage VON of rate amplifier are in positive half period or negative half-cycle, sample corresponding detection resistance
The voltage at both ends, and obtain the electric current of loudspeaker by processing, so as to realize the detection for loudspeaker electric current, and without pair
D-type audio power amplifier addition is anti-to cut top distortion function, ensure that the performance of D-type audio power amplifier.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
The embodiment of invention for those of ordinary skill in the art without creative efforts, can also basis
The attached drawing of offer obtains other attached drawings.
Fig. 1 is a kind of schematic diagram of current detection circuit disclosed by the embodiments of the present invention；
Fig. 2 is the waveform diagram of switch control signal Switch_selt in (VOP-VON) positive and negative half period；
Fig. 3 is a kind of schematic diagram of current detection circuit disclosed in another embodiment of the present invention；
Fig. 4 is a kind of schematic diagram of current detection circuit disclosed in another embodiment of the present invention；
Fig. 5 is a kind of schematic diagram of current detection circuit disclosed in another embodiment of the present invention.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
In order to make the foregoing objectives, features and advantages of the present invention clearer and more comprehensible, with reference to the accompanying drawing and specific real
Applying mode, the present invention is described in further detail.
In this application, the terms "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion,
So that the process, method, article or equipment for including a series of elements not only includes those elements, but also including not having
The other element being expressly recited, or further include for elements inherent to such a process, method, article, or device.Do not having
There is the element limited in the case where more limiting by sentence "including a ...", it is not excluded that in the mistake including the element
There is also other identical elements in journey, method, article or equipment.
In order to sacrifice the performance of D-type audio power amplifier, the embodiment of the present invention when solving the problem of detection loudspeaker electric current
A kind of current detection circuit of loudspeaker is disclosed, as shown in Figure 1, current detection circuit disclosed in the present embodiment and D class audio frequency power
Amplifier 400 is connected with loudspeaker 500, and depending on actual conditions, the branch road of the loudspeaker 500 can may also be in series with inductance L；This
Current detection circuit disclosed in embodiment include: the first detection resistance RSP, the second detection resistance RSN, sampling selection circuit 100,
Input selection circuit 200 and processing circuit 300；Wherein:
One end of first detection resistance RSP is connected with the first input end SN1 of input selection circuit 200, and tie point is as D
The first input end of the current detection circuit of genus audio power amplifier 400, the output stage with D-type audio power amplifier 400
The source electrode of the low side NMOS transistor Z2 of VON is connected.
One end of second detection resistance RSN is connected with the second input terminal SN2 of input selection circuit 200, and tie point is as D
Second input terminal of the current detection circuit of genus audio power amplifier 400, the output stage with D-type audio power amplifier 400
The source electrode of the low side NMOS transistor Z1 of VOP is connected.
It should be noted that the resistance value of the first detection resistance RSP and the second detection resistance RSN are equal.
The third of the other end of first detection resistance RSP, the other end of the second detection resistance RSN and input selection circuit is defeated
Enter and hold SN3, is grounded.
First output end of input selection circuit 200 is connected with the first input end of processing circuit 300；Input selection circuit
200 second output terminal is connected with the second input terminal of processing circuit 300.
The output end of processing circuit is the output end of the current detection circuit of the loudspeaker.
Three input terminals of sampling selection circuit 100 are separately connected sampling clock 600, output stage VOP and output stage VON phase
Even.
It should be noted that the frequency of sampling clock 600 is the pulse width of the current potential of output stage VOP and output stage VON
256 times of modulating frequency can also carry out other settings according to specific application environment in practical application, and only one kind is shown herein
Example, is not limited to that, within the scope of protection of this application.
The output end of sampling selection circuit 100 is connected with the switch control terminal of input selection circuit 200.
Specific working principle are as follows:
Selection circuit 100 is sampled according to the current potential of output stage VOP and the current potential of output stage VON, VOP-VON filter is calculated
Waveform after wave, by taking sine wave as an example, waveform is as shown in Fig. 2 top half；Selection circuit 100 is sampled in conjunction with sampling clock
600 frequency judges that output stage VOP and the potential difference (namely the filtered value of VOP-VON) of output stage VON are in positive half cycle
Phase or negative half-cycle, and export corresponding switch control signal Switch_selt.
As shown in Fig. 2, the potential difference as output stage VOP and output stage VON is in positive half period, selection circuit is sampled
The switch control signal Switch_selt of 100 outputs with certain current potential, such as high level, control input selection circuit 200 by its
First input end SN1 and its first output end form access, and its third input terminal SN3 are formed with its second output terminal logical
Road；So that processing circuit 300 can sample the voltage at the first both ends detection resistance RSP and be handled, PDM is obtained
(Pulse Density Modulation, pulse density modulated) code.
And when the potential difference of output stage VOP and output stage VON is in negative half-cycle, sampling selection circuit 100 exports
Switch control signal Switch_selt controls input selection circuit 200 for its third with another current potential, such as low level
Input terminal SN3 and its first output end form access, and its second input terminal SN2 and its second output terminal are formed access；Into
And enable processing circuit 300 to sample the voltage at the second both ends detection resistance RSN and handled, obtain pulse density modulated
Code PDM code.
The PDM code is by cic filter (Cascaded integrator-comb filter, integral-pectination cascade
Filter) loudspeaker electric current can be obtained.
The present invention is by increasing sampling selection circuit 100 and input selection circuit 200, according to D-type audio power amplifier
Output stage VOP and the potential difference of output stage VON be in positive half period or negative half-cycle, sample the electricity at corresponding detection resistance both ends
Pressure, and loudspeaker electric current is obtained by processing, so as to realize the current detecting for loudspeaker, and without to D class audio frequency function
Rate amplifier addition is anti-to cut top distortion function, ensure that the performance of D-type audio power amplifier.
Another embodiment of the present invention additionally provides a kind of current detection circuit of specific loudspeaker, in above-described embodiment and figure
On the basis of 1 and Fig. 2, optionally, as shown in figure 3, a kind of embodiment of its input selection circuit 200, comprising: first opens
Close S1, second switch S2, third switch S3, the 4th switch S4 and control module 201；Wherein:
First input end SN1 of the first end of first switch S1 as input selection circuit 200；The first of second switch S2
Hold the second input terminal SN2 as input selection circuit 200；The first end of third switch S3 is as input selection circuit 200
Third input terminal SN3.
The second end of first switch S1 is connected with the second end of third switch S3, and tie point is as input selection circuit 200
The first output end；The second end of second switch S2 is connected with the second end of the 4th switch S4, and tie point is as input selection electricity
The second output terminal on road 200.
The control terminal of first switch S1 is connected with the control terminal of the 4th switch S4, and the first of tie point and control module 201
Output end is connected；The control terminal of second switch S2 is connected with the control terminal of third switch S3, and the of tie point and control module 201
Two output ends are connected.
Switch control terminal of the input terminal of control module 201 as input selection circuit 200.
Specific working principle are as follows:
When the potential difference of output stage VOP and output stage VON are in positive half period, i.e. opening when input selection circuit 200
When the current potential for closing the switch control signal Switch_selt that control terminal receives is high level, the first output of control module 201
It holds V1 to export closure signal, controls first switch S1 and the 4th switch S4 closure；And its second output terminal V2 exports cut-off signals,
Second switch S2 and third switch S3 is controlled to disconnect.
When the potential difference of output stage VOP and output stage VON are in negative half-cycle, i.e. opening when input selection circuit 200
When the current potential for closing the switch control signal Switch_selt that control terminal receives is low level, the first output of control module 201
It holds V1 to export cut-off signals, controls first switch S1 and the 4th switch S4 and disconnect；And the second closure of its second output terminal V2 output
Signal controls second switch S2 and third switch S3 closure.
This gives a kind of specific embodiments of input selection circuit 200, it is not limited to this, actually answers
The circuit structure or chip that can be formed in other discrete devices is realized, depending on its specific application environment, as long as
It can be realized the scheme of above-mentioned working principle within the scope of protection of this application.
Remaining structure and principle are same as the previously described embodiments, no longer repeat one by one herein.
Optionally, such as Fig. 4, in another embodiment of the invention, a kind of embodiment of processing circuit 300, comprising: have
Source filter amplification circuit 301 and conversion module 302；Wherein:
First input end of the first input end of active power filtering amplifying circuit 301 as processing circuit 300；Active power filtering is put
Second input terminal of second input terminal of big circuit 301 as processing circuit 300；
First output end of active power filtering amplifying circuit 301 is connected with the first input end of conversion module 302, active power filtering
The second output terminal of amplifying circuit 301 is connected with the second input terminal of conversion module 302.
Output end of the output end of conversion module 302 as processing circuit 300.
It should be noted that conversion module 300 is Integrated Derivative analog-digital converter.
Specific working principle are as follows:
When the potential difference of output stage VOP and output stage VON are in positive half period, i.e., when input selection circuit 200 receives
When the current potential of the switch control signal Switch_selt arrived is high level, then active power filtering amplifying circuit 301 is to the first detection electricity
The voltage at the resistance both ends RSP is sampled, and carries out active power filtering and gain amplification disposal to it；Later, 302 pairs of conversion module warps
Crossing treated, voltage is converted, and obtains PDM code.
When the potential difference of output stage VOP and output stage VON are in negative half-cycle, i.e., when input selection circuit 200 receives
When the current potential of the switch control signal Switch_selt arrived is low level, then active power filtering amplifying circuit 301 is to D class audio frequency function
The voltage at the second both ends detection resistance RSN of rate amplifier 400 is sampled, and is carried out at active power filtering and gain amplification to it
Reason；Later, conversion module 302 converts voltage after treatment, obtains PDM code.
This gives a kind of specific embodiments of processing circuit 300, it is not limited to this, in practical application
The filter circuit of other forms, such as passive filter circuit can also be used, as long as can be realized corresponding filter function；
Also, its conversion module 300 is also not limited to Integrated Derivative analog-digital converter, can also be using the energy of discrete device composition
Enough realize the circuit of gain enlarging function；It can be depending on its specific application environment, within the scope of protection of this application.
Remaining structure and principle are same as the previously described embodiments, no longer repeat one by one herein.
Optionally, such as Fig. 5, in another embodiment of the invention, a kind of embodiment party of active power filtering amplifying circuit 301
Formula, comprising: operational amplifier AMP, 303 and of the first input resistance RIN1, the second input resistance RIN2 and the first filter branch
Second filter branch 304；Wherein:
The first end of operational amplifier AMP is connected with the input terminal of the first filter branch 303, tie point and the first input electricity
The one end for hindering RIN1 is connected；First input end of the other end of first input resistance RIN1 as active power filtering amplifying circuit 301.
The second end of operational amplifier AMP is connected with the input terminal of the second filter branch 304, tie point and the second input electricity
The one end for hindering RIN2 is connected；Second input terminal of the other end of second input resistance RIN2 as active power filtering amplifying circuit 301.
The third end of operational amplifier AMP is connected with the output end of the first filter branch 303, and tie point is as active power filtering
First output end of amplifying circuit 301.
The 4th end of operational amplifier AMP is connected with the output end of the second filter branch 304, and tie point is as active power filtering
The second output terminal of amplifying circuit 301.
Optionally, the first filter branch 303 includes first capacitor C1 and the first feedback resistance Rf1；First capacitor C1 and
One feedback resistance Rf1 is in parallel, input terminal of the one end being connected in parallel as the first filter branch 303；The other end being connected in parallel
Output end as the first filter branch 303.
Optionally, the second filter branch 304 includes the second capacitor C2 and the second feedback resistance Rf2；Second capacitor C2 and
Two feedback resistance Rf2 are in parallel, input terminal of the one end being connected in parallel as the second filter branch 304；The other end being connected in parallel
Output end as the second filter branch 304.
It should be noted that the resistance value of the first input resistance RIN1 and the second input resistance RIN2 are identical.
Specific working principle are as follows:
First input resistance RIN1, operational amplifier AMP and the first feedback resistance Rf1 constitute positive-feedback circuit, to having
The voltage of the first input end of source filter amplification circuit 301 plays the role of gain amplification, and direct current amplification factor are as follows: AV
=-Rf1/RIN1.
The second capacitor C2 in first capacitor C1 and the second filter branch 304 in first filter branch 303 is to active filter
The voltage of the first output end and the voltage of second output terminal of wave amplifying circuit 301 play the role of low-pass filtering, by D class audio frequency
Radio-frequency component in the current potential of the output stage VOP and output stage VON of power amplifier 400 filters out, and high-frequency noise is prevented to be folded
At to the signal-to-noise ratio for reducing current detecting in audio range, and -3dB the frequency of active power filtering amplifying circuit 301 be f (-
3dB)=1/ (2 × π × Rf1×C1)。
This gives a kind of specific embodiments of active power filtering amplifying circuit 301, it is not limited to this, real
Can also it be existed using the filter circuit of other forms as long as can be realized corresponding low-pass filtering function in the application of border
In the protection scope of the application.
Remaining structure and principle are same as the previously described embodiments, no longer repeat one by one herein.
The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present invention.
Various modifications to these embodiments will be readily apparent to those skilled in the art, as defined herein
General Principle can be realized in other embodiments without departing from the spirit or scope of the present invention.Therefore, of the invention
It is not intended to be limited to the embodiments shown herein, and is to fit to and the principles and novel features disclosed herein phase one
The widest scope of cause.
It should also be noted that, herein, relational terms such as first and second and the like are used merely to one
Entity or operation are distinguished with another entity or operation, without necessarily requiring or implying between these entities or operation
There are any actual relationship or orders.
Claims (10)
1. a kind of current detection circuit of loudspeaker, suitable for the loudspeaker being connected with D-type audio power amplifier, which is characterized in that
The current detection circuit of the loudspeaker includes: the first detection resistance, the second detection resistance, sampling selection circuit, input selection electricity
Road and processing circuit；Wherein:
One end of first detection resistance is connected with the first input end of the input selection circuit, and tie point is as the loudspeaker
The first input end of current detection circuit, the low side NMOS crystal with the output stage VON of the D-type audio power amplifier
The source electrode of pipe is connected；
One end of second detection resistance is connected with the second input terminal of the input selection circuit, and tie point is as the loudspeaker
Second input terminal of current detection circuit, the low side NMOS crystal with the output stage VOP of the D-type audio power amplifier
The source electrode of pipe is connected；
The of the other end of first detection resistance, the other end of second detection resistance and the input selection circuit
Three input terminals, are grounded；
First output end of the input selection circuit is connected with the first input end of the processing circuit；The input selection electricity
The second output terminal on road is connected with the second input terminal of the processing circuit；
The output end of the processing circuit is the output end of the current detection circuit of the loudspeaker；
It is described sampling selection circuit three input terminals respectively with sampling clock, the output stage VOP and the output stage VON phase
Even；
The output end of the sampling selection circuit is connected with the switch control terminal of the input selection circuit；
The sampling selection circuit is used for when the potential difference of the output stage VOP and the output stage VON are located at positive half period,
The first input end and the first output end for controlling the input selection circuit form access, third input terminal and second output terminal shape
At access；And when the potential difference of the output stage VOP and the output stage VON are located at negative half-cycle, the input choosing is controlled
The third input terminal and the first output end for selecting circuit form access, the second input terminal and second output terminal and form access.
2. the current detection circuit of loudspeaker according to claim 1, which is characterized in that the input selection circuit, comprising:
First switch, second switch, third switch, the 4th switch and control module；Wherein:
First input end of the first end of the first switch as the input selection circuit；The first end of the second switch
The second input terminal as the input selection circuit；The first end phase of the first end of the third switch and the 4th switch
Even, third input terminal of the tie point as the input selection circuit；
The second end of the first switch is connected with the second end that third switchs, tie point as the input selection circuit
One output end；The second end of the second switch is connected with the second end of the 4th switch, and tie point selects electricity as the input
The second output terminal on road；
The control terminal of the first switch is connected with the control terminal of the 4th switch, the first output of tie point and the control module
End is connected；The control terminal of the second switch is connected with the control terminal that third switchs, and the second of tie point and the control module
Output end is connected；
Switch control terminal of the input terminal of the control module as the input selection circuit.
3. the current detection circuit of loudspeaker according to claim 1, which is characterized in that the processing circuit, comprising: active
Filter amplification circuit and conversion module；Wherein:
First input end of the first input end of the active power filtering amplifying circuit as the processing circuit；The active power filtering
Second input terminal of second input terminal of amplifying circuit as the processing circuit；
First output end of the active power filtering amplifying circuit is connected with the first input end of the conversion module, the active filter
The second output terminal of wave amplifying circuit is connected with the second input terminal of the conversion module；
Output end of the output end of the conversion module as the processing circuit.
4. the current detection circuit of loudspeaker according to claim 3, which is characterized in that the active power filtering amplifying circuit,
It include: operational amplifier, the first input resistance, the second input resistance and the first filter branch and the second filter branch；Wherein:
The first end of the operational amplifier is connected with the input terminal of first filter branch, tie point and first input
One end of resistance is connected；First input end of the other end of first input resistance as the active power filtering amplifying circuit；
The second end of the operational amplifier is connected with the input terminal of second filter branch, tie point and second input
One end of resistance is connected；Second input terminal of the other end of second input resistance as the active power filtering amplifying circuit；
The third end of the operational amplifier is connected with the output end of first filter branch, and tie point is as the active filter
First output end of wave amplifying circuit；
4th end of the operational amplifier is connected with the output end of second filter branch, and tie point is as the active filter
The second output terminal of wave amplifying circuit.
5. the current detection circuit of loudspeaker according to claim 4, which is characterized in that first filter branch, comprising:
First capacitor and the first feedback resistance；Wherein:
The first capacitor is in parallel with first feedback resistance, and the one end being connected in parallel is defeated as first filter branch
Enter end, output end of the other end being connected in parallel as first filter branch.
6. the current detection circuit of loudspeaker according to claim 4, which is characterized in that second filter branch, comprising:
Second capacitor and the second feedback resistance；Wherein:
Second capacitor is in parallel with second feedback resistance, and the one end being connected in parallel is defeated as second filter branch
Enter end, output end of the other end being connected in parallel as second filter branch.
7. the current detection circuit of loudspeaker according to claim 3, which is characterized in that the conversion module is that integral-is micro-
Submodular converter.
8. the current detection circuit of loudspeaker according to claim 1, which is characterized in that first detection resistance and second
The resistance value of detection resistance is equal.
9. the current detection circuit of loudspeaker according to claim 1, which is characterized in that the frequency of the sampling clock is institute
256 times for stating the pulse-width modulation frequency of the current potential of output stage VOP and the current potential of the output stage VON.
10. the current detection circuit of loudspeaker according to claim 4, which is characterized in that first input resistance and
The resistance value of two input resistances is identical.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910035711.5A CN109546979B (en) | 2019-01-15 | 2019-01-15 | Current detection circuit of loudspeaker |
| US17/423,346 US11698393B2 (en) | 2019-01-15 | 2020-01-13 | Current detection circuit for loudspeaker |
| PCT/CN2020/071720 WO2020147672A1 (en) | 2019-01-15 | 2020-01-13 | Current detection circuit for loudspeaker |
| KR1020217025609A KR102577482B1 (en) | 2019-01-15 | 2020-01-13 | Current detection circuit for loudspeaker |
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