A kind of High-gain differential signal amplification circuit
Technical field
The present invention relates to a kind of High-gain differential signal amplification circuit, belong to electricity field.
Background technology
Differential amplifier circuit utilizes symmetry and the negative feedback of circuit parameter, effectively stablize quiescent point, to amplify difference mode signal suppression common-mode signal as marked feature, it is widely used in the input stage of direct-coupled circuit and measuring circuit, but the most structure of differential amplifier circuit is complicated, it is loaded down with trivial details to analyze.
Conventional differential amplifier circuit is limited due to common-mode input range, has certain limitations the input signal input amplitude of oscillation, and the gain of single-stage amplifying circuit is relatively low simultaneously, and speed is relatively slow, is unfavorable for processing the voltage signal that data traffic is big, voltage swing is big.
Summary of the invention
The invention provides a kind of High-gain differential signal amplification circuit, solve conventional circuit for amplifying differential signal and limit big to the signal input amplitude of oscillation, range of application is not wide, the problem low, slow-footed of gain simultaneously.
nullFor solving above-mentioned technical problem,The present invention is by the following technical solutions: a kind of High-gain differential signal amplification circuit,Including the first amplifier U1 and the second amplifier U2,The in-phase input end of the first amplifier U1 connects positive signal input circuit,The inverting input of described first amplifier U1 connects inversion signal input circuit,Electric capacity C1 it is also associated with between inversion signal input circuit and positive signal input circuit,Described first amplifier U1 outfan by resistance R1 connect described second amplifier U2 in-phase input end,Described second amplifier U2 outfan connects output circuit by resistance R3,The inverting input of described second amplifier U2 is connected to the second amplifier U2 outfan and common port of resistance R3,Described positive signal input circuit is also associated with grounded circuit,Grounded circuit connects output circuit by resistance R4,It is also associated with resistance R2 between inverting input and the in-phase input end of the second amplifier U2 of described first amplifier U1.
It is also associated with electric capacity C2 between inverting input and the in-phase input end of the second amplifier U2 of described first amplifier U1.
It is also associated with electric capacity C3 between earth terminal and the output circuit of described grounded circuit.
The voltage ratio of described resistance R1 and resistance R2 is 4-6:1.
All employings LM358 type amplifier of the first amplifier U1 and the second amplifier U2.
Compared with prior art, the invention has the beneficial effects as follows: this High-gain differential signal amplification circuit of present invention design, be not only simple in structure, the signal input amplitude of oscillation limits little, and signal-data processing amount is big, and signal gain is high, and processing speed is fast.
Accompanying drawing explanation
With detailed description of the invention, the present invention is described in further detail below in conjunction with the accompanying drawings.
Fig. 1 is the schematic diagram of the present invention.
Detailed description of the invention
The present invention is further illustrated below in conjunction with the accompanying drawings.
Embodiment 1
nullA kind of High-gain differential signal amplification circuit as shown in Figure 1,Including the first amplifier U1 and the second amplifier U2,The in-phase input end of the first amplifier U1 connects positive signal input circuit,The inverting input of described first amplifier U1 connects inversion signal input circuit,Electric capacity C1 it is also associated with between inversion signal input circuit and positive signal input circuit,Described first amplifier U1 outfan by resistance R1 connect described second amplifier U2 in-phase input end,Described second amplifier U2 outfan connects output circuit by resistance R3,The inverting input of described second amplifier U2 is connected to the second amplifier U2 outfan and common port of resistance R3,Described positive signal input circuit is also associated with grounded circuit,Grounded circuit connects output circuit by resistance R4,It is also associated with resistance R2 between inverting input and the in-phase input end of the second amplifier U2 of described first amplifier U1.
The C1 of the present embodiment is used for eliminating offset influence, after faint AC differential signal is amplified and input signal is converted into DC voltage by the first amplifier U1, by resistance R1 and resistance R2 dividing potential drop to next stage direct current incoming level, next stage direct current incoming level regulates output voltage amplitude by resistance R3 and resistance R4, with the signal obtaining high-gain, voltage swing is big after inputting the second amplifier U2;The first amplifier U1 of the present embodiment can increase the signal input amplitude of oscillation, and offset influence can be eliminated, improve signal input precision, simultaneously by the common effect of the first amplifier U1 and the second amplifier U2, improve signal-data processing amount, add signal gain and processing speed.
Embodiment 2
The present embodiment adds following structure on the basis of embodiment 1: be also associated with electric capacity C2 between inverting input and the in-phase input end of the second amplifier U2 of described first amplifier U1.
The present embodiment electric capacity C2 is used for filtering, and can eliminate the external interference of the first amplifier U1 output signal.
Embodiment 3
The present embodiment has done following optimization on the basis of embodiment 1 or embodiment 2: be also associated with electric capacity C3 between earth terminal and the output circuit of described grounded circuit.
The present embodiment electric capacity C3 is equally used for filtering, can eliminate the external interference of the second amplifier U2 output signal, improves and amplifies signal accuracy.
Embodiment 4
The present embodiment has done following optimization on the basis of any of the above-described embodiment: the voltage ratio of described resistance R1 and resistance R2 is 4-6:1.
In the present embodiment, when the voltage ratio of resistance R1 and resistance R2 is in the range of 4-6:1, input voltage can be down to the 1/3-1/2 of supply voltage, and amplification effect now is best, can improve signal gain.
Embodiment 5
Embodiment 5 is most highly preferred embodiment of the invention
The present embodiment has done following optimization on the basis of any of the above-described embodiment: all employings LM358 type amplifier of described first amplifier U1 and the second amplifier U2.
In the present embodiment, LM358 type amplifier includes dual operational amplifier that two independent, that high-gain, internal frequency compensate, and price is low, excellent performance, can improve the gain of signal amplification circuit.
It is embodiments of the invention as mentioned above.The present invention is not limited to above-mentioned embodiment, and anyone should learn the structure change made under the enlightenment of the present invention, and every have same or like technical scheme, within each falling within protection scope of the present invention with the present invention.