JPH0416715A - Hot wire air flowmeter - Google Patents
Hot wire air flowmeterInfo
- Publication number
- JPH0416715A JPH0416715A JP2119861A JP11986190A JPH0416715A JP H0416715 A JPH0416715 A JP H0416715A JP 2119861 A JP2119861 A JP 2119861A JP 11986190 A JP11986190 A JP 11986190A JP H0416715 A JPH0416715 A JP H0416715A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- temperature
- voltage
- output
- current
- 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
- 238000010438 heat treatment Methods 0.000 claims abstract description 6
- 239000000758 substrate Substances 0.000 claims abstract description 6
- 238000006243 chemical reaction Methods 0.000 claims description 18
- 230000003321 amplification Effects 0.000 claims description 6
- 238000003199 nucleic acid amplification method Methods 0.000 claims description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims 1
- 229910052710 silicon Inorganic materials 0.000 claims 1
- 239000010703 silicon Substances 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
Landscapes
- Measuring Volume Flow (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は自動車用熱線式空気流量計の電子回路に関する
。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic circuit for a hot-wire air flowmeter for an automobile.
従来の装置は、特開昭５８−８７４２０号記載の様に基
板温度変化による出力信号のオフセット成分の変化のみ
を調整する様になっていた。Conventional devices, as described in Japanese Patent Laid-Open No. 58-87420, are designed to adjust only the change in the offset component of the output signal due to a change in substrate temperature.
［発明が解決しようとする課題］
上記従来技術は出力信号の増幅特性が変化する点につい
て考慮されておらず、測定流量に対しである一点に於い
てのみしか温度特性を調整できないという問題が有った
。[Problems to be Solved by the Invention] The above-mentioned conventional technology does not take into account the fact that the amplification characteristics of the output signal change, and has the problem that the temperature characteristics can only be adjusted at one point with respect to the measured flow rate. It was.
本発明の目的は、基板温度変化による、オフセットと増
幅特性の変化を別々に調整する事によって、より精度の
高い空気流量計を提供する事に有る。An object of the present invention is to provide a more accurate air flow meter by separately adjusting changes in offset and amplification characteristics due to changes in substrate temperature.
本発明の他の目的は、オフセットと増幅特性の温度変化
を調整する機能を１つの電源回路を用いて構成し、より
小規模な基板温度特性調整回路を提供する事に有る。Another object of the present invention is to provide a smaller-scale substrate temperature characteristic adjustment circuit by configuring the function of adjusting temperature changes in offset and amplification characteristics using one power supply circuit.
上記目的を達成する為に、出力調整回路のオフセット電
圧とＶＦ変換回路の変換特性に別々に温度特性を持たせ
たものである。In order to achieve the above object, the offset voltage of the output adjustment circuit and the conversion characteristic of the VF conversion circuit are provided with temperature characteristics separately.
また、出力調整回路のオフセット電圧に温度特性を持た
せる為には、出力調整回路を構成する抵抗に温度に比例
した電流を流す様にしたものである。Furthermore, in order to give the offset voltage of the output adjustment circuit a temperature characteristic, a current proportional to the temperature is caused to flow through the resistor constituting the output adjustment circuit.
更に、ＶＦ変換回路の変換特性に温度特性を持たせるに
は、ＶＦ変換回路を構成する比較器のしきい値電圧に温
度特性を持たせる様にしたものである。Furthermore, in order to give temperature characteristics to the conversion characteristics of the VF conversion circuit, the threshold voltage of the comparator constituting the VF conversion circuit is made to have temperature characteristics.
バンドギャップ基準電圧回路は２つのトランジスタに電
流密度が所定の比になる様なコレクタ電流を流したとき
に、各々のトランジスタのベース・エミッタ間電圧の差
が一方のトランジスタのエミッタに直列に接続された抵
抗による電圧降下の差と等しくなる様に構成され、抵抗
による電圧降下とベース・エミッタ間電圧の和を基準電
圧源として用いる。このとき、抵抗及びトランジスタの
コレクタ電流はサーマルボルテージＶＴ＝ＫＴ／ｑに比
例した値となり絶対温度に比例する。又、トランジスタ
のベース・エミッタ間電圧は飽和電流の温度特性により
温度の上昇に対して低下する特性を示す。これにより得
られる基準電圧は、抵抗値を調整する事によって任意の
温度特性を持たせる事ができ、又、コレクタ電流をカレ
ントミラー等の手段を用いて取り出す事によって温度特
性を持つ定電源を得る事ができる。周波数変換回路のし
きい値電圧等の電圧変化によりその変換特性が変化する
様な回路に、このバンドギャップ基準電源を用い、又コ
レクタ電流に比例する電流をオペアンプ回路の入力バイ
アス等に加えた場合、基準電圧を調整する事によって増
幅特性の、又、電流バイアスされたオペアンプ等の入力
インピーダンスを変える事によりオフセット電圧の温度
特性を調整する事ができる。In a bandgap reference voltage circuit, when a collector current is passed through two transistors so that the current density becomes a predetermined ratio, the difference in voltage between the base and emitter of each transistor is connected in series to the emitter of one transistor. The reference voltage source is the sum of the voltage drop caused by the resistance and the base-emitter voltage. At this time, the collector currents of the resistors and transistors have values proportional to the thermal voltage VT=KT/q, and are proportional to the absolute temperature. Further, the base-emitter voltage of a transistor exhibits a characteristic that it decreases as the temperature rises due to the temperature characteristics of the saturation current. The reference voltage obtained by this can have arbitrary temperature characteristics by adjusting the resistance value, and a constant power source with temperature characteristics can be obtained by extracting the collector current using a means such as a current mirror. I can do things. When this bandgap reference power supply is used in a circuit whose conversion characteristics change due to voltage changes such as the threshold voltage of a frequency conversion circuit, and when a current proportional to the collector current is applied to the input bias of an operational amplifier circuit, etc. The amplification characteristics can be adjusted by adjusting the reference voltage, and the temperature characteristics of the offset voltage can be adjusted by changing the input impedance of a current biased operational amplifier.
以下、本発明の一実施例を第１図により説明する。熱線
式空気流量計は空気流中に設置された発熱抵抗体２の温
度を一定に保つ様に定温度制御回路１にて制御し、熱線
の加熱に要した電流を検出し電圧信号■２とする。第１
図に示した実施例では、検出した電圧■２をオペアンプ
１１．抵抗１２．１３より成る出力調整回路に調整し、
積分器１４．コンパレータ１５．抵抗１６，１７゜１８
より成るＶＦ変換回路２０にて周波数信号に変換し出力
する。第１図の実施例に於いて、バンドギャップ基準電
源回路はトランジスタ３，４゜オペアンプ６、抵抗７，
８．９より成り、オペアンプ６の出力電圧が基準電圧と
なる。ＶＦ変換回路２０の変換特性は積分器１４の積分
時定数と抵抗１６，１７．１８によって基準電圧を分圧
して得られるヒステリシス電圧に反比例するので、基準
電圧に温度特性を持たせる事により、ＶＦ変換回路２０
の変換特性に温度特性を持たせる事ができる。発熱抵抗
体２と定温度制御回路１により得られた検出信号ｖ２は
抵抗１ｏを介してオペアンプ１１に入力し、オペアンプ
１１の入力端子と抵抗１０の間にコレクタを接続したト
ランジスタ５のコレクタ電流に温度依存特性を持たせる
事により、流量計の出力信号のオフセット成分を調整す
る事ができる。第１図の実施例に記載のバンドギャップ
電源に於いてはトランジスタ３．４に流れる電流は、オ
ペアンプ６を用いて抵抗８，９により定める一定の電流
比となる。このとき、トランジスタ３のベースエミッタ
電圧と抵抗７の電圧降下の和とトランジスタ４のベース
・エミッタ電圧が等しくなる様にオペアンプ６の出力電
圧が安定する。抵抗７の電圧降下はトランジスタ３，４
のベース・エミッタ電圧の差に等しいので、サーマルボ
ルテージＶＴ＝ｑ／ｈＴに比例した値となり、抵抗８，
９、トランジスタ３．４に流れる電流及びトランジスタ
４とカレントミラー回路を構成するトランジスタ５の電
流は正の温度特性を有する。An embodiment of the present invention will be described below with reference to FIG. The hot wire air flowmeter is controlled by a constant temperature control circuit 1 to keep the temperature of a heating resistor 2 installed in the air flow constant, detects the current required to heat the hot wire, and outputs a voltage signal 2. do. 1st
In the embodiment shown in the figure, the detected voltage 2 is applied to the operational amplifier 11. Adjust to the output adjustment circuit consisting of resistors 12 and 13,
Integrator 14. Comparator 15. Resistance 16,17°18
A VF conversion circuit 20 consisting of the following converts the signal into a frequency signal and outputs it. In the embodiment shown in FIG. 1, the bandgap reference power supply circuit includes transistors 3, 4° operational amplifier 6, resistor 7,
8.9, and the output voltage of the operational amplifier 6 becomes the reference voltage. The conversion characteristic of the VF conversion circuit 20 is inversely proportional to the integration time constant of the integrator 14 and the hysteresis voltage obtained by dividing the reference voltage by the resistors 16, 17, and 18. Therefore, by giving the reference voltage a temperature characteristic, the VF Conversion circuit 20
The conversion characteristics of can be given temperature characteristics. The detection signal v2 obtained by the heating resistor 2 and the constant temperature control circuit 1 is input to the operational amplifier 11 via the resistor 1o, and is applied to the collector current of the transistor 5 whose collector is connected between the input terminal of the operational amplifier 11 and the resistor 10. By providing temperature dependent characteristics, it is possible to adjust the offset component of the output signal of the flowmeter. In the bandgap power supply described in the embodiment of FIG. 1, the current flowing through transistor 3.4 is a constant current ratio determined by resistors 8 and 9 using operational amplifier 6. At this time, the output voltage of the operational amplifier 6 is stabilized so that the sum of the base-emitter voltage of the transistor 3 and the voltage drop across the resistor 7 becomes equal to the base-emitter voltage of the transistor 4. The voltage drop across resistor 7 is the voltage drop across transistors 3 and 4.
Since it is equal to the difference between the base and emitter voltages of
9. The current flowing through transistor 3.4 and the current flowing through transistor 5, which forms a current mirror circuit with transistor 4, have positive temperature characteristics.
一般にトランジスタのベース・エミッタ間電圧は負の温
度係数を有する事が知られており、ベース・エミッタ電
圧と前記サーマルボルテージに比例する抵抗電圧降下の
和である基準電圧は抵抗７゜８．９の抵抗値を変える事
により任意の温度係数を持たせる事ができるのでＶＦ変
換回路２０の変換特性に任意の温度係数を持たせられる
。又、トランジスタ５の電流は正の温度係数を持つので
抵抗１０の抵抗値を選ぶ事により出力信号のオフセット
成分の温度特性を任意に調整する事ができる。It is generally known that the voltage between the base and emitter of a transistor has a negative temperature coefficient, and the reference voltage, which is the sum of the base-emitter voltage and the resistance voltage drop proportional to the thermal voltage, is the voltage of the resistor 7°8.9. Since an arbitrary temperature coefficient can be provided by changing the resistance value, the conversion characteristics of the VF conversion circuit 20 can be provided with an arbitrary temperature coefficient. Furthermore, since the current of the transistor 5 has a positive temperature coefficient, by selecting the resistance value of the resistor 10, the temperature characteristics of the offset component of the output signal can be arbitrarily adjusted.
本実施例によれば、電子回路を構成する各素子の温度変
化による流量計の出力誤差を補正する事ができる。又、
本発明の別の一実施例を第２図を用いて説明する。第２
図の実施例は、トランジスタ２３．２４．２５のベース
電流をオペアンプ６の高力を分圧する抵抗２６．２７よ
り供給する様にしたものである、本実施例によればトラ
ンジスタ２３と２４のベース電流によりコレクタ電流の
誤差が解消でき、抵抗２６．２７を調整する事により、
基準電圧の値をその温度係数とは独立に任意に選定する
事ができる。According to this embodiment, it is possible to correct output errors of the flowmeter due to temperature changes in each element constituting the electronic circuit. or,
Another embodiment of the present invention will be described with reference to FIG. Second
In the illustrated embodiment, the base current of the transistors 23, 24, 25 is supplied from the resistors 26, 27 that divide the high voltage of the operational amplifier 6. According to this embodiment, the base current of the transistors 23, 24, and The error in the collector current can be eliminated by the current, and by adjusting the resistors 26 and 27,
The value of the reference voltage can be arbitrarily selected independently of its temperature coefficient.
本発明の別の一実施例を第３図を用いて説明する。第３
図の実施例は第１図及び第２図に於けるオペアンプ６及
び抵抗８，９の替わりにトランジスタ３９，４０．４１
より成るウィルソン型カレントミラー回路を用い、トラ
ンジスタ５の替わりにトランジスタ３７，３８，４２．
４３を用いて正の温度係数を有する電流を取り出したも
のである。本実施例によれば、定温度制御回路１により
得られる検品信号ｖ２が、トランジスタの飽和電圧より
小さい場合にも使用でき、又オペアンプ１１の反転、非
反転再入力端子に温度係数を持ったバイアス電流を与え
るので、出力信号のオフセット成分の温度特性を正、負
雨域に亘って任意に設定する事ができる。Another embodiment of the present invention will be described with reference to FIG. Third
The illustrated embodiment uses transistors 39, 40, 41 instead of the operational amplifier 6 and resistors 8, 9 in FIGS. 1 and 2.
Using a Wilson type current mirror circuit consisting of transistors 37, 38, 42 .
43 to extract a current having a positive temperature coefficient. According to this embodiment, it can be used even when the inspection signal v2 obtained by the constant temperature control circuit 1 is smaller than the saturation voltage of the transistor, and a bias with a temperature coefficient is applied to the inverting and non-inverting re-input terminals of the operational amplifier 11. Since a current is applied, the temperature characteristics of the offset component of the output signal can be arbitrarily set over the positive and negative rain regions.
本発明によれば、電子回路の温度特性を、オフセット成
分と増幅度成分に分けて各々独立に調整する事ができる
ので、熱線式空気流量計の基板温度が変化した場合の、
回路を構成する素子の特性変化等による出力信号の特性
変化を任意に補償する事ができる。また、バンドギャッ
プ基準電源回路を用いる事により常温に於ける電圧から
その温度係数が一意的に定められるので調整が容易にで
きる。According to the present invention, the temperature characteristics of the electronic circuit can be divided into the offset component and the amplification component and each can be adjusted independently, so that when the substrate temperature of the hot wire air flowmeter changes,
It is possible to arbitrarily compensate for changes in the characteristics of the output signal due to changes in the characteristics of elements constituting the circuit. Furthermore, by using a bandgap reference power supply circuit, the temperature coefficient can be uniquely determined from the voltage at room temperature, making adjustment easy.
第１図は本発明の一実施例の回路構成図、第２図、第３
図は本発明の他の一実施例の回路構成図である°。
１・・・定温度制御回路、２・・・発熱抵抗体、２０Ｖ
Ｆ変換回路、３０・・・バンドギャップ基準電源回路、
３１・・・８力調整回路。 −へ
代理人 弁理士 小川勝男ｌ−瘉″シ
第１図Figure 1 is a circuit configuration diagram of an embodiment of the present invention, Figures 2 and 3 are
The figure is a circuit configuration diagram of another embodiment of the present invention. 1... Constant temperature control circuit, 2... Heat generating resistor, 20V
F conversion circuit, 30... bandgap reference power supply circuit,
31...8 force adjustment circuit. -Representative Patent Attorney Katsuo Ogawal-Ka''shi Figure 1
Claims (1)
一定温度に保つ様に電流を供給する定温度制御回路と発
熱抵抗体に供給された制御電流を増幅する出力調整回路
と出力調整回路の出力電圧を周波数に変換するＶＦ変換
回路より成る自動車用空気流量計に於いて電子回路基板
の温度変化による出力信号のオフセット成分変化と、増
幅率変化を別々に調整する様にした事を特徴とする熱線
式空気流量計。 ２、請求項第１項に於て、ＶＦ変換回路のしきい値電圧
を設定する基準電圧発生回路にバンドギャップ電圧波を
用い、バンドギャップ電圧源の差動トランジスタを流れ
るバイアス電流に比例する電流を、出力調整回路を構成
する抵抗に流す事を特徴とする熱線式空気流量計。 ３、請求項第１項に於て、バンドギャップ電源及びＶＦ
変換回路を同一シリコン基板上に形成した事を特徴とす
る熱線式空気流量計。[Claims] 1. A heating resistor provided in an air passage, a constant temperature control circuit that supplies current to keep the heating resistor at a constant temperature, and amplifying the control current supplied to the heating resistor. In an automotive air flow meter consisting of an output adjustment circuit and a VF conversion circuit that converts the output voltage of the output adjustment circuit into a frequency, offset component changes in the output signal due to temperature changes on the electronic circuit board and changes in the amplification factor are adjusted separately. A hot-wire air flow meter that is characterized by being designed to 2. In claim 1, a bandgap voltage wave is used in the reference voltage generation circuit that sets the threshold voltage of the VF conversion circuit, and a current proportional to the bias current flowing through the differential transistor of the bandgap voltage source. A hot wire type air flowmeter characterized by passing the current through a resistor that constitutes an output adjustment circuit. 3. In claim 1, a bandgap power supply and a VF
A hot wire air flow meter characterized by having a conversion circuit formed on the same silicon substrate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2119861A JPH0416715A (en) | 1990-05-11 | 1990-05-11 | Hot wire air flowmeter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2119861A JPH0416715A (en) | 1990-05-11 | 1990-05-11 | Hot wire air flowmeter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0416715A true JPH0416715A (en) | 1992-01-21 |
Family
ID=14772087
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2119861A Pending JPH0416715A (en) | 1990-05-11 | 1990-05-11 | Hot wire air flowmeter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0416715A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5585748A (en) * | 1994-07-01 | 1996-12-17 | Nippondenso Co., Ltd. | Voltage-frequency converter circuit with temperature compensation |
-
1990
- 1990-05-11 JP JP2119861A patent/JPH0416715A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5585748A (en) * | 1994-07-01 | 1996-12-17 | Nippondenso Co., Ltd. | Voltage-frequency converter circuit with temperature compensation |
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