CN207910740U - A kind of gain increases and increased differential amplifier circuit with frequency - Google Patents
A kind of gain increases and increased differential amplifier circuit with frequency Download PDFInfo
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- CN207910740U CN207910740U CN201820229749.7U CN201820229749U CN207910740U CN 207910740 U CN207910740 U CN 207910740U CN 201820229749 U CN201820229749 U CN 201820229749U CN 207910740 U CN207910740 U CN 207910740U
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- differential amplifier
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Abstract
The utility model discloses a kind of gains to increase and increased differential amplifier circuit with frequency, including amplifier Q1, anti-phase input resistance R1, positive input resistance R2, feedback resistance R3, ground resistance R4, the inverting input In connection anti-phase input resistance R1 of amplifier Q1 constitutes inversion signal input terminal, the normal phase input end In+ connection positive input resistances R2 of amplifier Q1 constitutes positive signal input part, feedback resistance R3 mono- terminates the output end Out of amplifier Q1, one end meets inverting input In, ground resistance R4 mono- terminates normal phase input end In+, one end is grounded, one inductance L1 of feedback resistance R3 series connection, one inductance L2 of ground resistance R4 series connection.Due to an inductance of having connected at feedback resistance, the problem of eliminating differential amplifier circuit the gain caused by parasitic capacitance decline in high frequency.By using the frequency response characteristic of inductance, when low frequency amplifying circuit gain keep former designing gain constant substantially, when high frequency, improves the gain of circuit and the amplitude of output signal.
Description
Technical field
The utility model is related to a kind of circuit, especially a kind of gain increases and increased differential amplifier circuit with frequency.
Background technology
In electronic field, differential amplifier circuit is a kind of very common circuit.Ideally, differential amplifier circuit exists
In the case that each parameter setting is good, output keeps certain amplification factor with input, it is meant that in the bandwidth of amplifier, that is, works
Identical gain is kept in frequency range.But in a practical situation, there are parasitic capacitances in circuit, according to the Frequency Response of capacitance, when frequency
When rate is higher and higher, the impedance of load can decline, and the amplification factor of differential amplifier circuit can be caused to reduce in this way, i.e. gain can drop
Low, amplitude output signal reduces, or even causes to be distorted and be delayed.The prior art has by changing the feedback resistance of amplifier and defeated
Enter the ratio of resistance and make change in gain, but in actual circuit, for the signal of different frequency, the gain of circuit can not
It is always maintained at, but has a declining tendency with increasing for frequency.
Utility model content
To solve problem of the prior art, increases and increase with frequency the purpose of this utility model is to provide a kind of gain
Differential amplifier circuit, output when signal frequency increases in circuit increases gain, and gain is kept substantially when signal is low frequency
Former designing gain is constant.
The utility model is technical solution used by solving the problems, such as it：
A kind of gain increases and increased differential amplifier circuit with frequency, including amplifier Q1, anti-phase input resistance R1, just
Phase input resistance R2, feedback resistance R3, ground resistance R4, the inverting input In- connection anti-phase input resistance R1 of amplifier Q1
Inversion signal input terminal is constituted, the normal phase input end In+ connection positive input resistances R2 of amplifier Q1 constitutes positive phase signals input
End, feedback resistance R3 mono- terminate the output end Out of amplifier Q1, and one end meets inverting input In-, and ground resistance R4 mono- is terminated just
Phase input terminal In+, one end ground connection, feedback resistance R3 one inductance L1 of series connection, one inductance L2 of ground resistance R4 series connection.
Preferably, connect a filter capacitor C1 between the inversion signal input terminal and R1, positive signal input part with
Connect a filter capacitor C2 between R2.
Preferably, the anti-phase input resistance R1 is identical as positive input resistance R2 resistance values, feedback resistance R3 and ground connection electricity
It is identical to hinder R4 resistance values.
Preferably, the inductance L1 and L2 is identical.
Preferably, the capacitance C1 and C2 is identical.
Preferably, the Ratio invariableness of the resistance value of the feedback resistance R3 and the resistance value of anti-phase input resistance R1.
The utility model has the beneficial effects that：
By said program it is found that due to having connected an inductance in feedback resistance, differential amplifier circuit is eliminated in height
The problem of gain caused by parasitic capacitance declines when frequency.By using the frequency response characteristic of inductance, amplification electricity when low frequency
Road gain keeps former designing gain constant substantially, and when high frequency improves the gain of circuit and the amplitude of output signal.
Description of the drawings
Fig. 1 is the utility model circuit structure diagram.
Specific implementation mode：
The utility model is described in further detail with example below in conjunction with the accompanying drawings.
As shown in Figure 1, a kind of gain with frequency increase and increased differential amplifier circuit, including amplifier Q1, reverse phase are defeated
Enter resistance R1, positive input resistance R2, feedback resistance R3, ground resistance R4, the inverting input In- connection reverse phases of amplifier Q1
Input resistance R1 constitutes inversion signal input terminal, and the normal phase input end In+ connection positive input resistances R2 of amplifier Q1 is constituted just
Phase signals input terminal, feedback resistance R3 mono- terminate the output end Out of amplifier Q1, and one end connects inverting input In-, ground resistance
R4 mono- terminates normal phase input end In+, one end ground connection, feedback resistance R3 one inductance L1 of series connection, ground resistance R4 one electricity of series connection
Feel L2.
Specially：In order to avoid noise, connect a filter capacitor C1 between inversion signal input terminal and R1, positive phase signals
Connect a filter capacitor C2 between input terminal and R2, in this way can also DC-offset correction.
In order to ensure the symmetry characteristic of differential amplifier circuit, common-mode signal is eliminated as much as possible, the element in circuit
Respectively symmetrical, anti-phase input resistance R1 is identical as positive input resistance R2 resistance values, feedback resistance R3 and ground resistance R4 resistance value phases
Together.Inductance L1 and L2 is identical, and capacitance C1 and C2 is identical.The ratio of the resistance value of feedback resistance R3 and the resistance value of anti-phase input resistance R1
It is constant.
Its working principle is that：After amplifying circuit is started to work, two-way input signal enters from positive inversion signal input terminal
Circuit, since input voltage is smaller, the voltage swing of differential output signal is also little.Feedback unit acquires the letter of output end
Number, it is transmitted, constitutes closed loop.When signal frequency increases, due to parasitic capacitance present in circuit, according to capacitance frequency
Characteristic is rung, the impedance of capacitance is smaller when frequency is bigger, and the impedance loaded in circuit is caused to reduce, and amplitude output signal size is than reason
Output signal in the case of thinking is small, and with distortion and delay, and especially small signal is more also easy to produce decline in circuit transmission.And
According to the Frequency Response of inductance, impedance is bigger when frequency is bigger, therefore in high frequency, L1 will make the impedance of load increase, and balance out
Decaying caused by capacitance.The resistance R4 of normal phase input end In+ plays balanced action, in order to ensure the symmetry of differential amplifier circuit,
Therefore the inductance L2 that connects again after the balance resistance R4 of positive input terminal, at this time entire circuit can reach the effect of fading compensation.
Certainly, the above embodiment is not unique restriction to the utility model, other equivalent technical solutions should also be as
Within the protection domain of the invention.
Claims (6)
1. a kind of gain increases and increased differential amplifier circuit with frequency, including amplifier Q1, anti-phase input resistance R1, positive
Input resistance R2, feedback resistance R3, ground resistance R4, the inverting input In- connection anti-phase input resistance R1 structures of amplifier Q1
At inversion signal input terminal, the normal phase input end In+ connection positive input resistances R2 of amplifier Q1 constitutes positive signal input part,
Feedback resistance R3 mono- terminates the output end Out of amplifier Q1, and one end meets inverting input In-, and ground resistance R4 mono- terminates positive
Input terminal In+, one end ground connection, it is characterised in that：Feedback resistance R3 one inductance L1 of series connection, ground resistance R4 one inductance of series connection
L2。
2. a kind of gain according to claim 1 increases and increased differential amplifier circuit with frequency, it is characterised in that：Institute
The filter capacitor C1 that connects between inversion signal input terminal and R1 is stated, a filtering of connecting between positive signal input part and R2
Capacitance C2.
3. a kind of gain according to claim 1 increases and increased differential amplifier circuit with frequency, it is characterised in that：Institute
It is identical as positive input resistance R2 resistance values to state anti-phase input resistance R1, feedback resistance R3 is identical as ground resistance R4 resistance values.
4. a kind of gain according to claim 1 increases and increased differential amplifier circuit with frequency, it is characterised in that：Institute
It is identical to state inductance L1 and L2.
5. a kind of gain according to claim 2 increases and increased differential amplifier circuit with frequency, it is characterised in that：Institute
It is identical to state capacitance C1 and C2.
6. a kind of gain according to claim 1 increases and increased differential amplifier circuit with frequency, it is characterised in that：Institute
State the Ratio invariableness of the resistance value of feedback resistance R3 and the resistance value of anti-phase input resistance R1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820229749.7U CN207910740U (en) | 2018-02-08 | 2018-02-08 | A kind of gain increases and increased differential amplifier circuit with frequency |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820229749.7U CN207910740U (en) | 2018-02-08 | 2018-02-08 | A kind of gain increases and increased differential amplifier circuit with frequency |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207910740U true CN207910740U (en) | 2018-09-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820229749.7U Active CN207910740U (en) | 2018-02-08 | 2018-02-08 | A kind of gain increases and increased differential amplifier circuit with frequency |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109150123A (en) * | 2018-09-28 | 2019-01-04 | 佛山市顺德区中山大学研究院 | A kind of small-signal pre-amplification circuit of high-gain |
-
2018
- 2018-02-08 CN CN201820229749.7U patent/CN207910740U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109150123A (en) * | 2018-09-28 | 2019-01-04 | 佛山市顺德区中山大学研究院 | A kind of small-signal pre-amplification circuit of high-gain |
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