CN1171655A - Stabilization of operating point of push-pull output stage in power amplifier - Google Patents
Stabilization of operating point of push-pull output stage in power amplifier Download PDFInfo
- Publication number
- CN1171655A CN1171655A CN 96108691 CN96108691A CN1171655A CN 1171655 A CN1171655 A CN 1171655A CN 96108691 CN96108691 CN 96108691 CN 96108691 A CN96108691 A CN 96108691A CN 1171655 A CN1171655 A CN 1171655A
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- CN
- China
- Prior art keywords
- circuit
- power amplifier
- output
- current
- minimum value
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- Pending
Links
- 230000006641 stabilisation Effects 0.000 title 1
- 238000011105 stabilization Methods 0.000 title 1
- 238000001514 detection method Methods 0.000 claims description 8
- 238000005070 sampling Methods 0.000 claims description 6
- 230000009466 transformation Effects 0.000 claims description 5
- 238000000034 method Methods 0.000 abstract description 3
- 238000009499 grossing Methods 0.000 abstract description 2
- 230000000087 stabilizing effect Effects 0.000 abstract description 2
- 238000006243 chemical reaction Methods 0.000 abstract 1
- 230000000694 effects Effects 0.000 abstract 1
- 230000003068 static effect Effects 0.000 description 11
- 230000001737 promoting effect Effects 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
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Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/26—Push-pull amplifiers; Phase-splitters therefor
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
Abstract
A method for stabilizing the operating point of push-pull output stage in power amplifier circuit features that the dynamic minimal value of voltage sample sum (R + 1 i + 1 + R_ 1 i - 1) is detected and held. Its circuit includes said detector and holdercircuit, smoothing filter circuit and offset conversion controller circuit. Its advantages are high effect to stabilize operating point, reducing output impedance, and low distortion.
Description
The present invention relates to an audio power amplifier circuit transistor and recommend the output current amplifying stage and keep thermally-stabilised circuit, can be used in the transistor high-fidelity power amplifier.
At present, recommend in the output current amplifying stage at the transistor audio frequency power amplifier, stable for guaranteeing the output stage working heat, comprehensively take following measure on circuit design: setover with the temperature sensing element compensation (1); (2) the emitter feedback resistance is got appropriate value; (3) strengthen heat radiation etc., above method makes circuit design that limitation be arranged, and some circuit configurations can not adopt at all, the raising of restricting circuits performance.
The object of the present invention is to provide a power amplifier to recommend the stable of output services point.
Basic push-pull power amplifier circuital current amplifying stage is by biasing circuit, promoting the synthetic level of level and output forms, some circuit configurations can not promote level, the synthetic level of output is exported to form by positive half cycle and negative half period and is recommended synthetic output, positive and negative half cycle is exported available many homotype elements and is formed state in parallel to improve power output, reduces output impedance.The present invention detects for the output stage working point and raises the clothes circuit, and circuit is made of sample circuit, minimum value detection and holding circuit, smoothed filter circuit, biasing control transformation circuit, and the course of work is positive and negative half cycle output current weighting numerical value of sampling and R
+| i+|+R
-| i
-|, i in the formula
+, i
-Be positive and negative half cycle output stage electric current, when output stage adopts parallel way, i
+, i
-Can be part or all of parallel level output stage electric current, R
+, R
-Be i
+, i
-Weighted sampling resistance, sampling voltage send minimum value to detect and holding circuit, the minimum value that is detected send smoothing circuit to get gradual direct current signal, and this direct current signal is sent into biasing circuit in order to the signal of control biasing control transformation circuit generation control biasing size and constituted feedback control loop.When the detection minimum value diminished, the control biasing circuit increased output stage working point electric current, and the control biasing circuit reduces output stage working point electric current when the detection minimum value becomes big.
When the circuit parameter symmetry, sampling voltage R
+| i
+|+R
-| i
-| minimum be zero to be that the static working current place reaches at load current; When circuit parameter was not exclusively symmetrical, its minimum reached when load current is non-vanishing.
Certain in static working current, the output load current amplitude of oscillation is big more, dynamically the scope of minimum value detection is big more, detected dynamic minimum value is more little, when hunting range comprised minimizing load current, detected dynamic minimum value reached minimum, and when no AC load electric current output, the hunting range minimum, detected dynamic minimum value maximum.
When feed service system of the present invention work, always attempt to keep the dynamic minimum value that detects constant, promptly when minimum value becomes big, reduce static working current, when minimum value diminishes, the increase static working current.Static working current minimum when no AC load electric current output static is then arranged, reach maximum when output voltage swing reaches the minimum load current, promptly static working current is minimum is defined with maximum.And when circuit parameter when symmetry, minimum just reaches at the static working current place, and limited static working current minimum value and maximum reach simultaneously, so that static working current is stablized is constant.
The present invention can improve power amplifier push-pull current amplifying stage working point security and stability, power amplifier push-pull current amplifying stage configuration has more flexibility, promote the push-pull current amplifying stage that level and output stage are made up of the heteropolarity triode, because poor heat stability, prior art can not be made practical circuit, and use the present invention can make practical circuit, this configuration can reduce output impedance, reduces distortion.
Fig. 1, basic amplifier circuit figure.
Fig. 2, Detection ﹠ Controling circuit diagram.
Describe below in conjunction with accompanying drawing: C among Fig. 1
1Be input capacitance, IC
1, R
1, R
2, R
3, C
2Be voltage amplifier stage, voltage gain R
3/ R
2, amplification outputs to R
4, R
5Mid point.
T
1, T
2, T
3, T
4, R
4, R
5, R
6, R
7For electric current amplifies output stage.R
4, R
5Be biasing circuit resistance, 2 of A, B link to each other by T among 2 of A, B and Fig. 2
8, T
9Constant-current source at R
4, R
5The voltage of last generation provides bias voltage, and during the constant-current source change, bias voltage also changes.T
1, T
2Promote heteropolarity efferent duct T respectively for promoting level
3, T
4, at T
3, T
4The collector loop of output stage has inserted sample resistance R respectively
8, R
9, the voltage of C, D point-to-point transmission is R
8| i
T3|+R
9| i
T4|, i
T3, i
T4Be T
3, T
4Collector loop electric current C, D between voltage be detection signal of the presently claimed invention, C point high potential, D point electronegative potential, these 2 are connected with C, the D point of Fig. 3.
Amplifying signal is exported to load by the E point.IC
2, R
10, R
11, C
5Raise the clothes circuit for the output point quiescent voltage, its output is connected into the negative input end of voltage amplifier stage amplifier, is used for the static direct current current potential of stabilizing amplifier output point E.
Among Fig. 2, the C point connects power supply mid point E
0, D is connected in the testing circuit input, promptly detects V
C-V
DReversed phase signal V
D-V
CSo, V
C-V
DMinimum value be V
D-V
CMaximum.Constant-current source T
5With W structure discharge position translation circuit, the IC that connects after making
3, D
1, C
21The maximum of forming detects the level range of holding circuit in operate as normal, R
20, R
21, C
22Be smoothed filter circuit.
IC
4, R
22, R
23Detection signal behind the smothing filtering is amplified, promote by T
6, T
7, T
8, T
9, R
24, R
25, R
26, R
27, R
28The biasing control transformation circuit of forming, this circuit converts detectable voltage signals to T
8, T
9Constant current output.Constant current outputs to R
4, R
5A, B point, produce electric current amplifying stage bias voltage.
Returning the feedback control procedure is: work as V
C-V
DWhen the point minimum value increases, detect maximum output and reduce T
8, T
9Electric current reduces, R
4, R
5Upper offset voltage reduces, T
1, T
2, T
3, T
4The working point electric current reduces.Work as V
C-V
DWhen minimum value reduces, detect maximum output and increase T
8, T
9Electric current increases, R
4, R
5Upper offset voltage increases, T
1, T
2, T
3, T
4The working point electric current increases.
Claims (3)
1, a kind of power amplifier is recommended the stable of output services point, it is characterized in that: by sampling voltage numerical value be R
+| i
+|+R
-| i
-| dynamic minimum value control biasing circuit.
2, recommend the stable of output services point according to the described power amplifier of claim, it is characterized in that: the dynamic minimum value by sampling voltage numerical value detects and holding circuit, and biasing control transformation circuit is realized.
3, according to claim, described power amplifier is recommended the stable of output services point, it is characterized in that: dynamically adding smoothed filter circuit between minimum value detection and holding circuit and biasing control transformation circuit.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96108691 CN1171655A (en) | 1996-07-19 | 1996-07-19 | Stabilization of operating point of push-pull output stage in power amplifier |
| PCT/CN1997/000055 WO1998004035A1 (en) | 1996-07-19 | 1997-05-30 | Stable method of working point for push-pull output stage of power amplifying circuit and circuit thereof |
| AU29482/97A AU2948297A (en) | 1996-07-19 | 1997-05-30 | Stable method of working point for push-pull output stage of power amplifying circuit and circuit thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 96108691 CN1171655A (en) | 1996-07-19 | 1996-07-19 | Stabilization of operating point of push-pull output stage in power amplifier |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1171655A true CN1171655A (en) | 1998-01-28 |
Family
ID=5120053
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 96108691 Pending CN1171655A (en) | 1996-07-19 | 1996-07-19 | Stabilization of operating point of push-pull output stage in power amplifier |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN1171655A (en) |
| AU (1) | AU2948297A (en) |
| WO (1) | WO1998004035A1 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1020227C (en) * | 1990-07-05 | 1993-03-31 | 徐耀忠 | Efficient audio power amplifier |
| JP3321897B2 (en) * | 1992-05-29 | 2002-09-09 | ヤマハ株式会社 | Amplifier circuit |
| JP2976770B2 (en) * | 1993-09-01 | 1999-11-10 | ヤマハ株式会社 | Amplifier circuit |
-
1996
- 1996-07-19 CN CN 96108691 patent/CN1171655A/en active Pending
-
1997
- 1997-05-30 WO PCT/CN1997/000055 patent/WO1998004035A1/en active Application Filing
- 1997-05-30 AU AU29482/97A patent/AU2948297A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| AU2948297A (en) | 1998-02-10 |
| WO1998004035A1 (en) | 1998-01-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |