JPH06160318A - Temperature compensation circuit for gas sensor - Google Patents
Temperature compensation circuit for gas sensorInfo
- Publication number
- JPH06160318A JPH06160318A JP13194892A JP13194892A JPH06160318A JP H06160318 A JPH06160318 A JP H06160318A JP 13194892 A JP13194892 A JP 13194892A JP 13194892 A JP13194892 A JP 13194892A JP H06160318 A JPH06160318 A JP H06160318A
- Authority
- JP
- Japan
- Prior art keywords
- gas sensor
- heater
- circuit
- temperature
- heating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はガス検出素子を加熱する
ことにより動作させる、ガスセンサの温度補償回路に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature compensating circuit for a gas sensor which operates by heating a gas detecting element.
【０００２】[0002]
【従来の技術】従来、ガス検出素子を加熱することによ
り動作させるガスセンサに於いて、素子加熱用ヒータに
Ｐｔを用いない場合は、ヒータ印加電圧を一定に保った
ままで温度補償は行われておらず、Ｐｔを用いた場合、
図１に示すようなＰｔの抵抗温度特性を用いたブリッジ
回路により、ヒータ印加電圧値を制御するのみであっ
た。2. Description of the Related Art Conventionally, in a gas sensor that operates by heating a gas detection element, if Pt is not used for the element heating heater, temperature compensation is performed while the heater applied voltage is kept constant. If Pt is used,
Only the heater applied voltage value was controlled by the bridge circuit using the resistance temperature characteristic of Pt as shown in FIG.
【０００３】[0003]
【発明が解決しようとする課題】図１に示すヒータにＰ
ｔを用いた従来の温度補償回路に於いて、抵抗３、４、
５、Ｐｔヒータ６によりブリッジ回路を構成し、オペア
ンプ８、抵抗２、８、トランジスタ７によりブリッジが
平衡条件に達するように、Ｐｔヒータ６に電圧が印加さ
れる。このときＰｔヒータ６の目的温度での抵抗をＰｔ
の抵抗温度特性より算出し、ブリッジの平衡条件となる
抵抗３、４、５の抵抗値を決定する。この場合、Ｐｔヒ
ータ６への印加電圧が、雰囲気温度の低下、風速の増大
に対応して増加するよう、Ｐｔヒータ６への定常状態で
の印加電圧は、印加可能電圧より１／２から２／３の値
に設定されているため、定常状態では印加電圧と電源電
圧の差に相当する電力が、トランジスタ７により常時消
費されてしまい、回路全体ではＰｔヒータ６の加熱電力
の２ー３倍の電力を要するという欠点を有していた。The heater shown in FIG.
In the conventional temperature compensation circuit using t, resistors 3, 4,
5, a bridge circuit is formed by the Pt heater 6, and a voltage is applied to the Pt heater 6 so that the operational amplifier 8, resistors 2, 8 and transistor 7 reach a balanced condition in the bridge. At this time, the resistance of the Pt heater 6 at the target temperature is Pt.
The resistance values of the resistors 3, 4, and 5, which are the equilibrium conditions of the bridge, are determined from the resistance temperature characteristics of In this case, the applied voltage in the steady state to the Pt heater 6 is 1/2 to 2 less than the applicable voltage so that the applied voltage to the Pt heater 6 increases in accordance with the decrease of the ambient temperature and the increase of the wind speed. Since the value is set to / 3, the electric power corresponding to the difference between the applied voltage and the power supply voltage is constantly consumed by the transistor 7 in the steady state, and the entire circuit is 2 to 3 times the heating power of the Pt heater 6. It had the drawback of requiring electricity.
【０００４】[0004]
【課題を解決するための手段】本発明は上記の問題点に
鑑みてなされたもので、その目的は、ガスセンサの加熱
用ヒータのヒータ印加電圧をＰＷＭ方式の制御を行う手
段により回路内の電力損失を低減し、回路全体の消費電
力の低減化を図ることを目的とするガスセンサの温度補
償回路を提供することである。SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide electric power in a circuit by means of a PWM type control of a heater applied voltage of a heater for heating a gas sensor. It is an object of the present invention to provide a temperature compensating circuit for a gas sensor, which aims to reduce loss and power consumption of the entire circuit.
【０００５】[0005]
【作用】ガス検出素子を加熱することにより動作させる
ガスセンサに於いて、ヒータにより素子加熱を行う場
合、素子の熱時定数より１桁以上速い周波数で、電圧の
印加を０Ｎ、ＯＦＦさせ、ＯＮ時間とＯＦＦ時間の比を
制御するＰＷＭ方式によっても加熱温度を一定に保つこ
とが可能となる。又、ヒータに印加される電圧は印加可
能な電圧が印加されるため、図１に於いてはトランジス
タ７での電圧損失が０．７Ｖ以下となり、トランジスタ
７での電力損失が低減可能となる。しかしこの場合、ガ
スセンサの温度補償が正確になされているかどうかの確
認は、ヒータ印加電圧のＯＮ時間とＯＦＦ時間の比と、
ヒータ印加電圧の電圧値から算出しなくてはならず、ブ
リッジの平衡条件が正確に満たされているかどうかの確
認は、オシロスコープ等の高価で大型な装置が必要とな
る。このため、ヒータで一定電圧を供給し、印加電圧値
の制御を行う温度補償回路への切換機能を有していれ
ば、その印加電圧値から容易に素子加熱温度が算出可能
であり、検査も簡略化できる。[Function] In a gas sensor that operates by heating a gas detection element, when the element is heated by a heater, the voltage application is turned ON and OFF at a frequency faster than the thermal time constant of the element by one digit or more, and the ON time is increased. It is also possible to keep the heating temperature constant by a PWM method that controls the ratio of OFF time to OFF time. Further, since a voltage that can be applied is applied to the heater, the voltage loss in the transistor 7 is 0.7 V or less in FIG. 1, and the power loss in the transistor 7 can be reduced. However, in this case, it is necessary to check whether the temperature compensation of the gas sensor is accurately performed, by checking the ratio of ON time and OFF time of the heater applied voltage,
Since it has to be calculated from the voltage value of the heater applied voltage, it is necessary to use an expensive and large-scale device such as an oscilloscope to confirm whether the equilibrium condition of the bridge is accurately satisfied. Therefore, if the heater has a function of switching to a temperature compensation circuit that controls the applied voltage value by supplying a constant voltage, the element heating temperature can be easily calculated from the applied voltage value, and inspection is also possible. Can be simplified.
【０００６】[0006]
【実施例】以下、本発明の実施例を図に基ずいて説明す
る。図２は、本発明によるガスセンサの温度補償回路の
一実施例を示す回路図である。図２において、切換スイ
ッチ２１を抵抗に接続した場合、抵抗１２、１３、１
５、可変抵抗１４、Ｐｔヒータ１６によりブリッジを構
成し、オペアンプ１８、シュミットインバータ１９、２
０、抵抗１１、９、トランジスタ１７により、ブリッジ
の平衡条件に達するよう、ヒータへの印加電圧がＯＮ，
ＯＦＦされ、トランジスタ１７での電力損失が、図１の
回路と比較して約１／４になる。この場合、可変抵抗１
４によりブリッジの平衡条件をを変えて、Ｐｔヒータ１
６の温度を可変する事ができる。このとき、切換スイッ
チを抵抗１０に接続した場合、ブリッジの平衡条件を満
たすよう、Ｐｔヒータ１６に一定電圧が供給され、その
電圧値を読みとることにより素子加熱温度が算出でき、
もし加熱温度がずれている場合、可変抵抗１４により調
整可能となる。切換スイッチの切換により、ガスセンサ
の加熱温度の変化がないことは、放射温度計、並びにガ
スセンサの特性に変化がないことより確認されている。Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a circuit diagram showing an embodiment of a temperature compensation circuit for a gas sensor according to the present invention. In FIG. 2, when the changeover switch 21 is connected to resistors, the resistors 12, 13, 1
5, a variable resistor 14 and a Pt heater 16 form a bridge, and an operational amplifier 18 and a Schmitt inverter 19 and 2 are provided.
0, resistors 11, 9 and transistor 17 turn on the voltage applied to the heater to reach the bridge equilibrium condition.
When turned off, the power loss in the transistor 17 becomes about 1/4 of that in the circuit of FIG. In this case, the variable resistor 1
Change the equilibrium condition of the bridge by 4 and change the Pt heater 1
The temperature of 6 can be changed. At this time, when the changeover switch is connected to the resistor 10, a constant voltage is supplied to the Pt heater 16 so that the bridge equilibrium condition is satisfied, and the element heating temperature can be calculated by reading the voltage value,
If the heating temperature is deviated, it can be adjusted by the variable resistor 14. It has been confirmed that there is no change in the heating temperature of the gas sensor due to the changeover of the changeover switch, since there is no change in the characteristics of the radiation thermometer and the gas sensor.
【０００７】[0007]
【発明の効果】以上、説明したように、本発明によれ
ば、ガスセンサの加熱用ヒータのヒータ印加電圧を、Ｐ
ＷＭ方式により回路内の電力損失を低減し、回路全体の
消費電力を低減化した温度補償回路を、追加部品を少な
くローコストで提供できる。特に実施例においては、ガ
スセンサの加熱温度の検査及び調整が簡易的に行うこと
ができる。As described above, according to the present invention, the heater applied voltage of the heater for heating the gas sensor is set to P
It is possible to provide a temperature compensation circuit in which the power loss in the circuit is reduced by the WM method and the power consumption of the entire circuit is reduced, with a small number of additional components and at low cost. Particularly in the embodiment, the inspection and adjustment of the heating temperature of the gas sensor can be easily performed.
【０００８】[0008]
【図１】Ｐｔヒータを用いた場合の、従来の温度補償回
路を示す回路図。FIG. 1 is a circuit diagram showing a conventional temperature compensation circuit when a Pt heater is used.
【図２】本発明の一実施例を示す回路図。FIG. 2 is a circuit diagram showing an embodiment of the present invention.
１ 抵抗 ２ 抵抗 ３ 抵抗 ４ 抵抗 ５ 抵抗 ６ Ｐｔヒータ ７ トランジスタ ８ オペアンプ ９ 抵抗 １０ 抵抗 １１ 抵抗 １２ 抵抗 １３ 抵抗 １４ 可変抵抗 １５ 抵抗 １６ Ｐｔヒータ １７ トランジスタ １８ オペアンプ １９ インバータ ２０ インバータ ２１ 切換スイッチ 1 resistance 2 resistance 3 resistance 4 resistance 5 resistance 6 Pt heater 7 transistor 8 operational amplifier 9 resistance 10 resistance 11 resistance 12 resistance 13 resistance 14 variable resistance 15 resistance 16 Pt heater 17 transistor 18 operational amplifier 19 inverter 20 inverter 21 changeover switch
Claims (3)
させるガスセンサに於いて、加熱用ヒータ印加電圧をパ
ルス幅変調方式（以下ＰＷＭ方式）の制御を行うことに
より、ガス検出素子の温度補償を行うことを特徴とする
ガスセンサの温度補償回路。1. In a gas sensor operated by heating a gas detection element, the voltage applied to a heater for heating is controlled by a pulse width modulation method (hereinafter referred to as a PWM method) to compensate the temperature of the gas detection element. A temperature compensating circuit for a gas sensor, which is characterized by being performed.
用い、そのＰｔの抵抗温度特性から温度検知を行い、温
度補償を行うことを特徴とする特許請求項１記載のガス
センサの温度補償回路。2. The temperature compensating circuit for a gas sensor according to claim 1, wherein Pt is used as a heater for heating the gas sensor, and the temperature is detected from the resistance temperature characteristic of the Pt to perform temperature compensation.
を制御して温度補償を行う動作への切換機能を付加し、
ガスセンサの加熱温度ヒータ印加電圧値から加熱温度を
算出することにより、ガスセンサの加熱温度の確認を簡
易的に行うことを特徴とする特許請求項１記載のガスセ
ンサの温度補償回路。3. The temperature compensating circuit is provided with a switching function for controlling the heater applied voltage value to perform temperature compensation,
The temperature compensating circuit for the gas sensor according to claim 1, wherein the heating temperature of the gas sensor is easily confirmed by calculating the heating temperature from the heater applied voltage value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13194892A JPH06160318A (en) | 1992-04-23 | 1992-04-23 | Temperature compensation circuit for gas sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13194892A JPH06160318A (en) | 1992-04-23 | 1992-04-23 | Temperature compensation circuit for gas sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06160318A true JPH06160318A (en) | 1994-06-07 |
Family
ID=15069957
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13194892A Pending JPH06160318A (en) | 1992-04-23 | 1992-04-23 | Temperature compensation circuit for gas sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06160318A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7265560B2 (en) * | 2005-11-23 | 2007-09-04 | Therm-O-Disc, Incorporated | Temperature compensated vapor sensor |
-
1992
- 1992-04-23 JP JP13194892A patent/JPH06160318A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7265560B2 (en) * | 2005-11-23 | 2007-09-04 | Therm-O-Disc, Incorporated | Temperature compensated vapor sensor |
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