CN1681201A - Resistance-capacitance balanced feedback negative circuit - Google Patents
Resistance-capacitance balanced feedback negative circuit Download PDFInfo
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- CN1681201A CN1681201A CN 200410023080 CN200410023080A CN1681201A CN 1681201 A CN1681201 A CN 1681201A CN 200410023080 CN200410023080 CN 200410023080 CN 200410023080 A CN200410023080 A CN 200410023080A CN 1681201 A CN1681201 A CN 1681201A
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- resistance
- feedback circuit
- capacitor
- amplifier
- capacitance
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Abstract
The invention consists of resistor R2 connected with feedback circuit between output and inverting input of amplifier, the resistor R1 making ground connection with inverting input, and capacitor. The capacitor C2 connected with the feedback circuit between output and inverting input of amplifier is connected in series with resistor R2 to make it have phase balance with capacitor C1, and make impedance rate R2/R1 equal capacitive reactance rate C1/C2, which equals amplification of amplifier. The high resistant value resistor R3 is connected in parallel with the feedback circuit formed by R2 and C2.
Description
Technical field
The invention belongs to electronic circuit amplifier technical field, relate to a kind of capacitance-resistance balanced type negative-feedback circuit.
Background technology
In amplifying circuit (especially voicefrequency circuit), use negative-feedback circuit through regular meeting.The most basic negative-feedback circuit as shown in Figure 1.Its multiplication factor depends on resistance R
2With R
1The ratio.But sort circuit has a very serious defective: because capacitor C
1Existence, make signal, particularly low frequency signal (ten to tens hertz) after the amplification produce very big phase shift and multiple reduces (being distortion), one of solution is the cancellation capacitor C
1, but to add the mid point servo circuit simultaneously.This scheme circuit structure complexity, used components and parts also more (comprising a computing integrated package).Thereby make the also corresponding increase of production cost.
Summary of the invention
Technical problem to be solved by this invention is at existing above-mentioned defective in the existing amplifier negative-feedback circuit, and the capacitance-resistance balanced type negative-feedback circuit that a kind of practical, simple in structure, multiplication factor is stable, fidelity is good is provided.
Solve technical scheme that the technology of the present invention problem adopted and be this capacitance-resistance balanced type negative-feedback circuit and comprise the output that is connected amplifier and the feedback circuit resistance R between the reverse input end
2, the series connection that is connected with reverse input end ground connection resistance R
1, capacitor C
1, it is characterized in that on the feedback circuit between the output of amplifier and the reverse input end, being connected capacitor C
2With resistance R
2Series connection makes it the capacitor C that is connected with reverse input end ground connection
1Balance each other, make the ratio R of impedance
2/ R
1Equal the ratio C of capacitive reactance
1/ C
2, promptly equal the multiplication factor of operational amplifier, simultaneously and the resistance R of connecting
2, capacitor C
2The feedback circuit that the forms high value resistor R that is in parallel
3
The present invention only increases a resistance and an electric capacity in former feedback circuit, make the circuit multiplication factor stable, do not produce phase shifts, reduce the appearance of distortion phenomenon, its frequency response can be low to moderate 5Hz even 2Hz easily, expanded the LF-response of amplifier greatly, it is equivalent to the mid point servo circuit, but simplifies greatly than mid point servo circuit structure.And in the audio frequency negative-feedback circuit, do not had the prejudicial electrochemical capacitor of tonequality.To capacitor C
1, C
2Value can adopt less numerical value, can adopt the good nonpolar electric capacity of performance like this, be specially adapted to high-quality voice frequency electronics.
Description of drawings
Conventional negative-feedback circuit figure in Fig. 1 prior art amplifier
The negative-feedback circuit figure that has the mid point servo circuit in Fig. 2 prior art amplifier
Fig. 3 is capacitance-resistance balanced type negative-feedback circuit figure of the present invention
Among the figure: A-amplifier R-resistance C-electric capacity
Embodiment
Fig. 3 is a preferred forms of the present invention.Present embodiment is the prime that operational amplifier A is used for audio frequency amplifier, and output of the operational amplifier A of being connected and the feedback circuit resistance R between the reverse input end are arranged
2, the series connection that is connected with reverse input end ground connection resistance R
1, capacitor C
1, on the output of operational amplifier A and the feedback circuit between the reverse input end, be connected with capacitor C
2With resistance R
2Series connection makes it the capacitor C that is connected with reverse input end ground connection
1Balance each other, make the ratio R of impedance
2/ R
1Equal the ratio C of capacitive reactance
1/ C
2, like this, no matter how frequency changes, and the output that can both guarantee signal is identical all the time with multiplication factor and phase relation between the input.Simultaneously with the resistance R of connecting
2, capacitor C
2The feedback circuit that the forms high value resistor R that is in parallel
3(more than ten megaohms), its effect are to avoid exporting a DC offset voltage, and its resistance is must be enough big, could guarantee the LF-response cut-off frequency of needs, and 2Hz for example is owing to R
3Bigger, so require amplifier that a sufficiently high input impedance is arranged.If the multiplication factor of operational amplifier A is 33 times, desirable R
2=3.3k Ω, R
1=100 Ω, C
1=3.3 μ F, C
2=0.1 μ F, R
3=47M Ω, R
2/ R
1=C
1/ C
2=33, because the capacitor C of on feedback circuit, having connected
2Make it and capacitor C
1Balance has been eliminated by C
1The low-frequency distortion phenomenon that causes.In this audible feedback circuit, do not adopt electrochemical capacitor, and adopt the nonpolar electric capacity of quality better.Therefore be specially adapted to high-quality voice frequency electronics.It is high that the input impedance that an important requirement of its pair amplifier is an amplifier is wanted.
Adopt voice frequency electronics of the present invention, the audio playback effect has very significantly to be improved, and obviously increases telepresenc on the sense of hearing.
Claims (3)
1, a kind of capacitance-resistance balanced type negative-feedback circuit comprises the output that is connected amplifier and the feedback circuit resistance R between the reverse input end
2, the series connection that is connected with reverse input end ground connection resistance R
1, capacitor C
1, it is characterized in that on the feedback circuit between the output of amplifier and the reverse input end, being connected capacitor C
2With resistance R
2Series connection makes it the capacitor C that is connected with reverse input end ground connection
1Balance each other, have and the resistance R of connecting
2, capacitor C
2The high value resistor R that the feedback circuit that forms is in parallel
3
2, capacitance-resistance balanced type negative-feedback circuit according to claim 1 is characterized in that the ratio R of impedance
2/ R
1Equal the ratio C of capacitive reactance
1/ C
2
3, capacitance-resistance balanced type negative-feedback circuit according to claim 1 and 2 is characterized in that capacitor C
1, C
2Adopt the nonpolar electric capacity of quality better.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410023080 CN1681201A (en) | 2004-04-06 | 2004-04-06 | Resistance-capacitance balanced feedback negative circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410023080 CN1681201A (en) | 2004-04-06 | 2004-04-06 | Resistance-capacitance balanced feedback negative circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1681201A true CN1681201A (en) | 2005-10-12 |
Family
ID=35067661
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200410023080 Pending CN1681201A (en) | 2004-04-06 | 2004-04-06 | Resistance-capacitance balanced feedback negative circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1681201A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101350598B (en) * | 2007-07-19 | 2010-05-19 | 展讯通信（上海）有限公司 | Two-way feedback single-power supply audio power amplifier |
| CN101325402B (en) * | 2007-06-15 | 2010-09-29 | 展讯通信（上海）有限公司 | Audio power amplifier with improved low frequency performance |
| WO2022241627A1 (en) * | 2021-05-17 | 2022-11-24 | 广州拓品技术有限公司 | Feed forward amplification circuit, audio amplifier, and audio playing apparatus |
-
2004
- 2004-04-06 CN CN 200410023080 patent/CN1681201A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101325402B (en) * | 2007-06-15 | 2010-09-29 | 展讯通信（上海）有限公司 | Audio power amplifier with improved low frequency performance |
| CN101350598B (en) * | 2007-07-19 | 2010-05-19 | 展讯通信（上海）有限公司 | Two-way feedback single-power supply audio power amplifier |
| WO2022241627A1 (en) * | 2021-05-17 | 2022-11-24 | 广州拓品技术有限公司 | Feed forward amplification circuit, audio amplifier, and audio playing apparatus |
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Legal Events
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|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| AD01 | Patent right deemed abandoned | ||
| C20 | Patent right or utility model deemed to be abandoned or is abandoned |