CN208313429U - A kind of Electro-Optical Sensor Set of optional channel gain range - Google Patents

Abstract

The utility model relates to a kind of Electro-Optical Sensor Set of optional channel gain range, which includes: photodiode, across feed circuit between resistance amplifying circuit, in-phase proportion operational amplification circuit and grade.Optical signal is converted to current signal through photodiode, it is output to across resistance amplifying circuit, anti-phase input across resistance amplifier terminates current input signal, non-inverting input terminal ground connection, its inverting input terminal is connected to by feedback resistance across resistance amplifier output, the non-inverting input terminal of in-phase proportion amplifier is connect as the input signal of in-phase proportion operational amplification circuit simultaneously, the inverting input terminal of in-phase proportion amplifier passes through resistance eutral grounding, and the output of in-phase proportion operational amplifier circuit is fed back to by its inverting input terminal by feedback resistance, the output of in-phase proportion operational amplifier circuit is fed back into the inverting input terminal across resistance amplifying circuit amplifier by feedback resistance between grade.The photodetection circuit may be implemented the gain mode of multichannel, and can significantly increase the dynamic range of detectable input optical power.

Description

A kind of Electro-Optical Sensor Set of optional channel gain range

Technical field:

The utility model relates to technical field of photo communication, and in particular to a kind of photodetection of optional channel gain range Device.

Background technique:

With the fast development of information technology, optical communication technique is widely used in various fields.Preposition photoelectricity Important component of the detection circuit as optical communication technique, performance directly decide the performance of entire photoreceiver.Currently, There are three types of the preposition photodetection circuits of common photoreceiver, be respectively as follows: high resistant preamplifier, low-resistance preamplifier and Transimpedance preamplifier.High resistant pregain is big, high sensitivity, but dynamic range is small；Low-resistance preamplifier is dynamic State range is big, but gain is small, and sensitivity is low；Transimpedance preamplifier use high input impedance negative feedback structure, high sensitivity, Gain is big, and dynamic range is big.So generalling use transimpedance preamplifier in photoreceiver.Traditional transimpedance preamplifier will Photo-signal is converted into voltage signal, amplifies voltage signal using main amplifier.Problem of the existing technology is: 1, when When the lesser input light of detection of optical power, Signal-to-Noise is low, and signal can be submerged in noise, can not be accurately detected useful letter Number；2, in the biggish input light of detection of optical power, since transimpedance gain is larger, it is likely to result in the saturation distortion of signal.Cause This, traditional transimpedance preamplifier dynamic range is small, in order to improve dynamic range, it will usually sacrifice fractionated gain.

Utility model content:

The utility model provides a kind of Electro-Optical Sensor Set of optional channel gain range, can be according to optical power size Difference, select different gain modes, while not sacrificing gain, ensure that the dynamic model of detectable input optical power It encloses.

To achieve the goals above, the utility model provides a kind of photodetection dress of optional channel gain range Set, including photodiode, across resistance amplifying circuit, feed circuit between in-phase proportion operational amplification circuit and grade, it is described to be put across resistance Big circuit is by across resistance amplifier A1 and feedback resistance R₁Composition, the current signal of photodiode D1 output are connected to across resistance amplifying circuit The inverting input terminal of middle amplifier A1, the non-inverting input terminal ground connection of A1, across resistance amplifier feedback resistance R₁A1 is terminated to by the output of A1 Reverse input end；The output end of the homophase input termination A1 of in-phase proportion operational amplification circuit amplifier A2, the reversed input of A2 Terminating resistor R₃It is grounded again, with phase feedback resistance R₄The reverse input end of A2, feed circuit between grade are terminated to by the output of amplifier A2 By feedback resistance R between grade₂It constitutes, R₂The output end of one termination amplifier A2, the output end of a termination photodiode.

It further include feed circuit between the second in-phase proportion operational amplification circuit and the second level in foregoing circuit, described second is same Phase Proportion operational amplification circuit is by amplifier A3 and resistance R₆And R₇Composition, the output end of the homophase input termination amplifier A2 of amplifier A3, The reverse input end connecting resistance R of A3₆It is grounded again, with phase feedback resistance R₇The output end of one termination amplifier A3, another termination A3's is anti- To input terminal；Feed circuit is by feedback resistance R between grade between the second tunnel grade₃It constitutes, R₃The output end of one termination amplifier A3, one Terminate the reverse input end of amplifier A1.

Feed circuit respectively includes the corresponding road N between above-mentioned in-phase proportion operational amplification circuit and grade.

Above-mentioned photodiode D1 is PIN photodiode.

Compared with prior art, the utility model has the following beneficial effects:

Suitable gain is selected by feeding back between multichannel grade for the biggish optical signal of optical power change range to be detected Mode.When optical power is larger, lesser gain channel is selected, guarantees that signal will not saturation distortion；When optical power is smaller, choosing Biggish gain channel is selected, signal-to-noise ratio is improved, guarantees that signal will not be submerged in noise.The preposition photoelectricity of the utility model simultaneously Detector can be extended for N number of gain channel according to actual needs, while not sacrificing gain, also ensure detectable optical power Dynamic range.

Detailed description of the invention

Fig. 1 is the photodetection circuit of the utility model Larger Dynamic range；

Fig. 2 is the preposition photodetection circuit diagram of triple channel gain that the utility model is used for Larger Dynamic range；

Fig. 3 is a kind of principle sketch of acousto-optic frequency shifters frequency displacement measuring device；

Fig. 4 the is optical power beat signal that obtains when being 34 μ W；

Fig. 5 the is optical power beat signal that obtains when being 15.6mW.

Specific embodiment

In order to keep the purpose of this utility model, technical solution and advantage clearer, below in conjunction with attached drawing to this make into It is described in detail to one step, it is clear that described embodiment is only a part of the embodiment, instead of all the embodiments.It is based on Embodiment in this, all other implementation obtained by those of ordinary skill in the art without making creative efforts Example, belongs to the range of this protection.

Referring to Fig. 1, a kind of photodetection circuit for Larger Dynamic range is that binary channels gain is preposition in the present embodiment Photodetection circuit specifically includes photodiode, across feedback electricity between resistance amplifying circuit, in-phase proportion operational amplification circuit and grade Road, it is described across resistance amplifying circuit by across resistance amplifier A1 and feedback resistance R₁The current signal of composition, photodiode D1 output connects The inverting input terminal of amplifier A1 in across resistance amplifying circuit, the non-inverting input terminal ground connection of A1, across resistance amplifier feedback resistance R₁By A1 Output terminate to the reverse input end of A1；The output of the homophase input termination A1 of in-phase proportion operational amplification circuit amplifier A2 End, the reverse input end connecting resistance R of A2₃It is grounded again, with phase feedback resistance R₄The reversed input of A2 is terminated to by the output of amplifier A2 It holds, feed circuit is by feedback resistance R between grade between grade₂It constitutes, R₂The output end of one termination amplifier A2, a termination photodiode Output end.

Feed circuit is respectively one in the present embodiment between in-phase proportion operational amplification circuit therein and grade, according to need Corresponding two-way or the road N can be set.

Referring to fig. 2, a kind of photodetection circuit for Larger Dynamic range is the preposition light of triple channel gain in the present embodiment Electrical resistivity survey slowdown monitoring circuit.The preposition photodetection circuit of triple channel gain is to binary channels gain preposition photodetection circuit gain channel Expand, the two is identical in principle.The circuit includes: photodiode, across resistance amplifying circuit, two-way in-phase proportion operation Feed circuit between amplifying circuit and two-way grade.The photodiode D1 converts optical signals to current signal；Across resistance amplification electricity Routing is across resistance amplifier A1 and feedback resistance R₁Composition, photodiode D1 output current signal be connected to across resistance amplifying circuit in transport Put the inverting input terminal of A1, the non-inverting input terminal ground connection of A1, across resistance amplifier feedback resistance R₁The output end of one termination A1, it is another Terminate the reverse input end of A1；First via in-phase proportion operational amplification circuit is by amplifier A2 and resistance R₄And R₅Composition, amplifier A2 Homophase input termination amplifier A1 output end, the reverse input end connecting resistance R of A2₄It is grounded again, with phase feedback resistance R₅One termination The output end of amplifier A2, the reverse input end of another termination A2；Feed circuit is by feedback resistance R between grade between first via grade₂It constitutes, R₂The output end of one termination amplifier A2, the reverse input end of a termination amplifier A1；Second road in-phase proportion operational amplification circuit by Amplifier A3 and resistance R₆And R₇Composition, the output end of the homophase input termination amplifier A2 of amplifier A3, the reverse input end connecting resistance of A3 R₆It is grounded again, with phase feedback resistance R₇The output end of one termination amplifier A3, the reverse input end of another termination A3；Between the grade of second tunnel Feed circuit is by feedback resistance R between grade₃It constitutes, R₃The output end of one termination amplifier A3, the reverse input end of a termination amplifier A1；

The basic principle of the preposition photodetection circuit is: photodiode converts optical signals into current signal, electric current According to a certain percentage in resistance R₁、R₂、R₃Upper formation shunts, and current signal is converted into voltage signal U_O1、U_O2、U_O3, realize Triple channel gain, successively according to U_O3、U_O2、U_O1The preposition photodetection circuit of sequence detection output effect, final choose increase The output end that the good channel of beneficial effect is arrived as preposition photodetection circuit.

Photodiode receives optical signal in photosurface and generates current signal I, and electric current is according to a certain percentage in resistance R₁、R₂、R₃Upper formation shunts, and specific proportionate relationship derives as follows.

As can be seen from the figure the preposition photodetection circuit of the utility model has three road gain channels, respectively resistance R₁、R₂、R₃Corresponding channel remembers that the shunting of triple channel is followed successively by I₁、I₂、I₃, the output voltage in three channels is followed successively by U_O1、U_O2、 U_O3。

Gain channel one is analyzed, and R is flowed through₁On electric current I₁, according to the output voltage of ohm law gain channel one:

U_O1=I₁×R₁

Gain channel two is analyzed, and R is flowed through₂On electric current I₂, according to the output voltage of ohm law gain channel two:

U_O2=I₂×R₂

Gain channel three is analyzed, and R is flowed through₃On electric current I₃, according to the output voltage of ohm law gain channel three:

U_O3=I₃×R₃

U can be obtained according to the characteristic of in-phase proportion operational amplifier circuit_O1And U_O2Relationship it is as follows:

U_O2=A₂×U_O1

Wherein A₂Indicate the ratio enlargement multiple of amplifier A2；

U can similarly be obtained_O2And U_O3Relationship it is as follows:

U_O3=A₃×U_O2

Wherein A₃Indicate the ratio enlargement multiple of amplifier A3.

Following relationship can be obtained according to above reasoning:

I₂R₂=A₂×I₁R₁

I₃R₃=A₃×I₂R₂

Available I₁、I₂、I₃Shunt ratio it is as follows:

I₃:I₂:I₁=A₃A₂R₂R₁:A₂R₃R₁:R₂R₃

A1 amplifier selects AD8065 in this example, and A2 amplifier selects ADA4817, and A3 amplifier selects ADA4817, each in circuit Resistance is respectively as follows: R₁=470 Ω, R₂=3.6K Ω, R₃=28K Ω, R₄=100 Ω, R₅=3.9K Ω, R₆=100 Ω, R₇=3.9K Ω.It can be concluded that the ratio enlargement multiple A of amplifier A2₂The ratio enlargement multiple A of=40, amplifier A3₃=40, I₁、I₂、 I₃Shunt ratio are as follows: I₃:I₂:I₁=26.9:5.2:1.

As can be seen that the gain in channel three is maximum from analysis above, the gain of sensitivity highest, channel one is minimum, The gain in channel two is placed in the middle.

In order to further illustrate the using effect of the utility model, this circuit is used for acousto-optic frequency shifters frequency shift amount below In measuring device (referring to Fig. 3), the current signal converted to photodiode 6 is handled, and photodiode 6 here is PIN photodiode.

If Fig. 4 and Fig. 5 are the beat signals that do not obtain simultaneously of input optical power in interference light.Wherein Fig. 4 is that input is dry Relate to the beat signal that the gain channel three after removing direct current biasing when light optical power is 34uW by embodiment obtains, it can be seen that when When optical power is smaller, it can be very good to amplify beat signal using the biggish channel of gain.Fig. 5 is input interference light light The beat signal that is obtained by gain channel one when power is 15.6mW, it can be seen that when optical power is larger, using gain compared with Small channel can be very good to amplify beat signal.It can be seen that when needing the lesser light source of detection of optical power, it can To select the maximum third channel of gain, when needing the biggish light source of detection of optical power, gain can be selected the smallest by first Channel, when needing the moderate light source of detection of optical power, second channel that gain can be selected placed in the middle.

Claims (4)

1. a kind of Electro-Optical Sensor Set of optional channel gain range, it is characterised in that: amplify including photodiode, across resistance Feed circuit between circuit, in-phase proportion operational amplification circuit and grade, it is described across resistance amplifying circuit by across resistance amplifier A1 and feedback electricity Hinder R₁Composition, the current signal of photodiode D1 output are connected to the inverting input terminal across amplifier A1 in resistance amplifying circuit, A1's Non-inverting input terminal ground connection, across resistance amplifier feedback resistance R₁The reverse input end of A1 is terminated to by the output of A1；In-phase proportion operation The output end of the homophase input termination A1 of amplifying circuit amplifier A2, the reverse input end connecting resistance R of A2₃It is grounded again, with mutually feedback Resistance R₄The reverse input end of A2 is terminated to by the output of amplifier A2, feed circuit is by feedback resistance R between grade between grade₂It constitutes, R₂One Terminate the output end of amplifier A2, the output end of a termination photodiode.

2. a kind of Electro-Optical Sensor Set of optional channel gain range as described in claim 1, it is characterised in that: further include Feed circuit between second in-phase proportion operational amplification circuit and the second level, the second in-phase proportion operational amplification circuit is by amplifier A3 and resistance R₆And R₇Composition, the output end of the homophase input termination amplifier A2 of amplifier A3, the reverse input end connecting resistance R of A3₆Again Ground connection, with phase feedback resistance R₇The output end of one termination amplifier A3, the reverse input end of another termination A3；It is fed back between the grade of second tunnel Feedback resistance R between electric route level₃It constitutes, R₃The output end of one termination amplifier A3, the reverse input end of a termination amplifier A1.

3. a kind of Electro-Optical Sensor Set of optional channel gain range as described in claim 1, it is characterised in that: described same Feed circuit respectively includes the corresponding road N between Phase Proportion operational amplification circuit and grade.

4. a kind of Electro-Optical Sensor Set of optional channel gain range as described in claims 1 or 2 or 3, it is characterised in that: The photodiode D1 is PIN photodiode.