CN110557098A - positive feedback transimpedance amplification circuit and adjustment method - Google Patents
positive feedback transimpedance amplification circuit and adjustment method Download PDFInfo
- Publication number
- CN110557098A CN110557098A CN201910772145.6A CN201910772145A CN110557098A CN 110557098 A CN110557098 A CN 110557098A CN 201910772145 A CN201910772145 A CN 201910772145A CN 110557098 A CN110557098 A CN 110557098A
- Authority
- CN
- China
- Prior art keywords
- amplifier
- stage
- resistor
- positive feedback
- tia
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 9
- 230000003321 amplification Effects 0.000 title claims description 15
- 238000003199 nucleic acid amplification method Methods 0.000 title claims description 15
- 239000003990 capacitor Substances 0.000 claims abstract description 18
- 230000003287 optical effect Effects 0.000 claims description 3
- 238000005070 sampling Methods 0.000 claims description 3
- 230000007850 degeneration Effects 0.000 claims description 2
- 230000003071 parasitic effect Effects 0.000 abstract description 8
- 230000006641 stabilisation Effects 0.000 abstract description 2
- 238000011105 stabilization Methods 0.000 abstract description 2
- 230000008901 benefit Effects 0.000 description 4
- 230000003595 spectral effect Effects 0.000 description 4
- 230000004044 response Effects 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 238000013016 damping Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229910000679 solder Inorganic materials 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/26—Modifications of amplifiers to reduce influence of noise generated by amplifying elements
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/34—Negative-feedback-circuit arrangements with or without positive feedback
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/42—Modifications of amplifiers to extend the bandwidth
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/68—Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G3/00—Gain control in amplifiers or frequency changers without distortion of the input signal
- H03G3/20—Automatic control
- H03G3/30—Automatic control in amplifiers having semiconductor devices
Abstract
According to the positive feedback trans-impedance amplifying circuit disclosed by the invention, the output of the second-stage inverting voltage amplifier is introduced to the input end of the first-stage trans-impedance amplifier to form a positive feedback path, so that the limitation of a parasitic feedback capacitor on the bandwidth can be eliminated, and the bandwidth of an input frequency domain signal can be expanded; the adjusting method of the invention can easily control the stabilization time of the amplifier by adjusting the gain of the second stage inverting amplifier.
Description
Technical Field
The invention belongs to the technical field of electronic and transimpedance circuit design, and particularly relates to a positive feedback transimpedance amplification circuit and an adjustment method for eliminating bandwidth limitation caused by parasitic feedback capacitance.
Background
Current source signal detection (e.g., THz antenna, photodiode) requires a front-end transimpedance amplifier (TIA) to convert the current source into an amplified voltage signal, therefore, cascaded voltage amplification stages can be added to achieve the required signal voltage magnitude and overall circuit bandwidth requirements FIG. 1 illustrates in detail the schematic of a transimpedance amplification circuit, R f is a feedback resistor, associated with which is a parallel parasitic capacitance C f on a standard pad size FR4 board, a typical value of C f of 0.1 pF. can be reduced to approximately 0.05 pF. by reducing the pad size and using flow soldering techniques, however, the magnitude of R f is always limited by the bypass impedance of C f, since the bypass impedance of C f is comparable to R f at the response frequency as R f increases, thereby reducing the gain of the amplifier.
When the value of R f is 100M Ω, a C f value of 0.1pF limits the bandwidth of the amplifier (-3dB point) to 32MHz (the impedance of C f equals the impedance of R f at that frequency). to overcome this problem, the size of R f is reduced and a two-stage amplifier is used to increase the overall gain to the desired value.
For a high gain (gain greater than 10) voltage amplifier, both the signal gain and the noise gain increase linearly with the magnitude of the feedback resistance, reducing the magnitude of the feedback resistance increases the TIA bandwidth (subject to the constraint of C f), and using a second stage voltage gain amplifier to increase the overall gain of the circuit, always results in increased noise compared to a single stage TIA of the same bandwidth and overall gain.
Disclosure of Invention
in view of this, the present invention provides a positive feedback transimpedance amplifier circuit and an adjustment method for eliminating the bandwidth limitation caused by the parasitic feedback capacitor, which can eliminate the bandwidth limitation caused by the parasitic feedback capacitor, thereby achieving the maximum bandwidth and the lowest noise under the condition of extremely high gain.
A positive feedback transimpedance amplifier circuit is characterized in that a THz frequency domain signal is input to a negative input end of a TIA (transimpedance amplifier) of a first stage of a two-stage amplifier; the output of the second-stage inverting voltage amplifier with two-stage amplification is fed back to the negative input end of the TIA (transimpedance amplifier) to form positive feedback; the positive feedback is realized by adopting a resistor R2 and a capacitor C2 which are connected in parallel; the resistance value of the resistor R2 is 100G omega; the capacitance value of the capacitor C2 is equal to that of the negative feedback capacitor C1 of the first-stage transimpedance amplifier TIA.
Preferably, the THz frequency domain signal is a terahertz signal output by a terahertz asynchronous optical sampling system ASOPS.
A method for adjusting a positive feedback transimpedance amplifier circuit is characterized in that a resistor arranged between a first-stage transimpedance amplifier (TIA) and a second-stage amplifier is defined as a resistor R3; the degeneration resistor of the second stage inverting voltage amplifier is defined as a resistor R4; the stability of the positive feedback transimpedance amplification circuit is controlled by adjusting the resistance ratio of the resistor R3 to the resistor R4.
The invention has the following beneficial effects:
According to the positive feedback trans-impedance amplifying circuit disclosed by the invention, the output of the second-stage inverting voltage amplifier is introduced to the input end of the first-stage trans-impedance amplifier to form a positive feedback path, so that the limitation of a parasitic feedback capacitor on the bandwidth can be eliminated, and the bandwidth of an input frequency domain signal can be expanded; the adjusting method of the invention can easily control the stabilization time of the amplifier by adjusting the gain of the second stage inverting amplifier.
Drawings
FIG. 1 is a prior art transimpedance amplifier circuit;
FIG. 2 is a circuit diagram of a conventional two-stage amplifier;
FIG. 3 is a positive feedback loop of the present invention;
FIG. 4 is a graph of gain and noise for the amplifier of FIGS. 2 and 3;
FIG. 5 is a THz power spectrum superimposed on the noise signal of the two-stage amplifier circuit of FIG. 2 and the TIA positive feedback circuit of the present invention;
FIG. 6 is a positive feedback circuit output response for two values of R3 in FIG. 3; under-damping R3 ═ 2050 Ω, and critical damping R3 ═ 2060 Ω.
Detailed Description
The invention is described in detail below by way of example with reference to the accompanying drawings.
The circuit of the present invention is shown in fig. 3. The circuit consists of a trans-impedance amplifier (TIA) U1, a two-stage unity gain stable inverting voltage amplifier U2 and three feedback paths:
The three feedback paths are as follows:
a standard inverting feedback path from the output OUT of the transimpedance amplifier (TIA) U1 to its negative input summing node (denoted as "-" in fig. 3U 1); the feedback path is formed by a resistor R1 and a capacitor C1 connected in parallel. In this embodiment, the resistance of the resistor R1 is 102M Ω, and the capacitance of the capacitor C1 is 0.1 pF.
a second non-inverting feedback path from the output of the second stage inverting voltage amplifier U2 (designated "OUT 1") to the negative input summing node of the transimpedance amplifier U1 is formed by a resistor R2 and a capacitor C2 connected in parallel. In this embodiment, the resistance of the resistor R2 is 100G Ω, and the capacitance of the capacitor C2 is 0.1 pF.
The second stage inverting voltage amplifier U2 outputs from its OUT1 to its inverting summing node (denoted "-" in fig. 3U 2) a single feedback path consisting of a resistor R4 and a capacitor C4 in parallel. In this embodiment, the resistance of the resistor R4 is 2000 Ω, and the capacitance of the capacitor C4 is 0.1 pF.
A resistor R3 is connected in series between the output end of the trans-impedance amplifier U1 and the negative input summing node of the inverting voltage amplifier U2, and a capacitor C3 is connected in parallel to the two ends of the resistor R. In this embodiment, the resistance of the resistor R3 is 2040 Ω, and the capacitance of the capacitor C3 is 0.1 pF.
In fig. 3, the second stage inverting amplifier U2 is inverting, has a stable unity gain, and does not provide voltage amplification; both amplifiers U1 and U2 are inverting amplifiers, each with an output 180 degrees different from the input, so the total phase change is 360 degrees, so the output of U2 is in phase with the input of U1, i.e., the output of U2 provides in-phase feedback to the input of U1. The feedback is provided by a resistor (R2 in fig. 3) that occupies the same space as the package and solder of the TIA feedback resistor (R1 in fig. 3), but has a maximum value of 100G Ω; since the 100G Ω resistor is generally the highest value available, so that the positive dc feedback through resistor R2 is negligible, while resistor R2 provides an in-phase feedback signal through its parasitic capacitance C2, of the same magnitude as the anti-phase feedback signal from the TIA feedback resistor's parasitic capacitance (C1 in fig. 3), the positive capacitive feedback of C2 completely cancels the original negative feedback of C1 in amplitude and phase, i.e., reduces the net negative capacitive feedback signal to the minimum allowed within the limits of circuit stability, thereby maximizing the circuit bandwidth of the TIA first stage. This allows for maximum amplification in the first stage TIA, thereby minimizing overall circuit noise.
this circuit can reduce the noise spectral density of the THz signal superimposed from the ASOPS source by a factor of 7 (THz resolution and gain for the same bandwidth) compared to the standard two-stage amplification circuit in fig. 2. The gain and noise curves for both amplifiers are shown in fig. 4. For both circuits, the spectral noise density value peaks at 10.5 uV/Hz, but the standard two-stage amplifier circuit drops to a spectral noise density value of 9.5 uV/Hz at a lower frequency, whereas the positive feedback circuit of the present patent drops to a spectral noise density value of 1.3 uV/Hz by a factor of 7. Superimposing a noise signal at 100MHz pulse repetition rate onto the THz spectrum, an asynchronous optical sampling system (ASOPS) running at a standard offset frequency of 20Hz shows a reduction of the superimposed integrated noise signal (in this example) from 4mV to 1mV, by a factor of 4; as shown in fig. 5.
The amplification circuit of the present invention has less benefit on time domain signals because the "strong peaks" of the noise signal (which occurs when the bandwidth of the TIA is close to the stability limit, see fig. 4) limit the signal to noise advantage by a factor of 2. However, for ASOPS applications, the information is obtained in the frequency domain, and as the signal resolution increases (TIA bandwidth increases for a given offset frequency), the signal-to-noise ratio advantage increases by a factor of 7. This is because, as shown in fig. 5, the overlap of THz signals in the amplifier power spectrum gradually occurs before the noise peak.
The amplifier circuit of the present invention can easily control the settling time of the amplifier by the gain of the second voltage amplifier, that is, can be realized by adjusting the ratio of R3 to R4. If R3 is equal to R4, then the positive feedback through C2 is exactly opposite to the negative feedback through C1. In this case, the entire amplification circuit is unstable, and the value of R3 is slightly lowered to ensure less negative feedback and circuit stability. For example, setting R3 to 2060 ohms (R4 ═ 2k), the circuit is heavily damped, setting R3 to 2040 ohms, the circuit is slightly under-damped, but the rise time is faster, as shown in fig. 6. Thus, another advantage of the circuit is that the response characteristics of the amplifier circuit can be easily controlled and adjusted. The ratio of the R3 resistance to the R4 resistance can be set according to the parameter values of each component in the actual circuit to stabilize the circuit. As the value of R3 decreases to the value of R4, the circuit bandwidth increases due to positive capacitive feedback. At some value of R3, however, the circuit will be unstable because the positive capacitance feedback is too large to exceed the circuit stability parameters. But can only be determined by experiments on each circuit, since the initial conditions are unknown.
in summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (3)
1. A positive feedback transimpedance amplifier circuit is characterized in that a THz frequency domain signal is input to a negative input end of a TIA (transimpedance amplifier) of a first stage of a two-stage amplifier; the output of the second-stage inverting voltage amplifier with two-stage amplification is fed back to the negative input end of the TIA (transimpedance amplifier) to form positive feedback; the positive feedback is realized by adopting a resistor R2 and a capacitor C2 which are connected in parallel; the resistance value of the resistor R2 is 100G omega; the capacitance value of the capacitor C2 is equal to that of the negative feedback capacitor C1 of the first-stage transimpedance amplifier TIA.
2. A positive feedback transimpedance amplification circuit according to claim 1, wherein said THz frequency domain signal is a terahertz signal output by a terahertz asynchronous optical sampling system, ASOPS.
3. a method for adjusting a positive feedback transimpedance amplifier circuit according to claim 1 or 2, wherein a resistance provided between the first stage transimpedance amplifier TIA and the second stage amplifier TIA is defined as a resistance R3; the degeneration resistor of the second stage inverting voltage amplifier is defined as a resistor R4; the stability of the positive feedback transimpedance amplification circuit is controlled by adjusting the resistance ratio of the resistor R3 to the resistor R4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910772145.6A CN110557098A (en) | 2019-08-21 | 2019-08-21 | positive feedback transimpedance amplification circuit and adjustment method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910772145.6A CN110557098A (en) | 2019-08-21 | 2019-08-21 | positive feedback transimpedance amplification circuit and adjustment method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110557098A true CN110557098A (en) | 2019-12-10 |
Family
ID=68737990
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910772145.6A Pending CN110557098A (en) | 2019-08-21 | 2019-08-21 | positive feedback transimpedance amplification circuit and adjustment method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110557098A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112202410A (en) * | 2020-10-15 | 2021-01-08 | 中国科学院空天信息创新研究院 | Double-loop trans-impedance amplifier |
| CN112636702A (en) * | 2020-12-31 | 2021-04-09 | 山西大学 | Method for reducing parasitic capacitance of feedback resistor and improving bandwidth of trans-impedance amplifier |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0208433A2 (en) * | 1985-07-05 | 1987-01-14 | Robert G. Irvine | Response-gain independent amplifier |
| US7423483B1 (en) * | 2005-06-20 | 2008-09-09 | Marvell International Ltd. | Increasing amplifier bandwidth by positive capacitive feedback |
| CN101505140A (en) * | 2009-03-04 | 2009-08-12 | 中国电力科学研究院 | Trans-impedance amplifier with low noise and high gain-bandwidth product |
| US20170026011A1 (en) * | 2015-07-20 | 2017-01-26 | Mindspeed Technologies, Inc. | Transimpedance Amplifier with Bandwidth Extender |
| CN107144719A (en) * | 2017-05-04 | 2017-09-08 | 北京理工大学 | A kind of high-precision testing weak signals instrument and method of testing |
| 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 |
| CN109375194A (en) * | 2018-10-22 | 2019-02-22 | 天津大学 | AFE(analog front end) reading circuit for laser radar |
-
2019
- 2019-08-21 CN CN201910772145.6A patent/CN110557098A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0208433A2 (en) * | 1985-07-05 | 1987-01-14 | Robert G. Irvine | Response-gain independent amplifier |
| US7423483B1 (en) * | 2005-06-20 | 2008-09-09 | Marvell International Ltd. | Increasing amplifier bandwidth by positive capacitive feedback |
| CN101505140A (en) * | 2009-03-04 | 2009-08-12 | 中国电力科学研究院 | Trans-impedance amplifier with low noise and high gain-bandwidth product |
| US20170026011A1 (en) * | 2015-07-20 | 2017-01-26 | Mindspeed Technologies, Inc. | Transimpedance Amplifier with Bandwidth Extender |
| CN107144719A (en) * | 2017-05-04 | 2017-09-08 | 北京理工大学 | A kind of high-precision testing weak signals instrument and method of testing |
| 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 |
| CN109375194A (en) * | 2018-10-22 | 2019-02-22 | 天津大学 | AFE(analog front end) reading circuit for laser radar |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112202410A (en) * | 2020-10-15 | 2021-01-08 | 中国科学院空天信息创新研究院 | Double-loop trans-impedance amplifier |
| CN112202410B (en) * | 2020-10-15 | 2024-01-09 | 中国科学院空天信息创新研究院 | Dual loop transimpedance amplifier |
| CN112636702A (en) * | 2020-12-31 | 2021-04-09 | 山西大学 | Method for reducing parasitic capacitance of feedback resistor and improving bandwidth of trans-impedance amplifier |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4927664B2 (en) | Preamplifier circuit | |
| US8766728B2 (en) | Trans-impedance amplifier with enhanced dynamic range but invariable input impedance | |
| US7683720B1 (en) | Folded-cascode amplifier with adjustable continuous time equalizer | |
| US8139957B2 (en) | High sensitivity optical receiver employing a high gain amplifier and an equalizing circuit | |
| US8742852B2 (en) | Optical receiver compensating input offset | |
| US7453322B2 (en) | Transimpedance amplifier using negative impedance compensation | |
| US10944486B2 (en) | DC current cancellation scheme for an optical receiver | |
| JPWO2010100741A1 (en) | Optical communication device | |
| JP7115065B2 (en) | transimpedance amplifier | |
| US7477109B2 (en) | Process and temperature-compensated transimpedance amplifier | |
| US20040036536A1 (en) | Transimpedance amplifier and offset correction mechanism and method for lowering noise | |
| CN110557098A (en) | positive feedback transimpedance amplification circuit and adjustment method | |
| JP5176917B2 (en) | Preamplifier | |
| US7355471B2 (en) | Circuit for DC offset cancellation | |
| JP5628871B2 (en) | Automatic offset erase circuit | |
| CN109962684B (en) | High dynamic range trans-impedance amplifier with three controlled current branches | |
| US8836423B2 (en) | Method and apparatus for automatically adjusting the bandwidth of an electronic amplifier | |
| JP2003168933A (en) | Photoreceiving circuit | |
| US7695085B2 (en) | Variable gain amplifier having variable gain DC offset loop | |
| JPWO2008120663A1 (en) | Signal amplifier for optical receiver circuit | |
| US6876260B2 (en) | Elevated front-end transimpedance amplifier | |
| US7183859B2 (en) | Power supply rejection for high bandwidth transimpedance amplifier circuits (TIAs) | |
| CN110677134A (en) | Self-adaptive bandwidth adjusting circuit | |
| JP4058981B2 (en) | Optical receiver module | |
| JP2009232135A (en) | Optical signal reception circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20191210 |
|
| WD01 | Invention patent application deemed withdrawn after publication |