CN200973071Y - Audio power amplifier circuit - Google Patents
Audio power amplifier circuit Download PDFInfo
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- CN200973071Y CN200973071Y CN 200620014294 CN200620014294U CN200973071Y CN 200973071 Y CN200973071 Y CN 200973071Y CN 200620014294 CN200620014294 CN 200620014294 CN 200620014294 U CN200620014294 U CN 200620014294U CN 200973071 Y CN200973071 Y CN 200973071Y
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- amplifying circuit
- audio power
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- power amplifying
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Abstract
The utility model discloses an audio power amplifying circuit, wherein the technical problem to be solved is to use a low cost to obtain an audio effect closed to the natural sound. The utility model adopts such technical proposals: an audio power amplifying circuit is adopted, wherein the base electrode of the triode amplifying circuit is provided with a biasing circuit; the biasing circuit adopts the triode with an emitter output connected in a three-level series; each level of emitter output triode is symmetrically connected by a pair of PNP-type triode and NPN-type triode. Compared with the prior art, the biasing circuit of the utility model adopts the emitter output triode, utilizes the saturation voltage reduction of the triode to achieve the control over the supply of the complete temperature feedback and the maximal motivation current on the last-level biasing, improves the input resistance of the audio power amplifying circuit and ensures the stability of the amplifier and presents a vivid acoustic effect.
Description
Technical field
The utility model relates to the audio power amplifying circuit of a kind of acoustics circuit, particularly a kind of acoustics circuit.
Background technology
The tradition audifier is a ring the weakest in the sound equipment public address, the distortion of amplifier has been accomplished below 0.1% in theory, but loudspeaker are inductive loads, negative input end from the signal feedback of the output of power amplifier to voltage amplifier, again output signal is adjusted, the power amplifier of this structure adopts the mode of afterwards adjusting, can not make adjustment to the variation of signal in good time, the i.e. action of control loudspeaker rationally, allow and listen the sound equipment person can pick out the difference of natural phonation and electroacoustic easily, produce the peculiar modulated acoustic that loud speaker sends, just the sound equipment taste is heavier, for metallic sound, high pitch sound is all the more so.Even high-grade power amplifier and stereo set, adopt the element of high-quality and amplifier and the stereo set that consummate manufacture craft is made, also can't break away from this predicament.If accomplish outstanding acoustic fidelity effect, need pay high cost.
Summary of the invention
The purpose of this utility model provides a kind of audio power amplifying circuit, and the technical problem that solve is to obtain and natural phonation acoustics true to nature with low cost.
The utility model is by the following technical solutions: a kind of audio power amplifying circuit, the base stage of the transistor amplifier of audio power amplifying circuit is provided with biasing circuit, described biasing circuit adopts the triode of the emitter-base bandgap grading output of three grades of serial connections, penetrates grade output triode for every grade and is connected with NPN type triode symmetry by a pair of positive-negative-positive triode.
The transistor amplifier of the utility model audio power amplifying circuit is Darlington circuit or field effect transistor circuit.
The both ends of power that the final stage of the triode of the emitter-base bandgap grading output that the utility model symmetry connects connects is parallel with two voltage stabilizing didoes of serial connection in the same way.
The both ends of power that the final stage of the triode of the emitter-base bandgap grading output that the utility model symmetry connects connects is parallel with two electrochemical capacitors of serial connection in the same way.
The base stage of a pair of triode of chopped-off head of the triode of the emitter-base bandgap grading output that the utility model symmetry connects connects an end of first resistance, the output signal of another termination voltage amplifier of first resistance jointly through the resistance of serial connection.
The tie point of two voltage stabilizing didoes that are connected in series in the same way of the utility model, the tie point of two electrochemical capacitors that are connected in series in the same way are connected with transistor collector.
Positive-negative-positive triode of the present utility model adopts 2SA970, NPN type triode adopts 2SC2240, voltage stabilizing didoe adopts the 15V voltage stabilizing didoe, electrochemical capacitor adopts 1000 μ f, first resistance adopts 5K, and the triode first order is penetrated grade output resistance and adopted 4K, and the triode second level is penetrated grade output resistance and adopted 10K, the triode third level is penetrated grade output resistance and adopts 1K, and the base resistance of a pair of triode of chopped-off head adopts 4.7K.
The utility model compared with prior art, biasing circuit adopts the triode of emitter-base bandgap grading output, utilize the saturation voltage drop of triode, in the final stage biasing, accomplished the control of the supply of complete Temperature Feedback and maximum excitation electric current, improve the input impedance of audio power amplifying circuit, ensure the stability of amplifier, had the acoustic fidelity effect.
Description of drawings
Fig. 1 is the circuit theory diagrams of the utility model embodiment.
Fig. 2 is the equivalent circuit diagram of Fig. 1.
Fig. 3 is the circuit theory diagrams of conventional power amplifier.
Fig. 4 is the circuit block diagram of the utility model embodiment.
Fig. 5 is the audio power amplifying circuit schematic diagram of the utility model embodiment.
Embodiment
Below in conjunction with drawings and Examples the utility model is described in further detail.As shown in Figure 1, the base stage of the transistor amplifier of audio power amplifying circuit of the present utility model is provided with biasing circuit, biasing circuit adopts the triode of three grades of emitter-base bandgap grading outputs to be connected in series mutually, penetrates grade output triode for every grade and is connected with NPN type triode symmetry by a pair of positive-negative-positive triode.The both ends of power that the final stage of the triode of the symmetrical emitter-base bandgap grading output that connects connects is parallel with two voltage stabilizing didoes, two electrochemical capacitors that are connected in series in the same way of serial connection in the same way.The tie point of the tie point of two voltage stabilizing didoes that are connected in series in the same way, two electrochemical capacitors that are connected in series in the same way is connected with transistor collector.The base stage of a pair of triode of chopped-off head of the triode of the emitter-base bandgap grading output that symmetry connects connects an end of first resistance, the output of another termination voltage amplifier of first resistance jointly through the resistance of serial connection separately.
The positive-negative-positive triode of audio power amplifying circuit of the present utility model adopts about electric current 100MA, frequency 100MHZ, such as 2SA970, NPN type triode adopts about electric current 100MA, frequency 100MHZ, such as 2SC2240, voltage stabilizing didoe adopts the 15V voltage stabilizing didoe, electrochemical capacitor adopts 1000 μ f, first resistance R 1 adopts 5K, the triode first order is penetrated grade output resistance and is adopted 4K, the triode second level is penetrated grade output resistance and is adopted 10K, the triode third level is penetrated grade output resistance and adopts 1K, and the base resistance of a pair of triode of chopped-off head adopts 4.7K.
The bias voltage of the NPN triode of the audio power amplifying circuit of the utility model embodiment is formed by the E-B joint of positive source VCC, the 8th resistance R 8, the 5th triode Q5 in the biasing circuit, the E-B joint of the 3rd triode Q3, the E-B joint of the first triode Q1 and the pressure drop between second resistance R 2, the voltage of second resistance R 2 is 0V, obtains the voltage of 1.8V at the following pull end of the 8th resistance R 8; The bias voltage of PNP triode is formed by the pressure drop between B-E joint, the 9th resistance R 9 and the power cathode VDD of the B-E joint of the B-E of the 3rd resistance R 3, the second triode Q2 in biasing circuit joint, the 4th triode Q4, the 6th triode Q6, the 3rd resistance R 3 and and the 9th resistance R 9 between voltage be 1.8V, the bias voltage that needs of back level amplifying circuit just.
The progression of needed triode emitter follower serial connection in power amplification circuit, be according to Darlington circuit or the needed bias voltage of field effect transistor in the level amplifying circuit of back, need to determine what grade triode emitter followers serial connection, i.e. the series connection of the B-E of triode joint.
As shown in Figure 5, PNP group and NPN group triode are operated in the saturation conduction state, and when input was positive current, PNP triode group can withdraw from the saturation region, presents the current buffering magnifying state, backward Ji Darlington circuit output stage release current.But for NPN triode group, be saturation condition, output does not have too big variation when its base stage input forward current again, and therefore output remains on certain biasing scope.The electric current that needs as the output current and the back level amplifying circuit of the triode of biasing circuit is antipodal, so just can additional and temperature-compensating as linearity, finish the work of bias current and buffering.When output is disturbed by external electromotive force, such as the anti-motional electromotive force of loud speaker, be positive signal as output, this time, input just had the electric current of negative sense, and output is retracted dead-center position immediately, is a kind of negative feedback completely.
As shown in Figure 3, the power amplifier of prior art, adopt degenerative mode, from the output of power amplifier with the negative input end of signal feedback to voltage amplifier, signal to input is regulated, chopped-off head is two biasing resistors, chopped-off head triode output current provides bias current for back level triode, with the voltage of one-level triode from NPN to PNP is 1.2+1.2=2.4V, this voltage is fixed, and when NPN triode output current is about 10 amperes, will be raised to about 5V at the 1.2V of NPN drive(r) stage voltage, the 1.2V-5V of PNP triode is the 3.8V negative bias, causes intermodulation distortion.Just need quiescent current to surpass more than 10 Ampere currents if overcome intermodulation distortion, if amplifier need be exported the 10A electric current, be 160V when powering, static state is the 10A electric current, and the consumed power of amplifier is 1600 watts, and heat radiation can become problem.Therefore do not have the amplifier of intermodulation distortion, power is difficult to accomplish more than 100 watts.Also can obtain the quality of class a audio power amplifier by circuit such as dynamic bias, but, temperature drift not had good control ability, so can't become main flow because complex structure causes new harm to tonequality easily.With regard to exciting current, triode is a current control device, needs big electric current to drive, and just means that prime not only will have high performance index, also will have very strong driving force.This is a fatal bottleneck of voltage amplifier.If the signal of telecommunication that also needs to wait for the back level feeds back to prime, situation is just more bad.Sound is once-forming in moment, if repair the distortion of loud speaker end by negative feedback, only can in original distortion, increase new distortion clocklike, when the intrinsic characteristic of amplifier is mixed in the music signal and since characteristic be one to, people's ear feels exhausted easily, therefore be easy to feel electroacoustic, if pass through the interference of feedback adjusting and loudspeaker electromotive force again, let alone the thing of fidelity.
As shown in Figure 2, the biasing circuit equivalence of the audio power amplifying circuit of the utility model embodiment is the series connection of three diodes, during diode current flow, the voltage of the PN junction of three series connection just in time is 0.6+0.6+0.6=1.8V, equals to drive the bias voltage of three grades of Darlington circuits of back level.During work, the base stage of chopped-off head PNP triode and NPN triode links to each other, base current is provided mutually, current potential between the collector and emitter is smaller or equal to 0.6V, do not have littler variation again, be that first order PNP and NPN triode are operated under the saturation condition, import as positive signal, the NPN triode has only slight variation in saturation condition, and this positive signal can allow emitter reduce to the current potential between the base stage for the PNP triode, after electric current reduces, can cause withdrawing from the saturation region, as voltage follower, backward the level release current.On the contrary, for the negative signal of input, the NPN triode withdraws from saturation condition, makes voltage follower, and the PNP triode enters saturation condition, and PNP triode group emitter no longer includes big variation.
As shown in Figure 4, biasing circuit of the present utility model adopts the bootstrapping power supply, and the ground end that suspends is connected with amplifier out, during the vicissitudinous signal of input, exports and also follows, and is equal up to input current potential and output current potential.When signal joins input, circuit follows signal to move with suspending, Shu Ru electric current is very little in theory, very high impedance is arranged, that is to say that the voltage amplifier of prime needs much electric currents hardly, just can promote the biasing circuit of audio-frequency power amplifier of the present utility model, audio-frequency power amplifier itself does not need to provide to feed back signal to voltage amplifier yet, can stablize inductive load, accomplish the high damping coefficient, promptly improve input impedance as loudspeaker.
The biasing circuit of audio power amplifying circuit of the present utility model also has the function of making up the difference accurately to the drift of temperature, because three grades of expansion flow path directions of the sense of current of the triode of serial connection and output stage are opposite, so not only can offset some nonlinear distortions, more can compensate because the wild effect that temperature drift brings.When temperature raise, transistorized internal resistance reduced, and the B-E joint conducting of 6 diodes of equivalence strengthens, and static constant current partially reduces, and the bias current of level output also reduces backward, and electric current reduces the back temperature and descends, and gets off up to temperature stabilization.
In high power amplifier, the final stage power consumption is too big, can not accomplish the effect of Class A power amplification, because traditional circuit, keeps minimum biasing, and the symmetry tubes of back level will produce intermodulation distortion once anti-phenomenon is partially arranged.The biasing circuit of audio power amplifying circuit of the present utility model is operated in the zone of saturation, signal is opposite for PNP triode and NPN triode, under saturation condition, can only there be wherein one group to withdraw from saturated, other one group is retained in original position, when the conducting of PNP triode increases, no longer follow action owing to the PNP triode is saturated, and the conducting of NPN triode will reduce, the voltage of level output will increase backward, when same NPN triode conducting increases, no longer follow action owing to the NPN triode is saturated, the conducting of PNP triode will reduce, and the voltage of level output will increase backward, and no matter how many signals is, all the time having kept that back level driving tube is minimum can cut-ff voltage, has accomplished the linear current output of similar class A power amplifier.
The biasing circuit that the triode of audio power amplifying circuit of the present utility model constitutes is operated in the saturation conduction state, utilizes the tube voltage drop of the B-E knot of triode that biasing is provided.So tube voltage drop can not be lower than about 0.6V, as the electric current of change by the time have only two states, the one, more the degree of depth is saturated, but can not be lower than 0.6V, the 2nd, withdraw from saturated, enter the amplification region to cut-off region, when ending, resistance will be directly backward level discharge and drive maximum electric current, maximum current is decided by the resistance of the 8th resistance R 8 and the 9th resistance R 9, according to the resistance of selecting R8 and R9, just can determine the electric current that maximum level backward provides, be 100A such as back level maximum safe current, and the current amplification factor of back level is 10000 times, the maximum current that provides by the 8th resistance R 8 or the 9th resistance R 9 is 0.001 ampere so, and the current-limiting resistance that needs 0.001 ampere on 15V voltage is 1.5K.Generally get 50A.
The audio-frequency power amplifier of the utility model embodiment is simple in structure, only between six triodes, just finished complicated control, the performance of audio-frequency power amplifier is improved greatly, extra high input impedance is arranged, the voltage amplifier current drain is little, limit prime performance and feedback at the corresponding levels completely hardly, as long as voltage amplifier does not produce distortion, power is put amplifier just can not produce distortion, not needing provides feedback signal just can accomplish high damping input to prime, add and do not have the anti-intermodulation distortion that brings partially, have good temperature-compensating, for example under the condition that does not increase cost, frequency range is accomplished 0-400KHZ-1.5DB, switching rate is more than 350/US, and existing high power amplifier switching rate arrives 0-50KHZ-1.5DB at most in the 100V/US frequency.To full load, radiator remains on 50～60 ℃ from small-signal, and 40 ℃ of ambient temperatures have higher radiating efficiency and reliability.
Claims (7)
1. audio power amplifying circuit, the base stage of the transistor amplifier of audio power amplifying circuit is provided with biasing circuit, it is characterized in that: described biasing circuit adopts the triode of the emitter-base bandgap grading output of three grades of serial connections, penetrates grade output triode for every grade and is connected with NPN type triode symmetry by a pair of positive-negative-positive triode.
2. audio power amplifying circuit according to claim 1 is characterized in that: the transistor amplifier of described audio power amplifying circuit is Darlington circuit or field effect transistor circuit.
3. audio power amplifying circuit according to claim 2 is characterized in that: the both ends of power that the final stage of the triode of the emitter-base bandgap grading output that described symmetry connects connects is parallel with two voltage stabilizing didoes of serial connection in the same way.
4. audio power amplifying circuit according to claim 3 is characterized in that: the both ends of power that the final stage of the triode of the emitter-base bandgap grading output that described symmetry connects connects is parallel with two electrochemical capacitors of serial connection in the same way.
5. audio power amplifying circuit according to claim 4, it is characterized in that: the base stage of a pair of triode of chopped-off head of the triode of the emitter-base bandgap grading output that described symmetry connects is through the resistance of serial connection, connect an end of first resistance jointly, the output signal of another termination voltage amplifier of first resistance.
6. audio power amplifying circuit according to claim 5 is characterized in that: the tie point of the tie point of described two voltage stabilizing didoes that are connected in series in the same way, two electrochemical capacitors that are connected in series in the same way is connected with transistor collector.
7. audio power amplifying circuit according to claim 6, it is characterized in that: described positive-negative-positive triode adopts 2SA970, NPN type triode adopts 2SC2240, voltage stabilizing didoe adopts the 15V voltage stabilizing didoe, and electrochemical capacitor adopts 1000 μ f, and first resistance adopts 5K, the triode first order is penetrated grade output resistance and is adopted 4K, the triode second level is penetrated grade output resistance and is adopted 10K, and the triode third level is penetrated grade output resistance and adopts 1K, and the base resistance of a pair of triode of chopped-off head adopts 4.7K.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200620014294 CN200973071Y (en) | 2006-06-09 | 2006-06-09 | Audio power amplifier circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200620014294 CN200973071Y (en) | 2006-06-09 | 2006-06-09 | Audio power amplifier circuit |
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| Publication Number | Publication Date |
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| CN200973071Y true CN200973071Y (en) | 2007-11-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200620014294 Expired - Fee Related CN200973071Y (en) | 2006-06-09 | 2006-06-09 | Audio power amplifier circuit |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013020265A1 (en) * | 2011-08-08 | 2013-02-14 | Hu Zhangru | Output stage acceleration circuit of transistor audio power amplifier |
| CN103458341A (en) * | 2013-09-09 | 2013-12-18 | 胡福生 | Audio frequency amplifier adjunct circuit used for eliminating emitter output stage |
| CN107395142A (en) * | 2017-07-06 | 2017-11-24 | 李凤朝 | A kind of power amplification circuit |
| CN109104671A (en) * | 2018-08-24 | 2018-12-28 | 林汉民 | A kind of sound equipment power amplifier output-stage circuit |
| CN110855252A (en) * | 2019-11-20 | 2020-02-28 | 许昌开普检测研究院股份有限公司 | Current expansion circuit of power operational amplifier |
-
2006
- 2006-06-09 CN CN 200620014294 patent/CN200973071Y/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013020265A1 (en) * | 2011-08-08 | 2013-02-14 | Hu Zhangru | Output stage acceleration circuit of transistor audio power amplifier |
| CN103458341A (en) * | 2013-09-09 | 2013-12-18 | 胡福生 | Audio frequency amplifier adjunct circuit used for eliminating emitter output stage |
| CN103458341B (en) * | 2013-09-09 | 2016-06-29 | 胡福生 | A kind of audio frequency amplifier adjunct circuit being applied to cancel emitter-base bandgap grading output stage |
| CN107395142A (en) * | 2017-07-06 | 2017-11-24 | 李凤朝 | A kind of power amplification circuit |
| CN109104671A (en) * | 2018-08-24 | 2018-12-28 | 林汉民 | A kind of sound equipment power amplifier output-stage circuit |
| CN109104671B (en) * | 2018-08-24 | 2020-11-20 | 林汉民 | Output stage circuit of sound power amplifier |
| CN110855252A (en) * | 2019-11-20 | 2020-02-28 | 许昌开普检测研究院股份有限公司 | Current expansion circuit of power operational amplifier |
| CN110855252B (en) * | 2019-11-20 | 2023-07-14 | 许昌开普检测研究院股份有限公司 | Current spreading circuit of power operational amplifier |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20071107 |