CN208939925U - A kind of analog to digital conversion circuit with linear isolation characteristic - Google Patents
A kind of analog to digital conversion circuit with linear isolation characteristic Download PDFInfo
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- CN208939925U CN208939925U CN201821564117.2U CN201821564117U CN208939925U CN 208939925 U CN208939925 U CN 208939925U CN 201821564117 U CN201821564117 U CN 201821564117U CN 208939925 U CN208939925 U CN 208939925U
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Abstract
The utility model relates to signal processing technology fields in analog-to-digital conversion, analog to digital conversion circuit adjustable more particularly to a kind of output area and with linear isolation characteristic, it include: input signal conditioning module, it is converted into the voltage signal of required amplitude for the current or voltage signal by input, and the voltage signal is output to linear isolation module；The voltage signal is carried out analog isolation, finally voltage signal is adjusted according to chip demand, filtered by the linear isolation module, and output to A/D conversion module carries out analog-to-digital conversion, and the digital quantity after conversion substitutes into SCM program and carries out operation.The analog to digital conversion circuit uses the dual resisteance of analog isolation and isolated from power, enhance anti-interference ability, internal circuit configuration refining, the handover measurement of voltage and current can be realized by configuring port connection mode, by the parameter for changing internal poles small part device, the i.e. changeable gain coefficient for being input to output, adapts to different measuring systems.
Description
Technical field
The utility model relates to signal processing technology fields in analog-to-digital conversion, and in particular to a kind of output area is adjustable and has
The analog to digital conversion circuit of linear characteristic.
Technical background
In many commercial measurements such as computer data acquisition system, measuring instrumentss, require to use A/D conversion, by mould
Analog quantity is converted to the identifiable digital quantity of computer, and before A/D conversion, it requires to solve a common problem, is exactly work
The anti-interference problem of industry in-site modeling signal acquisition process, when carrying out in-site measurement, various electromagnetic signals can be with tested letter
Number enter measuring system, causes the accuracy of measurement to reduce, on the other hand, measuring system can also introduce with system under test (SUT) " altogether "
Interference, causes measuring system unstable.Traditional AFE(analog front end) processing circuit can only often handle a kind of voltage signal or electric current
Signal has a single function, and currently used partition method has isolated amplifier, digital photoisolator, the former has good linear
Degree and stability, but cost is too high, using with more demanding occasion, the latter can also will add with analog isolation
Additional device, but it is non-linear due to digital photoisolator itself, cause this isolation circuit linearity not high, measurement is inaccurate
Really.
In view of the defect of above-mentioned measurement method, we are badly in need of, and a kind of circuit structure is simple, and the linearity is good, and measurement function is more
Sample, test is accurate, interferes small, the measurement method of strong antijamming capability.
Utility model content
The purpose of this utility model is to provide a kind of structure is simple, strong antijamming capability, processing function multiplicity has line
The analog to digital conversion circuit of sexual isolation characteristic, according to the AFE(analog front end) processing circuit that the utility model designs, output voltage is linearly spent
Good, interference is small, and stability is strong.
The linear optical coupling model HCRN201, operational amplifier model OP-07.
Preferably, the chip of the A/D conversion module is speed and the adjustable 24 high-speed transitions chips of resolution ratio
LTC2440。
Preferably, the signal processing circuit includes a pulse input terminal X1；Three are used to that spike is inhibited to interfere
Magnetic bead FB1, FB2, FB3；One fuse F1；One resistance R1；Two divider resistances R2, R3；One voltage-stabiliser tube D1；Three
Filter capacitor C1, C2, C3.
Preferably, the linear isolation module includes two current-limiting resistances R4, R5；Two operational amplifiers IC1, IC2；
Two feedback capacities C4, C5；The resistance R6 of one control output voltage size；Filter capacitor C6, C7；One linear optical coupling
HCNR201 and its internal LED and two photodiode a PD1, PD2.
Preferably, the linear isolation module includes four capacitors C8, C9, C10, C11 of filtering part, two inductance
L1, L2, two resistance R7, R8；One AD conversion chip U1；
Preferably, a foot of the terminal X1 of the signal processing circuit, two feet, three feet respectively with FB1, FB2, FB3
One foot is connected；Two feet of FB1 and a foot of F1 connect, and two feet of F1 are connect with a foot of R1, D1, C1, C2, R2 respectively；FB2's
Two feet are connected with a foot of R1；Two feet of R2 are connected with a foot of signal processing circuit input terminal, C3 and R3 respectively；FB3,C1,
Two feet of D1, C2, C3, R3 are all connected with GND1.
Preferably, the input terminal of the linear isolation module is connected with a foot of current-limiting resistance R4；Current-limiting resistance R4's
Two feet respectively with a foot of feedback capacity C4, the reverse input end of operational amplifier IC1 and negative-feedback photodiode PD1's
Cathode is connected；A foot of current-limiting resistance R5 is connected with six feet of two feet of feedback capacity C4 and operational amplifier IC1 respectively；Limit
Two feet of leakage resistance R5 connect LED cathode, and LED anode meets VDD；The cathode of photodiode PD2 and the two of operational amplifier IC2
Foot, a foot of R6 and a foot of C5 are connected；The output end of IC2 respectively with two feet of R6, two feet of C5, a foot and C7 of C6
A foot be connected；The noninverting input of PD1 and the anode of PD1 meet GND1；The anode of LED meets power vd D；The seven of IC1, IC2
Foot is connected with power supply VCC+；Four feet of IC1, IC2 are connected with power supply VCC-；The noninverting input of IC2, the anode of PD2 and C6,
Two feet of C7 are connected with GND2, and the output end of IC2 is connected with the A/D modulus of conversion analog quantity input pin of single-chip microcontroller.
Preferably, the input terminal of the A/D conversion module is connected with one end of L1, C8 respectively；Two feet of L1 connect respectively
A foot of C10, R7 are connected；Two feet of C10 connect a foot of inductance L2 and resistance R8；Two feet of L2 connect a foot of C9；Two feet of R7
It is connected respectively with a foot of five feet of A/D conversion chip and C11；Two feet of C11 two feet with the hexagonal of U1 and R8 respectively
It is connected；Two feet of C8, C9, SDI, EXT, CS, VREF- of A/D conversion chip U1 meet GND；VREF+ meets power supply VCC1；
By adopting the above technical scheme, the utility model has following technical effect that the utility model
The analog to digital conversion circuit with linear characteristic of the utility model can be stablized, accurately to current or voltage signal
It is handled, after analog signal enters, first passes around magnetic bead and filter out spike interference, using capacitor filtering, divider resistance is acted on,
Desired voltage magnitude is obtained, obtained voltage signal entering signal processing module enters operational amplifier by current-limiting resistance,
The output of operational amplifier enters linear optical coupling, and the power supply before and after optocoupler and ground isolation prevent from interfering, after photoelectric conversion,
On the one hand negative feedback control is carried out, reaches stable LED output light intensity, improves the purpose of the linearity of linear optical coupling, another party
Face is exported to next stage resistance and operational amplifier, converts current signal to voltage signal, and adjustable resistance value makes to export
End reaches desired voltage values.After filtering, voltage signal enters A/D conversion module, completes analog quantity and turns to digital quantity
It changes, eventually enters into single-chip microcontroller and carry out sequential operation.The digitized simulation front-end processing circuit of the utility model realize voltage or
The digitlization of current signal, using the dual resisteance of analog isolation and isolated from power, enhance anti-interference ability, improve measurement
As a result accuracy, internal circuit configuration refining, the switching that voltage and current can be realized by configuring port connection mode are surveyed
Amount, by changing the parameter of internal poles small part device, i.e., the changeable gain coefficient for being input to output, to adapt to different surveys
System requirements are measured, it is easy to use, it is practical.
Detailed description of the invention
Fig. 1 is the structural schematic diagram for the analog to digital conversion circuit with linear isolation characteristic that the utility model is implemented:
Wherein 1, voltage signal；2, current signal；3, signal conditioning module；4, linear isolation module；5, A/D modulus of conversion
Block；6, one-chip computer module；
Fig. 2 is the schematic diagram of the signal conditioning module of the utility model；
Fig. 3 is the schematic diagram of the linear isolation module of the utility model.
Fig. 4 is the schematic diagram of the A/D conversion module of the utility model.
Specific embodiment
To keep the purpose of this utility model, technical solution and advantage clearer, below in conjunction with attached drawing and embodiment
The embodiments of the present invention is described in further detail.
As shown in Figure 1, the utility model provide a kind of output area it is adjustable and with linear isolation characteristic analog-to-digital conversion
Circuit, comprising: input signal conditioning module, for the current signal of input or voltage signal to be converted into the voltage of required amplitude
Signal, and the voltage signal is input to linear isolation module；The linear isolation module, by the voltage signal
Carry out analog isolation, while the power supply of isolation module front stage be isolated, finally by voltage signal according to self-demand into
Row is adjusted, filtering, is input to A/D conversion module and is carried out A/D conversion, voltage signal enters SCM program after being converted into digital quantity
Carry out operation.
As shown in Fig. 2, signal processing circuit provided by the utility model, including a pulse input terminal X1；Three use
Come the magnetic bead FB1, FB2, FB3 for inhibiting spike to interfere；One fuse F1；One resistance R1；Two divider resistances R2, R3；One
A voltage-stabiliser tube D1；Three filter capacitors C1, C2, C3.
Wherein, a foot of terminal X1, two feet, three feet are connected with a foot of FB1, FB2, FB3 respectively；Two feet and F1 of FB1
Foot connection, two feet of F1 connect with a foot of R1, D1, C1, C2, R2 respectively；Two feet of FB2 are connected with a foot of R1；R2
Two feet be connected respectively with a foot of signal processing circuit input terminal, C3 and R3；Two feet of FB3, C1, D1, C2, C3, R3 all with
GND1 is connected.
As shown in Fig. 2, linear isolation module provided by the utility model, including two current-limiting resistances R4, R5；Two operations
Amplifier IC1, IC2；Two feedback capacities C4, C5；The resistance R6 of one control output voltage size；Filter capacitor C6, C7；One
A linear optical coupling HCNR201 and its internal LED and two photodiode a PD1, PD2；Power supply VCC and VDD.
Wherein, the input terminal of linear isolation module is connected with a foot of current-limiting resistance R4；Two feet of current-limiting resistance R4 are distinguished
With a foot of feedback capacity C4, the reverse input end of operational amplifier IC1 and the cathode phase of negative-feedback photodiode PD1
Even；A foot of current-limiting resistance R5 is connected with six feet of two feet of feedback capacity C4 and operational amplifier IC1 respectively；Current-limiting resistance
Two feet of R5 connect LED cathode, and LED anode meets VDD；The cathode of photodiode PD2 and two feet of operational amplifier IC2, R6's
A foot of one foot and C5 are connected；The output end of IC2 respectively with two feet of R6, two feet of C5, a foot of C6 and a foot of C7
It is connected；The noninverting input of PD1 and the anode of PD1 meet GND1；The anode of LED meets power vd D；Seven feet and electricity of IC1, IC2
Source VCC+ is connected；Four feet of IC1, IC2 are connected with power supply VCC-；The noninverting input of IC2, the anode of PD2 and C6, C7
Two feet are connected with GND2, and the output end of IC2 is connected with the A/D modulus of conversion analog quantity input pin of single-chip microcontroller.
When input signal is current signal, current signal line need to be connected respectively to 1 foot and 3 feet of X1 connecting terminal, and
2,3 feet are shorted with conducting wire.Current signal passes through magnetic bead filtering interference signals first, and current signal is converted by resistance R1
At voltage signal.Voltage signal further filters out interference signal by capacitor, finally by the voltage divider principle of R2, R3, takes R3 two
The voltage output at end is to circuit linearity insulating circuit.
When input signal is voltage signal, voltage signal line need to be connected respectively to 1 foot and 2 feet of X1 connecting terminal, and 3 feet are outstanding
It is empty.
Input voltage VinIC1 operational amplifier reverse input end is loaded by current-limiting resistance R4.Operational amplifier output
End voltage makes LED have electric current I0 to flow through, and electric current I1 drives LED to shine, and PD1 connects the input terminal in amplifier IC1, with completion pair
The detection of LED output optical signal.The electric current for flowing through PD1 is I1=Vin/ R4, it is seen then that after R4 is determined, I1 is only proportional to input electricity
Press Vin.When other factors cause the electric current I0 of LED to change, the negative feedback of PD1 will inhibit the variation of I0, to ensure that
LED output light intensity is proportional to input voltage Vin.In design, LED shine when, two photodiode PD1 of HCNR201 and
The ratio between electric current of PD2 is K, then K=I2/I1.The output of IC2 is Vout=I2R6 can to sum up obtain Vout=KVinR5/R4,
It follows that the output of linear isolation module is not related with the intensity of illumination of LED, after a linear optical coupling determines, K is
The output of definite value, linear isolation module is only related with the resistance value of R4, R5, need to only adjust the two parameters, so that it may obtain it is expected defeated
Voltage out, and it is output to A/D conversion module.
It after voltage signal enters A/D conversion module, first passes around filter circuit and is filtered, into A/D conversion chip
LTC2440 starts to convert, and result of variations is removed device by external serial clock (SCK) signal generated.In SCK pulse
Before first rising edge of signal, entire device keeps sleep state.Data reach SCK pulse failing edge when, data from
SDO output, enables external circuit by the rising edge of data interlock and SCK pulse.
Linear isolation module maintains the relationship of input and output linearly, while analog signal is isolated, is also isolated
Power supply before and after optocoupler, it is suppressed that interference enhances stability.
In conclusion first passing around magnetic bead after analog signal enters and filtering out spike interference, using capacitor filtering, obtain
Voltage signal entering signal processing module anti-interference ability is enhanced using the dual resisteance of analog isolation and isolated from power,
The method for using negative feedback control simultaneously, the improved linearity and stability improve the accuracy of measurement result, eventually enter into
Analog quantity is converted to digital quantity by A/D conversion module, does next step operation into program.By configuring port connection mode i.e.
The handover measurement that voltage and current can be achieved, it is by changing the parameter of internal poles small part device, i.e., changeable to be input to output
Gain coefficient, it is easy to use to adapt to different measuring system demands, it is practical.
The utility model preferred embodiment and embodiment are elaborated above in conjunction with attached drawing, still
The utility model is not limited to the above embodiment and example, within the knowledge of those skilled in the art, may be used also
To make a variety of changes without departing from the concept of the premise utility.
Claims (9)
1. a kind of analog to digital conversion circuit with linear isolation characteristic characterized by comprising input signal conditioning module, line
Sexual isolation module, A/D conversion module；
The input signal conditioning module, for the current signal of input or voltage signal to be converted into the voltage of required amplitude
Signal, and the voltage signal is output to linear isolation module；
The linear isolation module, overall structure are made of two operational amplifiers and a linear optical coupling, and function is by institute
The voltage signal stated carries out analog isolation, while the power supply of isolation module front stage being isolated, and finally presses voltage signal
It is adjusted, filters according to self-demand, being input to A/D conversion module；
The A/D conversion module has used external A/D conversion chip, and interference is small, and conversion speed is fast, high resolution, function
It is that voltage signal is converted into digital quantity by treated, for single-chip microcontroller use.
2. the analog to digital conversion circuit according to claim 1 with linear isolation characteristic, which is characterized in that the input
Signal conditioning module includes voltage input channel and electric current input channel, and the two can switch over according to the actual situation.
3. the analog to digital conversion circuit according to claim 1 with linear isolation characteristic, which is characterized in that the linear light
Coupling model HCRN201, operational amplifier model OP-07, the A/D conversion module chip are that speed and resolution ratio are adjustable
24 high-speed transitions chip LTC2440.
4. the analog to digital conversion circuit according to claim 1 with linear isolation characteristic, which is characterized in that the input
Signal conditioning module includes a pulse input terminal X1；Three the magnetic bead FB1, FB2, FB3 for being used to that spike is inhibited to interfere；One
Fuse F1；One resistance R1；Two divider resistances R2, R3；One voltage-stabiliser tube D1；Three filter capacitors C1, C2, C3.
5. the analog to digital conversion circuit according to claim 1 with linear isolation characteristic, which is characterized in that described is linear
Isolation module includes two current-limiting resistances R4, R5；Two operational amplifiers IC1, IC2；Two feedback capacities C4, C5；One control
The resistance R6 of output voltage size processed；Filter capacitor C6, C7；One linear optical coupling HCNR201 and its internal LED
With two photodiodes PD1, PD2.
6. the analog to digital conversion circuit according to claim 1 with linear isolation characteristic, which is characterized in that the A/D
Conversion module includes four capacitor C8, C9, C10, C11 of filtering part, two inductance L1, L2, two resistance R7, R8；One
AD conversion chip U1.
7. the analog to digital conversion circuit according to claim 1 with linear isolation characteristic, which is characterized in that the input
A foot of terminal X1, two feet, three feet are connected with a foot of FB1, FB2, FB3 respectively in signal conditioning module；Two feet and F1 of FB1
Foot connection, two feet of F1 connect with a foot of R1, D1, C1, C2, R2 respectively；Two feet of FB2 are connected with a foot of R1；R2
Two feet be connected respectively with a foot of signal processing circuit input terminal, C3 and R3；Two feet of FB3, C1, D1, C2, C3, R3 all with
GND1 is connected.
8. the analog to digital conversion circuit according to claim 1 with linear isolation characteristic, which is characterized in that described is linear
The input terminal of isolation module is connected with a foot of current-limiting resistance R4；Two feet of current-limiting resistance R4 respectively with feedback capacity C4 one
Foot, the reverse input end of operational amplifier IC1 and the cathode of negative-feedback photodiode PD1 are connected；The one of current-limiting resistance R5
Foot is connected with six feet of two feet of feedback capacity C4 and operational amplifier IC1 respectively；Two feet of current-limiting resistance R5 connect LED yin
Pole, LED anode meet VDD；The cathode of photodiode PD2 and two feet of operational amplifier IC2, a foot of R6 and a foot of C5
It is connected；The output end of IC2 is connected with two feet of R6, two feet of C5, a foot of C6 and a foot of C7 respectively；PD1's is in the same direction defeated
The anode for entering end and PD1 meets GND1；The anode of LED meets power vd D；Seven feet of IC1, IC2 are connected with power supply VCC+；IC1,
Four feet of IC2 are connected with power supply VCC-；Two feet of the noninverting input of IC2, the anode of PD2 and C6, C7 are connected with GND2,
The output end of IC2 is connected with the A/D modulus of conversion analog quantity input pin of single-chip microcontroller.
9. the analog to digital conversion circuit according to claim 1 with linear isolation characteristic, which is characterized in that the A/D
The input terminal of conversion module is connected with one end of L1, C8 respectively；The foot that two feet of L1 meet C10, R7 respectively is connected；The two of C10
Foot connects a foot of inductance L2 and resistance R8；Two feet of L2 connect a foot of C9；Two feet of R7 respectively with five feet of A/D conversion chip with
And a foot of C11 is connected；Two feet of C11 are connected with two feet of the hexagonal of U1 and R8 respectively；Two feet of C8, C9, A/D convert core
SDI, EXT, CS, VREF- of piece U1 meets GND；VREF+ meets power supply VCC1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821564117.2U CN208939925U (en) | 2018-09-21 | 2018-09-21 | A kind of analog to digital conversion circuit with linear isolation characteristic |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821564117.2U CN208939925U (en) | 2018-09-21 | 2018-09-21 | A kind of analog to digital conversion circuit with linear isolation characteristic |
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| CN208939925U true CN208939925U (en) | 2019-06-04 |
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| CN201821564117.2U Expired - Fee Related CN208939925U (en) | 2018-09-21 | 2018-09-21 | A kind of analog to digital conversion circuit with linear isolation characteristic |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112505395A (en) * | 2020-11-30 | 2021-03-16 | 贵州航天风华实业有限公司 | Alternating voltage and frequency detection system |
-
2018
- 2018-09-21 CN CN201821564117.2U patent/CN208939925U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112505395A (en) * | 2020-11-30 | 2021-03-16 | 贵州航天风华实业有限公司 | Alternating voltage and frequency detection system |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20190604 Termination date: 20200921 |
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| CF01 | Termination of patent right due to non-payment of annual fee |