CN1248819A - Digital power amplifier - Google Patents
Digital power amplifier Download PDFInfo
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- CN1248819A CN1248819A CN 99116677 CN99116677A CN1248819A CN 1248819 A CN1248819 A CN 1248819A CN 99116677 CN99116677 CN 99116677 CN 99116677 A CN99116677 A CN 99116677A CN 1248819 A CN1248819 A CN 1248819A
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Abstract
The present invention discloses a digital power amplifier, including digital receiving circuit, filter, and sound volume control circuit, digital signal processor, and several positive-negative multibit power units which are identical in number. It is characterized by that the digital signal processor is used for processing input signal according to the set program, and its output is used for controlling pulse signal of several positive-negative multibit power units, and the described power units are mutually independently worked, so that its output is stable, and the total power of load is the sum of powers of all multibit power units. The output power of said invention and input voice digital code are correspondent, so that its response is quick, fidelity factor is high, structure is simple, it is a new generation sustitute for analogue power amplifier.
Description
The present invention relates to a kind of amplifier, especially audio-frequency power amplifier.
Audio-frequency power amplifier is a kind of device that sound is amplified, and uses very extensively, as radio station, broadcasting, cinema, automobile audio, the OK a karaoke club ok of family and movie theatre etc., concerns very close with the people's work life.Audio-frequency power amplifier with people's use substantially all is the analogue audio frequency power amplifier that adopts amplifying circuits such as Class A, Class B, class AB, OTL and OCL in the market.The power amplifier people research and development of this type of circuit many decades, many good circuit are also arranged, for the sound equipment cause has been made certain contribution.But, owing to transistorized transmission characteristic limits, the dynamic range in full frequency band, no absolute linearity will inevitably produce nonlinear distortion.Also have, selected element asymmetric also can cause distortion; The response of feedback circuit, compensating circuit, capacitor and inductor and variate etc. all can produce distortion, and fidelity is descended, and tonequality is undesirable.Also increase the volume of whole device simultaneously, improved cost.In recent years, digital technology is very fast at the research and the application development of sound equipment video field, as digital video disc DVD, dsd dolby surround digital AC-3, Digital Theater System DTS and digital signal processor DSP, and the extensive use of many matchmakers of computer and digital mobile phone etc.This explanation, digital circuit has more superiority than analog circuit, and progressively replaces analog circuit, in the sound equipment field, only remaining now amplifirer and audio amplifier (or loud speaker) be analog form still, and this explanation is a bigger difficult problem, has influenced the development of digital technology in this field.According to " electronics newspaper " and interrelated data record recently, Hesperian relevant companies such as Britain, Spain, Holland and Denmark are studied for many years the digital audio power amplifier, and the product that does not have success so far appears on the market.Japanese Sharp company has made a fully digitalization in 1997 1 bit amplifies/loud speaker, all is better than the analogue audio frequency power amplifier greatly at aspects such as tonequality, cost and volumes.But, this product also has many difficult problems on technology, production technology, mainly be incompatible fully on the principle, on the production technology with existing systems, we can say the existing sound appliances of production equipment, technology, product and consumer that to eliminate existing analogue amplifier and speaker system fully, too big with real gap, be unfavorable for people's needs.
The purpose of this invention is to provide a kind of high-fidelity, reliable operation, simple in structure, with analog audio compatibility, volume is little and cost is low digital power amplifier.
The power output of the digital power amplifier of above-mentioned purpose is followed formula: P (d)=d
n* P
2/ 2
1+ d
N-1* P
o/ 2
2+ ... d
2* P
o/ 2
N-1+ d
1* P
o/ 2
No, wherein, d
n=0 or 1, two states is by digital volume control output pulse decision; N=1,2,3,4 ... n
o, n≤no, the number of many bit powers unit is determined from several grades in the expression position, by the digital signal word length decision of digital signal processor output, as n
o=19, then the word length of digital audio and video signals is 20, and there is the power cell of positive and negative each 19 different proportion level many bit powers unit, from 1,2,3,4,5 ... to 19, n
oCan be 15,19,23,31 etc.; P
oBe the peak power output that requires, set by digital volume control.The circuit of realizing this formula comprises: (1) digital signal receiving circuit; (2) digital signal that receives is carried out Filtering Processing, and carry out the circuit of volume control as required; (3) contain setting program, the digital signal of input is handled, produce the digital signal processor of the digit pulse of each power cell of control; (4) several equal power unit module circuit of positive and negative unit number, its output is many level, etc. the power of pulsewidth, satisfies above-mentioned formula; (5) remove the low-pass filter circuit of low-frequency disturbance.More than each circuit according to the order of handling input signal, input and output connect in regular turn, constitute digital power amplifier.
Preceding two part digital received, digital filtering and the control of digital volume of the digital power amplifier of said structure all have ripe circuit in the prior art, can directly adopt; Digital volume control circuit wherein because handle in digital field, to the adjusting of volume, is exactly to the computing of numeral output result, therefore, can generation time postpone, corresponding distortion and new non-property line clutter, or introduces interfering components.The 3rd partly is to be exclusively used in processing digital signal, and produces the microcomputer chip of corresponding control figure pulse signal, contains the program of setting, the efficient of its processing digital signal and quality be any analog circuit can not compare.The power amplification of digital signal is made up of positive and negative some power unit modules, each modular power cells all works in constant power rating, the operating state of each modular power cells has only two kinds, it is exactly " 1 " power output, " 0 " is power output not, and each power output constantly is corresponding one by one with the audio frequency number of input, accurate positioning, response are enough fast.Their operating state is different from analog amplifier, no feedback circuit, and uncompensated network can not produce the response of nonlinear distortion and time delay, and amplitude-frequency response all can reach unprecedented high level.The output of several power cells etc. power synthetic rear drive load or loud speaker on bus of pulsewidth, many level.Therefore, this digital power amplifier, simple in structure, selection is easy, has reduced some unnecessary transmission links, and signal to noise ratio is high, and distortion is minimum, is the replacement technology and the product of present analog amplifier, and is inexpensive, satisfies popular high-caliber demand.
Below in conjunction with accompanying drawing, the present invention is described in detail.
Shown in Figure 1, be the former block diagram of this digital power amplifier.
Shown in Figure 2, be digit pulse sequential illustration of the present invention.
Shown in Figure 3, be the synthetic circuit theory diagrams of many bit powers of the present invention unit and power.
Digital audio input in Fig. 1, can be digital video disk DVD, VCD, digital audio source such as dsd dolby surround digital output AC-C, Digital Theater System DTS, digital audio and video signals is defeated by the digital received circuit, the digital received circuit adopts integrated circuit CS8412 of the prior art (being U.S.'s model, as follows).Digital filter circuit and volume control circuit also adopt integrated circuit PMD100 of the prior art, the signal that digital receiving circuit is provided carries out filtering and volume control, and produce that crystal oscillator clock pulse XICLK, sound channel digital signal DRO, bit clock signal go out BCRO, wordclock signal WCRO, bit clock signal advances BCR1, word location clock pulse DG and common ground GND etc., 44～38 corresponding pin of being defeated by digital signal processor P1016 respectively.Wherein, to the adjusting of volume, be to the result of the computing output of a numeral, can not produce other and disturb and bad composition, the volume power that sets is P
oDigital signal processor P1016, according to the signal of being imported, the routine processes of in this processor, setting, produce and control the digit pulse that comprises each power cell, as: n position negative power output control figure switching pulse DL-n, the negative dynamic power output in n position control figure switching pulse SDL-n, n position power positive output control figure switching pulse DH-n, n position orthokinesis power output control figure switching pulse SDH-n; Wherein n be 1,2,3 ... 19 power cell number, positive and negative power cell respectively has 19, the signal that same widths is responsible in each unit amplifies, and work in constant power and go into big state, unit number is many more, the deration of signal that every unit is responsible for is more little, and the reduction precision of audio frequency is higher, and fidelity better; Among Fig. 1, positive and negative each 19 power cell are arranged respectively in the both sides of digital signal processor P1016.The watt level of power cell is decided by the power output P that sets as requested
oWith digital bit position, for example, the 19th power cell is setpoint power output P
o1/2, the 1 then be P
o/ 524288, the stack that obtains total power output and be positive and negative each power cell in load is synthetic, satisfies formula: P (d)=d
n* P
o/ 2
1+ d
N-1* P
o/ 2
2+ ... d
2* P
o/ 2
N-1+ d
1* P
o/ 2
NoIn merit, n=1,2,3 ... n
o, n
o=19; d
n=0 or 1, by digital volume control output pulse decision; p
oBe the peak power output that requires.In Fig. 1, the position of each power cell and the size of power have all been made sign on every cell power module, as: negative the 2nd power cell ,-(1/2
18) P
O3: positive the 18th power cell ,+(1/2
2) P
oDeng.Every power cell all works in constant power rating, every power unit module all is subjected to dynamic power output control figure switching pulse SDL-n or SDH-n, and the control of power output control figure switching pulse DL-n or DH-n, their output is by negative power bus and positive bus, synthetic on the preceding bus of load (loud speaker), promptly power is synthetic.The synthetic place of power can be provided with low pass filter, with some low frequency interference signal eliminations, improves signal quality.In Fig. 2, illustrated for example under the control of dynamic power output control figure switching pulse SDH-18T and SDH-19, the output of the 18th and 19 positive unit, the sequential chart of the synthetic power that in load, obtains, as can be seen from the figure, this power is synthetic is the stack of the 18th and 19 power cells output.
In Fig. 3, in positive and negative each 19 power cell, to have chosen positive and negative each power cell circuit wantonly its operation principle has been described, remaining positive and negative power cell circuit is identical separately, and the course of work that power is synthetic is described together.N position negative output power cell in the drawings is by two NPN transistor N
2And N
3, a PNP transistor P
3, resistance R
2And R
3, constant-current source (1/2
n) I.Form, wherein I
oIt is above-mentioned setting volume power P
oIn electric current.Three transistor N
2, N
3And P
3Emitter link together; Transistor N
3Collector electrode connect load RL one end, base stage connects the output of the n position negative power output control figure switching pulse DL-n of digital signal processor P1016, this base stage also is connected (not drawing among the figure) with the input of an inverter.Transistor N
2Collector electrode pass through resistance R
2Connect positive supply, base stage meets transistor N
3The output of inverter that base stage connects, promptly anti-phase with negative power output control figure pulsed D L-n, be pulsed D L-n.Transistor P
3Base stage pass through resistance R
3Connect the negative dynamic power output control terminal in n position of digital signal processor P1016, collector electrode meets constant-current source (1/2n) I
oInput, the output of this constant-current source connects public ground.At three brilliant utmost point pipe N
2, N
3And P
3The left side of base input end is the input pulse sequential chart of each input of expression, from sequential chart as can be known, and the operation principle of this power cell circuit, transistor P
3Be negative power pre-acceleration digital dynamic power switch, transistor N
3Be negative power output switch, brilliant utmost point pipe N
2Be the power by-pass switch; When no negative power is quickened digital dynamic merit attitude switching pulse, transistor P
3And N
3Turn-off transistor N
2Conducting, constant-current source is not worked, inactivity output; When negative dynamic power switching pulse, i.e. pulse SDL-n=-1, brilliant utmost point pipe P
3Elder generation's conducting is played the effect of pre-acceleration, transistor N
2Former conducting, constant-current source (1/2n) I
oStart, electric current is from resistance R
2To transistor N
2And P
3, through constant current perseverance (1/2n) I
oTo negative current source, negative power output control pulse DL-n=1 is to transistor N
3During base stage, current source is stable, and reaches standard value, transistor N
3Admittance, transistor N
2Base stage input pulse DL-n=-1, transistor N
2Turn-off, electric current from load RL to transistor N
3And P
3, through constant-current source (1/2n) I
oTo negative supply, i.e. transistor N
3RL has output to load, obtains the power of negative sense in load.During end of output, turn-off transistor N earlier
3, transistor P is turn-offed in the back
3, guarantee the steady, accurate of output current.More than by transistor N
2, N
3And P
3, and resistance R
2, R
3And constant-current source (1/2n) I
oThe circuit that constitutes is many bits negative power element circuit.Because required power output is bigger, as 100～300W or bigger, the transistor P in many bit powers unit
3, N
2And N
3Often be operated in the state of high-voltage great-current, this just requires described transistor that the characteristic of high withstand voltage (more than the 300V), big electric current (more than the 10A) is arranged, also so to say that, powerful if desired output only needs to select for use the transistor of high withstand voltage big electric current to get final product at many these special power cell circuit in n position not.Need to prove that many bit powers element circuit generally all makes module, simplified structure, the convenient use.In like manner, the positive unit is by NPN transistor N
1, PNP transistor P
1And P
2, resistance R
1And R
4, constant-current source (1/2n) I
oConstitute; The input termination positive current of constant-current source, output meets transistor N
1Integrated electrode; Brilliant utmost point pipe N
1Base stage pass through resistance R
4Connect the n position orthokinesis power output control terminal of digital signal processor P1016, emitter and transistor P
1And P
2Emitter connect.Brilliant utmost point pipe P
1Base stage connect the n position positive output switching pulse output control terminal of signal processor P1016, base stage also with one in the drawings the input of unillustrated inverter join, collector electrode meets load RL.Transistor P
2Base stage meet transistor P
1The output end of oppisite phase of the inverter that base stage connect, collector electrode passes through resistance R
1Join with negative supply.Its corresponding pulse sequence figure is arranged on the right side of three transistor base inputs.The positive element circuit of said structure is many bits positive element circuit, and its operation principle is identical with many bits negative power unit, and just the power that gets on load RL is the power of forward.Certainly, on the circuit of load RL,, can insert low-pass filtering element or device, further improve the quality of power output in order to eliminate some low-frequency interference signals.
This digital power amplifier is work like this: digital audio and video signals is received by the digital received circuit, behind digital filtering and digital volume control circuit, the various signals that produce, send digital signal processor processes, produce DL-n in the digital arteries and veins of controlling the positive and negative power cell of each many bit, SDL-n, DH-n and SDH-n, the positive and negative power cell of each the many bit volume watt level that control sets according to volume, work in constant power rating, audio signal is amplified, each power cell is by the digital order of input, and correspondence is amplified with synthetic, again through low-pass filtering one by one, drive load or loud speaker at last, promptly sound amplifies the back reduction.
Claims (2)
1, a kind of digital power amplifier comprises digital received circuit, digital filtering and volume control circuit, it is characterized in that also comprising:
(1) contain setting program, the process in order input signal, output comprises the digital signal processor of the digit pulse of the positive and negative power cell of each many bit of control;
(2) several equal positive and negative many bit powers unit of number, the synthetic power of each power cell satisfies: P (d)=d
nP
o/ 2
1+ d
N-1* P
o/ 2
2+ ... + d
2* P
o/ 2
N-1+ d
1* P
o/ 2
NoFormula, wherein, d
n=0 or 1, two states is by digital volume output pulse decision; N=1,2,3 ... n
oNatural number, n≤n
o, n
oCan be 15,19,23,31 etc., determine the number of many bit powers unit; P
oBe the peak power output that requires, set by digital volume control.
2, digital power amplifier according to claim 1 is characterized in that: each negative many bit powers unit is by two NPN transistor (N
2And N
3), a PNP transistor (P
3), two resistance (R
2And R
3) and a constant-current source formation; Three transistorized emitters interconnect, transistor (N
2) collector electrode by resistance (R
2) connecing the positive source of electricity, base stage connects the output of an inverter; Transistor (N
3) collector electrode connect load (RL), base stage connects the negative power output control terminal of digital signal processor, base stage also meets transistor (N
2) input of inverter that base stage connects; Transistor (P
3) collector electrode connect the input of constant-current source, base stage is by resistance (R
3) connect the negative dynamic power output control terminal of described digital signal processor; The output termination negative supply of constant-current source; Each just many bit powers unit by two PNP transistor (P
1And P
2), a NPN transistor (N
1), two resistance (R
1And R
4) and a constant-current source formation, three transistorized emitters interconnect, transistor (N
1) collector electrode connect the constant-current source output, base stage is by resistance (R
4) connect the orthokinesis power output control terminal of described digital signal processor; The input of constant-current source connects positive supply; Transistor (P
1) collector electrode connect load (RL), base stage connects the positive output control terminal of described digital signal processor, base stage also connects the input of an inverter; Transistor (P
2) collector electrode by resistance (R
1) connecing negative supply, base stage meets transistor (P
1) output of inverter that base stage connects.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99116677 CN1110891C (en) | 1999-09-21 | 1999-09-21 | Digital power amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99116677 CN1110891C (en) | 1999-09-21 | 1999-09-21 | Digital power amplifier |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1248819A true CN1248819A (en) | 2000-03-29 |
| CN1110891C CN1110891C (en) | 2003-06-04 |
Family
ID=5279458
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 99116677 Expired - Fee Related CN1110891C (en) | 1999-09-21 | 1999-09-21 | Digital power amplifier |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1110891C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100433546C (en) * | 2001-03-26 | 2008-11-12 | 哈曼国际工业有限公司 | Digital signal processor enhanced pulse width modulation amplifier |
| CN101232744B (en) * | 2008-01-24 | 2011-11-30 | 中兴通讯股份有限公司 | Method and device for multi sound source sharing audio power amplifier |
-
1999
- 1999-09-21 CN CN 99116677 patent/CN1110891C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100433546C (en) * | 2001-03-26 | 2008-11-12 | 哈曼国际工业有限公司 | Digital signal processor enhanced pulse width modulation amplifier |
| CN101232744B (en) * | 2008-01-24 | 2011-11-30 | 中兴通讯股份有限公司 | Method and device for multi sound source sharing audio power amplifier |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1110891C (en) | 2003-06-04 |
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