CN116633284A - High-gain transimpedance amplifier and high-gain photoelectric converter - Google Patents

High-gain transimpedance amplifier and high-gain photoelectric converter Download PDF

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Publication number
CN116633284A
CN116633284A CN202310600228.3A CN202310600228A CN116633284A CN 116633284 A CN116633284 A CN 116633284A CN 202310600228 A CN202310600228 A CN 202310600228A CN 116633284 A CN116633284 A CN 116633284A
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module
current
signal
output
transimpedance amplifier
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陶永红
周芷怡
张少玲
罗刚
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Shanghai Mi Silicon Technology Co ltd
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Shanghai Mi Silicon Technology Co ltd
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Priority to CN202310600228.3A priority Critical patent/CN116633284A/en
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/04—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only
    • H03F3/08—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only controlled by light
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/45—Differential amplifiers
    • H03F3/45071—Differential amplifiers with semiconductor devices only
    • H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
    • H03F3/4508—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using bipolar transistors as the active amplifying circuit
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H03G3/3084—Automatic control in amplifiers having semiconductor devices in receivers or transmitters for electromagnetic waves other than radiowaves, e.g. lightwaves
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/66—Non-coherent receivers, e.g. using direct detection
    • H04B10/69—Electrical arrangements in the receiver
    • H04B10/693—Arrangements for optimizing the preamplifier in the receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/60—Receivers
    • H04B10/66—Non-coherent receivers, e.g. using direct detection
    • H04B10/69—Electrical arrangements in the receiver
    • H04B10/693—Arrangements for optimizing the preamplifier in the receiver
    • H04B10/6931—Automatic gain control of the preamplifier
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Amplifiers (AREA)

Abstract

The application provides a high-gain transimpedance amplifier and a high-gain photoelectric converter, wherein the high-gain transimpedance amplifier comprises a control module, an amplifier module, an output module and a current regulation module: the high-gain transimpedance amplifier receives a photocurrent signal output by the photodiode, and the photocurrent signal is amplified by the amplifier module to obtain emitter current; the control module is connected with the photodiode and the current regulation module and used for detecting a photocurrent signal and determining a first control signal corresponding to the strength of the photocurrent signal; the current regulating module receives the first control signal, generates auxiliary direct current corresponding to the first control signal, and regulates the current of the output module by using the auxiliary direct current; the output module outputs an amplified voltage signal according to the auxiliary direct current, the power supply voltage and the emitter current. By adopting the high-gain transimpedance amplifier and the high-gain photoelectric converter, the problems of limited gain effect, poor circuit stability and low frequency response speed in the conventional transimpedance amplifier circuit are solved.

Description

High-gain transimpedance amplifier and high-gain photoelectric converter
Technical Field
The application relates to the technical field of electronic circuits, in particular to a high-gain transimpedance amplifier and a high-gain photoelectric converter.
Background
The transimpedance amplifier is widely applied to the field of optical communication, and is used for receiving a weak photocurrent signal generated by a photodiode, converting and amplifying the weak photocurrent signal into a voltage signal and outputting the voltage signal to a subsequent circuit for processing. The optical signal intensity in the optical receiver and the range of the input current signal of the transimpedance amplifier are large due to the performance difference of the optical receiving and transmitting elements, the difference of the signal transmission distances, and the like. Therefore, a transimpedance amplifier for an optical receiver and the like needs to have a wide input dynamic range and a high gain, so that waveform distortion of an output voltage signal is avoided when the transimpedance amplifier receives a large input current, and the transimpedance amplifier has a high transimpedance gain when the transimpedance amplifier receives a small input current, so that a small current signal is converted into a large voltage signal, and the reduction of a signal-to-noise ratio caused by the influence of noise of a following main amplifier is avoided, thereby realizing accurate transmission of the signal and avoiding distortion.
At present, in order to receive a photocurrent signal with a large dynamic range, a typical transimpedance amplifier generally adjusts the gain of the transimpedance amplifier by adjusting a feedback resistor in a transimpedance feedback loop, but the adjusting mode reduces the bandwidth of the amplifier, so that the resistance value of the feedback resistor is limited and cannot be infinitely increased, the gain effect is limited, and the stability of the circuit and the frequency response characteristic of the transimpedance amplifier circuit are affected.
Disclosure of Invention
In view of the above, the present application is directed to a high-gain transimpedance amplifier and a high-gain photoelectric converter, which solve the problems of limited gain effect, poor circuit stability and low frequency response speed in the existing transimpedance amplifier circuit.
In a first aspect, an embodiment of the present application provides a high gain transimpedance amplifier, including a control module, an amplifier module, an output module, and a current adjustment module:
the high-gain transimpedance amplifier receives a photocurrent signal output by the photodiode, the output end of the photodiode is connected with the first input end of the amplifier module, and the photocurrent signal is amplified by the amplifier module to obtain emitter current;
the control module is connected with the photodiode and the current regulation module, detects the intensity of a photocurrent signal output by the photodiode, determines a first control signal corresponding to the intensity of the photocurrent signal, and inputs the first control signal to the current regulation module;
the current regulating module receives the first control signal, generates auxiliary direct current corresponding to the first control signal, and regulates the current of the output module by using the auxiliary direct current;
one end of the output module is connected with the second input end of the amplifier module and one end of the current regulating module, the other end of the output module is connected with the external power supply and the other end of the current regulating module, and the output module outputs an amplified voltage signal according to the auxiliary direct current, the power supply voltage of the external power supply and the emitter current.
Optionally, the amplifier module includes a main amplifier, a feedback resistor, a first triode, and an emitter resistor; one end of the main amplifier is used as a first input end of the amplifier module and is connected with the output end of the photodiode, and the other end of the main amplifier is connected with the base electrode of the first triode; the collector of the first triode is connected with one end of the output module as the second input end of the amplifier module, the emitter of the first triode is connected with one end of the emitter resistor, and the other end of the emitter resistor is grounded as the output end of the amplifier module; one end of the main amplifier is also connected with one end of the feedback resistor, and the other end of the feedback resistor is connected with one end of the emitter resistor.
Optionally, the output module includes a second triode and a first load resistor; one end of the first load resistor is used as the other end of the output module and is connected with an external power supply and the other end of the current regulating module, the other end of the first load resistor is connected with the collector electrode of the second triode, and the collector electrode of the second triode is also used as the output end of the output module to output amplified voltage; the base of the second triode is set to be a fixed voltage, so that the second triode is conducted, and one end of the emitter of the second triode serving as an output module is connected with the second input end of the amplifier module and one end of the current regulating module.
Optionally, the current regulation module comprises an auxiliary direct current source for generating an auxiliary direct current.
Optionally, the high gain transimpedance amplifier further comprises an automatic gain adjustment module; the other end of the automatic gain adjustment module is connected with the other end of the output module, the control end of the automatic gain adjustment module is connected with the control module and is used for receiving a second control signal output by the control module, and the gain of the automatic gain adjustment module is controlled according to the second control signal so as to control the shunt size of the total current; one end of the automatic gain adjustment module is connected with one end of the output module.
Optionally, the automatic gain adjustment module includes a third triode and a second load resistor; one end of the second load resistor is used as the other end of the automatic gain adjustment module and is connected with the other end of the output module, and the other end of the second load resistor is connected with the collector electrode of the third triode; the base electrode of the third triode is connected with the control module as a control end of the automatic gain adjustment module, receives a second control signal sent by the control module, and the emitter electrode of the third triode is connected with the second input end of the amplifier module as an output end of the automatic gain adjustment module.
Optionally, the first load resistor is a variable resistor; the control module is connected with the first load resistor, and the resistance value of the first load resistor is adjusted through the control module.
Optionally, the gains of the first triode and the second triode are 1.
Optionally, the second control signal includes a second on signal and a second off signal; the control module is used for detecting the intensity of the photocurrent signal, and if the photocurrent signal is smaller than a first set value, the control module outputs a second closing signal to the automatic gain adjustment module so as to close a current channel corresponding to the automatic gain adjustment module; if the photocurrent signal is greater than or equal to the first set value, the control module outputs a second starting signal to the automatic gain adjustment module so as to conduct a current path part corresponding to the automatic gain adjustment module; if the photocurrent signal is greater than or equal to the second set value, the control module outputs a third starting signal to the automatic gain adjustment module so as to fully conduct a current channel corresponding to the automatic gain adjustment module.
In a second aspect, the embodiment of the present application further provides a high-gain photoelectric converter, where the high-gain photoelectric converter includes the high-gain transimpedance amplifier, the photodiode, and an external power supply;
one end of the high-gain transimpedance amplifier is connected with the output end of the photodiode, and the other end of the high-gain transimpedance amplifier is connected with an external power supply;
the high-gain transimpedance amplifier receives the photocurrent signal output by the photodiode, and determines an output amplified voltage signal by using the power supply voltage of the external power supply and the photocurrent signal.
The embodiment of the application has the following beneficial effects:
the high-gain transimpedance amplifier and the high-gain photoelectric converter provided by the embodiment of the application can detect the photoelectric current signal by using the control module and determine the control signal corresponding to the intensity of the photoelectric current signal, the current regulating module generates the auxiliary direct current corresponding to the control signal, the auxiliary direct current is used for reducing the current actually flowing in the load circuit, and the voltage of the external power supply and the emitter voltage are used for obtaining the amplified voltage signal.
In order to make the above objects, features and advantages of the present application more comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 shows a circuit diagram of a high gain transimpedance amplifier provided by an embodiment of the present application;
FIG. 2 shows a circuit diagram of a high gain transimpedance amplifier incorporating an automatic gain adjustment module provided by an embodiment of the present application;
FIG. 3 is a circuit diagram of a high gain transimpedance amplifier having a variable resistor as a first load resistor according to an embodiment of the present application;
FIG. 4 shows a circuit diagram of a high gain transimpedance amplifier with an auxiliary DC power supply as a current mirror according to an embodiment of the present application;
fig. 5 shows a circuit diagram of a high-gain photoelectric converter provided by an embodiment of the present application.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. The components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. Based on the embodiments of the present application, every other embodiment obtained by a person skilled in the art without making any inventive effort falls within the scope of protection of the present application.
It should be noted that, before the present application proposes, the transimpedance amplifier is widely used in the field of optical communication, and it receives the weak photocurrent signal generated by the photodiode, converts and amplifies the weak photocurrent signal into a voltage signal, and outputs the voltage signal to a subsequent circuit for processing. The optical signal intensity in the optical receiver and the range of the input current signal of the transimpedance amplifier are large due to the performance difference of the optical receiving and transmitting elements, the difference of the signal transmission distances, and the like. Therefore, a transimpedance amplifier for an optical receiver and the like needs to have a wide input dynamic range and a high gain, so that waveform distortion of an output voltage signal is avoided when the transimpedance amplifier receives a large input current, and the transimpedance amplifier has a high transimpedance gain when the transimpedance amplifier receives a small input current, so that a small current signal is converted into a large voltage signal, and the reduction of a signal-to-noise ratio caused by the influence of noise of a following main amplifier is avoided, thereby realizing accurate transmission of the signal and avoiding distortion. At present, in order to receive a photocurrent signal with a large dynamic range, a typical transimpedance amplifier generally adjusts the gain of the transimpedance amplifier by adjusting a feedback resistor in a transimpedance feedback loop, but the adjusting mode reduces the bandwidth of the amplifier, so that the resistance value of the feedback resistor is limited and cannot be infinitely increased, the gain effect is limited, and the stability of the circuit and the frequency response characteristic of the transimpedance amplifier circuit are affected.
Based on the above, the embodiment of the application provides a high-gain transimpedance amplifier, which is used for improving the gain effect and the stability and the frequency response speed of a circuit.
Referring to fig. 1, fig. 1 is a circuit diagram of a high gain transimpedance amplifier according to an embodiment of the present application. As shown in fig. 1, the high-gain transimpedance amplifier provided by the embodiment of the present application includes an amplifier module 100, a control module 200, a current adjustment module 300, and an output module 400:
the high-gain transimpedance amplifier receives a photocurrent signal output by a photodiode, the output end of the photodiode is connected with the first input end of the amplifier module 100, and the photocurrent signal is amplified by the amplifier module 100 to obtain emitter current;
the control module 200 is connected with the photodiode and the current regulation module 300, detects the intensity of a photocurrent signal output by the photodiode, determines a first control signal corresponding to the intensity of the photocurrent signal, and inputs the first control signal to the current regulation module 300;
the current adjustment module 300 receives the first control signal, generates an auxiliary direct current corresponding to the first control signal, and adjusts the current of the output module 400 by using the auxiliary direct current;
one end of the output module 400 is connected with the second input end of the amplifier module 100 and one end of the current regulating module 300, the other end of the output module 400 is connected with the external power supply VDD and the other end of the current regulating module 300, and the output module 400 outputs an amplified voltage signal V according to the auxiliary DC current, the power supply voltage of the external power supply and the emitter current out 。
In the embodiment of the application, the photodiode converts the optical signal transmitted in the optical fiber into the photocurrent signal I in The transimpedance amplifier operates in a high-speed fiber optic system, for example: high-speed optical fiber with speed of 10Gbps, and photocurrent signal I in I.e. an ac signal with a rate of 10 Gps. Because the design requirement of the high-speed input signal on the transimpedance amplifier is that the number of transistors is as small as possible, the transimpedance amplifier is not suitable for adopting a more complex circuit structure, and the circuit structure of the transimpedance amplifier designed by the application is simpler and can meet the design requirement of the high-speed input signal.
The transimpedance amplifier receives the photocurrent signal output by the photodiode, amplifies and converts the photocurrent signal to obtain an amplified voltage signal V output by the transimpedance amplifier out . The power supply voltage of the external power supply is 3.3V.
The amplifier module 100 includes a main amplifier 110, a feedback resistor 120, a first triode 130, and an emitter resistor 140; one end of the main amplifier 110 is connected with the output end of the photodiode as a first input end of the amplifier module 100, and the other end of the main amplifier 110 is connected with the base electrode of the first triode 130; the collector of the first triode 130 is connected with one end of the output module 400 as the second input end of the amplifier module 100, the emitter of the first triode 130 is connected with one end of the emitter resistor 140, and the other end of the emitter resistor 140 is grounded as the output end of the amplifier module 100; one end of the main amplifier 110 is also connected to one end of the feedback resistor 120, and the other end of the feedback resistor 120 is connected to one end of the emitter resistor 140.
The output module 400 includes a second triode 420 and a first load resistor 410; one end of the first load resistor 410 is used as the other end of the output module 400 and is externally connected with electricityThe other end of the source VDD and the other end of the current regulating module 300 are connected, the other end of the first load resistor 410 is connected with the collector of the second triode 420, and the collector of the second triode 420 is also used as the output end of the output module 400 to output an amplified voltage signal V out The method comprises the steps of carrying out a first treatment on the surface of the The base electrode VB of the second triode 420 is set to a fixed voltage, so that the second triode is turned on, and the emitter electrode of the second triode 420 as one end of the output module 400 is connected with the second input end of the amplifier module 100 and one end of the current adjusting module 300.
The first transistor 130 and the second transistor 420 are NPN transistors with a gain of 1. For example: the first transistor 130 and the second transistor 420 are bipolar junction transistors (Bipolar Junction Transistor, BJTs) of NPN type.
The first transistor 130 is used as an emitter follower (emitter follower) that isolates the base from the emitter, avoiding load from affecting the amplifier output. The emitter current and the collector current of the first transistor 130 are equal.
The second transistor 420 is used as a common base amplifier (common-base amplifier as cascoding amplifier here) that isolates the emitter from the collector from each other. The emitter current and collector current of the second transistor 420 are equal.
The current adjusting module 300 includes an auxiliary dc current source, and the current adjusting module 300 is configured to generate an auxiliary dc current according to a third control signal output by the control module 200, where the auxiliary dc current plays a role in current splitting. In addition, the auxiliary direct current source is connected to the low-impedance node, so that the parasitic capacitance of the auxiliary direct current source has negligible influence on the working speed of the whole circuit.
Here, the dc collector operating current of the first transistor 130 is denoted as: i C1 The method comprises the steps of carrying out a first treatment on the surface of the The dc collector operating current of the second transistor 420 is denoted as: i C2 The method comprises the steps of carrying out a first treatment on the surface of the The auxiliary direct current generated by the current regulating module is recorded as: i L The method comprises the steps of carrying out a first treatment on the surface of the The direct current flowing through the first load resistor is denoted as: i RL The method comprises the steps of carrying out a first treatment on the surface of the The emitter current of the first transistor 130 is noted as: i E The method comprises the steps of carrying out a first treatment on the surface of the The current flowing through the emitter resistor 140 is denoted as：I 1 The method comprises the steps of carrying out a first treatment on the surface of the The ac voltage across emitter resistor 140 is noted as: v (V) E(AC) The method comprises the steps of carrying out a first treatment on the surface of the The dc voltage across emitter resistor 140 is noted as: v (V) E(DC) 。
Specifically, the photodiode converts an optical signal into a photocurrent signal I in(AC) The photocurrent signal is input to the amplifier module 100, and a forward DC bias voltage V is added to the input terminal of the main amplifier 110 in(DC) For example: v (V) in(DC) =0.85V, where AC denotes alternating current and DC denotes direct current.
At this time, the voltage across the emitter resistor is the emitter voltage, i.e., the voltage at the E point, which is noted as: v (V) E V is then E ＝V E(DC) +V E(AC) ＝V in(DC) +I in ( AC )×R F Wherein R is F Representing the resistance value of the feedback resistor 120. I E ＝I 1 ＝I 1(DC )+I out(AC) ＝V E /R E That is, the current of the emitter resistor 140 includes a direct current portion I 1(DC) Ac current portion I out(AC) Direct current part I 1(DC) By dc bias voltage V in(DC) And the resistance of the emitter resistor 140, for example: i 1(DC) =3ma, wherein R E The resistance of the emitter resistor 140 is shown.
Since the first transistor 130 and the second transistor 420 are transistors with gain of 1, I C1 ＝I C2 +I L ＝I RL +I L ＝I 1 ＝V E /R E . Without increasing auxiliary DC current, i.e. I L When=0, the current flowing through the emitter resistor, the first triode collector and emitter, the second triode collector and emitter, and the first load resistor 410 are equal to each other, and are equal to the current I flowing through the emitter resistor 140 1 At this time, the output voltage is V out ＝VDD-I RL ×R L At this time, the transimpedance amplifier ac gain is:
wherein R is L Representing the resistance value, V, of the first load resistor 410 out Representing the voltage at point F.
At this time, R can be increased by F Reducing R E Or increase R L To increase the gain of the transimpedance amplifier.
In the first case, if the resistance R of the feedback resistor 120 is increased F The bandwidth of the transimpedance amplifier is reduced, and therefore the upper limit of the resistance cannot be increased infinitely, the gain effect is improved only a limited amount, and R is changed F But also affects the stability of the circuit.
In the second case, if the resistance R of the emitter resistor 140 is reduced E Due to auxiliary DC current I L When 0 is, I 1 ＝I RL ＝V E /R E Thus reducing R E The current of the whole circuit is increased, namely the whole working current and the power consumption of the circuit are correspondingly increased. In addition, the operating voltage of the overall circuit needs to satisfy:
VDD＝V RL +V Q1(CE) +V Q2(CE) +V E ＝I RL ×R L +V Q1(CE) +V Q2(CE) +(V in(DC) +I in ( AC )×R F )＝(V in(DC) +I in(AC) ×R F )/R E ×R L +(V Q1(CE) +V Q2(CE) +V in(DC) )+I in(AC) ×R F ＝(V in(DC) +I in(AC) ×R F )/R E ×R L +V out_min +I in ( AC )×R F ≈(V in(DC) +I in(AC) ×R F )/R E ×R L +V out(DC)_min +I in(AC) ×R F 。
wherein V is RL Representing the voltage across the first load resistor, V E Representing the load voltage of the emitter resistor two sections, V Q1(CE) Representing the voltage between the collector and the emitter of the first transistor, V Q2(CE) Representing the voltage between the collector and emitter of the second transistor.
Here, V Q1(CE) And V Q2(CE) Comprises a DC part and an AC part, but the AC part is very small, so that only the DC part is considered to ensure that the V of the DC part Q1(CE) Denoted as V Q1(CE)(DC) V of the direct current part Q2(CE) Denoted as V Q2(CE)(DC) . When V is Q1(CE)(DC) When=0.5v, ac part V Q1(CE)(AC) Only about 10mV, so that only the DC part, i.e. V, is considered out_min ＝V out(DC)_min 。
When the first triode and the second triode work normally, it is required to ensure that the direct current voltage between the emitter and the collector of the two triodes is greater than a certain voltage value, for example: greater than 0.5V, i.e. the operating voltage V at the voltage output point if the circuit is to be ensured to operate normally out More than a certain value is required. Here, when V Q1(CE)(DC) ＝V Q2(CE)(DC) ＝0.5V、V in(DC) when=0.85V, V out(DC)_min =1.85V, i.e. minimum operating voltage V at voltage output point out(DC)_min ＝1.85V。
When photocurrent I in(AC) When the voltage is 0, only the direct current voltage is in the circuit of the transimpedance amplifier, and at the moment, V out(DC)_min +I RL ×R L =vdd, and V out(DC)_min Is also fixed, such as 1.85V above. Since the voltage VDD of the external power supply is also fixed, and I RL ＝V E /R E Therefore, R is reduced E Will increase I RL Increase I RL Will lead to R L Is reduced by R L Needs to be matched with R E Together, the gain of the transimpedance amplifier cannot be increased.
Third, if the resistance R of the first load resistor 410 is increased L Due to V out(DC)_min +I RL ×R L =vdd, then at I RL Increasing R without change L VDD would need to be increased, which would result in increased system power consumption.
In summary, by adjusting the resistance R of the first load resistor 410 L Adjusting the resistance R of the feedback resistor 120 F Adjusting the resistance R of the emitter resistor 140 E The gain of the transimpedance amplifier cannot be effectively increased. Therefore, the application introduces the auxiliary direct current source, generates the auxiliary direct current through the auxiliary direct current source, at the moment, I C1 ＝I C2 +I L ＝I RL +I L ＝I 1 ＝V E /R E 。
Here, the auxiliary dc source may generate an auxiliary dc current I with a certain magnitude according to the third control signal generated by the control module L Vdd=v at this time out(DC)_min +I RL ×R L ＝V o u t(DC)_min +(I 1 -I L )×R L At I 1 、V out(DC)_min And VDD (R) E 、R F Remaining unchanged), the current actually flowing in the first load resistor is reduced by introducing an auxiliary DC current, i.e. by I 1 Reduced to I 1 -I L At this time R L The value of (c) may also be increased accordingly. Since the gain of transimpedance amplifier=r F ×(1+R L /R E ) Thus R is L The gain is also increased by the increase of (a).
When auxiliary DC current I L ＝0、V out(DC)_min ＝1.85V、VDD＝3.3V、I 1 When=3ma, R L Maximum resistance R L_max = (3.3-1.85)/3 mA, when the applied auxiliary dc current is I L When=1.5 mA, R L_max = (3.3-1.85)/1.5 mA, i.e. R L The highest resistance value can be doubled, thereby improving the gain of the transimpedance amplifier.
In an alternative embodiment, the high gain transimpedance amplifier further comprises an automatic gain adjustment module; the other end of the automatic gain adjustment module is connected with the other end of the output module, the control end of the automatic gain adjustment module is connected with the control module and is used for receiving a second control signal output by the control module, and the gain of the automatic gain adjustment module is controlled according to the second control signal so as to control the shunt size of the total current; the output end of the automatic gain adjustment module is connected with the first output end of the output module.
Specifically, in order to enable the transimpedance amplifier to have a wider dynamic input range, stable signal amplification and transmission can be performed when the input photocurrent is larger, waveform distortion is avoided, and an automatic gain adjustment module can be added on the basis of the scheme.
The automatic gain adjustment module is described below with reference to fig. 2.
Fig. 2 shows a circuit diagram of a high gain transimpedance amplifier incorporating an automatic gain adjustment module provided by an embodiment of the present application.
As shown in fig. 2, an automatic gain adjustment module 500 is added in parallel with a first load resistor and a second triode in the high gain transimpedance amplifier. The automatic gain adjustment module 500 includes a third triode 520 and a second load resistor 510; one end of the second load resistor 510 is connected with the other end of the output module as the other end of the automatic gain adjustment module 500, and the other end of the second load resistor 510 is connected with the collector of the third triode 520; the base electrode of the third triode 520 is connected with the control module as a control end of the automatic gain adjustment module 500, receives the second control signal sent by the control module, and the emitter electrode of the third triode 520 is connected with the second input end of the amplifier module as one end of the automatic gain adjustment module 500.
Specifically, when the control module detects that the input photocurrent is small, for example: the photocurrent is less than 50 microamps, and the control module controls the base voltage of the third transistor 520 to be a smaller value by using the generated second control signal, for example: 0V, so that the third triode 520 is in a closed state, i.e. the automatic gain adjustment module does not work, and at the moment, alternating current only flows through the passage formed by the first load resistor and the second triode, thereby ensuring that a larger amplified voltage V is output out 。
When the control module detects that the input photocurrent is large, for example: the photocurrent is greater than 50 microamps, and the control module controls the base voltage of the third transistor 520 to be a larger value by using the generated second control signal, for example: 2.5V to make the third triode 520 in a conductive state, wherein part of the alternating current flows through the path formed by the second load resistor and the third triode to split the total current, thereby reducing the outputIs set to the amplified voltage V out And the fluctuation distortion of the output amplified voltage caused when the input photocurrent is large is avoided, so that the loop stability and the wide input dynamic range are ensured. The resistance value of the second load resistor may be 0.
In an alternative embodiment, the second control signal includes a second on signal and a second off signal; the control module is used for detecting the intensity of the photocurrent signal, and if the photocurrent signal is smaller than a first set value, the control module outputs a second closing signal to the automatic gain adjustment module so as to close a current channel corresponding to the automatic gain adjustment module; if the photocurrent signal is greater than or equal to the first set value, the control module outputs a second starting signal to the automatic gain adjustment module so as to conduct a current path part corresponding to the automatic gain adjustment module; if the photocurrent signal is greater than or equal to the second set value, the control module outputs a third starting signal to the automatic gain adjustment module so as to fully conduct a current channel corresponding to the automatic gain adjustment module.
Specifically, the third transistor 520 may be set to be turned off or on, that is, the base of the third transistor 520 has a high voltage state and a low voltage state. When the input photocurrent is detected to be smaller, the second turn-off signal generated by the control module controls the base electrode of the third triode 520 to be in a low voltage state, and the third triode 520 is completely turned off. When the input photocurrent is detected to be larger, the second turn-on signal generated by the control module controls the base electrode of the third triode 520 to be in a high voltage state, that is, the third triode 520 is completely turned on (at this time, the collector current of the third triode 520 is the largest and cannot continue to be larger).
The voltage of the base electrode of the third triode 520 may also be set to be adjustable within a set interval, at this time, the control module detects the magnitude of the input photocurrent, and generates a corresponding control signal according to the magnitude of the photocurrent to control the magnitude of the base electrode voltage of the third triode 520, thereby controlling the opening degree of the third triode, changing the ratio of the alternating current input by the collector electrode of the third triode 520 to the collector electrode output current of the first triode 130 to be adjusted between 0 and 1, and controlling the shunt magnitude of the automatic gain module.
When the first load resistor and the second load resistor, and the second triode and the third triode are symmetrically arranged, the currents flowing through the first load resistor and the second load resistor are equal and are (I) 1 -I L )/2。
In an alternative embodiment, the first load resistor is a variable resistor; the control module is connected with the first load resistor, and the resistance value of the first load resistor is adjusted through the control module.
The method of adjusting the variable resistor is described below with reference to fig. 3.
Fig. 3 is a circuit diagram of a high gain transimpedance amplifier having a variable resistor as a first load resistor according to an embodiment of the present application.
As shown in FIG. 3, when the input photocurrent is large, the current I flowing through the first load resistor can be maintained L The control module is connected with the variable resistor, and the resistance value of the variable resistor is controlled by a resistance adjusting signal output by the control module and is smaller than R L_max Thereby achieving the effect of reducing the gain of the cross-group amplifier.
In an alternative embodiment, the current regulation module comprises an auxiliary direct current source for generating an auxiliary direct current.
The current regulation module is described below with reference to fig. 4.
Fig. 4 shows a circuit diagram of a high gain transimpedance amplifier with an auxiliary dc power supply as a current mirror according to an embodiment of the present application.
As shown in fig. 4, the current adjusting module 300 includes a current mirror pair 310 and an auxiliary dc current source 320, the current mirror pair 310 is connected to the auxiliary dc current source 320, a first output terminal of the current mirror pair 310 is connected to an external power supply VDD, and a second output terminal of the current mirror pair 310 is connected to a second input terminal of the amplifier module. The current mirror pair 310 includes two MOS transistors. The control module controls the current generated by the auxiliary direct current source 320 according to the expected auxiliary direct current, and obtains the branch current of the total current after passing through the current mirror.
The auxiliary dc source 320 is used to generate an auxiliary current, and the generated auxiliary current may be converted into 1:1 or a fixed ratio after entering the current mirror, and if only the auxiliary dc source 320 is used, the current of other branches may be affected.
Compared with a high-gain transimpedance amplifier in the prior art, the high-gain transimpedance amplifier can detect an optical current signal by using the control module, determine a control signal corresponding to the intensity of the optical current signal, generate auxiliary direct current corresponding to the control signal by using the current regulation module, reduce the current actually flowing in a load circuit by using the auxiliary direct current, and obtain an amplified voltage signal by using the voltage of an external power supply and the emitter voltage, thereby solving the problems of limited gain effect, low circuit stability and low frequency response speed in the existing transimpedance amplifier circuit.
Based on the same inventive concept, the embodiment of the present application further provides a high-gain photoelectric converter corresponding to the high-gain transimpedance amplifier, and since the principle of solving the problem of the high-gain photoelectric converter in the embodiment of the present application is similar to that of the high-gain transimpedance amplifier in the embodiment of the present application, implementation of the photoelectric converter can refer to implementation of the method, and repeated parts are omitted.
Referring to fig. 5, fig. 5 is a schematic structural diagram of a high-gain photoelectric converter according to an embodiment of the application. As shown in fig. 5, the high-gain photoelectric converter includes the high-gain transimpedance amplifier 10, the photodiode 20, and the external power supply 30 described above;
one end of the high-gain transimpedance amplifier 10 is connected with the output end of the photodiode 20, and the other end of the high-gain transimpedance amplifier 10 is connected with an external power supply 30;
the high gain transimpedance amplifier 10 receives the photocurrent signal output from the photodiode 20, and determines an amplified voltage signal to be output by using the power supply voltage 30 of the external power supply and the photocurrent signal.
It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, and are not repeated herein.
In the several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. The above-described apparatus embodiments are merely illustrative, for example, the division of the units is merely a logical function division, and there may be other manners of division in actual implementation, and for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be through some communication interface, device or unit indirect coupling or communication connection, which may be in electrical, mechanical or other form.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, each functional unit in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.
The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a non-volatile computer readable storage medium executable by a processor. Based on this understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
Finally, it should be noted that: the above examples are only specific embodiments of the present application, and are not intended to limit the scope of the present application, but it should be understood by those skilled in the art that the present application is not limited thereto, and that the present application is described in detail with reference to the foregoing examples: any person skilled in the art may modify or easily conceive of the technical solution described in the foregoing embodiments, or perform equivalent substitution of some of the technical features, while remaining within the technical scope of the present disclosure; such modifications, changes or substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application. Therefore, the protection scope of the application is subject to the protection scope of the claims.

Claims (10)

1. The high-gain transimpedance amplifier is characterized by comprising a control module, an amplifier module, an output module and a current regulation module:
the high-gain transimpedance amplifier receives a photocurrent signal output by a photodiode, the output end of the photodiode is connected with the first input end of the amplifier module, and the photocurrent signal is amplified by the amplifier module to obtain emitter current;
the control module is connected with the photodiode and the current regulation module, detects the intensity of a photocurrent signal output by the photodiode, determines a first control signal corresponding to the intensity of the photocurrent signal, and inputs the first control signal to the current regulation module;
the current adjusting module receives the first control signal, generates auxiliary direct current corresponding to the first control signal, and adjusts the current of the output module by using the auxiliary direct current;
one end of the output module is connected with the second input end of the amplifier module and one end of the current regulating module, the other end of the output module is connected with an external power supply and the other end of the current regulating module, and the output module outputs an amplified voltage signal according to the auxiliary direct current, the power voltage of the external power supply and the emitter current.
2. The high gain transimpedance amplifier according to claim 1, wherein the amplifier module comprises a main amplifier, a feedback resistor, a first transistor and an emitter resistor;
one end of the main amplifier is used as a first input end of the amplifier module and is connected with the output end of the photodiode, and the other end of the main amplifier is connected with the base electrode of the first triode;
the collector of the first triode is used as a second input end of the amplifier module to be connected with one end of the output module, the emitter of the first triode is connected with one end of the emitter resistor, and the other end of the emitter resistor is used as an output end of the amplifier module to be grounded;
one end of the main amplifier is also connected with one end of the feedback resistor, and the other end of the feedback resistor is connected with one end of the emitter resistor.
3. The high gain transimpedance amplifier according to claim 1, wherein the output module comprises a second triode and a first load resistor;
one end of the first load resistor is used as the other end of the output module to be connected with the external power supply and the other end of the current regulating module, the other end of the first load resistor is connected with the collector electrode of the second triode, and the collector electrode of the second triode is also used as the output end of the output module to output amplified voltage;
the base of the second triode is set to be a fixed voltage, so that the second triode is conducted, and the emitter of the second triode is used as one end of the output module to be connected with the second input end of the amplifier module and one end of the current adjusting module.
4. The high gain transimpedance amplifier according to claim 1, wherein the current regulation module comprises an auxiliary dc current source for generating an auxiliary dc current.
5. The high gain transimpedance amplifier according to claim 1, further comprising an automatic gain adjustment module;
the other end of the automatic gain adjustment module is connected with the other end of the output module, and the control end of the automatic gain adjustment module is connected with the control module and is used for receiving a second control signal output by the control module and controlling the gain of the automatic gain adjustment module according to the second control signal so as to control the shunt size of the total current;
one end of the automatic gain adjustment module is connected with one end of the output module.
6. The high gain transimpedance amplifier according to claim 5, wherein the automatic gain adjustment module comprises a third transistor, a second load resistor;
one end of the second load resistor is used as the other end of the automatic gain adjustment module and is connected with the other end of the output module, and the other end of the second load resistor is connected with the collector electrode of the third triode;
the base electrode of the third triode is used as the control end of the automatic gain adjustment module to be connected with the control module and receives a second control signal sent by the control module, and the emitter electrode of the third triode is used as one end of the automatic gain adjustment module to be connected with the second input end of the amplifier module.
7. A high gain transimpedance amplifier according to claim 3, wherein the first load resistor is a variable resistor;
the control module is connected with the first load resistor, and the resistance value of the first load resistor is adjusted through the control module.
8. A high gain transimpedance amplifier according to claim 2 or claim 3, wherein the gains of the first transistor and the second transistor are both 1.
9. The high gain transimpedance amplifier according to claim 6, wherein the second control signal comprises a second on signal and a second off signal;
the control module is used for detecting the intensity of a photocurrent signal, and if the photocurrent signal is smaller than a first set value, the control module outputs a second closing signal to the automatic gain adjustment module so as to close a current channel corresponding to the automatic gain adjustment module;
if the photocurrent signal is greater than or equal to a first set value, the control module outputs a second starting signal to the automatic gain adjustment module so as to conduct a current path part corresponding to the automatic gain adjustment module;
and if the photocurrent signal is greater than or equal to the second set value, the control module outputs a third starting signal to the automatic gain adjustment module so as to fully conduct a current channel corresponding to the automatic gain adjustment module.
10. A high gain photoelectric converter, characterized in that the high gain photoelectric converter comprises the high gain transimpedance amplifier according to any one of claims 1 to 9, a photodiode, and an external power supply;
one end of the high-gain transimpedance amplifier is connected with the output end of the photodiode, and the other end of the high-gain transimpedance amplifier is connected with the external power supply;
and the high-gain transimpedance amplifier receives the photocurrent signal output by the photodiode and determines an output amplified voltage signal by using the power supply voltage of the external power supply and the photocurrent signal.
CN202310600228.3A 2023-05-25 2023-05-25 High-gain transimpedance amplifier and high-gain photoelectric converter Pending CN116633284A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117811516A (en) * 2024-03-01 2024-04-02 成都鹰谷米特科技有限公司 Variable transimpedance TIA amplifier integrated circuit and laser pulse detector

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117811516A (en) * 2024-03-01 2024-04-02 成都鹰谷米特科技有限公司 Variable transimpedance TIA amplifier integrated circuit and laser pulse detector
CN117811516B (en) * 2024-03-01 2024-05-24 成都鹰谷米特科技有限公司 Variable transimpedance TIA amplifier integrated circuit and laser pulse detector

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