CN206237367U - A kind of A genus audio power amplifiers based on advanced servo-actuated biasing - Google Patents
A kind of A genus audio power amplifiers based on advanced servo-actuated biasing Download PDFInfo
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- CN206237367U CN206237367U CN201620938590.7U CN201620938590U CN206237367U CN 206237367 U CN206237367 U CN 206237367U CN 201620938590 U CN201620938590 U CN 201620938590U CN 206237367 U CN206237367 U CN 206237367U
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Abstract
A kind of A genus audio power amplifiers based on advanced servo-actuated biasing, including voltage or current biasing circuit, full-wave rectifying circuit, amplitude holding circuit, change-over circuit and Audio power amplifier output circuit, Audio power amplifier output circuit receives audio signal and the advanced AC bias control signal for producing control voltage or current biasing circuit, voltage or current biasing circuit provide bias voltage or bias current for Audio power amplifier output circuit, Audio power amplifier output circuit is received needs the audio amplified to believe after delay circuit time delay into Audio power amplifier output circuit；Audio signal is by producing advanced servo-actuated bias control signal and being input into from the control signal input of voltage or current biasing circuit, the output for controlling its bias voltage or bias current after processing of circuit.The utility model reduces biasing to realize reducing power consumption in good time.
Description
Technical field
The utility model is related to Audio power amplifier field, and in particular to a kind of A genus audio power amplifiers it is advanced with
Dynamic biasing means and the A genus audio power amplifiers using the method.
Background technology
At present, with the development of multimedia technology, home audio power amplifier, power professional audio amplifier, automobile
Sound system audio power amplifier, portable multimedia apparatus audio-frequency power amplifier all developing rapidly, can be divided into A, B, AB,
The types such as D, G, H.
Wherein, B genus audio power amplifiers, power amplification efferent duct has the time of half to be in the whole signal period
Cut-off, although theoretic efficiency has serious intermodulation distortion up to 78.5%, and playback sound is very bad；AB
Genus audio power amplifier, power amplification efferent duct is full conducting in middle small-signal, is worked in the way of A classes, is being believed greatly
Number when be half conducting, efficiency is up to more than 50%, and good design, playback sound is pretty good, is to use most types at present, but
Intermodulation distortion problem is still present, high frequency distortion is linearly not good enough also than larger；D-type audio power amplifier, is with the side of switch
Formula work, efficiency high is up to more than 90%, but tonequality is bad, is used in less demanding tonequality, pursuit efficiency, the field of compact
Close；G classes and H genus audio power amplifiers, are worked in the way of A classes, AB classes, and efficiency is improved by Switching power voltage, effect
Rate is more than more than 50%, but circuit is complicated, relatively costly, and easily produces dynamic distortion.
And A genus audio power amplifiers, power amplification efferent duct is continuously turned in the whole signal period, does not have friendship to get over
Distortion, static distortion and dynamic distortion all very littles, linearly very good, the music that can best reset is with guarantee tonequality, sense of hearing
Best.Generally, in order to occur without amplitude limit, the static working current of A class power amplification efferent ducts is chosen to be maximum defeated
Go out the 50% of electric current, this to analog circuit in it is linear most beneficial, but no matter need to amplify either with or without audio signal input, phase
When the twice in rated power has all consumed the cooling system, it is necessary to too fat to move to silent.In A class audio frequency power amplifications
In device, the efficiency of simplest Single-end output circuit is 12.5%, and the efficiency of totem pole has 50%, and this needs to continue
Sine wave total power output and load impedance optimize can be only achieved.But, the peak value of music signal, i.e. audio signal with it is flat
What average ratio always changed, signal is also frequent asymmetric, efficiency in actual applications, always very low compared with theoretical value
, 1/4~1/5 appearance is generally obtained, for example, the efficiency of Single-end output circuit is 2.5% in practice, push-pull type is defeated
The efficiency for going out circuit is 10% or so.So, typical A genus audio power amplifiers have that many caloric values of power consumption are big, weight
Big price fatal defects high, except some should in the not discounted recording studio of the high-fidelity music center and minority of a few high-end
Beyond, other applications seldom, are even more difficult to popularize.
Because A genus audio power amplifiers have the generally acknowledged good pleasing to the ear sense of tonequality, and structure is relatively easy, so much
The designer of audio-frequency power amplifier is constantly directed to A genus audio power amplifiers, is carried out with tonequality is improved around efficiency is improved
Some design compromises, it is desirable to obtain more performance in a balanced way.It is common to have slip biasing, dynamic bias, in real time biasing, lasting height
The form such as biasing or super A classes, these form ingenuity are original, but generally existing improves problem coarse, that improvement is limited, especially
It is to set up these biasings and adjustment voltage or electric current to take more time, hence it is evident that lag behind input signal, generate more
Distortion, lose the good pleasing to the ear sense of tonequality of real A genus audio power amplifiers, be more also size and the biasing of biasing
Duration is improper, and efficiency improves unobvious.
Utility model content
Technical problem to be solved in the utility model is to provide a kind of A class audio frequency power based on advanced servo-actuated biasing and puts
Big device, it can not only be readily apparent that to improve the operating efficiency of A genus audio power amplifiers, and can give full play to audio
The advantage of power amplifier, i.e. distortion very little, linear fine, sense of hearing are optimal, are fully ensuring that amplifier in A class working conditions
On the premise of, the quiescent current of power amplification output circuit is reduced in time to reduce biasing, to realize reducing power consumption.
The utility model is adopted the following technical scheme that：
A kind of A genus audio power amplifiers based on advanced servo-actuated biasing described in the utility model, including voltage or electricity
Stream biasing circuit, full-wave rectifying circuit, amplitude holding circuit, change-over circuit and Audio power amplifier output circuit, the audio
Power amplification output circuit be used for receive need amplify audio signal corresponding to simulated audio signal, and it is described need amplify
Audio signal corresponding to simulated audio signal be used to produce the advanced AC bias of control voltage or current biasing circuit
Control signal, the voltage or current biasing circuit provide bias voltage or bias current for Audio power amplifier output circuit,
The amplifier also includes delay circuit, and Audio power amplifier output circuit is received and needs the audio amplified letter to prolong described in
When circuit delay after enter Audio power amplifier output circuit；The corresponding simulated audio signal of the audio letter for needing to amplify
By producing servo-actuated bias control signal in advance after full-wave rectifying circuit, amplitude holding circuit and bias voltage change-over circuit, surpass
Simultaneously control voltage or electric current are inclined from the control signal input input of voltage or current biasing circuit for preceding servo-actuated bias control signal
The output of the bias voltage or bias current of circuits；The full-wave rectifying circuit is used for advanced AC bias control signal
Full-wave rectification is carried out, the absolute value of bias control signal is obtained, advanced pulsation bias control signal is formed；Described amplitude keeps
Circuit ensures that power amplification circuit works in A class working conditions for generation, when the advanced arteries and veins for being input into the amplitude holding circuit
The amplitude of dynamic bias control signal is relative to become hour, and amplitude holding circuit delays the advanced servo-actuated slow drop that amplitude holding circuit is exported
The magnitude of voltage of bias control signal declines, and becomes when the amplitude of the advanced servo-actuated bias control signal of input amplitude holding circuit is relative
When big, the magnitude of voltage moment of the advanced servo-actuated slow drop bias control signal of amplitude holding circuit output rises；Described biased electrical
Voltage conversion circuit is used to carry out pulsation bias control signal with phase and anti-phase conversion and adjust amplitude, is allowed to be converted into amplitude
It is adapted to the bias control signal servo-actuated in advance of voltage or current biasing circuit needs.
The utility model can take following technical measures to realize the further optimization of the amplifier：
The amplitude holding circuit is made up of electric capacity C24, resistance R29 and operational amplifier U7A, and its input with it is complete
Ripple rectification circuit is connected, and output end is connected with change-over circuit；Wherein electric capacity is used to keep the voltage of input not decline, and resistance is used for
Release electric energy.
The amplifier includes Audio Buffer amplifying circuit, digital volume regulation circuit and audio voltage amplifying circuit, institute
Audio Buffer amplifying circuit is stated for carrying out impedance matching and voltage amplification, institute to the simulated audio signal after delay circuit time delay
Stating digital volume regulation circuit is used to that the simulated audio signal after the treatment of Audio Buffer amplifying circuit listen to the tune of volume
Section, the audio voltage amplifying circuit is put for carrying out voltage to the simulated audio signal after digital volume regulation processing of circuit
Greatly, the simulated audio signal after voltage amplification as Audio power amplifier output circuit input signal.
It is analog signal to need the audio signal amplified, and delay circuit is digital audio and video signals delay circuit and is put described
Analog to digital conversion circuit and D/A converting circuit 104,106, the simulation letter of audio signal input selection circuit output are set in big device
Number by forming digital audio and video signals after analog to digital conversion circuit conversion, the digital audio and video signals warp of analog-digital conversion circuit as described output
Advanced AC bias control signal is formed after crossing D/A converting circuit treatment, meanwhile, the number of analog-digital conversion circuit as described output
Word audio signal forms simulated audio signal simultaneously after being changed through the time delay of digital audio and video signals delay circuit and through D/A converting circuit
As the input signal of Audio power amplifier output circuit.
The audio signal for needing the audio signal amplified can also be data signal, and delay circuit prolongs for digital audio and video signals
When circuit.
Compared with prior art, the utility model has the advantages that：
After selection needs the audio signal amplified, the utility model enters the selected audio signal for needing to amplify
The appropriate transmission delay of row obtains the audio signal of time delay, while directly by the selected audio signal for needing to amplify (i.e. not
Through the audio signal of transmission delay) as AC bias control signal；Then, the audio signal of time delay is put by buffering, voltage
After the treatment such as big, being finally transferred to power amplification output circuit carries out power amplification；And AC bias control signal is whole through all-wave
The treatment of the circuits such as stream, amplitude holding and conversion, required for the power amplification output circuit of acquisition A genus audio power amplifiers
Bias voltage or bias current.
Wherein, bias control signal, bias voltage or bias current are advanced compared with the audio signal through time delay
, advanced bias control signal, advanced bias voltage or advanced bias current can be referred to as；Meanwhile, biasing control
The source of signal is exactly audio signal, the audio signal with time delay, i.e., through the audio signal of power amplification be afterwards most corresponding, and
And be each sound channel signal be it is corresponding, so the amplitude of bias voltage or bias current be with time delay audio believe
Number amplitude change according to certain ratio, be servo-actuated, through conventional circuit design, bias voltage can be caused completely
Or the amplitude of bias current meet the audio signal of corresponding time delay needed for A class working conditions requirement.Therefore, it can claim this
The bias voltage or bias current of sample are servo-actuated bias voltage or in advance servo-actuated bias current in advance, can claim such biasing side
Formula is advanced servo-actuated bias mode.
AC bias control signal enters amplitude holding circuit, amplitude after obtaining pulsation bias control signal through full-wave rectification
Holding circuit has delayed the slow drop bias control signal of advanced pulsation by the voltage holding effect of electric capacity and the discharge process of resistance
Voltage decline, if at this time there is the lower pulsation bias control signal of amplitude, i.e. musical sound is smaller, due to all-wave
The unilateral diode of rectification circuit can only be to be unable to resorption electric current to amplitude holding circuit submitting electric current to next stage circuit, this
Lower pulsation bias control signal immediately cannot drag down amplitude above high, guarantee big signal reliability above
Ground continues to complete power amplification in the state of A classes, only waits until that the bias control signal of amplitude is slow and is even lower, that is, delay and drop to
After bias control signal less than above-mentioned low amplitude value, the bias control signal of low amplitude value controls letter with the biasing of original amplitude
Number to compare and just uprise, amplitude holding circuit could be entered and the amplitude of oneself is formed；If at this time there is higher magnitude
Bias control signal, i.e., musical sound is larger, it becomes possible to immediately enters amplitude holding circuit and draws high amplitude and form new
Amplitude, and holding is that hold-off voltage declines, guaranteeing new big signal has advanced and enough big amount of bias to enter A classes
State.It can be seen that amplitude holding circuit can allow amplitude higher to keep i.e. hold-off voltage to decline all the time, that is never allow big
The biasing amplitude of signal is not enough and offset time is not enough, and the amplitude of the bias control signal of big signal obtains certain time delay,
It is advanced plus bias control signal, offset time in advance will not be delayed, and suitably continue for some times, this is allowed for
The amplitude size and time width of bias voltage or bias current are fully able to ensure that corresponding audio signal is reliably operated in
In the range of its A class working conditions.
The oscillogram obtained with double track digital oscilloscopes, is that a kind of advanced servo-actuated biasing A class earphone power of embodiment 3 is put
The oscillogram of drop bias control signal and the simulated audio signal of time delay is delayed in advanced pulsation during big device normal work, can from figure
To see, the simulated audio signal advanced several milliseconds of times that the advanced slow drop bias control signal of pulsation always correspond to time delay are servo-actuated
Ground provides bias control signal for power amplification output circuit, can ensure to provide enough biasings for all of audio signal,
Also biasing can in time be reduced and reducing the quiescent current of power amplification output circuit reduces power consumption.It can be seen that, the utility model
The checking of side circuit is obtained.
Specific advantage of the present utility model is：
First, by the transmission delay of the audio signal to needing to amplify, and to the suitable treatments of bias control signal, make
The amplitude size and time width for obtaining bias voltage or bias current are fully able to ensure that corresponding audio signal reliably works
In the range of its A class working conditions, it is fully able to allow power amplification output circuit correspondence just to believe in the audio of power amplification
Number, A class working conditions truly in advance, are reliably operated in, thoroughly overcome the next distortion of common variable bias hysteresis band and ask
Topic.So, audio-frequency power amplifier of the present utility model is real A genus audio power amplifiers, can give full play to A assonances
The optimal advantage of frequency power amplifier distortion very little, linear fine, sense of hearing.
2nd, the sound amplified the need for the audio signal that needs are videlicet amplified in the source of bias control signal, with time delay
Frequency signal, that is, the audio signal for eventually passing power amplification is corresponding, and be each sound channel signal be it is corresponding,
So the amplitude of bias voltage or bias current is as the amplitude of the audio signal of time delay changes according to certain ratio,
It is servo-actuated, has music just to have biasing, the very low bias state of conducting is held only in during without music, so, A class audio frequency work(
The quiescent bias current of rate amplifier is used in audio amplification, is not wasted；According to the servo-actuated of bias control signal
Feature, i.e., loud then big biasing, the then small biasing of small sound, noiseless then extremely low biasing, and during people's listening music under normal circumstances not
Big volume can be listened, and also has pause between program, music is even more size power and constantly varies, the peak value of audio signal
With average value than what is always changed, signal is also often asymmetric, and these situations are compared with existing A power-like amplifiers
Compared with, electricity consumption seldom, can save much more electric energy when the small sound of music or no music, and no longer as existing A classes power is put
Like that, in order to occur without amplitude limit is chosen to be the static working current of efferent duct maximum output current 50%, one one-tenth is not or not big device
Consuming electricity wastes electricity with becoming.So, the node measure that audio-frequency power amplifier of the present utility model is used is highly effective, effect
The raising of rate is obvious.
Brief description of the drawings
The circuit block diagram of the embodiment 1 of Fig. 1 A genus audio power amplifiers of the present utility model；
The circuit block diagram of the embodiment 2 of Fig. 2 A genus audio power amplifiers of the present utility model；
The embodiment 3 of Fig. 3 A genus audio power amplifiers of the present utility model circuit theory diagrams Part I (including：Number
Word tone frequency signal delay circuit, bias control signal D/A converting circuit, audio signal D/A converting circuit)；
The embodiment 3 of Fig. 4 A genus audio power amplifiers of the present utility model circuit theory diagrams Part II (including：Number
Word volume control circuit, voltage amplifier circuit, full-wave rectifying circuit, amplitude holding circuit, change-over circuit, current biasing circuit,
Power output circuit)；
Specific embodiment
Embodiment 1
Referring to Fig. 1, a kind of A genus audio power amplifiers, using biasing means servo-actuated in advance described in the utility model, its
Including：Audio signal input selection circuit 101, D/A converting circuit 102, S/PDIF receiving circuits 110, IIS input selection electricity
Road 103, audio signal delay circuit 108, bias control signal D/A converting circuit 104, audio signal D/A converting circuit
106, Audio Buffer/amplifying circuit 105, digital volume regulation circuit 107, audio voltage amplifying circuit 109, full-wave rectifying circuit
115, amplitude holding circuit 114, change-over circuit 113, voltage or current biasing circuit 112, A class audio frequency power amplification output circuits
111；Other compositions of the A genus audio power amplifier unrelated with the utility model, for example：Power supply circuit, display circuit,
Control circuit, audio effect processing, protection circuit etc., just do not repeat herein.
The function of each several part circuit or effect are as follows respectively：
Audio signal input selection circuit 101, for selecting the audio signal to be listened to；
Analog to digital conversion circuit 102, for selected simulated audio signal to be changed, becomes corresponding DAB letter
Number, to carry out digital delay；
S/PDIF receiving circuits 110, for receiving the digital audio and video signals of S/PDIF forms, and are converted to IIS forms
Digital audio and video signals；
IIS input selection circuits 103, for selecting the IIS as obtained by simulated audio signal through analog to digital conversion circuit conversion
Digital audio and video signals, or selection IIS digital audio and video signals as obtained by S/PDIF is received；
Audio signal delay circuit 108, the transmission for postponing digital audio and video signals, so as to bias voltage or bias current
Power amplification output circuit can be made just can in advance enter A class working conditions before the arrival of corresponding audio signal, keep away
Exempt from biasing delayed；
Bias control signal D/A converting circuit 104, for no-delay digital audio and video signals to be converted into biasing circuit
Required analog signal, that is, be converted into advanced AC bias control signal；It is simultaneously synchronous to DAC cores when volume is listened in regulation
Appropriate decay volume, the i.e. level adjustment of piece operation, makes bias control signal change with the size of audio signal amplitude, from
And obtain suitable servo-actuated biasing；
Audio signal D/A converting circuit 106, for the mould needed for being converted into listening to through the digital audio and video signals of time delay
Intend audio signal, that is, be converted into the simulated audio signal of time delay；
Audio Buffer/amplifying circuit 105, for the impedance matching and voltage amplification of audio signal；
Digital volume adjusts circuit 107, and volume is listened to for adjusting；
Audio voltage amplifying circuit 109, for the voltage amplification of audio signal, is allowed to appropriate power amplification；
Full-wave rectifying circuit 115, for carrying out full-wave rectification to AC bias control signal, obtains bias control signal
Absolute value, forms advanced pulsation bias control signal；
Amplitude holding circuit 114, the amplitude for keeping pulsation bias control signal delays its voltage to decline, and can allow all the time
Amplitude holding higher be hold-off voltage decline, that is never allow big signal biasing amplitude not enough and offset time not
Foot, the amplitude of bias control signal obtains certain time delay, and it is advanced to add bias control signal, and offset time is in advance not
Can be delayed, and some times are suitably continue for, this allows for the amplitude size and time width of bias voltage or bias current
It is fully able to ensure that corresponding audio signal is reliably operated in the range of its A class working conditions.
Change-over circuit 113, for pulsation bias control signal to be carried out with phase or anti-phase conversion, or carries out appropriate amplification
Or decay, it is allowed to be converted into the control signal of biasing circuit；
Voltage or current biasing circuit 112, for the offer for power amplification output circuit in advance be servo-actuated bias voltage or
Bias current is servo-actuated in advance, and can guarantee that corresponding audio signal is operated in A class working conditions；
A class audio frequencies power amplification output circuit 111, the power for amplifying audio signal enables to promote loudspeaker
Send that volume is suitable, sound melodious music.
A kind of A genus audio power amplifiers, using biasing means servo-actuated in advance described in the utility model, its work
Principle and process are as follows：
First, the audio input signal for needing to amplify is selected by audio signal input selection circuit 101, if selected
Simulated audio signal, then simulated audio signal enter analog to digital conversion circuit 102, it is converted after obtain corresponding IIS forms
Digital audio and video signals；If selected is digital audio and video signals, receives and be converted to by S/PDIF receiving circuits 110
The digital audio and video signals of IIS forms.
Then, the digital audio and video signals of above-mentioned two-way IIS forms, into IIS input selection circuits 103, the IIS for choosing
The digital audio and video signals of form are divided into two-way, all the way into digital audio and video signals delay circuit 108, carry out appropriate transmission delay
Obtain the digital audio and video signals of the IIS forms of time delay afterwards, the signal enters audio signal D/A converting circuit 106, it is converted after
The simulated audio signal amplified the need for obtaining time delay；Another road is directly entered bias control signal digital-to-analogue without transmission delay
Change-over circuit 104, it is converted after obtain advanced AC bias control signal, while in change-over circuit in transfer process
DAC chip coordinates listens to volume adjusting needs and suitably decays volume to obtain A class audio frequency work(according to the requirement of circuit design
The amplitude of bias voltage or bias current required for the power amplification output circuit of rate amplifier.
Then, the simulated audio signal for amplifying the need for time delay is processed in a conventional manner, respectively enters Audio Buffer/put
Big circuit 105, digital volume regulation circuit 107, audio voltage amplifying circuit 109, finally reach A class audio frequencies power amplification output
Circuit 111 carries out power amplification treatment.
Advanced AC bias control signal, into after full-wave rectifying circuit 115, obtains absolute value, the absolute value be with
Audio signal and change amplitude, then form advanced pulsation bias control signal.Advanced pulsation bias control signal enters
Enter amplitude holding circuit 114, amplitude holding circuit 114 has delayed the voltage of pulsation bias control signal to decline, if at this time
There is the lower pulsation bias control signal of amplitude, i.e. musical sound is smaller, due to the unilateral diode of full-wave rectifying circuit
Can only be to be unable to resorption electric current to amplitude holding circuit submitting electric current to next stage circuit, this lower pulsation biasing control letter
Number amplitude above high cannot be dragged down immediately, the big signal for guaranteeing above has reliably continued in the state of A classes
Success rate is amplified, and is only waited until that amplitude is slow and is even lower, the relative biasing for becoming amplitude of bias control signal of low amplitude value
Control signal, could enter amplitude holding circuit and form the amplitude of oneself；If at this time there is the biasing control of higher magnitude
Signal processed, i.e. musical sound are larger, it becomes possible to immediately enter amplitude holding circuit and draw high amplitude and form new amplitude, and
Holding is that hold-off voltage declines, and guaranteeing new big signal has advanced and enough big amount of bias to enter the state of A classes；It can be seen that
Amplitude holding circuit can allow amplitude higher to keep i.e. hold-off voltage decline all the time, that is never allow the biasing of big signal
Amplitude is not enough and offset time is not enough, and the amplitude of bias control signal obtains certain time delay, and adding bias control signal is
Advanced, offset time in advance will not be delayed, and suitably continue for some times.It is advanced after amplitude holding circuit
The slow drop bias control signal of pulsation, by change-over circuit 113, is carried out the slow drop bias control signal of advanced pulsation with mutually or anti-phase
Conversion, or appropriate amplification or attenuation processing is carried out, the control signal for being converted into voltage or current biasing circuit 112 is allowed to,
So biasing circuit 112 just can provide servo-actuated bias voltage in advance or in advance servo-actuated biased electrical for power amplification output circuit
Stream, allow each audio signal quiescent operation voltage or electric current as the amplitude size of audio signal is suitably biased in A classes
Working condition, amount of bias will not be excessive, and offset time also will not be delayed and extends too many, thoroughly overcomes common adjustable bias stagnant
The problem of dtmf distortion DTMF for bringing afterwards, while the operating efficiency of A genus audio power amplifiers is very high, it is achieved thereby that of the present utility model
Purpose.
Embodiment 2
Referring to Fig. 2, a kind of A genus audio power amplifiers, using biasing means servo-actuated in advance described in the utility model, its
Including：Simulated audio signal input selection circuit 201, volume control circuit 202, branch circuit 204, analog signal delay circuit
205, Audio Buffer circuit 206, audio voltage amplifying circuit 203, full-wave rectifying circuit 207, amplitude holding circuit 208, conversion
Circuit 209, voltage or current biasing circuit 210, A class audio frequencies power amplification output circuit 211；The A unrelated with the utility model
Other of genus audio power amplifier are required to be constituted, for example：At power supply circuit, display circuit, control circuit, audio
Reason, protection circuit etc., just do not repeat herein.
The function of each several part circuit or effect are as follows respectively：
Audio signal input selection circuit 201, for selecting the audio signal to be listened to；
Volume control circuit 202, the size of volume and bias control signal is listened to for adjusting；
Branch circuit 204, for simulated audio signal to be divided into two-way, all the way into after analog signal delay circuit 205
Become the simulated audio signal of time delay, another road turns into advanced AC bias control signal without time delay；
Analog signal delay circuit 205, the transmission for postponing simulated audio signal, so as to bias voltage or bias current
Power amplification output circuit can be made just can in advance enter A class working conditions before the arrival of corresponding audio signal；
Audio Buffer circuit 206, for the impedance matching of audio signal；
Audio voltage amplifying circuit 203, for the voltage amplification of audio signal, is allowed to appropriate power amplification；
Full-wave rectifying circuit 207, for carrying out full-wave rectification to AC bias control signal, obtains bias control signal
Absolute value, forms advanced pulsation bias control signal；
Amplitude holding circuit 208, the amplitude for keeping pulsation bias control signal delays its voltage to decline, and can allow all the time
Amplitude holding higher be hold-off voltage decline, that is never allow big signal biasing amplitude not enough and offset time not
Foot, the amplitude of bias control signal obtains certain time delay, and it is advanced to add bias control signal, and offset time is in advance not
Can be delayed, and some times are suitably continue for, this allows for the amplitude size and time width of bias voltage or bias current
It is fully able to ensure that corresponding audio signal is steadily operated in its confidence band of A class working conditions.
Change-over circuit 209, for pulsation bias control signal to be carried out with phase or anti-phase conversion, or carries out appropriate amplification
Or decay, it is allowed to be converted into the control signal of biasing circuit；
Voltage or current biasing circuit 210, for the offer for power amplification output circuit in advance be servo-actuated bias voltage or
Bias current is servo-actuated in advance, and can guarantee that corresponding audio signal is operated in A class working conditions；
A class audio frequencies power amplification output circuit 211, the power for amplifying audio signal enables to promote loudspeaker
Send that volume is suitable, sound melodious music.
A kind of A genus audio power amplifiers, using biasing means servo-actuated in advance described in the utility model, its work
Principle and process are as follows：
First, the analogue audio frequency input signal for needing to amplify is selected by audio signal input selection circuit 201, then mould
Intend audio signal and enter the regulation listening volume of volume control circuit 202, while being also the size for adjusting bias control signal；Then
Into branch circuit 204, simulated audio signal is divided into two-way, all the way into becoming time delay after analog signal delay circuit 205
The need for amplify simulated audio signal, another road turns into advanced AC bias control signal without time delay.
Then, the simulated audio signal for amplifying the need for time delay is processed in a conventional manner, respectively enters Audio Buffer electricity
Road 206, audio voltage amplifying circuit 203, finally reaching A class audio frequencies power amplification output circuit 211 carries out power amplification treatment.
Advanced AC bias control signal forms advanced pulsation biasing control letter after entering full-wave rectifying circuit 207
Number, advanced pulsation bias control signal enters amplitude holding circuit 208, then by change-over circuit 209, be converted into voltage or
The control signal of current biasing circuit 210, such biasing circuit 210 just can provide advanced servo-actuated for power amplification output circuit
Bias voltage is servo-actuated bias current in advance, it is achieved thereby that the purpose of this utility model.The work of bias control signal treatment
Principle is same as Example 1, not repeated description herein.
Embodiment 3
Referring to Fig. 3 and Fig. 4, a kind of A genus audio power amplifiers, using biasing side servo-actuated in advance described in the utility model
Method, is a simplified function, a kind of advanced servo-actuated biasing A class earphone work(being input into using two-channel IIS digital audio and video signals all the way
Rate amplifier, it includes：Digital audio and video signals delay circuit, bias control signal D/A converting circuit in Fig. 3, audio signal
Digital volume regulation circuit in D/A converting circuit, and Fig. 4, voltage amplifier circuit, full-wave rectifying circuit, amplitude keep electricity
Road, change-over circuit, voltage-controlled current biasing circuit, power output circuit；The A class audio frequency power unrelated with the utility model
Other of amplifier are required to be constituted, for example：Input selection circuit, S/PDIF receiving circuits, analog to digital conversion circuit, power supply supply
Circuit, display circuit, control circuit, audio effect processing, protection circuit etc., just do not repeat herein.
The function of each several part circuit or effect are as follows respectively：
Audio signal delay circuit, the transmission for postponing digital audio and video signals, so that bias current can put power
Big output circuit just can in advance enter A class working conditions before the arrival of corresponding audio signal；
Bias control signal D/A converting circuit, for no-delay digital audio and video signals to be converted into needed for biasing circuit
Analog signal, that is, be converted into advanced AC bias control signal；It is simultaneously synchronous to DAC chip U2 when volume is listened in regulation
Appropriate decay volume, the i.e. volume level of operation, makes bias control signal change with the size of audio signal amplitude, so that
Suitably it is servo-actuated bias current；
Audio signal D/A converting circuit, for the analog audio needed for being converted into listening to through the digital audio and video signals of time delay
Frequency signal, that is, be converted into the simulated audio signal of time delay；
Audio Buffer/amplifying circuit, for the impedance matching and voltage amplification of audio signal；
Digital volume adjusts circuit, and volume is listened to for adjusting, meanwhile, can be easily using digital volume regulative mode
The amplitude of linkage regulation bias control signal, enables bias control signal to be more accurately controlled biasing circuit；
Audio voltage amplifying circuit, for the voltage amplification of audio signal, is allowed to appropriate power amplification；
Full-wave rectifying circuit, for carrying out full-wave rectification to AC bias control signal, obtains the exhausted of bias control signal
To value, advanced pulsation bias control signal is formed；
Amplitude holding circuit, the amplitude for keeping pulsation bias control signal delays its voltage to decline, and can allow all the time more
Amplitude holding high be hold-off voltage decline, that is never allow big signal biasing amplitude not enough and offset time not
Foot, the amplitude of bias control signal obtains certain time delay, and it is advanced to add bias control signal, and offset time is in advance not
Can be delayed, and some times are suitably continue for, this amplitude size and time width for allowing for bias current are fully able to protect
Corresponding audio signal is demonstrate,proved reliably to be operated in the range of its A class working conditions；
Change-over circuit, for pulsation bias control signal to be carried out, with phase and anti-phase conversion, to be allowed to be converted into biased electrical
The voltage control signal on road；
Current biasing circuit, for the offer for power amplification output circuit in advance be servo-actuated bias current, and can guarantee that it is right
The audio signal amplified the need for answering is operated in A class working conditions；
A class audio frequency power amplification output circuits, the power for amplifying audio signal enables to promote loudspeaker to send
Volume is suitable, sound melodious music.
A kind of A genus audio power amplifiers, are simplified using biasing means servo-actuated in advance described in the utility model
Function, a kind of advanced servo-actuated biasing A class earphone power amplifiers being input into using two-channel IIS digital audio and video signals all the way,
Its operation principle and process are as follows：
First, the digital audio and video signals of IIS forms are divided into two-way, all the way into the time delay of digital audio and video signals delay circuit
Chip U1, U1 can select the digital audio and video signals delay chip of the TPA5051 models of TI companies, and the setting of amount of delay is by monolithic
Machine is configured by IIC ports to delay chip, the DAB letter of the IIS forms by obtaining time delay after transmission delay
Number, the signal enters the DAC chip U3 of audio signal D/A converting circuit, converted followed by be carried out by operational amplifier U5
LPF (LPF) obtains the simulated audio signal of time delay；Another road is directly entered bias control signal without transmission delay
The DAC chip U2 of D/A converting circuit, it is converted followed by have carried out LPF (LPF) by operational amplifier U4 and surpassed
Preceding AC bias control signal, while U2 coordinates listening volume adjusting needs and wanting according to circuit design in transfer process
Appropriate decay volume is sought so as to the width of the bias current required for the power amplification output circuit for obtaining A genus audio power amplifiers
Value.
After the simulated audio signal amplified the need for time delay is through volume adjusting, into voltage amplifier circuit, by operation amplifier
Device U10 is amplified, and is allowed to appropriate power amplification；Finally, the simulated audio signal of time delay is exported into the power amplification of A class audio frequencies
Circuit, exports suitable power and promotes earphone.
The amplitude of advanced AC bias control signal can be adjusted and obtained by DAC chip U2, can be according to time delay
Simulated audio signal total volume and biasing circuit be actually needed between relation, DAC chip U2 is decayed to required number
Value.
Advanced AC bias control signal enters the signal full-wave rectifying circuit being made up of operational amplifier U6 and is surpassed
Preceding pulsation bias control signal, then advanced pulsation bias control signal is electric by the amplitude holding being made up of C24, R29 and U7A
Road, has delayed the voltage of pulsation bias control signal to decline so that the amplitude size and time of bias voltage or bias current are wide
Degree is fully able to ensure that corresponding audio signal is reliably operated in the range of its A class working conditions.Simultaneously by U7A to inclined
Put control signal to be amplified, be allowed to suitable control electric current biasing；And D5 is used to clamp down on minimum bias voltage, it is ensured that power amplification
Output circuit will not end in no signal and small-signal.
U8A, U9A, Q1, R32, R33 constitute signaling conversion circuit, the pulsation bias control signal transformation for changing with being based on
It is the voltage signal based on positive supply change, for producing positive voltage bias control signal；U8B, U9C, Q2, R34, R35 are constituted
Signaling conversion circuit, the pulsation bias control signal for changing with being based on is changed into the voltage signal based on negative supply change, uses
In generation negative voltage bias control signal.U9B, Q3, R36, R37 constitute voltage-controlled positive current biasing circuit, U9D, Q6,
R38, R39 constitute voltage-controlled negative current biasing circuit；U10 constitutes voltage amplifier circuit, and audio signal is amplified to properly
Voltage amplitude；Q4, Q5, R48, R37, R38 constitute pushing grade circuit, for final power amplification output circuit provides audio signal
Promote；Q7, Q8, R49, R50 constitute power output stage, so far complete Audio power amplifier.
So biasing circuit just can provide servo-actuated bias current in advance for power amplification output circuit, can allow each
The quiescent operation voltage or electric current of audio signal are suitably biased in A class working conditions with the amplitude size of audio signal, partially
The amount of putting will not be excessive, and offset time also will not be delayed and extends too many, thoroughly overcomes the mistake that common variable bias hysteresis band comes
True problem, while the operating efficiency of A genus audio power amplifiers is very high, it is achieved thereby that the purpose of this utility model.
A kind of advanced servo-actuated biasing A class earphone power amplifiers, have designed and have trial-produceed successfully model machine described in embodiment 3,
Its actual working condition is fully achieved design requirement.
The audio signal of time delay and the quiescent current of power amplification output circuit, the pass of output current are tested with simulation software
System, the sine wave that the 1KHz of 0.0V, 0.5V, 1.0V, 2.0V, 6.0V peak value is input into respectively is tested, and is obtained data below and (is included
In number is average value)：
| Input numerical value (V) | Quiescent current (mA) is just | Quiescent current (mA) is born | Output current (mA) |
| 0.000(0.000) | 2.650 | -2.682 | 0.000(0.000) |
| 0.500(0.354) | 11.635 | -11.698 | 8.418(5.953) |
| 1.000(0.707) | 25.473 | -25.607 | 15.970(11.294) |
| 2.000(1.414) | 57.628 | -57.929 | 32.070(22.680) |
| 6.000(4.243) | 192.460 | -193.268 | 96.146(67.996) |
It can be seen that, by the bias current that advanced servo-actuated bias control signal is controlled, accordingly change with audio signal completely,
Rather than as typical A power-like amplifiers, the static working current of efferent duct is chosen to be most in order to occur without amplitude limit
The 50% of big output current, so as to reach the effect of power saving.
The oscillogram obtained with double track digital oscilloscopes, is that a kind of advanced servo-actuated biasing A class earphone power of embodiment 3 is put
The oscillogram of drop bias control signal and the simulated audio signal of time delay is delayed in advanced pulsation during big device normal work, can from figure
To see, the simulated audio signal advanced several milliseconds of times that the advanced slow drop bias control signal of pulsation always correspond to time delay are servo-actuated
Ground provides bias control signal for power amplification output circuit, can ensure to provide enough biasings for all of audio signal,
Also biasing can in time be reduced and reducing the quiescent current of power amplification output circuit reduces power consumption.It can be seen that, the utility model
The checking of side circuit is obtained.
The actual a kind of advanced servo-actuated biasing A class earphone power amplifiers for listening to embodiment 3, use thousand yuan of left sides of AKG brands
Right headphone listens to audio, and the fine dynamics of low frequency dive is powerful and resilient enough, intermediate frequency it is warm it is resistance to listen, high frequency is clear
Melodious be transferred to very big continuously listening sings vigorous dance with wild joy more than half an hour to overall sense of hearing very well, volume without at all crude, and ear is not yet
Can feel sick and be not suitable with.These senses of hearing comply fully with the performance of A genus audio power amplifiers.
We conducted power consumption test：
Supply voltage is ± 18V, and it is 6V to set not amplitude limit output voltage, connects the loudspeaker of 8 Ω, and peak power output is
4.5W, if the static working current of efferent duct is set as most in order to occur without amplitude limit according to existing A power-like amplifiers
The 50% of big output current,
The static working current of monophonic is：6V/8 Ω * 50%=0.375A,
It is to calculate simple consumption without the monaural power for amplifying music：(18+18) V*0.375A=13.5W
So continuously the electric quantity consumption of 5 hour two-channels of start is：13.5W*5H*2=135WH
In order to carry out analogy, it is 6V that the volume of the amplifier of embodiment 3 is set to output voltage, connects the loudspeaker of 8 Ω, even
Continued broadcasting is put the music on 5 hours, measures electric quantity consumption for 22WH, and the power consumption of advanced servo-actuated bias mode is about existing A classes biasing
The 16% of mode, power consumption is lower if volume is turned down, it is seen that power saving effect is extraordinary.
Related, example should be corresponded to by between the audio signal and the bias control signal without transmission delay of transmission delay
Such as, the regulation of volume must be related, and the treatment of audio must could only in this way be obtained before AC bias control signal is separated
To the servo-actuated bias voltage or servo-actuated bias current that more match, allow these bias voltages or bias current correspondence audio signal and
Speech size is suitable, allow each audio signal quiescent operation voltage or electric current as the amplitude size of audio signal is suitable
Be biased in A class working conditions, amount of bias will not be excessive, offset time also will not delayed and extension it is too many.
It is corresponding between the audio signal and the AC bias control signal without any transmission delay through time delay is ensured
On the premise of correlation, the burble point of AC bias control signal and the point of adjustment of listening volume can be according to design requirements neatly
Each node selection in audio signal link, without the burble point being confined to described in above-mentioned burble point and embodiment.
Through the above way, the utility model provides a kind of A genus audio power amplifiers based on advanced servo-actuated biasing,
The optimal advantage of A genus audio power amplifier distortions very little, linear fine, sense of hearing can be given full play to, while can be very bright
The operating efficiency of A genus audio power amplifiers is improved aobviously.Above by reference to having illustrated various preferred realities of the present utility model
Example is applied, but without departing from spirit and scope of the present utility model, those skilled in the art can carry out various to it
Formal modifications and changes, belong to protection domain of the present utility model.
Claims (5)
1. a kind of based on the advanced servo-actuated A genus audio power amplifiers for biasing, including voltage or current biasing circuit（112）, it is complete
Ripple rectification circuit（115）, amplitude holding circuit（114）, change-over circuit（113）With Audio power amplifier output circuit（111）, institute
State Audio power amplifier output circuit（111）For receiving the simulated audio signal corresponding to the audio signal for needing to amplify, and
Simulated audio signal corresponding to the audio signal for needing to amplify is used to produce control voltage or current biasing circuit（112）
Advanced AC bias control signal, the voltage or current biasing circuit（112）It is Audio power amplifier output circuit
（111）There is provided bias voltage or bias current, it is characterised in that the amplifier also includes delay circuit（108）, and audio work(
Rate amplification output circuit（111）Receiving needs the audio amplified to believe through the delay circuit（108）Enter audio work(after time delay
Rate amplification output circuit（111）；It is described to need the corresponding simulated audio signal of the audio amplified letter by full-wave rectifying circuit
（115）, amplitude holding circuit（114）And bias voltage change-over circuit（113）Servo-actuated bias control signal in advance is produced afterwards, in advance
It is servo-actuated bias control signal from voltage or current biasing circuit（112）Control signal input input and control voltage or electric current
Biasing circuit（112）Bias voltage or bias current output；The full-wave rectifying circuit（115）For to advanced exchange
Bias control signal carries out full-wave rectification, obtains the absolute value of bias control signal, forms advanced pulsation bias control signal；Institute
The amplitude holding circuit stated（114）Ensure that power amplification circuit works in A class working conditions for producing, when the input amplitude
Holding circuit（114）The amplitude of advanced pulsation bias control signal relative become hour, amplitude holding circuit（114）Delay amplitude
The magnitude of voltage of the advanced servo-actuated slow drop bias control signal of holding circuit output declines, when input amplitude holding circuit（114）'s
When the relative change of amplitude of advanced servo-actuated bias control signal is big, biasing control letter drops in the advanced servo-actuated slow of amplitude holding circuit output
Number magnitude of voltage moment rise；Described bias voltage change-over circuit is used to carry out pulsation bias control signal with mutually and anti-phase
Amplitude is converted and adjusted, is allowed to be converted into the advanced servo-actuated biasing control letter that amplitude is adapted to voltage or current biasing circuit needs
Number.
2. it is according to claim 1 based on the advanced servo-actuated A genus audio power amplifiers for biasing, it is characterised in that described
Amplitude holding circuit（114）It is made up of electric capacity C24, resistance R29 and operational amplifier U7A, and its input and full-wave rectification
Circuit（115）Connection, output end and change-over circuit（113）Connection；Wherein electric capacity C24 is used to keep the voltage of input not decline,
Resistance R29 is used to discharge electric energy.
3. it is according to claim 1 based on the advanced servo-actuated A genus audio power amplifiers for biasing, it is characterised in that described
Amplifier includes Audio Buffer amplifying circuit（105）, digital volume regulation circuit（107）With audio voltage amplifying circuit（109）,
The Audio Buffer amplifying circuit（105）For to delay circuit（108）Simulated audio signal after time delay carries out impedance matching
And voltage amplification, the digital volume regulation circuit（107）For to Audio Buffer amplifying circuit（105）Analog audio after treatment
Frequency signal listen to the regulation of volume, the audio voltage amplifying circuit（109）For adjusting circuit to digital volume（107）
Simulated audio signal after treatment carries out voltage amplification, and the simulated audio signal after voltage amplification is exported as Audio power amplifier
Circuit（111）Input signal.
4. it is according to claim 1 based on the advanced servo-actuated A genus audio power amplifiers for biasing, it is characterised in that to need
The audio signal of amplification is analog signal, delay circuit（108）For digital audio and video signals delay circuit and in the amplifier
Analog to digital conversion circuit is set（102）And D/A converting circuit（104、106）, audio signal input selection circuit（101）Output
Analog signal is by analog to digital conversion circuit（102）Digital audio and video signals, analog-digital conversion circuit as described are formed after conversion（102）Output
Digital audio and video signals by D/A converting circuit（104）Advanced AC bias control signal is formed after treatment, meanwhile, it is described
Analog to digital conversion circuit（102）The digital audio and video signals of output are through the time delay of digital audio and video signals delay circuit and through D/A converting circuit
（106）Simulated audio signal is formed after conversion and as Audio power amplifier output circuit（111）Input signal.
5. it is according to claim 1 based on the advanced servo-actuated A genus audio power amplifiers for biasing, it is characterised in that to need
The audio signal of amplification is data signal, delay circuit（108）It is digital audio and video signals delay circuit.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116566338A (en) * | 2023-04-27 | 2023-08-08 | 先歌国际影音股份有限公司 | Audio amplifying circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116566338A (en) * | 2023-04-27 | 2023-08-08 | 先歌国际影音股份有限公司 | Audio amplifying circuit |
| CN116566338B (en) * | 2023-04-27 | 2024-02-09 | 先歌国际影音股份有限公司 | Audio amplifying circuit |
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