CN208540150U - A kind of digital audio power amplification system - Google Patents
A kind of digital audio power amplification system Download PDFInfo
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- CN208540150U CN208540150U CN201821383333.7U CN201821383333U CN208540150U CN 208540150 U CN208540150 U CN 208540150U CN 201821383333 U CN201821383333 U CN 201821383333U CN 208540150 U CN208540150 U CN 208540150U
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Abstract
The utility model discloses a kind of digital audio power amplification systems, the equivalent output impedance that the digital audio power amplification system passes through raising the first current source module and the second current source module, and then reduce influence of first current source module to power supply rejection ratio, and improve the matching degree between divider resistance, and then the power supply rejection ratio of digital audio power amplification system is improved, eliminate the noise on loudspeaker.
Description
Technical field
The utility model relates to semiconductor integrated circuit technology fields, more specifically to a kind of digital audio-power amplifier
System.
Background technique
D-type audio power amplifier is widely applied since it is more than 80% efficiency at present, especially efficiently
Rate is most important for mobile device, can not only lengthen working hours, and can also reduce the calorific value of the handheld devices such as mobile phone.
In application fields such as mobile phones, volume and sound quality can have an important influence on user experience, and current trend is audio
Power amplifier exports higher power to obtain bigger volume and preferable sound quality.
But digital audio power amplification system is at present in order to export higher transmission power, it is necessary to extract from power supply a large amount of
Electric current, due to power supply have certain internal resistance, cause ceaselessly occur fluctuating on a large scale on power supply, that is, be unable to control electricity
Source inhibits ratio, and then biggish noise can be heard on loudspeaker.
Utility model content
In view of this, technical solution is such as to solve the above problems, the utility model provides a kind of digital audio power amplification system
Under:
A kind of digital audio power amplification system, comprising: the first current source module and the first power amplifier loop；First current source
Module includes: the first field-effect tube, the second field-effect tube, third field-effect tube, the 4th field-effect tube, first switch, second opens
Pass, the first operational amplifier and second operational amplifier；
The source electrode of first field-effect tube is connect with power voltage terminal, and drain the source with second field-effect tube respectively
Pole is connected with the inverting input terminal of first operational amplifier, and grid is connect with first voltage signal input part；
The drain electrode of second field-effect tube is connect with the input terminal of the first switch, and grid is put with first operation
The output end connection of big device；
The non-inverting input terminal of first operational amplifier is connect with second voltage signal input part；
The output end of the first switch is connect with the input terminal of the second switch, the output end of the second switch with
The drain electrode of the third field-effect tube connects；
The source electrode of the third field-effect tube respectively with the inverting input terminal of the second operational amplifier and the described 4th
The drain electrode of field-effect tube connects, and grid is connect with the output end of the second operational amplifier；
The non-inverting input terminal of the second operational amplifier is connect with tertiary voltage signal input part；
The grid of 4th field-effect tube is connect with the 4th voltage signal inputs, source electrode grounding connection；
First current source module and the first power amplifier loop constitute the first subsystem, the control terminal of the first switch and
Signal input part of the control terminal of the second switch as first subsystem, for receiving PWMP signal, described first
The connecting node of switch and the second switch is connect with the first input end of the first power amplifier loop, the first power amplifier ring
Signal output end of the output end on road as first subsystem.
Preferably, first field-effect tube and second field-effect tube are p-type field-effect tube；
The third field-effect tube and the 4th field-effect tube are N-type field-effect tube.
Preferably, the digital audio power amplification system, further includes: the second current source module and the second power amplifier loop；
The circuit structure of second current source module is identical with the circuit structure of first current source module, and described
The circuit structure of two power amplifier loops is identical with the circuit structure of the first power amplifier loop；
Second current source module and the second power amplifier loop constitute the second subsystem, the letter of second subsystem
Number input terminal is exported for receiving PWMN signal, the output end of the second power amplifier loop as the signal of second subsystem
End.
Preferably, the digital audio power amplification system, further includes: feedback module；
The first input end of the feedback module is connect with the first input end of the first power amplifier loop, the first output end
It is connect with the output end of the first power amplifier loop；
Second input terminal of the feedback module is connect with the first input end of the second power amplifier loop, second output terminal
It is connect with the output end of the second power amplifier loop；
The control terminal of the feedback module is for receiving control signal, and the control signal is for controlling the feedback module
In different working conditions, to adjust the resistors match degree of first subsystem and second subsystem, and then adjust
Save the power supply rejection ratio of the digital audio power amplification system；
The control signal, the PWMP signal are identical with the period of the PWMN signal.
Preferably, the feedback module, comprising: the first feedback resistance, the second feedback resistance, first resistor, second resistance,
3rd resistor, the 4th resistance, third switch, the 4th switch, the 5th switch, the 6th switch, the 7th switch, the 8th switch, the 9th
Switch and the tenth switch；
The input terminal of the input terminal of third switch and the 4th switch with the first power amplifier loop first
Input terminal connection；
Output of the output end of the output end of 5th switch and the 6th switch with the first power amplifier loop
End connection；
It is described 7th switch input terminal and it is described 8th switch input terminal with the second power amplifier loop first
Input terminal connection；
Output of the output end of the output end of 9th switch and the tenth switch with the second power amplifier loop
End connection；
The output end of the output end of third switch and the 7th switch with first feedback resistance first
End connection, the second end of first feedback resistance are connect with the first end of the first resistor, and the second of the first resistor
End is connect with the input terminal of the input terminal of the 5th switch and the 9th switch respectively；
The first end of the second resistance is connect with the first end of the first resistor, the second termination of the second resistance
Ground connection；
It is described 4th switch output end and it is described 8th switch output end with second feedback resistance first
End connection, the second end of second feedback resistance are connect with the first end of the 3rd resistor, and the second of the 3rd resistor
End is connect with the input terminal of the input terminal of the 6th switch and the tenth switch respectively；
The first end of 4th resistance is connect with the first end of the 3rd resistor, the second termination of the 4th resistance
Ground connection；
The third switch, the 4th switch, the 5th switch, the 6th switch, the described 7th switch, are described
The control terminal of 8th switch, the 9th switch and the tenth switch is for receiving the control signal, the control signal
For controlling third switch, the 4th switch, the 5th switch, the 6th switch, the 7th switch, described
The working condition of 8th switch, the 9th switch and the tenth switch；
When third switch, the 5th switch, the 8th switch and the tenth switch in the conductive state,
Rest switch is in close state；
When the 4th switch, the 6th switch, the 7th switch and the 9th switch in the conductive state,
Rest switch is in close state.
Preferably, the third switch, the 5th switch, the 8th switch and the tenth switch are p-type field
Effect pipe；
4th switch, the 6th switch, the 7th switch and the 9th switch are N-type field-effect tube.
Preferably, the third switch, the 5th switch, the 8th switch and the tenth switch are N-type field
Effect pipe；
4th switch, the 6th switch, the 7th switch and the 9th switch are p-type field-effect tube.
Preferably, the digital audio power amplification system, further includes: common-mode voltage generation module；
Second input terminal of the second input terminal of the first power amplifier loop and the second power amplifier loop with it is described total
The output end of mode voltage generation module connects.
Preferably, the common-mode voltage generation module, comprising: the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance
And capacitor；
The first end of 5th resistance is connect with voltage input end, the second end of the 5th resistance and the 6th electricity
The first end of resistance connects, and the second end of the 6th resistance is connect with the first end of the 7th resistance, the 7th resistance
Second end grounding connection；
The first end of 8th resistance is connect with the first end of the 7th resistance, the second end of the 8th resistance with
The first end of the capacitor connects, and the second end of the capacitor is connect with the second end of the 7th resistance；
Output end of the connecting node of 8th resistance and the capacitor as the common-mode voltage generation module.
Preferably, the 5th resistance, the 6th resistance are identical with the resistance value of the 7th resistance.
Compared to the prior art, of the utility model to have the beneficial effect that
The digital audio power amplification system, by the way that the first current source module to be set as including the first field-effect tube, second
Effect pipe, third field-effect tube, the 4th field-effect tube, first switch, second switch, the first operational amplifier and the second operation are put
Big device, and be attached according to circuit structure, the equivalent output impedance of the first current source module is improved, and then reduce the first electricity
Influence of the source module to power supply rejection ratio is flowed, to reduce the noise on loudspeaker.
Detailed description of the invention
In order to illustrate the embodiment of the utility model or the technical proposal in the existing technology more clearly, below will be to embodiment
Or attached drawing needed to be used in the description of the prior art is briefly described, it should be apparent that, the accompanying drawings in the following description is only
It is the embodiments of the present invention, for those of ordinary skill in the art, without creative efforts, also
Other attached drawings can be obtained according to the attached drawing of offer.
Fig. 1 is the structural schematic diagram of digital power amplifier system provided by the embodiment of the utility model；
Fig. 2 is another structural schematic diagram of digital power amplifier system provided by the embodiment of the utility model；
Fig. 3 is the structural schematic diagram of common-mode voltage generation module provided by the embodiment of the utility model.
Specific embodiment
The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model
Clearly and completely describe, it is clear that the described embodiments are only a part of the embodiments of the utility model, rather than whole
Embodiment.Based on the embodiments of the present invention, those of ordinary skill in the art are without making creative work
Every other embodiment obtained, fall within the protection scope of the utility model.
To keep the above objects, features, and advantages of the utility model more obvious and easy to understand, with reference to the accompanying drawing and have
Body embodiment is described in further detail the utility model.
With reference to Fig. 1, Fig. 1 is the structural schematic diagram of digital power amplifier system provided by the embodiment of the utility model, and effect will
Treated that pwm signal is converted into analog signal for digital module comprising the first subsystem；
As shown in Figure 1, first subsystem includes: the first current source module 11 and the first power amplifier loop 12；Described
The output end of one current source module 11 is connect with the first input end of the first power amplifier loop 12, first current source module
Signal input part of 11 input terminal as first subsystem, for receiving PWMP signal, the first power amplifier loop 12
Output end VOUTP of the output end as first subsystem；
As shown in Figure 1, first current source module 11 includes: the first field-effect tube M1, the second field-effect tube M2, third
Field-effect tube M3, the 4th field-effect tube M4, first switch S1, second switch S2, the first operational amplifier 111 and the second operation are put
Big device 112；
The source electrode of the first field-effect tube M1 is connect with power voltage terminal VDD, drain electrode respectively with second field-effect
The source electrode of pipe M2 is connected with the inverting input terminal of first operational amplifier 111, grid and first voltage signal input part VBP
Connection；
The drain electrode of the second field-effect tube M2 is connect with the input terminal of the first switch S1, grid and first fortune
Calculate the output end connection of amplifier 111；
The non-inverting input terminal and second voltage signal input part V of first operational amplifier 111BP1Connection；
The output end of the first switch S1 is connect with the input terminal of the second switch S2, and the second switch S2's is defeated
Outlet is connect with the drain electrode of the third field-effect tube M3；
The source electrode of the third field-effect tube M3 respectively with the inverting input terminal of the second operational amplifier 112 and described
The drain electrode of 4th field-effect tube M4 connects, and grid is connect with the output end of the second operational amplifier 112；
The non-inverting input terminal and tertiary voltage signal input part V of the second operational amplifier 112BN1Connection；
The grid and the 4th voltage signal inputs V of the 4th field-effect tube M4BNConnection, source electrode grounding connection；
That is, first current source module 11 and the first power amplifier loop 12 the first subsystem of composition, described first
The input terminal of the control terminal of switch S1 and the control terminal of the second switch S2 as first current source module 11 is also institute
The signal input part for stating the first subsystem, for receiving PWMP signal, the company of the first switch S1 and the second switch S2
Output end of the node as first current source module 11 is connect, is connect with the first input end of the first power amplifier loop 12,
Signal output end VOUTP of the output end of the first power amplifier loop 12 as first subsystem.
The digital audio power amplification system, by the way that the first current source module 11 to be set as including the first field-effect tube M1,
Two field-effect tube M2, third field-effect tube M3, the 4th field-effect tube M4, first switch S1, second switch S2, the first operation amplifier
Device 111 and second operational amplifier 112, and be attached according to circuit structure, improve the equivalent of the first current source module 11
Output impedance, and then reduce influence of first current source module 11 to power supply rejection ratio, to reduce the noise on loudspeaker.
Further, the first field-effect tube M1 and the second field-effect tube M2 is p-type field-effect tube, and described
Three field-effect tube M3 and the 4th field-effect tube M4 are N-type field-effect tube；
Or, the first field-effect tube M1 and the second field-effect tube M2 are N-type field-effect tube, the third field effect
Should pipe M3 and the 4th field-effect tube M4 be p-type field-effect tube.
Further, the digital audio power amplification system, further includes: the second subsystem；
As shown in Figure 1, second subsystem includes: the second current source module 13 and the second power amplifier loop 14；Described
The circuit structure of two current source modules 13 is identical with the circuit structure of first current source module 11, the second power amplifier loop
14 circuit structure is identical with the circuit structure of the first power amplifier loop 13；
The output end of second current source module 13 is connect with the first input end of the second power amplifier loop 14, described
Signal input part of the input terminal of second current source module 13 as second subsystem, it is described for receiving PWMN signal
Output end VOUTN of the output end of second power amplifier loop 14 as second subsystem；
As shown in Figure 1, second current source module 13 includes: the 5th field-effect tube M5, the 6th field-effect tube M6, the 7th
Field-effect tube M7, the 8th field-effect tube M8, switch A, switch B, third operational amplifier 131 and four-operational amplifier 132；
The source electrode of the 5th field-effect tube M5 is connect with power voltage terminal VDD, drain electrode respectively with the 6th field-effect
The source electrode of pipe M6 is connected with the inverting input terminal of the third operational amplifier 131, grid and first voltage signal input part VBP
Connection；
The drain electrode of the 6th field-effect tube M6 is connect with the input terminal of the switch A, and grid is put with the third operation
The output end connection of big device 131；
The non-inverting input terminal and second voltage signal input part V of the third operational amplifier 131BP1Connection；
The output end of the switch A is connect with the input terminal of the switch B, the output end of the switch B and the described 7th
The drain electrode of field-effect tube M7 connects；
The source electrode of the 7th field-effect tube M7 respectively with the inverting input terminal of the four-operational amplifier 132 and described
The drain electrode of 8th field-effect tube M8 connects, and grid is connect with the output end of the four-operational amplifier 132；
The non-inverting input terminal and tertiary voltage signal input part V of the four-operational amplifier 132BN1Connection；
The grid and the 4th voltage signal inputs V of the 8th field-effect tube M8BNConnection, source electrode grounding connection；
That is, second current source module 13 and the second power amplifier loop 14 constitute the second subsystem, the switch A
Control terminal and the switch B input terminal of the control terminal as second current source module 13, be also second subsystem
The signal input part of system, for receiving PWMN signal, the connecting node of the switch A and the switch B are as second electricity
The output end for flowing source module 13, connect with the first input end of the second power amplifier loop 14, the second power amplifier loop 14
Signal output end VOUTN of the output end as second subsystem.
The digital audio power amplification system, by the way that the second current source module 13 to be set as including the 5th field-effect tube M5,
Six field-effect tube M6, the 7th field-effect tube M7, the 8th field-effect tube M8, switch A, switch B, third operational amplifier 131 and
Four-operational amplifier 132, and be attached according to circuit structure, the equivalent output impedance of the second current source module 13 is improved,
And then reduce influence of second current source module 13 to power supply rejection ratio, to reduce the noise on loudspeaker.
Further, the 5th field-effect tube M5 and the 6th field-effect tube M6 is p-type field-effect tube, and described
Seven field-effect tube M7 and the 8th field-effect tube M8 are N-type field-effect tube；
Or, the 5th field-effect tube M5 and the 6th field-effect tube M6 are N-type field-effect tube, the 7th effect
Should pipe M7 and the 8th field-effect tube M8 be p-type field-effect tube.
Further, as shown in Figure 1, the digital audio power amplification system, further includes: feedback module 15；
The first input end of the feedback module 15 is connect with the first input end of the first power amplifier loop 12, and first is defeated
Outlet is connect with the output end of the first power amplifier loop 12；
Second input terminal of the feedback module 15 is connect with the first input end of the second power amplifier loop 14, and second is defeated
Outlet is connect with the output end of the second power amplifier loop 14；
The control terminal of the feedback module 15 is for receiving control signal, and the control signal is for controlling the feedback mould
Block 15 is in different working conditions, to adjust the resistors match degree of first subsystem and second subsystem, into
And adjust the power supply rejection ratio of the digital audio power amplification system；
The control signal, the PWMP signal are identical with the period of the PWMN signal.
Further, as shown in Figure 1, the digital audio power amplification system, further includes: common-mode voltage generation module 16；
Second input terminal of the second input terminal of the first power amplifier loop 12 and the second power amplifier loop 14 is and institute
State the output end connection of common-mode voltage generation module 16.
The common-mode voltage generation module 16 is for generating common mode voltage signal VREF, for maintaining first current source
The stability of the output signal of module 11 and second current source module 13.
Further, as shown in Fig. 2, the first power amplifier loop 12 includes the 5th operational amplifier 21, the drive of power amplifier loop
Dynamic model block 23, first capacitor C1, field-effect tube P1 and field-effect tube N1；
The inverting input terminal of 5th operational amplifier 21 is connect with the output end of first current source module 11, the 5th fortune
The non-inverting input terminal for calculating amplifier 21 is connect with the output end of common-mode voltage generation module 16, the output of the 5th operational amplifier 21
End is connect with the input terminal of the power amplifier loop drive module 23, the first output end of the power amplifier loop drive module 23 and institute
State the grid connection of field-effect tube P1, the second output terminal of the power amplifier loop drive module 23 and the grid of the field-effect tube N1
Pole connection.
The source electrode of the field-effect tube P1 is connect with voltage input end PVDD, the drain electrode of the field-effect tube P1 and the field
The drain electrode of effect pipe N1 connects, the source electrode grounding connection of the field-effect tube N1, the field-effect tube P1 and the field-effect tube
Output end VOUTP of the connecting node of N1 as the first power amplifier loop 12.
The first end of the first capacitor C1 is connect with the output end of the 5th operational amplifier 21, second end with it is described
The inverting input terminal of 5th operational amplifier 21 connects.
Further, as shown in Fig. 2, the second power amplifier loop 14 includes the 6th operational amplifier 22, the drive of power amplifier loop
Dynamic model block 24, the second capacitor C2, field-effect tube P2 and field-effect tube N2；
The inverting input terminal of 6th operational amplifier 22 is connect with the output end of second current source module 13, the 6th fortune
The non-inverting input terminal for calculating amplifier 22 is connect with the output end of common-mode voltage generation module 16, the output of the 6th operational amplifier 22
End is connect with the input terminal of the power amplifier loop drive module 24, the first output end of the power amplifier loop drive module 24 and institute
State the grid connection of field-effect tube P2, the second output terminal of the power amplifier loop drive module 24 and the grid of the field-effect tube N2
Pole connection.
The source electrode of the field-effect tube P2 is connect with voltage input end PVDD, the drain electrode of the field-effect tube P2 and the field
The drain electrode of effect pipe N2 connects, the source electrode grounding connection of the field-effect tube N2, the field-effect tube P2 and the field-effect tube
Output end VOUTN of the connecting node of N2 as the second power amplifier loop 14.
The first end of the second capacitor C2 is connect with the output end of the 6th operational amplifier 22, second end with it is described
The inverting input terminal of 6th operational amplifier 22 connects.
Further, as shown in Fig. 2, the feedback module 15, comprising: the first feedback resistance RFB1, the second feedback resistance
RFB2, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4, third switch S3, the 4th switch S4, the 5th open
Close S4, the 6th switch S6, the 7th switch S7, the 8th switch S8, the 9th switch S9 and the tenth switch S10；
The input terminal of the input terminal of the third switch S3 and the 4th switch S4 with the first power amplifier loop 12
First input end connection；
The output end of the output end of the 5th switch S5 and the 6th switch S6 with the first power amplifier loop 12
Output end connection；
The input terminal of the input terminal of the 7th switch S7 and the 8th switch S8 with the second power amplifier loop 14
First input end connection；
The output end of the output end of the 9th switch S9 and the tenth switch S10 with the second power amplifier loop 14
Output end connection；
The output end of the output end of the third switch S3 and the 7th switch S7 with first feedback resistance
The first end of RFB1 connects, and the second end of the first feedback resistance RFB1 is connect with the first end of the first resistor R1, institute
The second end for stating first resistor R1 is connect with the input terminal of the input terminal of the 5th switch S5 and the 9th switch S9 respectively；
The first end of the second resistance R2 is connect with the first end of the first resistor R1, and the of the second resistance R2
Two end grounding connections；
The output end of the output end of the 4th switch S4 and the 8th switch S8 with second feedback resistance
The first end of RFB2 connects, and the second end of the second feedback resistance RFB2 is connect with the first end of the 3rd resistor R3, institute
The second end for stating 3rd resistor R3 connects with the input terminal of the input terminal of the 6th switch S6 and the tenth switch S10 respectively
It connects；
The first end of the 4th resistance R4 is connect with the first end of the 3rd resistor R3, and the of the 4th resistance R4
Two end grounding connections；
The third switch S3, the 4th switch S4, the 5th switch S4, the 6th switch S6, the described 7th
Switch S7, the 8th switch S8, the 9th switch S9 and the tenth switch S10 control terminal for receiving the control
Signal, the control signal is for controlling the third switch S3, the 4th switch S4, the 5th switch S4, described the
The work of six switch S6, the 7th switch S7, the 8th switch S8, the 9th switch S9 and the tenth switch S10
State；
It is led when the third switch S3, the 5th switch S5, the 8th switch S8 and the tenth switch S10 are in
When logical state, rest switch is in close state；
It is led when the 4th switch S4, the 6th switch S6, the 7th switch S7 and the 9th switch S9 are in
When logical state, rest switch is in close state.
It should be noted that being to use by setting first resistor R1, second resistance R2,3rd resistor R3 and the 4th resistance R4
In making the digital audio power amplification system generate higher output voltage.
Optionally, the third switch S3, the 4th switch S4, the 5th switch S4, the 6th switch S6, institute
Stating the 7th switch S7, the 8th switch S8, the 9th switch S9 and the tenth switch S10 is field-effect tube.
Optionally, the third switch S3, the 5th switch S5, the 8th switch S8 and the tenth switch S10
It is p-type field-effect tube；
The 4th switch S4, the 6th switch S6, the 7th switch S7 and the 9th switch S9 are N-type field
Effect pipe.
Optionally, the third switch S3, the 5th switch S5, the 8th switch S8 and the tenth switch S10
It is N-type field-effect tube；
The 4th switch S4, the 6th switch S6, the 7th switch S7 and the 9th switch S9 are p-type field
Effect pipe.
Further, as shown in figure 3, the common-mode voltage generation module 16, comprising: the 5th resistance R5, the 6th resistance R6,
7th resistance R7, the 8th resistance R8 and capacitor C；
The first end of the 5th resistance R5 is connect with voltage input end PVDD, the second end of the 5th resistance R5 and institute
The first end connection of the 6th resistance R6 is stated, the second end of the 6th resistance R6 is connect with the first end of the 7th resistance R7,
The second end grounding connection of the 7th resistance R7；
The first end of the 8th resistance R8 is connect with the first end of the 7th resistance R7, and the of the 8th resistance R8
Two ends are connect with the first end of the capacitor C, and the second end of the capacitor C is connect with the second end of the 7th resistance R7；
Output end of the connecting node of the 8th resistance R8 and capacitor C as the common-mode voltage generation module 16
VREF。
Wherein, the 5th resistance R5, the 6th resistance R6 are identical with the resistance value of the 7th resistance R7.
Based on the digital audio power amplification system of the above-mentioned offer of the utility model embodiment, first to the first current source module 11
It is described with the principle of the second current source module 13.
Wherein, the equivalent output impedance of the first field-effect tube M1, the second field-effect tube M2 and the first operational amplifier 111
Ro1p is,
Ro1p=A × gm2×ro1×ro2
Wherein, A is the DC current gain of the first operational amplifier 111, gm2For the mutual conductance of the second field-effect tube M2, ro1It is
The output impedance of one field-effect tube M1, ro2For the output impedance of the second field-effect tube M2.
Third field-effect tube M3, the 4th field-effect tube M4 and the equivalent output impedance ro1n of second operational amplifier 112 be,
Ro1n=A × gm3×ro3×ro4
Wherein, A is the DC current gain of second operational amplifier 112, gm3For the mutual conductance of third field-effect tube M3, ro3It is
The output impedance of three field-effect tube M3, ro4For the output impedance of the 4th field-effect tube M4.
So, the output impedance rop of first current source module 11 is,
Rop=ro1p//ro1n
The output impedance rop of first current source module 11 is much larger than the first feedback resistance RFB1 or the second feedback resistance
RFB2。
Similarly, the equivalent output impedance of the 5th field-effect tube M5, the 6th field-effect tube M6 and third operational amplifier 131
Ro2p is,
Ro2p=A × gm6×ro5×ro6
Wherein, A is the DC current gain of third operational amplifier 131, gm6For the mutual conductance of the 6th field-effect tube M6, ro5It is
The output impedance of five field-effect tube M5, ro6For the output impedance of the 6th field-effect tube M6.
The equivalent output impedance ro2n of 7th field-effect tube M7, the 8th field-effect tube M8 and four-operational amplifier 132 is,
Ro2n=A × gm7×ro7×ro8
Wherein, A is the DC current gain of four-operational amplifier 132, gm7For the mutual conductance of the 7th field-effect tube M7, ro7It is
The output impedance of seven field-effect tube M7, ro8For the output impedance of the 8th field-effect tube M8.
So, the output impedance ron of second current source module 13 is,
Ron=ro2p//ro2n
The output impedance ron of second current source module 13 is much larger than the first feedback resistance RFB1 or the second feedback resistance
RFB2。
It follows that the digital audio power amplification system, by improving the first current source module 11 and the second current source module
13 output impedance, and then reduce the influence of the first current source module 11 and the second current source module 13 to power supply rejection ratio, with
Reduce the noise on loudspeaker.
As described in Figure 2, the first resistor R1 and second resistance R2 forms partial pressure, wherein R2=2*R1, similarly, institute
It states 3rd resistor R3 and the 4th resistance R4 and forms partial pressure, wherein R4=2*R3, at this time the first subsystem and the second subsystem
The ceiling voltage of output end be 2/3 times of voltage input end PVDD, common mode voltage signal VREF becomes voltage input end PVDD
1/3 times, this mean that when voltage input end PVDD be 10V when, common mode voltage signal VREF be 3.3V, in the first current source
Module, the second current source module, the first power amplifier loop and the second power amplifier loop supply voltage be equal to 5V in the case where, circuit is still
It so can work normally, and then realize the function of High voltage output.
Based on the digital audio power amplification system of above-mentioned offer, when the feedback module 15 be not provided with the first switch S1,
The second switch S2, the third switch S3, the 4th switch S4, the 5th switch S5, the 6th switch S6, institute
When stating the 7th switch S7 and the 8th switch S8, the feedback module 15 divides for two parts, and a part is by the first feedback resistance
RFB1, first resistor R1 and second resistance R2 are constituted, corresponding with the progress of the first subsystem to connect, and another part is by the second feedback
Resistance RFB2,3rd resistor R3 and the 4th resistance R4 are constituted, corresponding with the progress of the second subsystem to connect.
As can be seen from the above description, the output impedance of first current source module 11 is rop, the second current source mould
The output impedance of block 13 is ron.
So signal fluctuation Δ Vip of the output end Vip of the first current source module 11 is,
Wherein, Δ VOUTPFor the output end V of the first subsystemOUTPOutput pulsation.
Since the first power amplifier loop 12 is very big in low-band gain, from the input VREF of the first operational amplifier 21 to
The gain of Vip is equal to 1, therefore has,
Wherein, Δ PVDD is the voltage fluctuation of voltage input end.
Arrangement can obtain,
Similarly it is found that
Wherein, Δ VOUTNFor the output end V of the second subsystemOUTNOutput pulsation.
Since in actual fabrication technique, the resistance value of resistance will appear certain fluctuation, at this time first resistor R1, second resistance
R2, 3rd resistor R3With the 4th voltage R4Dividing ratios and design value will appear deviation, while the first feedback resistance RFB1With
Two feedback resistance RFB2Resistance value be also not completely equivalent.
It is assumed that
Since the output impedance of the first current source module 11 is rop and the output impedance of second current source module 13 is
Ron is far longer than the first feedback resistance RFB1With the second feedback resistance RFB2, therefore, even if the first feedback resistance RFB1It is anti-with second
Feed resistance RFB2Resistance value be not completely equivalent, influence of the difference of β 1 and β 2 to PSRR can be ignored.
Once again, it is assumed that
α 1- α 2=Δ α
It is possible to obtain,
ΔVOUT=Δ VOUTP-ΔVOUTN
Wherein, Δ VOUTFor total output pulsation of digital audio power amplification system.
That is,
So, the power supply rejection ratio PSRR of digital audio power amplification system is,
It can be concluded that, the principal element of the power supply rejection ratio PSRR of high-voltage digital audio power amplification system is influenced from above-mentioned formula
It is first resistor R1, second resistance R2, 3rd resistor R3With the 4th voltage R4Matching degree.
Therefore, the present embodiment is by being arranged the third switch S3, the 4th switch S4, the 5th switch S4, institute
The 6th switch S6, the 7th switch S7, the 8th switch S8, the 9th switch S9 and the tenth switch S10 are stated, is led to
It crosses the switching within the different PWMP signal periods and PWMN signal period and uses feedback module 15, for example, in control signal SWAP
When signal is high level, the third switch S3, the 5th switch S5, the 8th switch S8 and the tenth switch S10
In the conductive state, rest switch is in close state, the output end V of the first subsystemOUTPPass through the first feedback resistance RFB1、
First resistor R1With second resistance R2Electric current is poured into or extracts to the output end Vip of the first current source module, at this point, the second subsystem
The output end V of systemOUTNPass through the second feedback resistance RFB2, 3rd resistor R3With the 4th resistance R4Output to the second current source module
End Vin pours into or extracts electric current.When SWAP signal is low level, the 4th switch S4, the 6th switch S6, described the
Seven switch S7 and the 9th switch S9 are in the conductive state, and rest switch is in close state, the output end of the first subsystem
VOUTPPass through the second feedback resistance RFB2, 3rd resistor R3With the 4th resistance R4It is poured into the output end Vip of the first current source module
Or electric current is extracted, at this point, the output end V of the second subsystemOUTNPass through the first feedback resistance RFB1, first resistor R1And second resistance
R2Electric current is poured into or extracted to the output end Vin of the second current source module.
It should be noted that PWMP signal period and PWMN signal period are identical with the SWAP signal period.
Therefore, it can be deduced that,
At this point, the output end V of the first subsystemOUTPFeedback proportional and the second subsystem output end VOUTNFeedback ratio
Example is identical, the divider resistance as caused by manufacturing process in power supply rejection ratio PSRR formula mismatch factor Δ α can perfection disappear
It removes, and then improves the power supply rejection ratio PSRR of digital audio power amplification system.
A kind of digital audio power amplification system provided by the utility model is described in detail above, it is used herein
Specific case is expounded the principles of the present invention and embodiment, and the explanation of above example is only intended to help
Understand the method and its core concept of the utility model；At the same time, for those skilled in the art, according to the utility model
Thought, there will be changes in the specific implementation manner and application range, in conclusion the content of the present specification should not be understood
For limitations of the present invention.
It should be noted that all the embodiments in this specification are described in a progressive manner, each embodiment weight
Point explanation is the difference from other embodiments, and the same or similar parts between the embodiments can be referred to each other.
For the device disclosed in the embodiment, since it is corresponded to the methods disclosed in the examples, so being described relatively simple, phase
Place is closed referring to method part illustration.
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.Moreover, the terms "include", "comprise" or its any other variant are intended to contain
Lid non-exclusive inclusion, so that the element that the process, method, article or equipment including a series of elements is intrinsic,
It further include either the element intrinsic for these process, method, article or equipments.In the absence of more restrictions,
The element limited by sentence "including a ...", it is not excluded that in the process, method, article or equipment including the element
In there is also other identical elements.
The foregoing description of the disclosed embodiments can be realized professional and technical personnel in the field or using originally practical new
Type.Various modifications to these embodiments will be readily apparent to those skilled in the art, and determine herein
The General Principle of justice can be realized in other embodiments without departing from the spirit or scope of the present utility model.Cause
This, the present invention will not be limited to the embodiments shown herein, and is to fit to and principles disclosed herein
The widest scope consistent with features of novelty.
Claims (10)
1. a kind of digital audio power amplification system characterized by comprising the first current source module and the first power amplifier loop；It is described
First current source module includes: the first field-effect tube, the second field-effect tube, third field-effect tube, the 4th field-effect tube, first opens
Pass, second switch, the first operational amplifier and second operational amplifier；
The source electrode of first field-effect tube is connect with power voltage terminal, drain electrode respectively with the source electrode of second field-effect tube and
The inverting input terminal of first operational amplifier connects, and grid is connect with first voltage signal input part；
The drain electrode of second field-effect tube is connect with the input terminal of the first switch, grid and first operational amplifier
Output end connection；
The non-inverting input terminal of first operational amplifier is connect with second voltage signal input part；
The output end of the first switch is connect with the input terminal of the second switch, the output end of the second switch with it is described
The drain electrode of third field-effect tube connects；
The source electrode of the third field-effect tube is imitated with the inverting input terminal of the second operational amplifier and described 4th respectively
Should pipe drain electrode connection, grid connect with the output end of the second operational amplifier；
The non-inverting input terminal of the second operational amplifier is connect with tertiary voltage signal input part；
The grid of 4th field-effect tube is connect with the 4th voltage signal inputs, source electrode grounding connection；
First current source module and the first power amplifier loop constitute the first subsystem, the control terminal of the first switch and described
Signal input part of the control terminal of second switch as first subsystem, for receiving PWMP signal, the first switch
It is connect with the connecting node of the second switch with the first input end of the first power amplifier loop, the first power amplifier loop
Signal output end of the output end as first subsystem.
2. digital audio power amplification system according to claim 1, which is characterized in that first field-effect tube and described
Two field-effect tube are p-type field-effect tube；
The third field-effect tube and the 4th field-effect tube are N-type field-effect tube.
3. digital audio power amplification system according to claim 1, which is characterized in that the digital audio power amplification system, also
It include: the second current source module and the second power amplifier loop；
The circuit structure of second current source module is identical with the circuit structure of first current source module, second function
The circuit structure for putting loop is identical with the circuit structure of the first power amplifier loop；
Second current source module and the second power amplifier loop constitute the second subsystem, and the signal of second subsystem is defeated
Enter end for receiving PWMN signal, signal output end of the output end of the second power amplifier loop as second subsystem.
4. digital audio power amplification system according to claim 3, which is characterized in that the digital audio power amplification system, also
It include: feedback module；
The first input end of the feedback module is connect with the first input end of the first power amplifier loop, the first output end and institute
State the output end connection of the first power amplifier loop；
Second input terminal of the feedback module is connect with the first input end of the second power amplifier loop, second output terminal and institute
State the output end connection of the second power amplifier loop；
The control terminal of the feedback module is in for receiving control signal, the control signal for controlling the feedback module
Different working conditions to adjust the resistors match degree of first subsystem and second subsystem, and then adjusts institute
State the power supply rejection ratio of digital audio power amplification system；
The control signal, the PWMP signal are identical with the period of the PWMN signal.
5. digital audio power amplification system according to claim 4, which is characterized in that the feedback module, comprising: first is anti-
Feed resistance, the second feedback resistance, first resistor, second resistance, 3rd resistor, the 4th resistance, third switch, the 4th switch, the
Five switches, the 6th switch, the 7th switch, the 8th switch, the 9th switch and the tenth switch；
First input of the input terminal of the input terminal of the third switch and the 4th switch with the first power amplifier loop
End connection；
The output end of the output end of 5th switch and the 6th switch connects with the output end of the first power amplifier loop
It connects；
First input of the input terminal of the input terminal of 7th switch and the 8th switch with the second power amplifier loop
End connection；
The output end of the output end of 9th switch and the tenth switch connects with the output end of the second power amplifier loop
It connects；
The output end of the output end of the third switch and the 7th switch connects with the first end of first feedback resistance
It connects, the second end of first feedback resistance is connect with the first end of the first resistor, the second end point of the first resistor
It is not connect with the input terminal of the input terminal of the 5th switch and the 9th switch；
The first end of the second resistance is connect with the first end of the first resistor, and the second end of the second resistance, which is grounded, to be connected
It connects；
The output end of the output end of 4th switch and the 8th switch connects with the first end of second feedback resistance
It connects, the second end of second feedback resistance is connect with the first end of the 3rd resistor, the second end point of the 3rd resistor
It is not connect with the input terminal of the input terminal of the 6th switch and the tenth switch；
The first end of 4th resistance is connect with the first end of the 3rd resistor, and the second end of the 4th resistance, which is grounded, to be connected
It connects；
The third switch, the 4th switch, the 5th switch, the 6th switch, the 7th switch, the described 8th
For receiving the control signal, the control signal is used for the control terminal of switch, the 9th switch and the tenth switch
Control the third switch, the 4th switch, the 5th switch, the 6th switch, the 7th switch, the described 8th
The working condition of switch, the 9th switch and the tenth switch；
When third switch, the 5th switch, the 8th switch and the tenth switch in the conductive state, remaining
Switch is in close state；
When the 4th switch, the 6th switch, the 7th switch and the 9th switch in the conductive state, remaining
Switch is in close state.
6. digital audio power amplification system according to claim 5, which is characterized in that the third switch, the described 5th open
It closes, the 8th switch and the tenth switch are p-type field-effect tube；
4th switch, the 6th switch, the 7th switch and the 9th switch are N-type field-effect tube.
7. digital audio power amplification system according to claim 5, which is characterized in that the third switch, the described 5th open
It closes, the 8th switch and the tenth switch are N-type field-effect tube；
4th switch, the 6th switch, the 7th switch and the 9th switch are p-type field-effect tube.
8. digital audio power amplification system according to claim 3, which is characterized in that the digital audio power amplification system, also
It include: common-mode voltage generation module；
Second input terminal of the second input terminal of the first power amplifier loop and the second power amplifier loop is electric with the common mode
Press the output end connection of generation module.
9. digital audio power amplification system according to claim 8, which is characterized in that the common-mode voltage generation module, packet
It includes: the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance and capacitor；
The first end of 5th resistance is connect with voltage input end, second end and the 6th resistance of the 5th resistance
First end connection, the second end of the 6th resistance are connect with the first end of the 7th resistance, and the second of the 7th resistance
Hold grounding connection；
The first end of 8th resistance is connect with the first end of the 7th resistance, the second end of the 8th resistance with it is described
The first end of capacitor connects, and the second end of the capacitor is connect with the second end of the 7th resistance；
Output end of the connecting node of 8th resistance and the capacitor as the common-mode voltage generation module.
10. digital audio power amplification system according to claim 9, which is characterized in that the 5th resistance, the 6th electricity
It hinders identical with the resistance value of the 7th resistance.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109068241A (en) * | 2018-08-27 | 2018-12-21 | 上海艾为电子技术股份有限公司 | A kind of digital audio power amplification system |
| CN110868162A (en) * | 2019-11-29 | 2020-03-06 | 上海艾为电子技术股份有限公司 | Digital audio power amplifier and power amplifier loop |
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2018
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109068241A (en) * | 2018-08-27 | 2018-12-21 | 上海艾为电子技术股份有限公司 | A kind of digital audio power amplification system |
| CN109068241B (en) * | 2018-08-27 | 2024-05-03 | 上海艾为电子技术股份有限公司 | Digital audio power amplifier system |
| CN110868162A (en) * | 2019-11-29 | 2020-03-06 | 上海艾为电子技术股份有限公司 | Digital audio power amplifier and power amplifier loop |
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