CN2422778Y - Electric current audio frequency amplifier - Google Patents
Electric current audio frequency amplifier Download PDFInfo
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- CN2422778Y CN2422778Y CN 00222691 CN00222691U CN2422778Y CN 2422778 Y CN2422778 Y CN 2422778Y CN 00222691 CN00222691 CN 00222691 CN 00222691 U CN00222691 U CN 00222691U CN 2422778 Y CN2422778 Y CN 2422778Y
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Abstract
The utility model relates to a current audio frequency power amplifier which comprises two symmetrical amplifying circuits of which the feedback is current negative feedback, and a feedback loop composed of resistors R1 and R2, wherein the resistor R2 is connected between the inverse input end of the amplifying circuit 1 and the end 2 of a loudspeaker 1, and the other feedback loop is composed of resistors R3 and R4. The resistor R4 is connected between the inverse input end of an amplifying circuit 2 and a current sampling resistor R5. The utility model has the advantages of high fidelity and no transient intermodulation distortion, and can make fully use of a power supply winding and filtering capacitors, the load end is free from phase fault and earth fault, and the utility model is suitable for professional audio power amplifiers with high power.
Description
The utility model relates to audio-frequency power amplifier.
The audio-frequency power amplifier of prior art adopts the voltage negative feedback system to carry out the audio power amplification and has following defective: 1.. and power amplifier output end voltage Vo can make it stable by the voltage negative feedback, is not subjected to the influence of loudspeaker impedance Z.But the power output Po of audio frequency power amplifier and output current Io can be subjected to the influence of loudspeaker impedance Z, and inversely proportional relation.
At low-frequency range and high band, increase along with loudspeaker impedance Z, when power amplifier output end voltage Vo is constant, the electric current I o that flows through in the loudspeaker voice coil can reduce surely, voice coil loudspeaker voice coil suffered electromagnetic viscosimeter power (F=BIL) in loud speaker magnetic field is reduced, and voice coil loudspeaker voice coil and cone are combined, and the ability of cone compressing air vibration also just weakens, thereby cause that the sound wave acoustic pressure and the sound intensity reduce, the loudness of low-and high-frequency signal reduces.
We know, the loss in transmission course of low-and high-frequency code book is just bigger, broadcast out if drive loud speaker with such power amplifier again, the spectrum energy that will inevitably change in the former audio signal distributes, and the loudness ratio of each frequency signal in the whole audio section is changed.Simultaneously, the low-and high-frequency signal is very big to the tone color influence again, is determining the sense of reality, spatial impression and the direction accurate positioning of audio signal.If weaken and change their shared loudness ratios without reason, the original sound of just can not all resetting out truly.2.. take a sample in the negative feedback voltage V of power amplifier output
fBe subjected to the influence of loudspeaker impedance Z.Because loudspeaker impedance Z is the function of frequency f, is non-linear element, so negative feedback voltage V
fWith loudspeaker voice coil electric current I o is not linear relationship one to one, can exist certain phase difference.When electric current I o in the loudspeaker voice coil changes, V
fJust can not in time catch up with the variation of Io, accurately regulate the output current of power amplifier, the timely suffered electromagnetic viscosimeter power of control loudspeaker voice coil loudspeaker voice coil (cone), thus produce and transient distortion occurs.On the other hand, leading or lag behind the negative feedback voltage V of voice coil loudspeaker voice coil electric current I o
fSend the power amplifier input again back to, can modulate original input signal again, bring even more serious intermodulation distortion.So transistor voltage negative feedback audio-frequency power amplifier will inevitably produce transient intermodulation.
The electric current audio-frequency power amplifier that provides a kind of fidelity high is provided the purpose of this utility model.
Technical solutions of the utility model are as follows:
Scheme 1:
The electric current audio-frequency power amplifier comprises: the amplifying circuit of two symmetries, feedback system are Current Negative Three-Point Capacitance,
First amplifying circuit is:
The input connecting resistance R1 of signal VS, resistance R 1 connects the reverse input end of amplifying circuit AMP1, the input end grounding in the same way of amplifying circuit AMP1, input 1 end of the output termination loud speaker SP1 of amplifying circuit AMP1, feedback loop is made up of resistance R 1, R2, the reverse input end of R2 one termination amplifying circuit AMP1,2 ends of another termination loud speaker SP1 of R2;
Second amplifying circuit is:
The input connecting resistance R3 of signal VS, resistance R 3 connects the reverse input end of amplifying circuit AMP2, the input end grounding in the same way of amplifying circuit AMP2, connect input 2 ends of loud speaker SP1 behind the output termination current sampling resistor R5 of amplifying circuit AMP2 again, feedback loop is made up of resistance R 3, R4, the reverse input end of R4 one termination amplifying circuit AMP2, another termination current sampling resistor R5 of R4.
Scheme 2: do load with two loud speakers, concrete connected mode is changing on the basis of such scheme 1: second loud speaker SP2 of series connection between the output of amplifying circuit AMP2 and current sampling resistor R5, resistance R 4 connects 3 ends of loud speaker SP2.
Circuit theory is: audio excitation signal is by the input of VS end, audio signal is amplified in NPN pipe among the positive half cycle AMP1 and the PNP pipe conducting among the AMP2, audio signal is amplified in PNP pipe among the negative half period AMP1 and the NPN pipe conducting among the AMP2, voltage VC almost all is added on load loud speaker two ends, output voltage peak value on the loud speaker is 2 times of OCL structure, the power output peak value improves about 4 times, the feedback loop of sign-changing amplifier AMP1 is by resistance R 1, R2 forms, the feedback loop of sign-changing amplifier AMP2 is by resistance R 3, R4 forms, R5 is the current sampling resistor on the load loud speaker, convert the variation of the electric current in the load loud speaker to change in voltage by R5, and this changing value is fed back to linearly the negative input end of AMP1 and AMP2 through resistance R 2 and R4, the positive and negative real input signal value of power amplifier AMP amplitude is changed, thereby reach the purpose of control amplifier output current, play the effect that current power amplifies.Its circuit model is voltage-controlled current source (VCCS) type.
Advantage of the present utility model is: the fidelity height, and there is not transient intermodulation in it, can make power supply winding and filter capacitor obtain omnidistance the utilization, and load end has advantages such as the phase fault of not being afraid of, shorted to earth again.So, be well suited for and be applied in the high-power professional audio power amplifier.And the supporting use of amplifying circuit of suitable and prime frequency division mode.The characteristics of this structure Current Negative Three-Point Capacitance audio frequency power amplifier have:
1.. load terminal voltage Vo, the power output P of power amplifier
oCan form proportional relationship along with the variation of load loudspeaker impedance Z changes.That is to say that Current Negative Three-Point Capacitance has the certain power compensating action to impedance Z with frequency change, its load characteristic is just opposite with voltage negative feedback power amplifier;
2.. the voice coil loudspeaker voice coil electric current I o that power amplifier outputs to loudspeaker no longer is subjected to the influence of loudspeaker impedance Z, is controlled by input signal Vs fully and determines.Therefore, load loud speaker two terminal shortcircuits can not bring over-current phenomenon avoidance to power amplifier yet, and load loud speaker two ends when open circuit, the rising of output end voltage Vo is subjected to the restriction of supply voltage again, bring harm also can not for the final stage power tube, so simplified the power amplifier protective circuit greatly;
3.. feedback signal voltage V
fWith loudspeaker voice coil electric current I o is linear proportionate relationship, does not have phase difference, thereby avoided occurring transient intermodulation on circuit structure.
4.. this circuit structure can make duplicate supply winding and filter capacitor obtain omnidistance the utilization, brings phenomenons such as power amplifier low frequency self-excitation sound and positive-negative half-cycle wave distortion distortion when having avoided using by turns two big filter capacitors because of parameter errors such as capacity, capacitive reactances.
5.. the impedance Z value changes almost nil to the influence of loudspeaker voice coil electric current I o.So, even impedance Z be non-linear, the time function that become or frequency, all very small to the influence of this structure power amplifier output current Io value.
6.. this electric current audio-frequency power amplifier uses high voltage nargin and constant current mode to adapt to the variation requirement of load impedance and big Dynamic Signal, come with big electric current nargin and constant voltage mode than prior art voltage negative feedback power amplifier, have higher temperature stability.Volume, the weight of this electric current audio-frequency power amplifier self and power unit are reduced greatly, and cost of manufacture reduces greatly, has lower loss and the efficient of Geng Gao in the electroacoustic conversion process of energy.
Description of drawings:
Fig. 1: electric current audio-frequency power amplifier basic diagram.
Fig. 2: the electric current audio-frequency power amplifier drives two loaded line figure.
Fig. 3: electric current audio-frequency power amplifier embodiment 1 line map.
Embodiment 1: among Fig. 3, the electric current audio-frequency power amplifier comprises:
Prime at amplifying circuit AMP1 and AMP2 has:
A, input sensitivity are regulated and load impedance selects circuit to comprise: the input interface CP1 of audio signal, volume potentiometer CPW, DIP switch SK1 is that diverter switch is selected in 4 Ω and 8 Ω loads, and DIP switch SK2 is a varying input signal sensitivity VS selector switch, resistance R 2～R6 and amplifier IC1;
B, single-ended unbalanced signal comprise to the translation circuit of both-end balanced signal: amplifier IC2 and resistance R 7～R11; Amplifying circuit AMP1 and AMP2 are three-stage amplifier:
The chopped-off head signal amplification of C, power amplifier comprises: amplifier piece IC3, IC4, potentiometer P1, P2, building-out capacitor C2, C3, resistance R 12-R17.
D, second level voltage amplification comprise: pliotron and resistance R 18-R25, potentiometer P3-P6 among two groups of BG1, BG2 and BG3, the BG4.
E, output final stage comprise: BG5, BG6 and BG7, two groups of high power valves of BG8, resistance R 26-R34, potentiometer P7-P10, loud speaker SP.
Also have: F, power unit interface are CP2, CP3.
G, resistance R 13, R14, R15, R16 are respectively the negative feedback resistors of two halves bridge circuit, and R13 connects 1 pin of IC2,2 pin and the R14 of another termination IC3 of R13, and R14 connects 2 ends of loud speaker SP; R15 connects 7 pin of IC2, and 2 pin and the R16 of another termination IC4 of R15, R16 connect 2 ends that meet loud speaker SP behind the R34; R34 is the current sampling resistor of load loud speaker SP.The span of R13, R15 should be controlled at 1K Ω-47K Ω, and the span of R15, R16 should be controlled at 1K Ω-10K Ω, and the span of R34 should be controlled at 0.2 Ω-0.8 Ω.
H, each integrated package model are: IC1 is NE5532, and IC2 is NE5532, and IC3 is NE5534, and IC4 is NE5534
Operation principle:
Audio signal is from interface CP1 input, and CPW is the volume potentiometer interface, and electric current audio-frequency power amplifier volume is controlled.DIP switch SK1 forms 4 Ω and 8 Ω loads are selected to switch, and DIP switch SK2 is a varying input signal sensitivity VS selector switch, and they are formed with resistance R 2～R6 and amplifier IC1A, and input sensitivity is regulated and load impedance is selected circuit.
Amplifier IC2 and resistance R 7～R11 form the translation circuit from single-ended unbalanced signal to the both-end balanced signal, to satisfy the positive and negative dual signal input requirement of electric current audio-frequency power amplifier.
The chopped-off head signal of power amplifier amplifies to be finished with amplifier IC3, IC4, why selects amplifier for use at this, mainly is to consider with high-performance amplifier ratio to use the symmetrical consistency of discrete component more guaranteed, is suitable for the industrial mass making and produces.Potentiometer P1, P2 are mainly used in and adjust power amplifier output zero potential, and capacitor C 2, C3 are building-out capacitors, prevent the amplifier self-excitation.
Second level voltage amplification is made up of pliotron among two groups of BG1, BG2 and BG3, the BG4 and resistance,
The output final stage is made up of BG5, BG6 and two groups of high power valves of BG7, BG8 and resistance.
Potentiometer P3～P10 is used for adjusting respectively the quiescent point of 8 triode BG1～BG8, removes in advance the trouble that must carry out strict test pairing to NPN and positive-negative-positive triode from.And, this in practical application circuit and ambient temperature, match the adjustment quiescent point, specific aim is stronger, and the pairing performance of PNP/NPN pipe is also more guaranteed.The concrete method of adjustment of P1～P10 potentiometer is as follows:
1.. before energising, switch S K1, SK2 choose corresponding signal input sensitivity Vs and load impedance Zo value.The sliding contact of potentiometer P1P2 is threaded to the centre position, and the sliding contact of P3～P10 potentiometer is threaded to A among the figure, B point position;
2.. transfer P1, P2 potentiometer, make load SP both end voltage difference V
1-V
2≤ ± 10mV;
3.. transfer two groups of potentiometers of P3P4, P5P6 in twos in turn, make the quiescent current of this grade about 10mA, (survey V
P7-P10≈ 2V);
4.. transfer two groups of potentiometers of P7P8, P9P10 in twos in turn, make the quiescent current of this grade about 100mA, (survey V
R30-R33≈ 20mV);
5.. readjustment P1, P2 potentiometer make load SP both end voltage difference V
1-V
2≤ ± 10mV.
Circuit connecting relation among the embodiment 1:
The CP1:1 pin connects 1 pin of CPW,
3 pin connect 3 pin of CPW, 5 pin of R1,1C2B, 3 pin of IC4; The CPW:2 pin meets C1; The IC1B:5 pin meets R1, C1, and 6,7 pin join, and meets R2, R3, and SK1:1,2 pin meet R2, R3,
The 5-8 pin meets R4-R6, and the SK2:1-3 pin meets R4-R6,
The 5-8 pin connects 1 pin of IC1A, and the IC1A:1 pin connects 3 pin of IC2A
3 pin meet R7, R9
8 pin connect 4 pin of IC2A, 1 pin of CP2,
2 pin connect 8 pin of SK1
The 8 pin IC2A:1 pin that 4 pin meet IC2A meet R13,
2 pin meet R7, R8,
3 pin connect 1 pin of IC1A,
4 pin connect 1 pin of CP2,
8 pin connect 3 pin of CP2, and the IC2B:5 pin connects 3 pin of IC4,
6 pin meet R10, R11
7 pin connect 2 pin that R11, R15IC3:3 pin meet CP2,
7 pin connect 1 pin of R12, CP2, and R12 connects the moved end of P1,
1,8 pin meet P1,
5,8 pin meet C2,
6 pin meet P3, P4,
4 pin connect 3 pin of CP2,
2 pin meet R14, and the IC4:2 pin meets R15, R16,
3 pin connect 5 pin of IC2B, 2 pin of CP2,
4 pin connect 3 pin of CP2,
5,8 pin meet C3,
1,8 pin meet P2,
7 pin connect the P2 moved end after meeting R17, and 7 pin also connect 1 pin of CP2,
6 pin meet P5, P6, BG1: base stage meets R19, and R19 connects the P3 moved end,
Emitter meets P7
Collector electrode meets R18, and R18 connects P3 one end, another termination of P3 P4, and BG2: base stage meets R20, and R20 connects the P4 moved end, and emitter meets P8, and P8 meets P7,
Collector electrode meets R21, and R21 connects 3 pin of the P4 other end and BG6 collector electrode and CP3, and the connected mode of BG3, BG4 is identical with BG1, BG2, and BG5: base stage meets R26, and R26 connects the moved end of P7,
Emitter meets R30, and R30 meets R31, loud speaker SP
Collector electrode connects 1 pin of BG1 collector electrode and CP3, and BG6: base stage meets R27, and R27 connects the P8 moved end,
Emitter meets loud speaker SP after meeting R31,
Collector electrode connects 3 pin of BG2 collector electrode and CP3, and the connected mode of BG7, BG8 is identical with BG5, BG6.
Claims (4)
1, electric current audio-frequency power amplifier, its feature comprises: the amplifying circuit of two symmetries, feedback system are Current Negative Three-Point Capacitance,
First amplifying circuit is: the input connecting resistance R1 of signal VS, resistance R 1 connects the reverse input end of amplifying circuit AMP1, the input end grounding in the same way of amplifying circuit AMP1, input 1 end of the output termination loud speaker SP1 of amplifying circuit AMP1, feedback loop is made up of resistance R 1, R2, the reverse input end of R2 one termination amplifying circuit AMP1,2 ends of another termination loud speaker SP1 of R2;
Second amplifying circuit is: the input connecting resistance R3 of signal VS, resistance R 3 connects the reverse input end of amplifying circuit AMP2, the input end grounding in the same way of amplifying circuit AMP2, connect input 2 ends of loud speaker SP1 behind the output termination current sampling resistor R5 of amplifying circuit AMP2 again, feedback loop is made up of resistance R 3, R4, the reverse input end of R4 one termination amplifying circuit AMP2, another termination current sampling resistor R5 of R4.
2, electric current audio-frequency power amplifier according to claim 1, its feature comprises: do load with two loud speakers, second loud speaker SP2 of series connection between the output of amplifying circuit AMP2 and current sampling resistor R5, resistance R 4 connects 3 ends of loud speaker SP2.
3, electric current audio-frequency power amplifier according to claim 1, its feature comprises:
Prime at amplifying circuit AMP1 and AMP2 has: A, input sensitivity are regulated and load impedance selects circuit to comprise: the input interface CP1 of audio signal, volume potentiometer CPW, DIP switch SK1 is that diverter switch is selected in 4 Ω and 8 Ω loads, DIP switch SK2 is a varying input signal sensitivity VS selector switch, resistance R 2～R6 and fortune IC1;
B, single-ended unbalanced signal comprise to the translation circuit of both-end balanced signal: amplifier IC2 and resistance R 7～R11;
Amplifying circuit AMP1 and AMP are that the chopped-off head signal amplification of three-stage amplifier: C, power amplifier comprises: amplifier piece IC3, IC4, potentiometer P1, P2, building-out capacitor C2, C3, resistance R 12-R17.
D, second level voltage amplification comprise: pliotron and resistance R 18-R25, potentiometer P3-P6 among two groups of BG1, BG2 and BG3, the BG4.
E, output final stage comprise: BG5, BG6 and BG7, two groups of high power valves of BG8, resistance R 26-R34, potentiometer P7-P10, loud speaker SP.
F, power unit interface are CP2, CP3.
G, resistance R 13R14, R15R16 are respectively the negative feedback resistors of two halves bridge circuit, and R13 connects 1 pin of IC2,2 pin and the R14 of another termination IC3 of R13, and R14 connects 2 ends of loud speaker SP; R15 connects 7 pin of IC2, and 2 pin and the R16 of another termination IC4 of R15, R16 connect 2 ends that meet loud speaker SP behind the R34; R34 is the current sampling resistor of load loud speaker SP.
H, each integrated package model are: IC1 is NE5532, and IC2 is NE5532, and IC3 is NE5534, and IC4 is NE5534.
4, electric current audio-frequency power amplifier according to claim 3, its feature comprises: circuit connecting relation: the CP1:1 pin connects 1 pin of CPW, and 3 pin connect 3 pin of CPW, 5 pin of R1, IC2B, 3 pin of IC4; The CPW:2 pin meets C1; The IC1B:5 pin meets R1, C1,6,7 pin join, and meet R2, R3, SK1:1,2 pin meet R2, R3, the 5-8 pin meets R4-R6, the SK2:1-3 pin meets R4-R6, the 5-8 pin connects 1 pin of IC1A, 3 pin, 3 pin that the IC1A:1 pin meets IC2A meet R7, R9 8 pin connect 4 pin of IC2A, 1 pin of CP2, the 8 pin IC2A:1 pin that 8 pin, 4 pin that 2 pin meet SK1 meet IC2A meet R13,2 pin meet R7, R8,3 pin connect 1 pin of IC1A, 4 pin connect 1 pin of CP2,8 pin connect 3 pin of CP2, the IC2B:5 pin connects 3 pin of IC4,6 pin meet R10, R11 7 pin meet R11, the R15IC3:3 pin connects 2 pin of CP2,7 pin meet R12,1 pin of CP2, R12 connects the moved end of P1,2,8 pin meet P1,5,8 pin meet C2,6 pin meet P3, P4,4 pin connect 3 pin of CP2, and 2 pin meet R14, and the IC4:2 pin meets R15, R16,3 pin connect 5 pin of IC2B, 2 pin of CP2,4 pin connect 3 pin of CP2,5,8 pin meet C3,1,8 pin meet P2,7 pin connect the P2 moved end after meeting R17, and 7 pin also connect 1 pin of CP2, and 6 pin meet P5, P6, BG1: base stage meets R19, R19 connects the P3 moved end, and emitter meets P7, and collector electrode meets R18, R18 connects P3 one end, another termination of P3 P4, BG2: base stage meets R20, and R20 connects the P4 moved end, emitter meets P8, P8 meets P7, and collector electrode meets R21, and R21 connects 3 pin of the P4 other end and BG6 collector electrode and CP3, BG3, the connected mode of BG4 and BG1, BG2 is identical, BG5: base stage meets R26, and R26 connects the moved end of P7, and emitter meets R30, R30 meets R31, loud speaker SP collector electrode connects 1 pin of BG1 collector electrode and CP3, BG6: base stage meets R27, and R27 connects the P8 moved end, and emitter meets loud speaker SP after meeting R31, collector electrode meets 3 pin of BG2 collector electrode and CP3, BG7, the connected mode of BG8 and BG5, BG6 is identical.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 00222691 CN2422778Y (en) | 2000-04-03 | 2000-04-03 | Electric current audio frequency amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 00222691 CN2422778Y (en) | 2000-04-03 | 2000-04-03 | Electric current audio frequency amplifier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2422778Y true CN2422778Y (en) | 2001-03-07 |
Family
ID=33587374
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 00222691 Expired - Fee Related CN2422778Y (en) | 2000-04-03 | 2000-04-03 | Electric current audio frequency amplifier |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2422778Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101472209B (en) * | 2007-12-27 | 2012-10-10 | 鸿富锦精密工业（深圳）有限公司 | Apparatus for processing audio |
| CN105281684A (en) * | 2014-07-18 | 2016-01-27 | 雅马哈株式会社 | Power amplifier |
| CN106487354A (en) * | 2015-09-01 | 2017-03-08 | 安桥株式会社 | Music player |
-
2000
- 2000-04-03 CN CN 00222691 patent/CN2422778Y/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101472209B (en) * | 2007-12-27 | 2012-10-10 | 鸿富锦精密工业（深圳）有限公司 | Apparatus for processing audio |
| CN105281684A (en) * | 2014-07-18 | 2016-01-27 | 雅马哈株式会社 | Power amplifier |
| CN105281684B (en) * | 2014-07-18 | 2018-06-19 | 雅马哈株式会社 | Power amplifier |
| CN106487354A (en) * | 2015-09-01 | 2017-03-08 | 安桥株式会社 | Music player |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |