CN204697045U - The data reading circuit of gas sensor and checkout gear - Google Patents
The data reading circuit of gas sensor and checkout gear Download PDFInfo
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- CN204697045U CN204697045U CN201520239084.4U CN201520239084U CN204697045U CN 204697045 U CN204697045 U CN 204697045U CN 201520239084 U CN201520239084 U CN 201520239084U CN 204697045 U CN204697045 U CN 204697045U
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Abstract
The utility model provides a kind of data reading circuit of gas sensor, comprising: the current input module providing two-way same current; The output in the first loop described in one termination, the gas sensing resistance of other end ground connection; The output of second servo loop described in a termination after multiple thyrite series connection, the other end is by a last trading day ground connection; Operational amplifier, two inputs connect the output voltage of described first loop and second servo loop respectively, are compared and export comparative voltage by receive two output voltages; With default, this comparative voltage is judged that voltage compares by Approach by inchmeal logic, after carrying out Approach by inchmeal calibration according to comparative result to the digital signal sequences controlling each thyrite, as the digital signal that this circuit exports.Operational amplifier just plays a degenerative effect, and the nonlinear characteristic of operational amplifier does not have any impact to system, and thyrite also adopts numerically controlled mode, eliminates the non-linear factor that analogue enlargement brings.
Description
Technical field
The utility model relates to integrated circuit technique, particularly relates to a kind of data reading circuit and checkout gear of gas sensor.
Background technology
Sensor parameters main is at present all by amplifying the output signal of transducer, then exported by analog-digital converter and realizes.Because the linear operating region of operational amplifier is extremely limited, it is larger that nonlinear area exports impact to the data of gas sensor.Because the electrical resistance gas solubility of gas sensor is changing into linear changing relation, traditional mode is by after amplifier by this signal, then output signal is obtained by analog-digital converter, but in this course, the amplifier nonlinearity properties influence linear character of final output signal, usual needs add linear gauging circuit after amplifier, and the nonlinear characteristic of operational amplifier accurately to calculate, even if add linear gauging circuit, can not the impact of erase amplifier nonlinear characteristic completely.
Utility model content
The utility model object is the data reading circuit providing a kind of gas sensor, effectively eliminates the impact that operational amplifier nonlinear area causes circuit.
The utility model provides a kind of data reading circuit of gas sensor, comprising:
Current input module, comprises input and is connected to power supply and the first loop and the second servo loop that export same current;
Gas sensing resistance, the output in the first loop described in a termination, other end ground connection;
Multiple thyrite, the output of second servo loop described in the termination after the plurality of thyrite series connection, the other end is by a last trading day ground connection, and the resistance Geometric Sequence arrangement of the plurality of thyrite is connected in series;
First operational amplifier, two inputs connect the output voltage of described first loop and second servo loop respectively, are compared and export comparative voltage by receive two output voltages;
Approach by inchmeal logic, be connected with thyrite described in each, receive described comparative voltage and under the excitation of clock signal, with default, this comparative voltage is judged that voltage compares, after carrying out Approach by inchmeal calibration according to comparative result to the digital signal sequences controlling each thyrite, as the digital signal that this circuit exports.
Preferably, described Approach by inchmeal logic meets following formula when carrying out Approach by inchmeal calibration to the digital signal sequences of each thyrite:
As Vx>VDD/2, Dout'=Dout+2
m/ 2
n+1;
As Vx<VDD/2, Dout'=Dout-2
m/ 2
n+1;
Wherein, in formula, VDD is supply voltage, VDD/2 judges voltage for presetting, Vx is the comparative voltage that the first operational amplifier exports, and Dout is the digital signal of front primary calibration, and Dout' is when the digital signal of previous calibration, m is the figure place of output digit signals, n is the number of times compared, and stop as n >=N calibrating and exporting data, N is the number of thyrite.
Particularly, the plurality of thyrite be connected in series, its each resistance is from connecing one end of described last trading day to connecing the output of described second servo loop in Geometric Sequence arrangement from small to large.
Particularly, described current input module comprises current mirror circuit, the second operational amplifier and band-gap reference, wherein,
Described current mirror circuit comprises the first controllable semiconductor element be arranged on described first loop and the second controllable semiconductor element be arranged on described second servo loop, the control pole of described second controllable semiconductor element and the first controllable semiconductor element connects the output of described second operational amplifier, band-gap reference described in the negative input termination of described second operational amplifier, the output in the first loop described in positive input termination.
Particularly, described first controllable semiconductor element and described second controllable semiconductor element are P-type mos field effect transistor, the source electrode of described first controllable semiconductor element and described second controllable semiconductor element connects power supply altogether, the grid of described first controllable semiconductor element and described second controllable semiconductor element is as described control pole, and the drain electrode of described first controllable semiconductor element and described second controllable semiconductor element is respectively as the output of described first loop and described second servo loop.
Further, described current input module also comprises the first electric capacity, between the output that described first electric capacity is connected on described second operational amplifier and ground.
Particularly, use bipolar transistor as band-gap reference.
Further, also comprise the second electric capacity, between the output that described second electric capacity is connected on described first operational amplifier and ground.
Further, also comprise compensating module, this compensating module controls described last trading day to eliminate the skew of described gas sensing resistance.
The utility model additionally provides a kind of checkout gear, comprises the data reading circuit of above-mentioned gas sensor.
The data reading circuit of above-mentioned gas sensor, operational amplifier just plays a degenerative effect, the nonlinear characteristic of operational amplifier does not have any impact to system, and thyrite also adopts numerically controlled mode, eliminates the non-linear factor that analogue enlargement brings.Compared with calibrating with traditional+1 or-1, Approach by inchmeal logical circuit can accelerate the time of calibrating greatly.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of the data reading circuit of gas sensor in the utility model preferred embodiment.
Embodiment
In order to make the technical problems to be solved in the utility model, technical scheme and beneficial effect clearly understand, below in conjunction with drawings and Examples, the utility model is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the utility model, and be not used in restriction the utility model.
Refer to Fig. 1, the utility model be equipped with set by checkout gear in the utility model preferred embodiment provides a kind of data reading circuit of gas sensor, this circuit, based on the solution of resistance calibration, effectively eliminates the shadow that operational amplifier nonlinear area causes circuit.This circuit comprises: current input module 11, gas sensing resistance R0, multiple thyrite R1 ~ Rn, the first operational amplifier U1, Approach by inchmeal logical one 2.
Current input module 11 comprises input and is connected to power vd D and the first loop 11A and the second servo loop 11B that export same current.
Gas sensing resistance, the output of the first loop 11A described in a termination, other end ground connection; The output of second servo loop 11B described in a termination after the plurality of thyrite R1 ~ Rn connects, the other end is by a last trading day Rc ground connection, and the resistance Geometric Sequence arrangement of the plurality of thyrite R1 ~ Rn is connected in series; First operational amplifier U1, two inputs connect the output voltage of described first loop 11A and second servo loop 11B respectively, are compared and export comparative voltage by receive two output voltages; Approach by inchmeal logical one 2 is connected with thyrite R1 ~ Rn described in each, and receive described comparative voltage and under the excitation of clock signal 13, with default, this comparative voltage is judged that voltage compares, according to comparative result, Approach by inchmeal calibration carried out to the digital signal sequences controlling each thyrite R1 ~ Rn.
After calibration completes, with the thyrite R1 ~ Rn of series connection, the resistance of gas sensing resistance R0 adds that the resistance of last trading day is identical, and the digital signal sequences now controlling thyrite R1 ~ Rn is the digital signal of circuit output.Such as gas sensing resistance R0=Rc+312R, the Serial No. of output by for 312 binary one 00111000.In this example, the resistance of definition R1 is R, then R2, R3 ... the resistance of Rn-1, Rn is respectively: 4R, 8R ... 2
n-1r, 2
nr.Compared with calibrating with traditional+1 or-1, Approach by inchmeal logical circuit can accelerate the time of calibrating greatly.First operational amplifier U1 has been the effect of comparing, and the nonlinear characteristic of operational amplifier does not have any impact to system, and thyrite R1 ~ Rn also adopts numerically controlled mode, eliminates the non-linear factor that analogue enlargement brings.
In the present embodiment, data reading circuit also comprises compensating module 14, and this compensating module 14 controls described last trading day Rc to eliminate the offset resistance of described gas sensing resistance R0, improves system linearity degree.
In addition, the negative input end of the first operational amplifier U1 and positive input terminal connect the output of the first loop 11A and second servo loop 11B respectively.
Current input module 11 comprises current mirror circuit 112, second operational amplifier U2 and band-gap reference 114.Described current mirror circuit 112 comprises the first controllable semiconductor element M1 be arranged on the first loop 11A and the second controllable semiconductor element M2 be arranged on described second servo loop 11B, the control pole of described second controllable semiconductor element M2 and the first controllable semiconductor element M1 connects the output of described second operational amplifier U2, band-gap reference 114 described in the negative input termination of described second operational amplifier U2, the output of the first loop 11A described in positive input termination.Particularly, use bipolar transistor as band-gap reference 114.
Particularly, described first controllable semiconductor element M1 and described second controllable semiconductor element M2 is P-type mos field effect transistor, the source electrode of described first controllable semiconductor element M1 and described second controllable semiconductor element M2 connects power supply altogether, the grid of described first controllable semiconductor element M1 and described second controllable semiconductor element M2 is as described control pole, and the drain electrode of described first controllable semiconductor element M1 and described second controllable semiconductor element M2 is respectively as the output of described first loop 11A and described second servo loop 11B.
Further, described current input module 11 also comprises the first electric capacity C1, between the output that described first electric capacity C1 is connected on described second operational amplifier U2 and ground.First electric capacity C1 is used for systems stabilisation.
In a preferred embodiment, the second electric capacity C2 for systems stabilisation is also connected with between the output of described first operational amplifier U1 and ground.
In the present embodiment, the plurality of thyrite be connected in series, its each resistance is from connecing one end of described last trading day to connecing the output of described second servo loop 11B in Geometric Sequence arrangement from small to large.With reference to Fig. 1, the resistance of definition R1 is R, then R2, R3 ... the resistance of Rn-1, Rn is respectively: 4R, 8R ... 2
n-1r, 2
nr.
In addition, Approach by inchmeal logical one 2 meets following formula when carrying out Approach by inchmeal calibration to the digital signal sequences of each thyrite R1 ~ Rn:
As Vx>VDD/2, Dout'=Dout+2
m/ 2
n+1;
As Vx<VDD/2, Dout'=Dout-2
m/ 2
n+1;
Wherein, in formula, VDD is supply voltage, VDD/2 judges voltage for presetting, Vx is the comparative voltage that the first operational amplifier U1 exports, and Dout is the digital signal of front primary calibration, and Dout' is when the digital signal of previous calibration, m is the figure place of output digit signals, n is the number of times compared, and stop as n >=N calibrating and exporting data, N is the number of thyrite.
In the present embodiment, band-gap reference 112 provides a reference voltage for whole circuit, by the negative feedback effect of the second operational amplifier U2, the high level of gas sensing resistance R0 and thyrite is consistent, connect two identical P-type mos field effect transistor M1 and M2 because the second operational amplifier U2 be connected with reference voltage exports simultaneously, so this field effect transistor has identical grid voltage, source electrode is simultaneously by Power supply, drain due to the feedback effect of the second operational amplifier U2, drain voltage also can be consistent substantially, because field effect transistor is operated in saturation region, even if drain voltage has little bit different, but grid and source voltage are completely always, so can ensure that the loop current at these two field effect transistor places is equal.
Because the resistance opening quick resistance of gas sensor is changing into linear changing relation with gas solubility, traditional mode is by after operational amplifier by this signal, then output signal is obtained by analog-digital converter, but in this course, the nonlinear characteristic of operational amplifier have impact on the linear character of final output signal, usual needs add linear gauging circuit after amplifier, and the nonlinear characteristic of operational amplifier accurately to calculate, even if add linear gauging circuit, can not the impact of erase amplifier nonlinear characteristic completely.And in this programme, operational amplifier U2 just plays a degenerative effect, the nonlinear characteristic of operational amplifier does not have any impact to system, and thyrite R1 ~ Rn also adopts numerically controlled mode, eliminates the non-linear factor that analogue enlargement brings.
The foregoing is only preferred embodiment of the present utility model; not in order to limit the utility model; all do within spirit of the present utility model and principle any amendment, equivalent to replace and improvement etc., all should be included within protection range of the present utility model.
Claims (10)
1. a data reading circuit for gas sensor, is characterized in that, comprising:
Current input module, comprises input and is connected to power supply and the first loop and the second servo loop that export same current;
Gas sensing resistance, the output in the first loop described in a termination, other end ground connection;
Multiple thyrite, the output of second servo loop described in the termination after the plurality of thyrite series connection, the other end is by a last trading day ground connection, and the resistance Geometric Sequence arrangement of the plurality of thyrite is connected in series;
First operational amplifier, two inputs connect the output voltage of described first loop and second servo loop respectively, are compared and export comparative voltage by receive two output voltages;
Approach by inchmeal logic, be connected with thyrite described in each, receive described comparative voltage and under the excitation of clock signal, with default, this comparative voltage is judged that voltage compares, after carrying out Approach by inchmeal calibration according to comparative result to the digital signal sequences controlling each thyrite, as the digital signal that this circuit exports.
2. the data reading circuit of gas sensor as claimed in claim 1, is characterized in that, described Approach by inchmeal logic meets following formula when carrying out Approach by inchmeal calibration to the digital signal sequences of each thyrite:
As Vx>VDD/2, Dout'=Dout+2
m/ 2
n+1;
As Vx<VDD/2, Dout'=Dout-2
m/ 2
n+1;
Wherein, in formula, VDD is supply voltage, VDD/2 judges voltage for presetting, Vx is the comparative voltage that the first operational amplifier exports, and Dout is the digital signal of front primary calibration, and Dout' is when the digital signal of previous calibration, m is the figure place of output digit signals, n is the number of times compared, and stop as n >=N calibrating and exporting data, N is the number of thyrite.
3. the data reading circuit of gas sensor as claimed in claim 1 or 2, it is characterized in that, the plurality of thyrite be connected in series, its each resistance is from connecing one end of described last trading day to connecing the output of described second servo loop in Geometric Sequence arrangement from small to large.
4. the data reading circuit of gas sensor as claimed in claim 1 or 2, it is characterized in that, described current input module comprises current mirror circuit, the second operational amplifier and band-gap reference, wherein,
Described current mirror circuit comprises the first controllable semiconductor element be arranged on described first loop and the second controllable semiconductor element be arranged on described second servo loop, the control pole of described second controllable semiconductor element and the first controllable semiconductor element connects the output of described second operational amplifier, band-gap reference described in the negative input termination of described second operational amplifier, the output in the first loop described in positive input termination.
5. the data reading circuit of gas sensor as claimed in claim 4, it is characterized in that, described first controllable semiconductor element and described second controllable semiconductor element are P-type mos field effect transistor, the source electrode of described first controllable semiconductor element and described second controllable semiconductor element connects power supply altogether, the grid of described first controllable semiconductor element and described second controllable semiconductor element is as described control pole, the drain electrode of described first controllable semiconductor element and described second controllable semiconductor element is respectively as the output of described first loop and described second servo loop.
6. the data reading circuit of gas sensor as claimed in claim 4, it is characterized in that, described current input module also comprises the first electric capacity, between the output that described first electric capacity is connected on described second operational amplifier and ground.
7. the data reading circuit of gas sensor as claimed in claim 4, it is characterized in that, described band-gap reference is bipolar transistor.
8. the data reading circuit of gas sensor as claimed in claim 1 or 2, is characterized in that, also comprise the second electric capacity, between the output that described second electric capacity is connected on described first operational amplifier and ground.
9. the data reading circuit of gas sensor as claimed in claim 1 or 2, it is characterized in that, also comprise compensating module, this compensating module controls described last trading day to eliminate the skew of described gas sensing resistance.
10. a checkout gear, is characterized in that, comprises the data reading circuit of the gas sensor described in any one of claim 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520239084.4U CN204697045U (en) | 2015-04-20 | 2015-04-20 | The data reading circuit of gas sensor and checkout gear |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520239084.4U CN204697045U (en) | 2015-04-20 | 2015-04-20 | The data reading circuit of gas sensor and checkout gear |
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| Publication Number | Publication Date |
|---|---|
| CN204697045U true CN204697045U (en) | 2015-10-07 |
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| CN201520239084.4U Active CN204697045U (en) | 2015-04-20 | 2015-04-20 | The data reading circuit of gas sensor and checkout gear |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105758898A (en) * | 2016-04-15 | 2016-07-13 | 中国科学院过程工程研究所 | High-sensitivity self-feedback type alarm circuit for gas sensor |
| CN106160742A (en) * | 2015-04-20 | 2016-11-23 | 郑州炜盛电子科技有限公司 | The data reading circuit of gas sensor and detection device |
-
2015
- 2015-04-20 CN CN201520239084.4U patent/CN204697045U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106160742A (en) * | 2015-04-20 | 2016-11-23 | 郑州炜盛电子科技有限公司 | The data reading circuit of gas sensor and detection device |
| CN105758898A (en) * | 2016-04-15 | 2016-07-13 | 中国科学院过程工程研究所 | High-sensitivity self-feedback type alarm circuit for gas sensor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20221215 Address after: 030000 Floor 1, Building 2, No. 89, Nanneihuan West Street, Wanbailin District, Taiyuan, Shanxi Province Patentee after: Shanxi Tengxing Sensing Technology Co.,Ltd. Address before: No. 299, Jinsuo Road, High tech Development Zone, Zhengzhou, Henan 450000 Patentee before: Zhengzhou Weisen Electronics Technology Co.,Ltd. |
|
| TR01 | Transfer of patent right |