CN203896316U - Alternating current signal amplifying circuit - Google Patents
Alternating current signal amplifying circuit Download PDFInfo
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- CN203896316U CN203896316U CN201420245102.5U CN201420245102U CN203896316U CN 203896316 U CN203896316 U CN 203896316U CN 201420245102 U CN201420245102 U CN 201420245102U CN 203896316 U CN203896316 U CN 203896316U
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Abstract
An alternating current signal amplifying circuit comprises a main amplifying circuit and a feedback branch which is serially connected between the input end and output end of the main amplifying circuit. The feedback branch comprises a first comparator, a current-limiting drive circuit and a second comparator which are in serial connections. The positive electrode input end of the first comparator is connected to the output end of the main amplifying circuit, the negative electrode input end is connected to a reference voltage, and the output end is connected to the current-limiting drive circuit; the positive electrode input end of the second comparator is connected to the current-limiting drive circuit, the negative electrode input end is connected to the reference voltage, and the output end is connected to the positive electrode input end of the main amplifying circuit; the current-limiting drive circuit is a drive circuit with the delay function, and the delay time of the current-limiting drive circuit is much larger than the period of the alternating current signal. The alternating current signal amplifying circuit has the direct-current dysregulated signal correcting function, the direct-current value of the alternating current signal can be maintained and corrected, the low-error direct-current voltage value at the output end of the amplifying circuit can be acquired, and normal transmission of the alternating current signal can be prevented from being influenced.
Description
Technical field
The utility model relates to a kind of AC signal amplifying circuit.
Background technology
Be the function that analog integrated circuit design is used often to the amplification of AC signal, the amplification of AC signal can utilize bandwidth larger, and the operational amplifier of speed is realized.
As shown in Figure 1, it is a typical two-stage amplifying circuit, the gain of first order amplifier AMP1 and second level amplifier AMP2 is respectively by resistance R 1, R2 and resistance R 3, the resistance ratio value of R4 is realized, for example, in the time of R2:R1=10, it is 11 times to the multiplication factor of AC signal, adopt the reason of two-stage amplifying circuit to be to obtain larger gain and the amplitude of oscillation, in the time of designing integrated circuit, if signal transmission path is longer, also can use above-mentioned two-stage amplifying circuit, amplifier AMP1 and amplifier AMP2 are arranged near signal receiving end and signal output part, to ensure to obtain enough signal strength signal intensities.Be connected to the reference voltage of two amplifier ins
vreffor the DC voltage value of output signal, the amplification process of AC signal is not affected.
The resistance R that connects first order amplifier AMP1 positive input should be large as far as possible, as power taking resistance R=1M ohm in Fig. 1, to reduce the decay of AC signal as far as possible, the value size that connects the capacitor C 1 of first order amplifier AMP1 positive input is determined by the frequency of input exchange signal, the for example AC signal to 15M hertz, capacitor C 1 value can be 1-10 pico farad.
But in ic manufacturing process, due to fabrication error, device is physical environment and the impact of periphery electromagnetic environment while using around, the offset error of operational amplifier is inevitable, the imbalance of operational amplifier is mainly not mated and cause by the load pipe of input stage and input stage, although the absolute value of error itself is less, but because the gain of operational amplifier is amplified, the error obtaining at output is just very important, the imbalance of operational amplifier not only causes the fault in enlargement of AC signal, also can destroy DC point, the for example two-stage amplifying circuit in Fig. 1, in the time not lacking of proper care, the input of two amplifiers and the voltage of output should be all reference voltage
vref, suppose that ten millivolts of offset voltages that polarity is identical have all appearred in present two amplifiers, R2:R1=R4:R3=10, B point voltage is
vref+ 10 millivolts, C point voltage is
vref+ 110 millivolts, D point voltage is
vref+ 120 millivolts, output VOUT point voltage is
vref+ 120+1200=
vref+ 1320 millivolts, apart from fiducial value
vrefdepart from 1.32V, output bias to AC signal and above-mentioned computational process are similar, the error of 10 millivolts can cause the voltage deviation value of 132 times at output, and in most of low pressure applications situations, it is insupportable that output voltage produces so large departing from.
Utility model content
The utility model provides a kind of AC signal amplifying circuit, there is DC maladjustment correction form signals function, can, to the correction that preserves value of the D. C. value of AC signal, can obtain the DC voltage value of low error at the output of amplifying circuit, can not affect the normal transmission of AC signal simultaneously.
In order to achieve the above object, the utility model provides a kind of AC signal amplifying circuit, and this AC signal amplifying circuit comprises amplification main circuit and is connected on the feedback branch amplifying between main circuit input and output;
The first comparator, current-limiting drive circuit and the second comparator that described feedback branch comprises series connection; The electrode input end of described the first comparator connects the output that amplifies main circuit, and negative input connects reference voltage, and output connects current-limiting drive circuit;
The electrode input end of described the second comparator connects current-limiting drive circuit, and negative input connects reference voltage, and output connects the electrode input end that amplifies main circuit;
Described current-limiting drive circuit is the drive circuit with delay function, and the delay time of this current-limiting drive circuit is much larger than the cycle of AC signal.
Described amplification main circuit comprises some grades of amplifiers, the electrode input end of first order amplifier connects the AC signal of input, the electrode input end of one-level amplifier after the output of previous stage amplifier connects, AC signal after the output output of afterbody amplifier is amplified, the negative input of the electrode input end of first order amplifier and every one-level amplifier is all connected reference voltage.
Described reference voltage is the DC voltage value of the output signal of amplifying circuit.
The utlity model has DC maladjustment correction form signals function, can, to the correction that preserves value of the D. C. value of AC signal, can obtain the DC voltage value of low error at the output of amplifying circuit, can not affect the normal transmission of AC signal simultaneously.
Brief description of the drawings
Fig. 1 is the circuit diagram of amplifying circuit in background technology.
Fig. 2 is the circuit diagram of the AC signal amplifying circuit that provides of the utility model.
Embodiment
Illustrate preferred embodiment of the present utility model according to Fig. 2 below.
As shown in Figure 2, the utility model provides a kind of AC signal amplifying circuit, and this AC signal amplifying circuit comprises amplification main circuit and is connected on the feedback branch amplifying between main circuit input and output.
The first comparator C OMP1, current-limiting drive circuit 101 and the second comparator C OMP2 that described feedback branch comprises series connection.
The electrode input end of described the first comparator C OMP1 connects the output OUT that amplifies main circuit, and negative input connects reference voltage
vref, output connects current-limiting drive circuit 101.
The electrode input end of described the second comparator C OMP2 connects current-limiting drive circuit 101, and negative input connects reference voltage
vref, output connects the electrode input end A that amplifies main circuit.
Described current-limiting drive circuit 101 is the drive circuits with delay function, need to ensure that the delay time of this current-limiting drive circuit 101 is much larger than the cycle of AC signal.
Described current-limiting drive circuit 101 comprises P type MOS(metal-oxide semiconductor (MOS)) transistor P1 and N-type MOS transistor N1, also comprise the second current source I2 of the first current source I1 and ground connection, described P type MOS transistor P1 is connected the output of the first comparator C OMP1 with the gate terminal of N-type MOS transistor N1, the drain electrode end of P type MOS transistor P1 connects the drain electrode end of N-type MOS transistor N1, the source terminal of P type MOS transistor P1 connects the first current source I1, and the source terminal of N-type MOS transistor N1 connects the second current source I2.
Described current-limiting drive circuit 101 also comprises the capacitor C 2 of ground connection, and it connects the electrode input end of the second comparator C OMP2.
Described amplification main circuit comprises some grades of amplifiers, embodiment as shown in Figure 2, this amplification main circuit is two-stage amplifying circuit, this amplification main circuit comprises first order amplifier AMP1 and second level amplifier AMP2, described first order amplifier AMP1 electrode input end connects input capacitance C1 and input resistance R, the negative input of first order amplifier AMP1 connects input resistance R1, between the negative input of first order amplifier AMP1 and output, connect feedback resistance R2, the negative input of described second level amplifier AMP2 connects input resistance R3, between the negative input of described second level amplifier AMP2 and output, connect feedback resistance R4.
The electrode input end A of first order amplifier AMP1 connects the AC signal of input by input capacitance C1, the electrode input end A of first order amplifier AMP1 connects reference voltage by resistance R
vref, the negative input of first order amplifier AMP1 connects reference voltage
vref, the output of first order amplifier AMP1 connects the electrode input end of second level amplifier AMP2, and the negative input of second level amplifier AMP2 connects reference voltage
vref, the AC signal after the output OUT output of second level amplifier AMP2 is amplified.
Above-mentioned reference voltage
vreffor the DC voltage value of the output signal of amplifying circuit.
Fig. 2 is a kind of embodiment of the present utility model, has increased by two comparators and a feedback branch that current-limiting drive circuit forms, and the benchmark voltage of two comparators is the DC voltage value of the output signal of amplifying circuit
vref, the effect of current-limiting drive circuit is to control feedback quantity, avoids the AC signal of normal amplification to cause interference.
As shown in Figure 2, the resistance R that connects first order amplifier AMP1 positive input should be large as far as possible, as power taking resistance R=1M ohm in Fig. 2, to reduce the decay of AC signal as far as possible, the value size that connects the capacitor C 1 of first order amplifier AMP1 positive input is determined by the frequency of input exchange signal, the for example AC signal to 15M hertz, capacitor C 1 value can be 1-10 pico farad.Suppose that ten millivolts of offset voltages have appearred in the first order amplifier amplifying in main circuit, R2:R1=R4:R3=10, due to the existence that first order amplifier AMP1 has 10 millivolts of offset voltages, makes the DC voltage value that B is ordered be greater than reference voltage
vref, cause the output voltage OUT that amplifies main circuit to be greater than reference voltage
vref, the first comparator C OMP1 output high level, N-type MOS transistor N1 conducting, receives peace current discharge with 100, and E point voltage drops to lower than reference voltage
vref, the output stage A point voltage of the second comparator C OMP2 is drop-down, and A point voltage is reduced, and can make in theory A point voltage infinite approach
vref-10 millivolts, thus make to amplify the output voltage OUT infinite approach reference voltage of main circuit
vref, because existence and the gain of offset error can not be infinitely great, the output voltage OUT that amplifies main circuit can not equal reference voltage
vref, but voltage and reference voltage that the output OUT of amplification main circuit is ordered
vrefdifference significantly narrowed down to and can be ignored.
The object of feedback branch is to correct the deviation of direct voltage, therefore need to design current-limiting drive circuit, in the present embodiment, all be designed to 100 for the second current source I2 of the first current source I1 of charging and electric discharge and receive peace, capacitor C 2 values are 2 pico farads simultaneously, for 15,000,000 AC signal, due to the existence in electric capacity and cut-off current source, make the time that discharges and recharges of electric capacity much larger than the AC signal cycle, therefore can not affect the normal transmission of AC signal, the value of capacitor C 2 can not be very large, otherwise will occupy sizable area in integrated circuit.
The utility model has provided a kind of AC signal amplifying circuit that possesses DC maladjustment correction form signals function, the D. C. value of AC signal has been carried out to value preserving to be corrected, can obtain the DC voltage value of low error at output, can not affect the normal transmission of AC signal simultaneously, amplifying circuit can be applied to the two-stage amplifying circuit in Fig. 1, also can be applied to 1 grade or 3 grades of above amplifying circuits, the design of described current-limiting drive circuit can be also other drive circuits with delay function, as long as time delay is much larger than the cycle of AC signal.
Although content of the present utility model has been done detailed introduction by above preferred embodiment, will be appreciated that above-mentioned description should not be considered to restriction of the present utility model.Read after foregoing those skilled in the art, for multiple amendment of the present utility model and substitute will be all apparent.Therefore, protection range of the present utility model should be limited to the appended claims.
Claims (3)
1. an AC signal amplifying circuit, is characterized in that, this AC signal amplifying circuit comprises amplification main circuit and is connected on the feedback branch amplifying between main circuit input and output;
The first comparator, current-limiting drive circuit and the second comparator that described feedback branch comprises series connection;
The electrode input end of described the first comparator connects the output that amplifies main circuit, and negative input connects reference voltage, and output connects current-limiting drive circuit;
The electrode input end of described the second comparator connects current-limiting drive circuit, and negative input connects reference voltage, and output connects the electrode input end that amplifies main circuit;
Described current-limiting drive circuit is the drive circuit with delay function, and the delay time of this current-limiting drive circuit is greater than the cycle of AC signal.
2. AC signal amplifying circuit as claimed in claim 1, it is characterized in that, described amplification main circuit comprises some grades of amplifiers, the electrode input end of first order amplifier connects the AC signal of input, the electrode input end of one-level amplifier after the output of previous stage amplifier connects, AC signal after the output output of afterbody amplifier is amplified, the negative input of the electrode input end of first order amplifier and every one-level amplifier is all connected reference voltage.
3. AC signal amplifying circuit as claimed in claim 2, is characterized in that, the DC voltage value of the output signal that described reference voltage is amplifying circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420245102.5U CN203896316U (en) | 2014-05-14 | 2014-05-14 | Alternating current signal amplifying circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420245102.5U CN203896316U (en) | 2014-05-14 | 2014-05-14 | Alternating current signal amplifying circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203896316U true CN203896316U (en) | 2014-10-22 |
Family
ID=51722668
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420245102.5U Active CN203896316U (en) | 2014-05-14 | 2014-05-14 | Alternating current signal amplifying circuit |
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| CN (1) | CN203896316U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106685247A (en) * | 2017-01-12 | 2017-05-17 | 中国科学院地质与地球物理研究所 | Precise rectification system for weak small signals |
-
2014
- 2014-05-14 CN CN201420245102.5U patent/CN203896316U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106685247A (en) * | 2017-01-12 | 2017-05-17 | 中国科学院地质与地球物理研究所 | Precise rectification system for weak small signals |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address | ||
| CP03 | Change of name, title or address |
Address after: 201203 No. 12, Lane 647, Songtao Road, Shanghai China (Shanghai) Free Trade Pilot Area Patentee after: Juchen Semiconductor Co., Ltd. Address before: 201203 No. 12, Lane 647, Songtao Road, Zhangjiang High-tech Park, Pudong New Area, Shanghai Patentee before: Giantec Semiconductor Inc. |