CN105978510A - Power amplifier and input signal adjusting method - Google Patents
Power amplifier and input signal adjusting method Download PDFInfo
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- CN105978510A CN105978510A CN201610140446.3A CN201610140446A CN105978510A CN 105978510 A CN105978510 A CN 105978510A CN 201610140446 A CN201610140446 A CN 201610140446A CN 105978510 A CN105978510 A CN 105978510A
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- 230000001105 regulatory effect Effects 0.000 claims description 9
- 238000004088 simulation Methods 0.000 claims description 9
- 239000011800 void material Substances 0.000 claims description 3
- 239000003990 capacitor Substances 0.000 description 15
- 230000005236 sound signal Effects 0.000 description 12
- 238000001208 nuclear magnetic resonance pulse sequence Methods 0.000 description 8
- 238000005070 sampling Methods 0.000 description 7
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- 230000003321 amplification Effects 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
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Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/56—Modifications of input or output impedances, not otherwise provided for
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
- H03F3/217—Class D power amplifiers; Switching amplifiers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/45—Differential amplifiers
- H03F3/45071—Differential amplifiers with semiconductor devices only
- H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
- H03G3/3005—Automatic control in amplifiers having semiconductor devices in amplifiers suitable for low-frequencies, e.g. audio amplifiers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/03—Indexing scheme relating to amplifiers the amplifier being designed for audio applications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/351—Pulse width modulation being used in an amplifying circuit
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- Power Engineering (AREA)
- Multimedia (AREA)
- Amplifiers (AREA)
- Circuit For Audible Band Transducer (AREA)
Abstract
A power amplifier and an input signal adjusting method are provided; the power amplifier includes a class-D amplifier and an input signal supplier. The class-D amplifier includes an input portion and a switching device. The switching device is switched according to an input signal that is input to the input portion so that a current is supplied to a load from a power source via the switching device. The input signal supplier supplies the input signal to the input portion of the class-D amplifier, calculates a virtual output voltage to be output from a virtual power source having a prescribed internal impedance characteristic when a current to flow through the load is output from the virtual power source, and adjust an amplitude of the input signal according to the virtual output voltage.
Description
Technical field
It relates to a kind of power amplifier and a kind of input signal control method, and more
More particularly to a kind of power amplifier being suitably used as guitar amplifier.
Background technology
In recent years, the power amplifier of use semiconductor device, such as class-D amplifier, as
Audio-frequency power amplifier has been introduced into being widely used.Such as, in class-D amplifier, output
The level pwm pulse sequence that generated by pulsewidth modulation according to input audio signal of transistor and quilt
On/off switch, and via output stage transistor, electric current is supplied to speaker from power supply.D class
Amplifier can supply power to speaker efficiently, because they output impedances are the lowest,
And therefore the loss of output stage transistor is the lowest.Although more specifically, the impedance of speaker
It is 8 to 16 Ω, but the output impedance of class-D amplifier is approximately equal to 0 Ω.
Additionally, in class-D amplifier, the voltage being imported into speaker is generally fed back to defeated
Enter portion, and control class-D amplifier according to the difference between input audio signal and negative-feedback signal.
Therefore, class-D amplifier be able to carry out wherein corresponding to input audio signal voltage independent of
The constant voltage being supplied to frequency speaker drives.Correlation technique document relates to D class put
The exemplary document of big device is WO2003/090343.
Even if in the today using the power amplifier of semiconductor device to commonly use, vacuum tube is put
Big device is still frequently used as the guitar amplifier of the output signal amplifying electric guitar.This is because
Vacuum tube amplifier allows speaker to send the sound with the preferred quality of player with high volume level
Sound, this is contrary with the power amplifier using semiconductor device.
In the case of using vacuum tube amplifier, reproduced sound quality tool is had a significant impact
Factor is the characteristic of the power source for vacuum tube amplifier.More specifically, put for vacuum tube
Big device, uses and has internal capacitor and the power amplifier of relatively large internal driving.As a result,
Vacuum tube amplifier can provide the big instantaneous maximum power relative to continuous wave peak power,
And allow to the instantaneous sound sending high volume level.Thus, vacuum tube amplifier relies on it
Constant current output characteristics and above-mentioned power source characteristic achieve the reproduction with unique qualities
Sound.
But, vacuum tube amplifier is big and be not easy to process due to their size and weight.Very
Blank pipe amplifier uses output impedance high in output stage and therefore bears lossy in output stage
Pyatyi vacuum tube, which results in them and another of load (speaker) can not be driven efficiently to ask
Topic.
Therefore, in order to drive load efficiently, it is necessary to use class-D amplifier.In this situation
Under, in order to allow class-D amplifier to perform the water identical with the level that vacuum tube amplifier is realized
Flat audio reproduction, it is contemplated that class-D amplifier is used and the power supply for vacuum tube amplifier
The method of identical power supply.But, the power supply for vacuum tube amplifier has ratio for D class
The internal driving value that the power supply of amplifier is bigger.This power supply with high internal driving by with
When class-D amplifier, create class-D amplifier and be difficult to carry out the problem that constant voltage drives,
And therefore class-D amplifier can not be appropriately performed its function.
Summary of the invention
Make the disclosure the most in these cases, and therefore, aiming at of the disclosure carries
For a kind of power amplifier and a kind of input signal control method, enabling do not damaging D class
In the case of the function of amplifier, it is thus achieved that with use except class-D amplifier in addition to, use and D
The amplifier (such as, vacuum tube amplifier) of the power supply that the normally used power supply of class A amplifier A is different
The audio reproduction of the level that the level that obtained is identical.
The disclosure provides a kind of power amplifier, including:
Class-D amplifier, described class-D amplifier includes input unit and switching device, its breaker in middle
Device switches according to the input signal being imported into this input unit, in order to by described switch dress
Put electric current from power supply supply to load；And
Input signal supply, described input signal supply is configured to described input signal
It is supplied to the described input unit of class-D amplifier, calculates from having appointment internal driving characteristic
The virtual output that will export from virtual power supply when virtual power supply output flows through the electric current of described load
Voltage, and the amplitude of described input signal is regulated according to described virtual output voltage.
In the disclosure, according to the void occurred when flowing through the electric current of load from virtual power supply output
Intend the virtual output voltage of power supply, regulate shaking of the input signal to the input unit of class-D amplifier
Width, thus regulates the electric current being supplied to load from class-D amplifier.This makes it possible to do not damaging
In the case of the function of class-D amplifier, it is thus achieved that as by using any various types of virtual electricity
The audio reproduction that the amplifier in source is obtained.
Accompanying drawing explanation
Fig. 1 is the circuit diagram illustrating the configuration according to the power amplifier that embodiment of the disclosure.
Fig. 2 is the circuit diagram of the configuration of the equivalent circuit illustrating the virtual power supply used in embodiment.
Fig. 3 is to illustrate the signal performed by the DSP of the input signal supply used in embodiment
The block diagram of the details processed.
Fig. 4 illustrates the example frequency characteristic of the impedance of full-range speaker.
Fig. 5 A and 5B is shown respectively the frequency of the output voltage of class-D amplifier and vacuum tube amplifier
Rate characteristic.
Fig. 6 compares the output current characteristic of the power amplifier according to embodiment and vacuum tube is put
Big device and the output current characteristic with reference to example power amplifier.
Fig. 7 is the ripple of the example waveform illustrating the supply voltage of vacuum tube amplifier and output signal
Shape figure.
Fig. 8 is the circuit of the configuration of the power amplifier illustrating another embodiment according to the disclosure
Figure.
Detailed description of the invention
Describe below with reference to the accompanying drawings and embodiment of the disclosure.Fig. 1 illustrates according to the disclosure
The circuit diagram of the configuration of the power amplifier of embodiment.In order to promote the reason to power amplifier 1
Solve, also figure 1 illustrates its speaker SP for the load of power amplifier 1.
As shown in fig. 1, power amplifier 1 includes that input signal supply 50, D class are amplified
Device 100, load current feedback circuit 200 and filter current feedback circuit 300.
Input signal supply 50 is in the audio signal being imported into power amplifier 1
AIN upper execution amplitude regulation, and thus by input signal AIN ' it is supplied to class-D amplifier 100
Circuit.Power amplifier 1 according to embodiment is used as electric guitar amplifier, at this
In the case of Zhong, the output signal of electric guitar is supplied to input signal as audio signal AIN and supplies
Answer device 50.The details of input signal supply 50 is described below.
Class-D amplifier 100 include operational amplifier (or comparator block) 110, output stage 120,
Wave filter 130 and feedback resistor 140.
Operational amplifier 110 is used as the defeated of the input signal to its input class-D amplifier 100
Enter the circuit in portion.Input signal AIN ' inputted to operational amplifier from input signal supply 50
The in-phase input terminal of 100.
Output stage 120 includes the transistor 121 as switching device and transistor 122, transistor
Between 121 lead-out terminals 123 being provided at positive supply+B and output stage 120, and crystal
Pipe 122 is provided between the lead-out terminal 123 of negative supply-B and output stage 120.Such as,
Transistor 121 and 122 is MOSFET (mos field effect transistor).?
In output stage 120, according to the output signal of operational amplifier 110, positive supply+B is by connecting
Transistor 121 and disconnection transistor 122 are connected to lead-out terminal 123, or negative supply-B
It is connected to lead-out terminal 123 with connecting transistor 122 by disconnecting transistor 121.Therefore,
The output signal of output stage 120 has square waveform.
Wave filter 130 is to eliminate the output signal from output stage 120 to be in higher than audio section
High fdrequency component in frequency range, and remaining audio section frequency component is supplied to speaker
The low pass filter of SP.Wave filter 130 includes inducer 131 and capacitor 132.Inducer
One terminal (joint of 131 lead-out terminals 123 being provided at output stage 120 and speaker SP
Point 133) between.One end of capacitor 132 is coupled in inducer 131 and speaker SP
Between node 133, and the other end is via the current detecting of filter current feedback circuit 300
Resistor 310 ground connection.It is to say, capacitor 132 is connected in parallel to its raising for load
Sound device SP.
Feedback resistor 140 is provided at node 133 and the anti-phase input of operational amplifier 110
Between terminal, node 133 is between inducer 131 and speaker SP.Feedback resistor 140
It is the output voltage of speaker SP to be fed back to operational amplifier 110 (it is class-D amplifier 100
Input unit), and thus cause class-D amplifier 100 free-running self-oscillation feedback circuit
A part.During to specify self-oscillating frequency vibration, class-D amplifier 100 is based on input signal AIN ',
Pwm pulse sequence is exported from output stage 120 by pulsewidth modulation.Wave filter 130 is used for eliminating
It is in higher than the high fdrequency component in the frequency range of self-oscillating frequency from pwm pulse sequence, and
And consequential signal is supplied to speaker SP.The configuration of class-D amplifier 100 is described in this
Complete.
Load current feedback circuit 200 is that (it will be class-D amplifier for flowing through speaker SP
The load of 100) load current negative feedback to the fortune of the input unit that it is class-D amplifier 100
Calculate the circuit of amplifier 100.Load current feedback circuit 200 include current sensing resistor 210,
Enlarging section 220 and coupling part 230.
Current sensing resistor 210 is provided at the end relative with node 133 of speaker SP
Between son and ground wire.Enlarging section 220 has operational amplifier 221 and resistor 222 and 223.
The reversed input terminal of operational amplifier 221 is via resistor 222 ground connection, and via resistance
Device 223 is connected to the lead-out terminal of operational amplifier 221.Across current sensing resistor 210
Voltage is applied to the non-inverting terminal of operational amplifier 221.Therefore, enlarging section 220 is with gain (Ra
+ Rb)/Ra amplifies across the voltage of current sensing resistor 210 and output result signal, wherein
Ra and Rb is the resistance of resistor 222 and 223 respectively.In an embodiment, due to this
Voltage amplification across current sensing resistor 220 is sufficiently high by enlarging section 220 by mode
Voltage, it is possible to make the resistance of current sensing resistor 210 little.
Coupling part 230 is lead-out terminal and the operational amplifier 110 being provided at enlarging section 220
Inverting terminal between resistor 231 and being connected in series of capacitor 232.Coupling part 230
For being regulated the frequency characteristic of degenerative feedback quantity by load current feedback circuit 220.
Filter current feedback circuit 300 is for flowing through the capacitor 132 of wave filter 130
Current Negative Three-Point Capacitance to the electricity of the operational amplifier 110 of the input unit that it is class-D amplifier 100
Road.Filter current feedback circuit 300 includes current sensing resistor 310 and coupling part 320.
Coupling part 320 is the inverting terminal being provided at operational amplifier 110, with current sense resistor
Resistor 321 between junction point between device 310 and capacitor 132 and capacitor 322
It is connected in series.Coupling part 320 is for regulating negative feedback by filter current feedback circuit 300
The frequency characteristic of feedback quantity.
It follows that input signal supply 50 will be described.Input signal supply 50 is for really
Fixed its is the appointment occurred when flowing through the electric current of speaker SP (load) from virtual power supply output
The virtual output voltage of the output voltage of virtual power supply, and according to determined by virtual output electricity
Pressure regulates input signal AIN of input unit to class-D amplifier 100 ' the circuit of amplitude.
The appointment virtual power supply used in this embodiment is the power supply having and specifying internal driving characteristic；?
In this embodiment, virtual power supply is assumed intentionally for vacuum tube amplifier and have high resistant
Anti-power supply.
The reason of the upstream that input signal supply 50 is provided at class-D amplifier 100 is as follows.
Generally, in vacuum tube amplifier, use has bigger than the internal driving value of D class vacuum tube
The power supply of internal driving value.In the audio reproduction using vacuum tube amplifier, via vacuum
It is the biggest according to the impedance variation of speaker that pipe amplifier flows through the load current of speaker from power supply
The change of degree ground.As a result, load current causes at power source internal and is used as to determine that speaker is again
The big voltage drop of one factor of the unique qualities of existing sound.
A kind of for realizing the sound of quality level as using vacuum tube amplifier to be obtained
The method reproduced will be the electricity using and self having the high internal driving as being used for vacuum tube amplifier
Source, as the power supply of the output stage 120 of class-D amplifier 100.
But, in order to realize grasping in the amplification of fast-changing audio signal with high speed transient response
Making, it is necessary for using the power supply with low internal driving.Have high internal driving, as with
Power supply in vacuum tube amplifier can not realize providing the power amplification of this superelevation transient response.
In view of above-mentioned situation, in this embodiment, such as having for normal class D amplifier
Power supply+the B and-B of little internal driving value are used as the electricity of the output stage 120 of class-D amplifier 100
Source, and internal signal supply 50 is provided at the upstream of class-D amplifier 100, to compensate
Use to power supply+B He-B.
Input signal supply 50 determines that it is and is flowing through speaker SP's from virtual power supply output
The virtual power supply occurred during load current (is the electricity for vacuum tube amplifier in this embodiment
Source) the virtual output voltage of output voltage, and according to determined by output voltage regulation defeated
Enter the amplitude of signal AIN '.For example it is assumed that transistor 121 has be turned on, and load electricity
Stream I flows through speaker SP via transistor 121 from power supply+B.And also assume that when negative
Carry electric current I by when virtual power supply exports, the virtual output voltage of virtual power supply due to
+ α B (0 < α < 1) is become from+B) across the voltage drop of internal driving of virtual power supply
Based on these it is assumed that input signal supply 50 is by being multiplied by α by audio signal AIN,
And amplitude regulation signal the AIN '=α AIN as result is supplied to class-D amplifier 100
Regulate the amplitude of audio signal AIN being imported into power amplifier 1.Adjust by this way
The amplitude of joint input signal makes it possible to achieve and uses the quality water that vacuum tube amplifier is obtained
The audio reproduction of flat identical quality level.
As shown in fig. 1, input signal supply 50 include A/D converter 51, DSP 52,
D/A converter 53, detecting circuit 54 and A/D converter 55.Detecting circuit 54 is to across electric current
The AC electrical voltage full-wave rectification of detection resistor 210, and make it smooth on a timeline, and
Output represents the simulation letter of the amplitude envelope waveform of the AC electric current flowing through current sensing resistor 210
Number.A/D converter 51, D/A converter 53, A/D converter 55 and DSP 52 are with public
Sampling clock φ simultaneously operating.
Even more specifically, A/D converter 55 is by sampling to analogue signal according to sampling clock φ
The analogue signal exported from detecting circuit 54 is converted to digital signal, and exports as knot
The digital signal of fruit.A/D converter 51 is by sampling to audio signal AIN according to sampling clock φ
Digital signal will be converted to from audio signal AIN being imported into power amplifier 1, and
Export the digital signal as result.DSP 52 uses the output of A/D converter 51 and 55 to believe
Number perform and public digital processing Tong Bus for sampling clock φ, and export and believe as the digital of result
Number.D/A converter 53 keeps the output signal with public DSP 52 Tong Bu for sampling clock φ, and
And this output signal is converted to its input signal AIN being analogue signal ', and will be as knot
Input signal AIN of fruit ' export to class-D amplifier.
The Digital Signal Processing that by DSP 52 perform is described below.DSP 52 is by simulation drawing 2
Shown in the operation of equivalent circuit of virtual power supply 56 carry out design factor α (hereinafter described), with
And the output signal of A/D converter 51 is multiplied by factor alpha, and export the signal as result.
In order to promote the understanding of the details to the process that DSP 52 performs, the most not illustrate only void
Intend power supply 56, and be also shown for output stage 120.
As shown in Figure 2, virtual power supply 56 includes internal DC voltage source Vi, inner inductor
L, internal resistor R and internal capacitor C.The minus earth of internal DC voltage source Vi.
The positive pole of internal DC voltage source Vi connects via the series connection of inner inductor L and internal resistor R
Connect high potential power supply terminal (that is, the connected electricity of power supply+B being connected to output stage 120
Source terminal).Internal capacitor C is connected high potential power supply terminal and the ground wire of output stage 120
Between.In the power supply of vacuum tube amplifier, the inductance of inner inductor L is about tens
Henry, the resistance of internal resistor R is about tens ohm, and the electric capacity of internal capacitor C
It is about tens microfarads.These values depend on the type of vacuum tube amplifier.
Use the virtual power supply 56 with above-mentioned configuration, following equations (1) provide it virtual defeated
Go out voltage:
Vo=Vi IZ (1)
Wherein Z is internal inductance L, internal resistance R and the resultant impedance of internal capacitance C, with
And I represents the load current indicated by the output signal of A/D converter 55.
In equation (1), impedance Z and load current I depend on frequency f.Therefore, virtual
The virtual output voltage Vo of power supply 56 also depends on frequency f, and is therefore write as Vo (f).
DSP 52 sample sequence based on the load current I received in the set period in past is true
Frequency characteristic I (f) of fixed load electric current I, and based on determined by the frequency of load current I special
Property I (f) and frequency characteristic Z (f) according to the impedance Z of above-mentioned equation (1) calculate virtual power supply
Frequency characteristic Vo (f) of the virtual output voltage Vo of 56.Then, DSP 52 is by by virtual electricity
Frequency characteristic Vo (f) of the virtual output voltage Vo in source 56 is divided by the supply voltage of output stage 120
+ B carrys out design factor α (f)=Vo (f)/B.
Afterwards, DSP 52 coefficient of utilization α (f) performs letter in the output signal of A/D converter 51
Number process.Fig. 3 is the block diagram of the details of the signal processing being shown with factor alpha (f).Such as Fig. 3
Shown in, by N number of BPFs 501_k (k=1 to N), N number of multiplier 502_k (k=1 to N)
With N number of phase shifter 503_k (k=1 to N), and adder 504 performs the letter of coefficient of utilization α (f)
Number process.
In this embodiment, it is the factor alpha (f) to frequency f continuous print function as it, to from can
(k=1 is extremely to listen that select in frequency range and for signal processing N number of representative frequency fk
N) design factor α (fk) (k=1 to N).BPFs 501_k (k=1 to N) shown in Fig. 3
The mid frequency of passband be respectively set to fk (k=1 to N).BPFs 501_k (k=1 to N)
The signal being in they passbands respectively is selected from the output signal of A/D converter 51, and
And export signals selected.
Multiplier 502_k (k=1 to N) and phase shifter 503_k (k=1 to N) composition are used for will
The output signal of BPFs 501_k (k=1 to N) is multiplied by the dress of factor alpha (fk) (k=1 to N) respectively
Put.Even more specifically, factor alpha (fk) is plural number, and be given by following equations (2):
α (fk)=a (fk) exp (j θ (fk)) (2)
The output signal of BPFs 501_k (k=1 to N) is divided by multiplier 502_k (k=1 to N)
It is not multiplied by the absolute value a (fk) of factor alpha (fk) (k=1 to N), and exports multiplication result.Phase shifter
503_k (k=1 to N) will correspond to the phase shift of argument θ (fk) (k=1 to N) and gives multiplication respectively
The output signal of device 502_k (k=1 to N), and export the signal as result.Adder 504
The output signal of phase shifter 503_k (k=1 to N) is added with together with, and output result signal.
The output signal of adder 504 is carried out D/A conversion by D/A converter 53, and as result
Analogue signal as input signal AIN ' be input to class-D amplifier 100.To according to enforcement
Being described in this and complete of the configuration of the power amplifier 1 of example.
It follows that could be made that the explanation how power amplifier 1 according to embodiment operates.?
In class-D amplifier 100, in output signal device 130 after filtering and the feedback of output stage 120
During resistor 140, this output signal is endowed phase place and rotates, and thus is fed back to computing
Amplifier 110 (input unit).As a result, class-D amplifier 100 self-oscillation.Class-D amplifier 100
Be designed to its self-oscillating frequency sufficiently higher than input signal AIN ' frequency range.
In view of the output signal of output stage 120 is square wave, because square wave is at wave filter 130
Through First-order Integral in (capacitor 132), so the signal waveform at node 133 is triangle.
Operational amplifier 110 is by input signal AIN ' with via feedback resistor 140 at node 133
The triangular wave of feedback compares.As a result, generated by pulsewidth modulation according to input audio signal
Pwm pulse sequence exported from operational amplifier 110, and then via output stage 120
It is input to wave filter 130.From pwm pulse sequence, high frequency is eliminated by wave filter 130
Component, and the signal as result is supplied to speaker SP.
More specifically, when input signal AIN ' voltage equal to 0V time, output stage 120 exports
There is the pwm pulse sequence of 50% dutycycle, and speaker SP receives voltage 0V.With
Input signal AIN ' voltage in positive direction from 0V change, from output stage 120 output
The dutycycle of pwm pulse sequence becomes 100% (under maximum case) from 50%, and is answered
Voltage for speaker SP becomes+B (under maximum case) from 0V.On the other hand, with
Input signal AIN ' voltage in negative direction from 0V change, from output stage 120 output
The dutycycle of pwm pulse sequence becomes 0% (under minimum) from 50%, and is employed
Voltage in speaker SP becomes-B (in minimum) from 0V.By this way, exist
Close to input signal AIN in waveform ' signal be applied to speaker SP.
When class-D amplifier 100 performs amplifieroperation in the above described manner, load current feedback electricity
Road 200 will flow through what the load current I negative feedback of speaker SP was class-D amplifier 100 to it
The operational amplifier 110 of input unit, and filter current feedback circuit 300 will flow through wave filter
The Current Negative Three-Point Capacitance of 130 gives identical operational amplifier 110.Knot as these negative feedback controls
Really, independent of the driving frequency of speaker SP, the load current flowing through speaker SP keeps perseverance
Fixed.
Additionally, when class-D amplifier 100 performs amplifieroperation, input signal supply 50
Regulate will be supplied to the defeated of class-D amplifier 100 according to the load current I flowing through speaker SP
Enter the amplitude of signal AIN '.Even more specifically, the DSP 52 of input signal supply 50 is true
Fixed its be that the virtual power supply of generation is (in this embodiment when from virtual power supply output load current I
The power supply for vacuum tube amplifier) the virtual output voltage Vo of output voltage.And DSP
52 supplies have used the factor alpha determined by virtual output voltage Vo to regulate the input of its amplitude
Signal AIN '=α AIN.
By regulation input signal AIN ' amplitude, for connecting the output of class-D amplifier 100
The pulse width of the pulse of the switching device of level 120 is conditioned, and from class-D amplifier 100
Output is thus conditioned to the load current I of speaker SP.The result regulated as these, produces
Raw with at the sound by the identical level of the level in the case of vacuum tube amplifier driving speaker SP
Sound reproduces.
It follows that the advantage that embodiment will be described.Fig. 4 illustrates the impedance of full-range speaker
Example frequency characteristic.Generally, full-range speaker has the resonant frequency of about 80 to 100Hz
F0, and their impedance is high at resonant frequency f0.Frequency range around resonant frequency f0
Determine that the essential scope of the sound quality of electric guitar, because this frequency range is corresponding to will be by electricity
The range of the sound that the 5th and the 6th string of guitar produces.
There is the degenerative power amplifier (such as, general class-D amplifier) of output voltage,
Perform the power amplifier that constant voltage drives the most on a speaker, not by the impedance of speaker
Frequency characteristic impact in the case of, use corresponding to input audio signal voltage drive raise
Sound device.Therefore, as shown in Figure 5 A, though the resonant frequency that the impedance of speaker is high wherein
In frequency range around f0, also drive speaker with constant voltage.As a result, the shaking of speaker
Dynamic amplitude, and the amplitude preservation of the sound therefore sent from speaker is constant.
On the other hand, generally, the vacuum tube amplifier as output amplifier uses output
The Pyatyi vacuum tube that impedance is high.Use the vacuum tube amplifier of Pyatyi vacuum tube with corresponding to being supplied
The constant current that the input signal of the grid of vacuum tube is unrelated with the impedance variation of speaker should be given
Drive speaker.Therefore, as shown in Figure 5 B, the resonance frequency that the impedance of speaker is high wherein
In frequency range around rate f0, vacuum tube amplifier increases with its voltage driving speaker.
The vibration amplitude of speaker and the amplitude of sound therefore sent from speaker increase.
Result so that the sound that the 5th and the 6th string of electric guitar generates is unique, strong sound
Sound, and player understands this feature firmly.Such as, when speaker is by its maximum output
When power is the vacuum tube amplifier driving of 100W, speaker frequency around resonant frequency f0
It is endowed the crest voltage close to 90V in the range of rate, and therefore, it is possible to sends sound strong, big
The sound of amount.
In the case of being driven by general class-D amplifier at such as speaker, at resonance frequency
Sufficiently large load current is supplied in the frequency range around rate f0 speaker, and D class is amplified
Device needs the supply voltage with high output stage, and is thus able to provide big output.So
And, in the case of speaker is driven by this high power class-D amplifier, even if raising wherein
In the frequency range that the impedance of sound device is low, also perform constant voltage and drive, and overcurrent can
To flow through speaker, speaker may be caused impaired.
On the contrary, in this embodiment, when D class speaker 100 performs amplifieroperation, load
The load current negative feedback flowing through speaker SP is amplified for D class by current feedback circuit 200 to it
The operational amplifier 110 of the input unit of device 100, and filter current feedback circuit 300 will stream
The Current Negative Three-Point Capacitance of filtered device 130 gives identical operational amplifier 110.If speaker SP
Drive frequency variations so that increase the impedance of speaker SP, and thus reduce and flow through
The load current of speaker SP, then be supplied to D class via load current feedback circuit 200 and put
The feedback signal of the input unit of big device 100 reduces, thus increases the defeated of class-D amplifier 100
Go out signal.As a result, the active voltage of speaker SP it is supplied to increase from class-D amplifier 100,
Thus increase the load current flowing through speaker SP.
On the other hand, if the drive frequency variations of speaker SP so that reduce speaker
The impedance of SP, and thereby increase the load current flowing through speaker SP, then via load
Current feedback circuit 200 is supplied to the feedback signal of the input unit of class-D amplifier 100 and increases,
Thus reduce the output signal of class-D amplifier 100.As a result, supply from class-D amplifier 100
The active voltage that should give speaker SP reduces, thus reduces the load electricity flowing through speaker SP
Stream.As the result of this negative feedback control, independent of the driving frequency of speaker SP, flow through
The load current of speaker SP keeps constant.
As it has been described above, in this embodiment, negative anti-by the load current that will flow through speaker SP
The input unit of class-D amplifier of feeding 100, it is possible to effectively increase or reduce class-D amplifier
The output impedance of 100, and constant holding can be derived from class-D amplifier 100 and flowing through and raise
The load current of sound device SP.This allows to by allowing the impedance of speaker SP wherein to increase
The enough of speaker SP is flowed through in big 80 to the 100Hz frequency range near resonant frequency f0
Big load current realizes sending the sound of big volume.
Additionally, in this embodiment, owing to performing to protect independent of the driving frequency of speaker SP
Hold and flow through the control that the load current of speaker SP is constant, so around except resonant frequency f0
80 to 100Hz frequency range outside frequency range in prevent overcurrent to flow through to raise one's voice
Device SP, and it is possible to prevent speaker impaired.By this way, making according to embodiment
It is capable of tradition with the power amplifier 1 of semiconductor device to be only capable of and pass through vacuum tube amplifier
The high-quality that realizes, the audio reproduction of big volume.
This embodiment also provide be prevented from class-D amplifier 100 self-oscillating frequency reduce
Advantage, this will be described in more detail below.Self-oscillation amplifier in such as class-D amplifier 100
In, by regulation open-loop gain characteristic, and phase characteristic, self-oscillating frequency is set above sound
The frequency (such as, 200 to 500kHz) of frequency range (less than 20kHz) is necessary.
But, in this embodiment, primary feedback path is the road of load current feedback circuit 200
Footpath, and the percentage ratio of the contribution of Voltage Feedback is little.Therefore, it is the filtering of Voltage Feedback point
Impedance at the output node 133 of device 130 reduces, so that it is for determining self-oscillating frequency
The open-loop gain characteristic, of one of factor degenerate.If do not taken appropriate measures, then self-oscillation frequency
Rate becomes less than the frequency (such as, 30 to 50 of expected frequence (such as, 200 to 500kHz)
kHz).Under the circumstances, in this embodiment, except load current feedback circuit 200
Outside, additionally provide filter current feedback circuit 300.
In wave filter 130, by the high fdrequency component of the pwm pulse exported from output stage 120
(higher than LC resonant frequency) generates and flows through the electricity being parallel capacitances connected in parallel to speaker SP (load)
The electric current of container 132.By the electric current of the capacitor 132 of the filtered device of feedback flow 130, energy
Enough prevent high frequency open-loop gain characteristic, from degenerating, it is possible to so that the self-vibration of class-D amplifier 100
Swing frequency and be equal to be not equipped with the frequency of traditional self-oscillation amplifier of load current feedback circuit 200.
Additionally, it is different from vacuum tube amplifier, according to the merit using semiconductor device of embodiment
The size of rate amplifier 1 and weight can be reduced, and are easy to process.It addition, and vacuum
Pipe amplifier is different, according to the D class that the loss in the employing wherein output stage 120 of embodiment is low
The power amplifier 1 of amplifier 100 can drive speaker SP with altofrequency.
Further, in this embodiment, owing to providing input signal supply 50, so
Can include that the operation of vacuum tube amplifier of power supply is reproduced vacuum by class-D amplifier by simulation
The audio reproduction of pipe amplifier.This advantage is described below.
Fig. 6 is shown through removing input signal supply from the power amplifier 1 according to embodiment
50 and obtain output current characteristic I1 of power amplifier, the output electric current of vacuum tube amplifier
Characteristic I2 and output current characteristic I3 of the power amplifier 1 according to embodiment.In figure 6,
Horizontal axis repre-sents time t, and vertical axis representative is from the load current of power amplifier supply.Figure
6 are shown in the amplitude of input signal AIN 0V at time t=0 when being stepped up, from respectively
Power amplifier be supplied to load current I1, I2, I3 of speaker (load) in time
Change.
As shown in Figure 6, in the power amplifier without input signal supply 50, in input
After the amplitude of signal AIN is stepped up at time t=0, corresponding to input signal AIN
The constant load current I1 of amplitude continues to be supplied to load.
On the other hand, the vacuum tube amplifier being used as guitar amplifier is carried out close to constant current
The operation of operation.Impedance being total at speaker of the speaker of its load being vacuum tube amplifier
Height around vibration frequency f0.Consequently, it can happen the output signal of vacuum tube amplifier be limited in
It is applied to the event of the mains voltage level of vacuum tube amplifier.Fig. 7 illustrates that this vacuum tube is put
The exemplary operations of big device.
When the amplitude of input signal AIN to vacuum tube amplifier is increased to too at time t=0
Big value so that when its output signal is limited, is applied to the power supply electricity of vacuum tube amplifier
Pressure+B and-B and its output signal Vsp change as illustrated in fig. 7.It is to say, time
Between after t=0, the supply voltage+B and-B that are applied to vacuum tube amplifier are gradually lowered, and
And the clip level of output signal Vsp of vacuum tube amplifier is gradually lowered.
As a result, in vacuum tube amplifier, as shown in Figure 6, shaking in input signal AIN
Width is increased to the biggest value at time t=0 so that when its output signal is limited, flow through load
Load current I2 disappearance over time and slowly reduce.If vacuum tube amplifier is being raised one's voice
Output signal Vsp as shown in Figure 7 is produced in frequency range around the resonant frequency f0 of device,
Then it is capable of the audio reproduction with superelevation acoustic pressure sensation.This class feature of vacuum tube amplifier
For guitar player's particular importance.
Above-mentioned phenomenon occurs due to the power supply for vacuum tube amplifier.As shown in Figure 2,
Power supply for vacuum tube amplifier includes capacitor C.When input signal AIN amplitude progressively
During rising, the electric charge being stored in capacitor C is supplied to load via vacuum tube amplifier.
Therefore, the amplitude in input signal AIN is increased to the biggest value its output signal is limited
Moment, big electric current by from vacuum tube amplifier supply to load.But, along with electric capacity afterwards
Device C is discharged, owing to the internal driving of power supply is high, for the power supply of vacuum tube amplifier
Output voltage and be therefore supplied to the load current of load gradually to subtract from vacuum tube amplifier
Little.By this way, vacuum tube amplifier can provide the big wink relative to continuous peak power
Time peak power, and so that instantaneous can send big volume sound.
In the power amplifier 1 according to embodiment, in input signal supply 50 simulation drawing 2
The operation of shown virtual power supply 56, and during according to virtual power supply 56 output load current I (f)
Occur virtual output voltage Vo (f) regulate input signal AIN ' amplitude.Therefore, with vacuum
The situation of pipe amplifier is identical, flows through the load current I3 amplitude in input signal AIN of load
Disappear over time after being stepped up and slowly reduce.
On the other hand, in this embodiment, identical with general class-D amplifier, have low interior
Power supply+the B and-B of portion's impedance are connected to the output stage 120 of class-D amplifier 100, and defeated
Go out level 120 and export its H level and the rectangular pulse of L level respectively+B and-B.And it is defeated
Enter signal providers 50 and will be endowed input signal AIN of class-D amplifier 100 by regulation '
Amplitude, it is achieved that the output current characteristic similar with the output current characteristic of vacuum tube amplifier.
Thus, this embodiment is capable of the water identical with the level using vacuum tube amplifier to be realized
Flat audio reproduction.
<other embodiments>
It is hereinbefore described an embodiment of the disclosure.Other of the disclosure may embodiment
As follows:
(1) power amplifier 1 can be configured by this way: relate to shown in Fig. 2 is virtual
The information of the configuration of power supply 56, such as L, R and C value is stored in memorizer, and DSP
52 read this information, and design factor α (f) based on load current I (f) from memorizer.
(2) power amplifier 1 may be such that argument θ (fk) ignoring factor alpha (f), and
And omit phase shifter 503_k (k=1 to N).
(3) in the above-described embodiments, information based on the configuration relating to virtual power supply 56 calculates
Virtual output voltage Vo (f) occurred when virtual power supply 56 output load current I (f).As generation
Replacing, power amplifier 1 may be such that output electric current I (f) of instruction display virtual power supply 56
With table of output voltage characteristic etc. is stored by the output electric current of the relation between output voltage Vo (f)
In memory, and DSP 52 calculates based on load current I (f) and the information that is stored in memorizer
Virtual output voltage Vo (f).In this case, in order to reduce data volume and the meter of DSP 52 of table
Calculation amount, can only use the absolute value of output electric current I (f) and output voltage Vo (f), i.e. ignore them
Argument, define output electric current to output voltage characteristic.
(4) although in the above-described embodiments, input signal AIN to class-D amplifier 100 '
Amplitude regulation in only relate to flow through the load current of speaker SP, but in input signal AIN '
Amplitude regulation in, in addition to load current, it is also possible to relate to being applied to speaker SP's
Output voltage.
(5) it is will to be connected to have the vacuum tube of output transformator amplify at the power supply being to be simulated
In the case of the power supply of device, the DSP 52 of input signal supply 50 can perform signals below
Processing and amplifying.First, order is for the internal inductance of power circuit of vacuum tube amplifier, inside
Resistance and internal capacitance are represented by L, Rs and C, and make the output transformation of vacuum tube amplifier
The number of turn of the primary side of device and the number of turn of primary side are represented by n1 and n2.Flow through output transformator
The electric current of armature winding become equal to (n2/n1) I, wherein I is by the secondary from output transformator
Winding is supplied to the electric current of speaker SP.Electric current (n2/n1) I is put to vacuum tube from power supply output
Big device.
Assuming that virtual power supply has internal inductance Ld=L × (n2/n1)2, internal resistance Rsd=Rs ×
(n2/n1)2With internal capacitance Cd=C × (n1/n2)2.DSP 52 flows through according in virtual power supply output
The virtual output voltage of the virtual power supply occurred during the electric current of speaker SP, it is right to perform to be used for regulate
Input signal AIN of class-D amplifier 100 ' the signal processing and amplifying of amplitude.According to this enforcement
The power amplifier 1 of example allows to reproduce the vacuum tube amplifier institute such as with output transformator
The audio reproduction performed.
(6) although in the above-described embodiments, regulate based on the load current flowing through speaker SP
Input signal AIN to class-D amplifier 100 ' amplitude, but can be based on being applied to raising
The output voltage of sound device SP performs input signal AIN ' amplitude regulation.
Fig. 8 is to be shown in which to perform input letter based on the output voltage being applied to speaker SP
The circuit diagram of the configuration of the power amplifier 1a of the amplitude regulation of number AIN '.Configure by this way
Power amplifier 1a: resistor 521 and 522 is added to putting according to the power of above-described embodiment
Big device 1, and the input signal supply of power amplifier 1 is replaced by input signal supply 50a
Device 50.In input signal supply 50a, DSP 52a replace input signal supply 50
DSP 52.
As shown in Figure 8, the output voltage being applied to speaker SP is also applied to having electricity
The bleeder circuit of resistance device 521 and 522.There is bleeder circuit defeated of resistor 521 and 522
Go out voltage to be detected circuit 54 and detect, and be converted to be supplied to DSP by A/D converter 55
The digital signal of 52a.DSP 52a based on be supplied to speaker SP by A/D converter 55
The output voltage of output signal instruction, and the impedance operator of the speaker SP stored in advance,
Calculate the load current I flowing through speaker SP.It is endowed the impedance of the speaker SP of DSP 52
Characteristic can be to be obtained by the measurement on speaker SP when activating power amplifier 1a
Impedance operator, or the impedance operator obtained by measurement when factory shipment.
Similar to the DSP 52 used in above-described embodiment, DSP 52a calculates defeated at virtual power supply
The virtual output voltage Vo of the virtual power supply 56 occurred when going out load current I, uses by virtual defeated
Go out the amplitude of the output signal of the factor alpha regulation A/D converter 51 that voltage Vo determines, and will
Input signal AIN of amplitude regulation '=α AIN is supplied to class-D amplifier 100.This embodiment carries
Supply the advantage identical with the advantage of above-described embodiment.
Above-mentioned power amplifier according to disclosure embodiment and input signal will be regulated below
The feature of method is summarized as projects [1]-[12].
[1] disclosure provides a kind of power amplifier, including:
Class-D amplifier, described class-D amplifier includes input unit and switching device, wherein said
Switching device switches according to the input signal being imported into described input unit, in order to by described
Switching device by electric current from power supply supply to load；And
Input signal supply, described input signal supply is configured to described input signal
It is supplied to the described input unit of described class-D amplifier, calculates special from having appointment internal driving
Property virtual power supply output will virtual from virtual power supply output when flowing through the electric current of described load
Output voltage, and the amplitude of described input signal is regulated according to described virtual output voltage.
[2] according in the power amplifier described in project [1], described input signal supply bag
Including signal processing circuit, described signal processing circuit internal driving based on virtual power supply characteristic is held
Row signal processing and amplifying is to regulate the amplitude of described input signal, and described virtual power supply is for very
The simulation of the power supply of blank pipe amplifier.
[3] according in the power amplifier described in project [2], described signal processing circuit based on
Described virtual power supply performs signal processing and amplifying, and described virtual power supply is to put for described vacuum tube
The simulation of big device power circuit, described virtual power supply has internal inductance Ld=L × (n2/n1)2, interior
Portion resistance Rsd=Rs × (n2/n1)2With internal capacitance Cd=C × (n1/n2)2, it is wherein L, Rs
With C namely for the internal inductance of described power circuit of described vacuum tube amplifier, inside
Resistance and internal capacitance, and n1 and n2 be described vacuum tube amplifier output transformator
Primary side and the number of turn of primary side.
[4] according in the power amplifier described in any one of project [1] to [3], described input is believed
The information of number supply configuration based on the equivalent circuit indicating described virtual power supply, from flowing through
State the described virtual output voltage of virtual power supply described in the described Current calculation of load.
Similarly, such as, described input signal supply is based on being counted by described virtual power supply
The described amplitude of input signal described in the coefficient adjustment that the virtual output voltage calculated determines.
[5] according in the power amplifier described in any one of project [1] to [3], described input is believed
Number supply according to the output electric current of described virtual power supply to output voltage characteristic, based on flowing through
State the described virtual output voltage of virtual power supply described in the described Current calculation of load.
[6] according in the power amplifier described in any one of project [1] to [5], wrap further
Include:
Load current feedback circuit, described load current feedback circuit is configured to flowing through described
The described Current Negative Three-Point Capacitance of load gives the described input unit of described class-D amplifier.
[7] present disclose provides a kind of input unit being input to class-D amplifier for regulation
The input signal control method of input signal, described class-D amplifier includes described input unit and opens
Closing device, wherein said switching device switches according to described input signal, in order to by described
Switching device by electric current from power supply supply to load, described input signal control method includes:
Calculate and flowing through described load from the virtual power supply output with appointment internal driving characteristic
Will be from the virtual output voltage of virtual power supply output during electric current；And
The amplitude of described input signal is regulated according to described virtual output voltage.
[8] according in the input signal control method described in project [7], described in described calculating
In virtual output voltage, virtual power supply described in internal driving property calculation based on virtual power supply
Described virtual output voltage, described virtual power supply is the simulation of the power supply for vacuum tube amplifier.
[9] according in the input signal control method described in project [8], described in described calculating
In virtual output voltage, based on including internal inductance Ld=L × (n2/n1)2, internal resistance Rsd=Rs
×(n2/n1)2With internal capacitance Cd=C × (n1/n2)2Described virtual power supply calculate described virtual electricity
The described virtual output voltage in source, is wherein that L, Rs and C are namely for vacuum tube amplifier
The internal inductance of power circuit, internal resistance and internal capacitance, and n1 and n2 be described
The primary side of the output voltage device of vacuum tube amplifier and the number of turn of primary side.
[10] according in the input signal control method described in any one of project [7] to [9], in institute
State in the described virtual output voltage of calculating, joining of equivalent circuit based on the described virtual power supply of instruction
The information put, from flowing through the described virtual of virtual power supply described in the described Current calculation of described load
Output voltage.
[11] according in the input signal control method described in any one of project [7] to [9], in institute
Stating in the described virtual output voltage of calculating, the output electric current according to described virtual power supply is electric to output
Pressure characteristic, based on flowing through the described virtual of virtual power supply described in the described Current calculation of described load
Output voltage.
[12] according in the input signal control method described in any one of project [7] to [11], enter
One step includes:
The described Current Negative Three-Point Capacitance described input to described class-D amplifier of described load will be flowed through
Portion.
Claims (12)
1. a power amplifier, including:
Class-D amplifier, described class-D amplifier includes input unit and switching device, wherein said
Switching device switches according to the input signal being imported into described input unit, in order to by described
Switching device by electric current from power supply supply to load；And
Input signal supply, described input signal supply is configured to described input signal
It is supplied to the described input unit of described class-D amplifier, calculates special from having appointment internal driving
Property virtual power supply output will virtual from virtual power supply output when flowing through the electric current of described load
Output voltage, and the amplitude of described input signal is regulated according to described virtual output voltage.
Power amplifier the most according to claim 1, wherein said input signal supply
Including signal processing circuit, described signal processing circuit internal driving based on virtual power supply characteristic
Perform signal processing and amplifying with regulate described input signal amplitude, described virtual power supply be for
The simulation of the power supply of vacuum tube amplifier.
Power amplifier the most according to claim 2, wherein said signal processing circuit base
Performing signal processing and amplifying in described virtual power supply, described virtual power supply is for described vacuum tube
The simulation of the power circuit of amplifier, described virtual power supply have internal inductance Ld=L ×
(n2/n1)2, internal resistance Rsd=Rs × (n2/n1)2With internal capacitance Cd=C × (n1/n2)2, its
In be L, Rs and C inside namely for the described power circuit of described vacuum tube amplifier
Inductance, internal resistance and internal capacitance, and n1 and n2 be the defeated of described vacuum tube amplifier
Go out the primary side of transformator and the number of turn of primary side.
4. according to the power amplifier described in any one of claims 1 to 3, wherein said input
The information of signal providers configuration based on the equivalent circuit indicating described virtual power supply, from flowing through
The described virtual output voltage of virtual power supply described in the described Current calculation of described load.
5. according to the power amplifier described in any one of claims 1 to 3, wherein said input
Signal providers according to the output electric current of described virtual power supply to output voltage characteristic, based on flowing through
The described virtual output voltage of virtual power supply described in the described Current calculation of described load.
6., according to the power amplifier described in any one of claim 1 to 5, farther include:
Load current feedback circuit, described load current feedback circuit is configured to flowing through described
The described Current Negative Three-Point Capacitance of load gives the described input unit of described class-D amplifier.
7. an input signal control method, is input to the input of class-D amplifier for regulation
The input signal in portion, described class-D amplifier includes input unit and switching device, wherein said opens
Close device to switch according to described input signal, in order to by described switching device by electric current from electricity
Source supply is to load, and described input signal control method includes:
Calculate and flowing through described load from the virtual power supply output with appointment internal driving characteristic
Will be from the virtual output voltage of virtual power supply output during electric current；And
The amplitude of described input signal is regulated according to described virtual output voltage.
Input signal control method the most according to claim 7, wherein in described calculating institute
State in virtual output voltage, virtual power supply described in internal driving property calculation based on virtual power supply
Described virtual output voltage, described virtual power supply is the mould of the power supply for vacuum tube amplifier
Intend.
Input signal control method the most according to claim 8, wherein in described calculating institute
State in virtual output voltage, based on including internal inductance Ld=L × (n2/n1)2, internal resistance Rsd
=Rs × (n2/n1)2With internal capacitance Cd=C × (n1/n2)2Described virtual power supply calculate described void
Intend the described virtual output voltage of power supply, be wherein that L, Rs and C are put namely for vacuum tube
The internal inductance of power circuit, internal resistance and the internal capacitance of device, and n1 and n2 greatly is
The primary side of the output transformator of described vacuum tube amplifier and the number of turn of primary side.
10. according to the input signal control method described in any one of claim 7 to 9, wherein
In the described virtual output voltage of described calculating, based on the equivalent circuit indicating described virtual power supply
The information of configuration, from flowing through described in virtual power supply described in the described Current calculation of described load
Virtual output voltage.
11. according to the input signal control method described in any one of claim 7 to 9, wherein
In the described virtual output voltage of described calculating, according to the output electric current of described virtual power supply to defeated
Go out voltage characteristic, based on flowing through described in virtual power supply described in the described Current calculation of described load
Virtual output voltage.
12., according to the input signal control method described in any one of claim 7 to 11, enter one
Step includes:
The described Current Negative Three-Point Capacitance described input to described class-D amplifier of described load will be flowed through
Portion.
Applications Claiming Priority (4)
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| JP2015-050897 | 2015-03-13 | ||
| JP2015050897 | 2015-03-13 | ||
| JP2015-247521 | 2015-12-18 | ||
| JP2015247521A JP6651835B2 (en) | 2015-03-13 | 2015-12-18 | Power amplifier |
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| CN105978510A true CN105978510A (en) | 2016-09-28 |
| CN105978510B CN105978510B (en) | 2019-09-20 |
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Cited By (1)
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| CN110855250A (en) * | 2019-11-29 | 2020-02-28 | 哈尔滨工业大学 | Linear power amplifier driving method with variable power supply voltage |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP6809703B2 (en) * | 2016-11-28 | 2021-01-06 | 協同電子エンジニアリング株式会社 | Class D power amplifier |
| JP7411411B2 (en) * | 2019-12-27 | 2024-01-11 | ローランド株式会社 | Musical signal amplifier |
| JP2024075948A (en) | 2022-11-24 | 2024-06-05 | ローランド株式会社 | Amplifier |
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Also Published As
| Publication number | Publication date |
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| JP2016171559A (en) | 2016-09-23 |
| CN105978510B (en) | 2019-09-20 |
| JP6651835B2 (en) | 2020-02-19 |
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