CN111416580A - Variable gain and stable-bandwidth micro-amplitude signal pre-amplification circuit - Google Patents
Variable gain and stable-bandwidth micro-amplitude signal pre-amplification circuit Download PDFInfo
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Abstract
The invention relates to the technical field of integrated circuits, and discloses a micro amplitude signal pre-amplifying circuit with stable variable gain and bandwidth, which comprises an operational amplifier AMP1, an operational amplifier AMP2, a variable gain digital input end REG, a gain adjustable negative feedback network and a bandwidth adjustable phase compensation network; the non-inverting input terminals of the operational amplifiers AMP1 and AMP2 are pre-amplified differential input terminals, and the gain-adjustable negative feedback network is connected between the output terminals and the inverting input terminals of the operational amplifiers AMP1 and AMP2 in a bridge manner; the phase compensation network is positioned at the output end of the pre-amplifying circuit; the variable gain digital input end REG is respectively connected with a gain adjustable negative feedback network and a phase compensation network; the invention integrates the variable gain amplification structure and the bandwidth stabilization structure, and can improve the linearity and the bandwidth consistency of the amplification circuit so as to obtain a large-amplitude signal with high signal-to-noise ratio.
Description
Technical Field
The invention relates to the technical field of electronic circuits, in particular to a micro-amplitude signal pre-amplifying circuit with variable gain and stable bandwidth.
Background
The original analog signal, which is generally a tiny signal, is generally preprocessed to suppress noise and improve the factors such as zero pole that affect the circuit performance due to its weak driving capability, and the pre-amplifier circuit is widely used in various electronic systems. The conventional amplifier has insufficient gain or overshooting gain, and the bandwidth of the operational amplifier system changes when the gain of the amplifier changes, which causes great errors to subsequent circuits. Therefore, the differential operational amplifier can effectively suppress noise; then, the binary code is used for controlling the variable gain loop, so that the relation between the gain and the dynamic range can be better processed; and meanwhile, the zero pole is adjusted according to the change of the gain, so that the linearity and the bandwidth consistency of the operational amplification circuit are improved.
Referring to fig. 1 typically, in the prior art, a small signal passes through a differential operational amplifier circuit to pre-amplify an input signal, although a dual operational amplifier differential operational amplifier circuit is used to effectively suppress noise, an optimal gain stage cannot be selected according to input signals with different amplitudes, but bandwidth variation caused by gain variation is not compensated.
Disclosure of Invention
In view of the defects in the prior art, an embodiment of the present invention provides a variable gain and bandwidth-stabilized small amplitude signal pre-amplifying circuit to solve the above-mentioned problems in the background art.
In order to achieve the purpose, the invention provides the following technical scheme:
a variable gain and bandwidth stable fine amplitude signal pre-amplifying circuit comprising:
a variable gain amplification structure and a bandwidth stabilization structure; the variable gain amplifying structure comprises a gain adjustable negative feedback network, and the variable gain amplifying structure is connected with a variable gain digital input end REG and changes a resistance value to realize variable gain amplification; the bandwidth stabilizing structure comprises a broadband adjustable phase compensation network, and the bandwidth stabilizing structure is formed by connecting a variable gain digital input end REG, changing the capacitance value of a capacitor and combining an operational amplifier zero-pole network. In the invention, the variable gain amplifying structure specifically comprises a gain adjustable negative feedback network and a variable gain digital input end REG; the gain adjustable negative feedback network is connected between the output end and the inverting input end of the operational amplifier AMP1 and the operational amplifier AMP2 in a bridge mode and is connected with the variable gain digital input end REG to select different gains; the bandwidth stabilizing structure specifically comprises a phase compensation network with adjustable bandwidth and a variable gain digital input end REG; the phase compensation network is positioned at the output ends of the operational amplifier AMP1 and the operational amplifier AMP2 and is connected with the variable gain digital input end REG; the structure can be combined with a zero-pole compensation circuit of the operational amplifier, and the method for stabilizing the bandwidth is to adjust the zero-pole of the compensation circuit according to the gain change so that the bandwidth of the operational amplifier is kept stable.
Specifically, a variable gain digital input end REG is respectively connected to a gain adjustable negative feedback network and a phase compensation network; adjusting a switch according to a binary code input by the REG to change the resistance value R2 of the variable resistor, wherein the binary code represents a feedback network for selecting different gains; and meanwhile, according to a binary code input by the REG, the switch is adjusted, so that the capacitance value C1 of the variable capacitor is changed, and the RC zero pole of the operational amplifier phase is moved to the set bandwidth.
As a further aspect of the present invention, the present invention includes an operational amplifier AMP1, an operational amplifier AMP2, a variable gain digital input REG, a gain adjustable negative feedback network and a bandwidth adjustable phase compensation network;
the non-inverting input end of the operational amplifier AMP1 and the non-inverting input end of the operational amplifier AMP2 are used as pre-amplified differential signal input ends; the output terminal of the operational amplifier AMP1 and the output terminal of the operational amplifier AMP2 serve as two output terminals of the pre-amplification circuit.
In the invention, a variable gain amplification structure and a bandwidth stabilization structure are integrated; the non-inverting input end of the operational amplifier AMP1 and the non-inverting input end of the operational amplifier AMP2 are used as pre-amplified differential signal input ends, the gain-adjustable negative feedback network is composed of a resistor network, and a resistance value is changed by connecting a variable gain digital input end REG to realize a variable gain amplification structure by using a binary code; the phase compensation network consists of a resistor and a capacitor network, and is combined with the operational amplifier zero-pole network to form a bandwidth stable structure by connecting the variable gain digital input end REG.
As a further scheme of the invention, the output end of the operational amplifier AMP1 and the output end of the operational amplifier AMP2 are respectively connected with the phase compensation network with adjustable bandwidth; the gain adjustable negative feedback network is connected between the output end and the inverting input end of the operational amplifier AMP1 and the operational amplifier AMP2 in a bridge mode, and the variable gain digital input end REG is connected with the gain adjustable negative feedback network and the bandwidth adjustable phase compensation network respectively.
As a further scheme of the present invention, the positive terminal of the AMP1 is connected to the positive input of the amplifying circuit, the negative terminal is connected to the feedback resistance network, and the output of the AMP1 is an operational amplifier positive output; and the positive end of the AMP2 is connected with the negative input of the amplifying circuit, the negative end of the AMP2 is connected with the feedback resistance network, and the output of the AMP2 is the negative output of the operational amplifier. In the present invention, the non-inverting input terminal of the operational amplifier AMP1 and the non-inverting input terminal of the operational amplifier AMP2 serve as the differential signal input terminals INP and INN of the pre-amplification circuit; the output end of the operational amplifier AMP1 and the output end of the operational amplifier AMP2 are used as two output ends OUTP, OUTN of the pre-amplification circuit; the inverting input terminal of the operational amplifier AMP1 and the inverting input terminal of the operational amplifier AMP2 are connected to both output terminals of the pre-amplifying circuit via a gain adjustable negative feedback network constituted by a resistor network.
As a further scheme of the invention, the gain adjustable negative feedback network comprises a resistor R2, a resistor R3 and a resistor R4; one end of the resistor R3 is connected with the output of the operational amplifier AMP1, the other end of the resistor R3 is connected with the variable resistor R2, and the common end of the resistor R3 and the resistor R2 is connected with the inverting input end of the operational amplifier AMP1 to form a negative feedback loop; one end of the resistor R4 is connected with the output of the operational amplifier AMP2, the other end of the resistor R4 is connected with the variable resistor R2, and the common end of the resistor R4 and the resistor R2 is connected with the inverting input end of the operational amplifier AMP2 to form a negative feedback loop; wherein, the resistances of the resistor R3 and the resistor R4 are the same.
As a further aspect of the present invention, the wideband adjustable phase compensation network includes a resistor R1, a variable capacitor C1, a resistor R5, and a variable capacitor C2; the output end of the operational amplifier AMP1 is connected in series with a resistor R1 through a capacitor C1 to the phase compensation end of the operational amplifier AMP1, and the output end of the operational amplifier AMP2 is connected in series with a resistor R5 through a capacitor C2 to the phase compensation end of the operational amplifier AMP 2.
As a further aspect of the present invention, the variable gain digital input REG is respectively connected to a gain adjustable negative feedback network and a phase compensation network; adjusting a switch according to a binary code input by the REG to change the resistance value R2 of the variable resistor, wherein the binary code represents a feedback network for selecting different gains; and meanwhile, according to a binary code input by the REG, the switch is adjusted, so that the capacitance value C1 of the variable capacitor is changed, and the RC zero pole of the operational amplifier phase is moved to the set bandwidth.
As a further scheme of the invention, the operational amplifiers AMP1 and AMP2 are two identical operational amplifiers; the non-inverting input end of the operational amplifier AMP1 and the non-inverting input end of the operational amplifier AMP2 are used as differential signal input ends INP and INN of the pre-amplification circuit; the output terminal of the operational amplifier AMP1 and the output terminal of the operational amplifier AMP2 serve as two output terminals OUTP, OUTN of the pre-amplification circuit. In the invention, the operational amplifiers AMP1 and AMP2 adopt two identical operational amplifiers; the positive end of the AMP1 is connected with the positive input of the amplifying circuit, the negative end of the AMP1 is connected with the feedback resistance network, and the output of the AMP1 is the positive output of the operational amplifier; the positive end of the AMP2 is connected with the negative input of the amplifying circuit, the negative end of the AMP2 is connected with the feedback resistance network, and the output of the AMP2 is the negative output of the operational amplifier; by adopting two identical operational amplifier units, the complexity of the design of a single operational amplifier can be reduced, and the pattern mismatch can be reduced.
The pre-amplifying circuit comprises an operational amplifier AMP1, an operational amplifier AMP2, a variable gain digital input end REG, a gain adjustable negative feedback network and a bandwidth adjustable phase compensation network; the non-inverting input terminals of the operational amplifiers AMP1 and AMP2 are pre-amplified differential input terminals, and the gain-adjustable negative feedback network is connected between the output terminals and the inverting input terminals of the operational amplifiers AMP1 and AMP2 in a bridge manner; the phase compensation network is positioned at the output end of the pre-amplifying circuit; the variable gain digital input end REG is respectively connected with a gain adjustable negative feedback network and a phase compensation network; the invention integrates the variable gain amplification structure and the bandwidth stabilization structure, and can improve the linearity and the bandwidth consistency of the amplification circuit so as to obtain a large-amplitude signal with high signal-to-noise ratio.
The invention has the beneficial effects that:
1. the invention adopts a method of combining a variable gain amplification structure and a bandwidth stabilization structure, and can be combined with a zero-pole compensation circuit of an operational amplifier, so that the operational amplifier bandwidth is kept stable when the gain is changed, the linearity and the bandwidth consistency of the operational amplifier circuit are improved, and a large-amplitude signal with high signal-to-noise ratio is obtained.
2. The invention is applied to an integrated circuit system for pre-amplifying a tiny signal with weak driving capability, so that an amplifying circuit can select an optimal gain gear according to input signals with different amplitudes, simultaneously adjust a zero pole to compensate bandwidth change caused by the gain change, and improve the linearity and the bandwidth consistency of an operational amplifying circuit, thereby obtaining a large-amplitude signal with high signal-to-noise ratio.
To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
Description of the drawings:
FIG. 1 is a circuit diagram of a prior art dual operational amplifier differential pre-amplifying circuit;
FIG. 2 is a circuit diagram of a variable gain and bandwidth stabilized pre-amplification circuit for small amplitude signals according to the present invention;
fig. 3 is a graph of the amplitude-frequency response waveform of the present invention.
The specific implementation mode is as follows:
the invention will be described more fully and clearly in connection with the accompanying drawings and the accompanying knowledge, and it is to be understood that the circuit diagrams described are merely exemplary embodiments of the invention, and are not intended to represent all exemplary embodiments.
Referring to fig. 2 to fig. 3, the present invention provides a gain-variable and bandwidth-stable small amplitude signal pre-amplifying circuit, which mainly solves the problem that the system bandwidth changes when the gain of an operational amplifier changes. The pre-amplifying circuit comprises an operational amplifier AMP1, an operational amplifier AMP2, a variable gain digital input REG, a gain adjustable negative feedback network and a bandwidth adjustable phase compensation network; the non-inverting input terminals of the operational amplifiers AMP1 and AMP2 are pre-amplified differential input terminals, and the gain-adjustable negative feedback network is connected between the output terminals and the inverting input terminals of the operational amplifiers AMP1 and AMP2 in a bridge manner; the phase compensation network is positioned at the output end of the pre-amplifying circuit; the variable gain digital input end REG is respectively connected with a gain adjustable negative feedback network and a phase compensation network; the invention integrates a variable gain amplification structure and a bandwidth stabilization structure, can improve the linearity of an amplification circuit and the consistency of bandwidth so as to obtain a large-amplitude signal with high signal-to-noise ratio, and is applied to an integrated circuit system for pre-amplifying a tiny signal with weak driving capability. The amplifying circuit can select the optimal gain gear according to input signals with different amplitudes, and meanwhile, the zero pole is adjusted to compensate bandwidth change caused by gain change, so that the linearity and the bandwidth consistency of the operational amplifying circuit are improved, and a large-amplitude signal with a high signal-to-noise ratio is obtained. It is noted that in the summary and the detailed description of the present invention, the resistors and capacitors are referred to as the resistors and capacitors in fig. 2.
The specific scheme is as follows:
referring to fig. 2, the system comprises an operational amplifier AMP1, an operational amplifier AMP2, a variable gain digital input REG, a gain adjustable negative feedback network 1, and a bandwidth adjustable phase compensation network 2; the invention integrates a variable gain amplification structure and a bandwidth stabilization structure;
in the invention, the non-inverting input end of the operational amplifier AMP1 and the non-inverting input end of the operational amplifier AMP2 are used as differential signal input ends for pre-amplification, the gain-adjustable negative feedback network 1 is composed of a resistance network, and a resistance value is changed by connecting a variable gain digital input end REG so as to realize a variable gain amplification structure by using a binary code; the phase compensation network 2 with adjustable bandwidth consists of a resistor and a capacitor network, and is combined with an operational amplifier zero-pole network to form a bandwidth stable structure by connecting a variable gain digital input end REG; according to the binary code input by REG, the resistance value R2 of the variable resistor and the capacitance value of the variable capacitor C1 are changed, so that the optimal gain gear is selected according to input signals with different amplitudes, and the zero pole is adjusted to compensate the bandwidth change caused by the gain change.
In a preferred embodiment of the present invention, the non-inverting input of the operational amplifier AMP1 and the non-inverting input of the operational amplifier AMP2 are pre-amplified differential signal inputs INP and INN; the inverting input end of the operational amplifier AMP1 and the inverting input end of the operational amplifier AMP2 are connected with a gain-adjustable negative feedback network formed by a resistor network; the output end of the operational amplifier AMP1 and the output end of the operational amplifier AMP2 are used as two pre-amplified output ends OUTP, OUTN; the variable gain amplifying structure comprises a gain adjustable negative feedback network and a variable gain digital input end REG; the gain adjustable negative feedback network is connected across the output and inverting inputs of operational amplifier AMP1 and operational amplifier AMP2, and is connected to the variable gain digital input REG to select different gains.
In the invention, the bandwidth stabilizing structure comprises a phase compensation network 2 with adjustable bandwidth, a variable gain digital input end REG; the phase compensation network is positioned at the output ends of the operational amplifier AMP1 and the operational amplifier AMP2 and is connected with the variable gain digital input end REG; the structure can be combined with a zero-pole compensation circuit of the operational amplifier, and the method for stabilizing the bandwidth is to adjust the zero-pole of the compensation circuit according to the gain change so that the bandwidth of the operational amplifier is kept stable.
In the invention, a variable gain digital input end REG is respectively connected to a gain adjustable negative feedback network and a phase compensation network; adjusting a switch according to a binary code input by the REG to change the resistance value R2 of the variable resistor, wherein the binary code represents a feedback network for selecting different gains; and meanwhile, according to a binary code input by the REG, the switch is adjusted, so that the capacitance value C1 of the variable capacitor is changed, and the RC zero pole of the operational amplifier phase is correspondingly moved to the set bandwidth.
In summary, the present invention provides a digital signal processing method, which comprises an operational amplifier AMP1, an operational amplifier AMP2, a variable gain digital input REG, a gain adjustable negative feedback network, and a bandwidth adjustable phase compensation network; the non-inverting input terminals of the operational amplifiers AMP1 and AMP2 are pre-amplified differential input terminals, and the gain-adjustable negative feedback network is connected between the output terminals and the inverting input terminals of the operational amplifiers AMP1 and AMP2 in a bridge manner; the phase compensation network is positioned at the output end of the pre-amplifying circuit; the variable gain digital input end REG is respectively connected with a gain adjustable negative feedback network and a phase compensation network; the invention integrates the variable gain amplification structure and the bandwidth stabilization structure, and can improve the linearity and the bandwidth consistency of the amplification circuit so as to obtain a large-amplitude signal with high signal-to-noise ratio.
The following provides specific examples of the invention
Referring to fig. 2, the invention provides a gain-variable and bandwidth-stable micro-amplitude signal pre-amplifying circuit;
the device comprises an operational amplifier AMP1, an operational amplifier AMP2, a variable gain digital input end REG, a gain adjustable negative feedback network and a bandwidth adjustable phase compensation network; the non-inverting input end of the operational amplifier AMP1 and the non-inverting input end of the operational amplifier AMP2 are used as pre-amplified differential signal input ends, and the gain-adjustable negative feedback network is bridged between the output end and the inverting input end of the operational amplifier AMP1 and the operational amplifier AMP2 and then connected with the variable gain digital input end REG to form a variable gain amplification structure; adjusting a switch according to a binary code input by the REG to change the resistance value R2 of the variable resistor so as to select different gains; the phase compensation network is positioned at the output ends of the operational amplifier AMP1 and the operational amplifier AMP2 and then connected with the variable gain digital input end REG to form a bandwidth stable structure; according to the binary code input by REG, the capacitance value of the variable capacitor C1 is changed to make the RC zero pole of the operational amplifier phase move to the set bandwidth.
Wherein, the operational amplifier AMP1 and the operational amplifier AMP2 are two identical operational amplifiers; the positive end of the AMP1 is connected with the positive input of the amplifying circuit, the negative end of the AMP1 is connected with the feedback resistance network, and the output of the AMP1 is the positive output of the operational amplifier; the positive end of the AMP2 is connected with the negative input of the amplifying circuit, the negative end of the AMP2 is connected with the feedback resistance network, and the output of the AMP2 is the negative output of the operational amplifier; by adopting two identical operational amplifier units, the complexity of the design of a single operational amplifier can be reduced, and the pattern mismatch can be reduced. The gain adjustable negative feedback network is bridged between the output end and the inverting input end of the operational amplifier AMP1 and AMP2 and consists of a resistor R2, a resistor R3 and a resistor R4; one end of R3 is connected with the output of the operational amplifier AMP1, the other end is connected with the variable resistor R2, and the common end of R3 and R2 is connected with the inverting input end of the operational amplifier AMP1 to form a negative feedback loop; one end of R4 is connected with the output of the operational amplifier AMP2, the other end is connected with the variable resistor R2, and the common end of R4 and R2 is connected with the inverting input end of the operational amplifier AMP2 to form a negative feedback loop; wherein, the resistances of the resistor R3 and the resistor R4 are the same.
In this embodiment, one end of the variable gain digital input REG is connected to the gain adjustable negative feedback network, the binary code thereof represents the feedback network with different gains selected, and the switch is adjusted according to the binary code input by REG to change the resistance value R2 of the variable resistor, so that the gain can be changed; the other end is connected to a phase compensation network, and a switch is adjusted according to a binary code input by the REG, so that the capacitance value C1 of the variable capacitor is changed, and the RC zero pole of the operational amplifier phase can be moved to the set bandwidth. In this embodiment, the phase compensation network includes a resistor R1, a variable capacitor C1, a resistor R5, and a variable capacitor C2; the output end of the operational amplifier AMP1 is connected in series with a resistor R1 through a capacitor C1 to the phase compensation end of the operational amplifier AMP1, and the output end of the operational amplifier AMP2 is connected in series with a resistor R5 through a capacitor C2 to the phase compensation end of the operational amplifier AMP 2. The method for stabilizing the bandwidth is to adjust the zero pole of the compensation circuit according to the gain change, so that the bandwidth of the operational amplifier is kept stable.
The specific working principle of the invention is as follows: the micro signals are pre-amplified through input ends INP and INN of the double operational amplifier differential circuit, and output ends of the micro signals are connected to inverting input ends of the operational amplifiers AMP1 and AMP2 through a gain adjustable negative feedback network; the differential output end OUTP and OUTN of the amplifying circuit are connected to a compensation end through a phase compensation network with adjustable bandwidth; the variable gain digital input REG generates different binary codes, and the values of the resistor R2 and the capacitor C1 are changed to determine different gains and adjust the zero pole; when the binary code makes R2 change, the gain of the amplifying circuit changes, and the bandwidth of the amplifying circuit also changes due to the constraint of the gain-bandwidth product; therefore, the binary code generated by REG changes the value of the capacitor C1 to make the RC zero pole of its operational amplifier phase correspondingly move to the set bandwidth, thereby realizing bandwidth stabilization.
According to the virtual short break property of the positive input end and the negative input end of the ideal operational amplifier, the current I flowing through the resistor R2 is:
I=(VINP-VINN)/R2 （1）
the positive and negative end output voltages of the amplifying circuit are respectively as follows:
VOUTP=VINP+I×R3=VINP+(VINP-VINN)×R3/R2 （2）
VOUTN=VINN-I×R4=VINN-(VINP-VINN)×R4/R2 （3）
and then obtaining a gain formula of the amplifying circuit from R3= R4:
GAIN=(1+2R3/R2) （4）
from the formula (4), it can be seen that the gain of the amplifying circuit is determined only by the value of the variable resistor R2, the switch is adjusted according to the binary code input by REG, the resistance value of R2 is reasonably set, and the optimal gain gear can be selected according to the input signals with different amplitudes; meanwhile, due to the constraint of the gain-bandwidth product, when the closed-loop gain of the amplifying circuit is increased, the bandwidth is narrowed, as shown in a wave characteristic diagram of fig. 3, so that the capacitance value of the capacitor C1 is changed by using the zero-pole compensation circuit, the-3 dB point of the amplifying circuit is moved to the set bandwidth, and the operational amplifier bandwidth is kept stable.
The invention adopts a method of combining a variable gain amplification structure and a bandwidth stabilization structure, and can be combined with a zero-pole compensation circuit of an operational amplifier, so that the operational amplifier bandwidth is kept stable when the gain is changed, the linearity and the bandwidth consistency of the operational amplifier circuit are improved, and a large-amplitude signal with high signal-to-noise ratio is obtained; the method is applied to an integrated circuit system for pre-amplifying the tiny signals with weak driving capability, so that the amplifying circuit can select the optimal gain gear according to the input signals with different amplitudes, simultaneously adjust the bandwidth change caused by the zero-pole compensation gain change, and improve the linearity and the bandwidth consistency of the operational amplifying circuit, thereby obtaining the large-amplitude signals with high signal-to-noise ratio.
The technical principle of the present invention has been described above with reference to specific embodiments, which are merely preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. Other embodiments of the invention will occur to those skilled in the art without the exercise of inventive faculty, and such will fall within the scope of the invention.
Claims (8)
1. A variable gain and bandwidth stable micro amplitude signal pre-amplifying circuit, comprising:
a variable gain amplification structure and a bandwidth stabilization structure; the variable gain amplifying structure comprises a gain adjustable negative feedback network, and the variable gain amplifying structure is connected with a variable gain digital input end REG and changes a resistance value to realize variable gain amplification; the bandwidth stabilizing structure comprises a broadband adjustable phase compensation network, and the bandwidth stabilizing structure is formed by connecting a variable gain digital input end REG, changing the capacitance value of a capacitor and combining an operational amplifier zero-pole network.
2. The variable gain and bandwidth stable minute amplitude signal pre-amplifying circuit as claimed in claim 1, comprising an operational amplifier AMP1, an operational amplifier AMP2, a variable gain digital input REG, a gain adjustable negative feedback network and a bandwidth adjustable phase compensation network;
the non-inverting input end of the operational amplifier AMP1 and the non-inverting input end of the operational amplifier AMP2 are used as pre-amplified differential signal input ends; the output terminal of the operational amplifier AMP1 and the output terminal of the operational amplifier AMP2 serve as two output terminals of the pre-amplification circuit.
3. The variable gain and bandwidth stabilized fine amplitude signal pre-amplifying circuit as claimed in claim 2, wherein; the output end of the operational amplifier AMP1 and the output end of the operational amplifier AMP2 are respectively connected with the phase compensation network with adjustable bandwidth; the gain adjustable negative feedback network is connected between the output end and the inverting input end of the operational amplifier AMP1 and the operational amplifier AMP2 in a bridge mode, and the variable gain digital input end REG is connected with the gain adjustable negative feedback network and the bandwidth adjustable phase compensation network respectively.
4. The variable gain and bandwidth stabilized small amplitude signal pre-amplifier circuit as claimed in claim 3, wherein said AMP1 has its positive terminal connected to the positive input of the amplifier circuit and its negative terminal connected to the feedback resistor network, and its output is the operational amplifier positive output; and the positive end of the AMP2 is connected with the negative input of the amplifying circuit, the negative end of the AMP2 is connected with the feedback resistance network, and the output of the AMP2 is the negative output of the operational amplifier.
5. The variable gain and bandwidth stable fine amplitude signal pre-amplifying circuit as claimed in any one of claims 1 to 4, wherein said gain adjustable negative feedback network comprises a resistor R2, a resistor R3, a resistor R4; one end of the resistor R3 is connected with the output of the operational amplifier AMP1, the other end of the resistor R3 is connected with the variable resistor R2, and the common end of the resistor R3 and the resistor R2 is connected with the inverting input end of the operational amplifier AMP1 to form a negative feedback loop; one end of the resistor R4 is connected with the output of the operational amplifier AMP2, the other end of the resistor R4 is connected with the variable resistor R2, and the common end of the resistor R4 and the resistor R2 is connected with the inverting input end of the operational amplifier AMP2 to form a negative feedback loop; wherein, the resistances of the resistor R3 and the resistor R4 are the same.
6. The variable gain and bandwidth stable minute amplitude signal pre-amplifying circuit as claimed in claim 5, wherein said wideband adjustable phase compensation network comprises a resistor R1, a variable capacitor C1, a resistor R5, a variable capacitor C2; the output end of the operational amplifier AMP1 is connected in series with a resistor R1 through a capacitor C1 to the phase compensation end of the operational amplifier AMP1, and the output end of the operational amplifier AMP2 is connected in series with a resistor R5 through a capacitor C2 to the phase compensation end of the operational amplifier AMP 2.
7. The variable gain and bandwidth-stabilized small amplitude signal pre-amplifying circuit according to claim 5, wherein the variable gain digital input REG is connected to a gain-adjustable negative feedback network and a phase compensation network, respectively; adjusting a switch according to a binary code input by the REG to change the resistance value R2 of the variable resistor, wherein the binary code represents a feedback network for selecting different gains; and meanwhile, according to a binary code input by the REG, the switch is adjusted, so that the capacitance value C1 of the variable capacitor is changed, and the RC zero pole of the operational amplifier phase is moved to the set bandwidth.
8. The variable gain and bandwidth stabilized fine amplitude signal pre-amplifying circuit as claimed in claim 6, wherein said operational amplifiers AMP1, AMP2 are two identical operational amplifiers; the non-inverting input end of the operational amplifier AMP1 and the non-inverting input end of the operational amplifier AMP2 are used as differential signal input ends INP and INN of the pre-amplification circuit; the output terminal of the operational amplifier AMP1 and the output terminal of the operational amplifier AMP2 serve as two output terminals OUTP, OUTN of the pre-amplification circuit.
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| CN113271076A (en) * | 2021-04-26 | 2021-08-17 | 歌尔微电子股份有限公司 | Gain-variable operational amplification circuit and electronic equipment |
| CN116599478A (en) * | 2023-07-17 | 2023-08-15 | 江苏润石科技有限公司 | Bandwidth-stable configurable gain differential amplifier and control method thereof |
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| US20030169104A1 (en) * | 2002-03-08 | 2003-09-11 | Huckins Kevin A. | Miller de-compensation for differential input, differential output amplifier |
| CN101262262A (en) * | 2007-03-06 | 2008-09-10 | 日本电气株式会社 | Power amplifier circuit, control method thereof and control program thereof |
| US20160037092A1 (en) * | 2014-07-30 | 2016-02-04 | Dongbu Hitek Co., Ltd. | Image Sensor |
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| CN113271076A (en) * | 2021-04-26 | 2021-08-17 | 歌尔微电子股份有限公司 | Gain-variable operational amplification circuit and electronic equipment |
| CN113271076B (en) * | 2021-04-26 | 2023-03-31 | 歌尔微电子股份有限公司 | Gain-variable operational amplification circuit and electronic equipment |
| CN116599478A (en) * | 2023-07-17 | 2023-08-15 | 江苏润石科技有限公司 | Bandwidth-stable configurable gain differential amplifier and control method thereof |
| CN116599478B (en) * | 2023-07-17 | 2023-09-12 | 江苏润石科技有限公司 | Bandwidth-stable configurable gain differential amplifier and control method thereof |
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