CN208902784U - Signal isolation circuit is used in a kind of detection - Google Patents
Signal isolation circuit is used in a kind of detection Download PDFInfo
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- CN208902784U CN208902784U CN201821620558.XU CN201821620558U CN208902784U CN 208902784 U CN208902784 U CN 208902784U CN 201821620558 U CN201821620558 U CN 201821620558U CN 208902784 U CN208902784 U CN 208902784U
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- signal
- isolation
- sample circuit
- circuit
- gating
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Abstract
The utility model relates to a kind of detection signal isolation circuits, including several for acquiring the sample circuit of AIN signal, CPU and the output end being connect with CPU, isolated amplifier and photoisolator are provided between each sample circuit and the CPU, sample circuit connects the isolated amplifier and photoisolator by isolation gating unit, when the virtual value of the sampled signal of sample circuit output is greater than predeterminated voltage, the isolation gating unit is connected to the sample circuit and photoelectric isolating circuit, when sampled signal is less than predeterminated voltage, the isolation gating unit is connected to the sample circuit and photoisolator.The setting of two kinds of isolators and isolation gating unit is so that the isolation circuit can adapt to the acquisition of the multiple analog signal under a variety of environment.
Description
Technical field
The utility model relates to analog to digital conversion circuit fields, more particularly, to a kind of detection signal isolation circuit.
Background technique
In electric power terminal device application environment, it is often necessary to collect some analog quantity informations in site environment
CPU (Central Processing Unit, central processing unit) is monitored, and collected analog quantity information may be voltage
Signal is also likely to be current signal.Under normal circumstances, voltage signal input range is in 0~5V, current signal input range 4~
20mA.In order to accurately be acquired to analog signals, while not introducing various electromagnetic interferences, it is necessary to external circuits with
It is isolated between CPU, isolation amplifying method and Phototube Coupling method usually can be used in isolation.
It in the prior art, is usually to first pass through isolation circuit processing, then be directly entered CPU's to the acquisition of analog quantity information
Analog-to-digital conversion interface.Its principle is as shown in Figure 1, wherein AIN is analog signal.The processing method of isolation circuit not only includes number
Photoisolator further includes isolated amplifier.
Isolated amplifier makes between the output of amplifier and input absolutely not electrical link using magnetic coupling method, thus
Make it that interference source both be isolated, it is suppressed that interference signal, and complete the amplification to signal.Isolated amplifier has been internally integrated height
The unit components such as the input and output amplifier of performance, modem, signal coupling transformer.Though but this isolated amplifier
Right precision is high, and the distortion factor is smaller, when being acquired for high current signal or big voltage signal, although can guarantee height
Isolation under the premise of precision, but itself power consumption is big, it, will for the signal acquisition circuit being integrated in fixed equipment
Accordingly increase the consumption of electric energy, such as automobile, power distribution cabinet etc..
And the method for Phototube Coupling is then more commonly used, it is a kind of side for carrying out photoelectric conversion as medium using optical signal
Method.Electrically, this method is completely isolated by measuring system and in-site measurement environment, reduces external interference to the shadow of system
It rings.Although its power consumption is low, for isolated amplifier, detection accuracy is relatively low, and it is outer to be typically necessary increase
It encloses circuit and guarantees its precision.
Based on the feature of both the above partition method, existing signal acquisition circuit is for customized under a particular condition
Made of signal acquisition circuit, every AIN interface is cured as a kind of function, more when needing to acquire by signal acquisition circuit
When planting a variety of AIN under environment, general applicability is not strong.
Utility model content
The purpose of the utility model is to provide a kind of detection signal isolation circuit, which can adapt to more
Multiple analog signal acquisition under kind environment.
The above-mentioned purpose of utility model of the utility model has the technical scheme that
A kind of detection signal isolation circuit, including several for acquiring the sample circuit, CPU and and CPU of AIN signal
The output end of connection is provided with isolated amplifier and photoisolator, sample circuit between each sample circuit and the CPU
Connect the isolated amplifier and photoisolator by isolation gating unit, when sample circuit output sampled signal it is effective
When value is greater than predeterminated voltage, the isolation gating unit is connected to the sample circuit and photoelectric isolating circuit, when sampled signal is small
When predeterminated voltage, the isolation gating unit is connected to the sample circuit and photoisolator.
By using above-mentioned technical proposal, each sample circuit is all connected with two kinds of isolators, i.e. isolated amplifier and light
Electric isolator, isolation gating unit can gate different isolators according to the virtual value of sampled signal.It is effective when sampled signal
When value is greater than predeterminated voltage, illustrate that AIN signal voltage value collected is larger, for biggish signal, generally for its precision
Requirement can reduce, while requiring to reduce the consumption of power, at this point, by photoelectric isolating circuit realization to sampled signal every
From, the power consumption of isolator can be reduced under the premise of realization is effectively isolated, when the virtual value of sampled signal be less than it is default
When voltage, illustrates that AIN signal voltage value collected is lower, belong to tiny signal, for tiny signal, it is desirable that it is in isolation
Under the premise of can guarantee high-precision isolation and fidelity, at this time select isolated amplifier as isolator, it is ensured that small
The accuracy of signal data acquisition.Two kinds of isolators and be isolated gating unit setting so that the isolation circuit can adapt to it is more
The acquisition of multiple analog signal under kind environment.
As the improvement of the utility model, the isolation gating unit includes:
Comparison module couples the sample circuit, for receiving sampled signal, presets when the virtual value of sampled signal is greater than
When voltage, output photoelectric gating signal, when the virtual value of sampled signal is less than predeterminated voltage, output isolation gating signal；
Gating module, couple comparison module, when receive isolation gating module when, be connected to the sample circuit and it is described every
From amplifier, when receiving photoelectricity gating signal, it is connected to the sample circuit and the photoisolator.
As the improvement of the utility model, the photoisolator and the isolated amplifier sequential series are in sample circuit
Between CPU, the gating module includes the first short switch and in parallel with photoisolator and isolated amplifier respectively
Two short switches, the first short switch response isolation gating signal closure, the second short switch response light electric separation are logical
Signal closure.
As the improvement of the utility model, the photoisolator and the first fixed resistance be composed in series with it is described first short
The photoelectricity branch of way switch parallel connection, the isolated amplifier and the second fixed resistance are composed in series with second short switch simultaneously
The amplification branch of connection.
As the improvement of the utility model, first short switch and the second short switch are disposed as silicon-controlled.
As the improvement of the utility model, the comparison module includes；
Reference cell, the first reference resistance and the second reference resistance including being serially connected with power supply, the first reference resistance and
The node of two reference resistances coupling exports the predeterminated voltage；
The positive input of comparator, the comparator couples the reference cell, for receiving the predeterminated voltage, than
The sample circuit is coupled by a filter capacitor compared with the inverting input terminal of device.
As the improvement of the utility model, photoelectrical coupler is serially connected between the comparator and the gating module.
As the improvement of the utility model, the output end of the photoelectrical coupler connects the triggering of second short switch
It holds, and connects the triggering end of first short switch by a phase inverter.
In conclusion the advantageous effects of the utility model are as follows:
1. applied widely, by built-in isolated amplifier and photoisolator, enable the signal isolation circuit
Detection suitable for multi-signal；
2. it is highly-safe, by the way that photoelectrical coupler is arranged, realize the electricity between isolation gating circuit and two isolators
Isolation avoids the unstability due to isolation gating circuit work from influencing the work of isolator.
Detailed description of the invention
Fig. 1 is analog to digital conversion circuit in the prior art；
Fig. 2 is the circuit diagram of the signal isolation circuit in the utility model；
Fig. 3 is isolation gating unit electrical block diagram.
In figure, 1, comparison module；2, gating module.
Specific embodiment
The utility model is described in further detail below in conjunction with attached drawing.
Referring to Fig. 2, signal isolation circuit is used for a kind of detect disclosed by the utility model, including several for acquiring AIN
The acquisition branch of signal, the CPU being connect with each acquisition branch and the output end being connect with CPU.Wherein, CPU preferably has
There is the single-chip microcontroller of built-in ADC function, output end is multiple-channel output port.
Each acquisition branch includes for acquiring the sample circuit of AIN signal, gating being isolated with what sample circuit connected
Unit and be isolated gating unit connection isolated amplifier and photoisolator.Sample circuit collects defeated after AIN signal
Corresponding sampled signal out.When the virtual value of the sampled signal of sample circuit output is greater than predeterminated voltage, the isolation gating
Unit is connected to the sample circuit and photoelectric isolating circuit, when sampled signal is less than predeterminated voltage, the isolation gating unit
It is connected to the sample circuit and photoisolator.
Herein without limitation to the selection of photoisolator and isolated amplifier, but illustrate model in the utility model
In enclosing, isolated amplifier is preferably the isolated amplifier of ISO124U model, and the model of photoisolator is preferably EL357N-C.
As shown in figure 3, isolation gating unit includes comparison module 1 and the gating module connecting with comparison module 12.
Comparison module 1 couples sample circuit, for receiving sampled signal, when the virtual value of sampled signal is greater than default electricity
When pressure, output photoelectric gating signal, when the virtual value of sampled signal is less than predeterminated voltage, output isolation gating signal.
Gating module 2, couple comparison module 1, when receive isolation gating module 2 when, connection sample circuit and it is described every
From amplifier, when receiving photoelectricity gating signal, it is connected to the sample circuit and the photoisolator.
Wherein, photoisolator and the isolated amplifier sequential series are between sample circuit and CPU, gating module 2
Including silicon-controlled D1 and silicon-controlled D2 in parallel with photoisolator and isolated amplifier respectively.Silicon-controlled D1's and silicon-controlled D2
Triggering end is for receiving above-mentioned photoelectricity gating signal and isolation gating signal.
Preferably, photoisolator is composed in series the photoelectricity branch in parallel with silicon-controlled D1 with fixed resistance R4, and isolation is put
Big device is composed in series the amplification branch in parallel with silicon-controlled D2 with fixed resistance R5.When silicon-controlled D1 is triggered, silicon-controlled D1
The short circuit to photoisolator will be formed, so that the sampled signal of sample circuit output is exported by isolated amplifier to CPU, when
When silicon-controlled D2 is triggered, short circuit of the silicon-controlled D2 by formation to isolated amplifier, so that the sampled signal of sample circuit output
It is exported by photoisolator to CPU.The setting of fixed resistance R4 and fixed resistance R5 provide photoelectricity branch and amplification branch
The enough resistance values in road can be respectively formed when so that silicon-controlled D1 or silicon-controlled D2 being set out to photoisolator or isolation
Effective short circuit of amplifier.
Above-mentioned comparison module 1 includes reference cell, comparator DT and photoelectrical coupler U1.
Reference cell, fixed resistance R1 and potentiometer R2 including being serially connected with power supply, fixed resistance R1 and potentiometer R2 coupling
The node connect exports above-mentioned predeterminated voltage；The positive input of comparator DT couples reference cell, for receiving predeterminated voltage, than
Inverting input terminal compared with device DT couples sample circuit by a filter capacitor C.The sampled signal of sample circuit output is by filtering
When capacitor C, filter capacitor C reaches the balance of charge and discharge, to generate the virtual value of a reaction sampled signal size, the virtual value
It is proportional to power virtual value when sampled signal passes through electronic component.When virtual value is greater than preset voltage value, comparator DT's
Output end exports the first comparison signal of low potential, when virtual value is less than preset voltage value, the output end output of comparator DT
Second comparison signal of high potential.
The output end of the input terminal coupling comparator DT of photoelectrical coupler U1, the output end of photoelectrical coupler U1 pass through on one
Pull-up resistor R3 connection positive pole.Meanwhile the output end of photoelectrical coupler U1 is directly connected to the triggering end of silicon-controlled D2, and passes through
One phase inverter U2 connects the triggering end of silicon-controlled D1.When comparator DT exports the first comparison signal, silicon-controlled D2, which is triggered, to be led
Logical, sample circuit is connected to CPU by photoisolator, and when comparator DT exports the second comparison signal, silicon-controlled D1 is triggered
Conducting, sample circuit are connected to CPU by isolated amplifier.
When the virtual value of sampled signal be greater than predeterminated voltage when, illustrate that AIN signal voltage value collected is larger, for compared with
Big signal, the requirement generally for its precision can reduce, while require to reduce the consumption of power, at this point, passing through Phototube Coupling
Circuit realizes isolation to sampled signal, can reduce the power consumption of isolator under the premise of realization is effectively isolated, when adopting
When the virtual value of sample signal is less than predeterminated voltage, illustrates that AIN signal voltage value collected is lower, belong to tiny signal, for
Tiny signal, it is desirable that it can guarantee high-precision isolation and fidelity under the premise of isolation, select isolated amplifier at this time
As isolator, it is ensured that the accuracy of tiny signal data acquisition.Two kinds of isolators and the setting that gating unit is isolated
So that the isolation circuit can adapt to the acquisition of the multiple analog signal under a variety of environment.
The embodiment of present embodiment is the preferred embodiment of the utility model, and not limitation is originally practical new according to this
The protection scope of type, therefore: the equivalence changes that all structures, shape, principle according to the utility model are done should all be covered by practical
Within novel protection scope.
Claims (8)
1. a kind of detection signal isolation circuit, which is characterized in that including several for acquiring sample circuit, the CPU of AIN signal
And the output end being connect with CPU, isolated amplifier and Phototube Coupling are provided between each sample circuit and the CPU
Device, sample circuit connect the isolated amplifier and photoisolator by isolation gating unit, when adopting for sample circuit output
When the virtual value of sample signal is greater than predeterminated voltage, the isolation gating unit is connected to the sample circuit and photoelectric isolating circuit,
When sampled signal is less than predeterminated voltage, the isolation gating unit is connected to the sample circuit and photoisolator.
2. a kind of detection signal isolation circuit according to claim 1, which is characterized in that the isolation gating unit packet
It includes:
Comparison module (1), couples the sample circuit, for receiving sampled signal, presets when the virtual value of sampled signal is greater than
When voltage, output photoelectric gating signal, when the virtual value of sampled signal is less than predeterminated voltage, output isolation gating signal；
Gating module (2), couple comparison module (1), when receive isolation gating module (2) when, be connected to the sample circuit with
The isolated amplifier is connected to the sample circuit and the photoisolator when receiving photoelectricity gating signal.
3. a kind of detection signal isolation circuit according to claim 2, which is characterized in that the photoisolator and institute
Isolated amplifier sequential series are stated between sample circuit and CPU, the gating module (2) include respectively with photoisolator and
The first short switch and the second short switch of isolated amplifier parallel connection, the first short switch response isolation gating signal are closed
It closes, the second short switch response light electronic gating signal closure.
4. a kind of detection signal isolation circuit according to claim 3, which is characterized in that the photoisolator and the
One fixed resistance is composed in series the photoelectricity branch in parallel with first short switch, the isolated amplifier and the second fixed electricity
Resistance is composed in series the amplification branch in parallel with second short switch.
5. a kind of detection signal isolation circuit according to claim 3, which is characterized in that first short switch
It is disposed as with the second short switch silicon-controlled.
6. a kind of detection signal isolation circuit according to claim 3, which is characterized in that comparison module (1) packet
It includes；
Reference cell, the first reference resistance and the second reference resistance including being serially connected with power supply, the first reference resistance and the second base
The node of quasi- resistance coupling exports the predeterminated voltage；
The positive input of comparator, the comparator couples the reference cell, for receiving the predeterminated voltage, comparator
Inverting input terminal the sample circuit is coupled by a filter capacitor.
7. a kind of detection signal isolation circuit according to claim 6, which is characterized in that the comparator and the choosing
Photoelectrical coupler is serially connected between logical module (2).
8. it is according to claim 7 it is a kind of detection use signal isolation circuit, which is characterized in that the photoelectrical coupler it is defeated
Outlet connects the triggering end of second short switch, and the triggering end of first short switch is connected by a phase inverter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821620558.XU CN208902784U (en) | 2018-09-30 | 2018-09-30 | Signal isolation circuit is used in a kind of detection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821620558.XU CN208902784U (en) | 2018-09-30 | 2018-09-30 | Signal isolation circuit is used in a kind of detection |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208902784U true CN208902784U (en) | 2019-05-24 |
Family
ID=66574682
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201821620558.XU Expired - Fee Related CN208902784U (en) | 2018-09-30 | 2018-09-30 | Signal isolation circuit is used in a kind of detection |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN208902784U (en) |
-
2018
- 2018-09-30 CN CN201821620558.XU patent/CN208902784U/en not_active Expired - Fee Related
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| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20190524 Termination date: 20210930 |
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| CF01 | Termination of patent right due to non-payment of annual fee |