JP3811906B2 - Temperature measurement circuit - Google Patents
Temperature measurement circuit Download PDFInfo
- Publication number
- JP3811906B2 JP3811906B2 JP8032496A JP8032496A JP3811906B2 JP 3811906 B2 JP3811906 B2 JP 3811906B2 JP 8032496 A JP8032496 A JP 8032496A JP 8032496 A JP8032496 A JP 8032496A JP 3811906 B2 JP3811906 B2 JP 3811906B2
- Authority
- JP
- Japan
- Prior art keywords
- resistor
- value
- temperature
- sensor
- operational amplifier
- 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.)
- Expired - Fee Related
Links
- 238000009529 body temperature measurement Methods 0.000 title claims description 21
- 238000006243 chemical reaction Methods 0.000 claims description 11
- 230000003247 decreasing effect Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 14
- 238000005259 measurement Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 2
Images
Landscapes
- Measuring Temperature Or Quantity Of Heat (AREA)
- Measurement Of Current Or Voltage (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は演算増幅器を用いた電圧電流変換回路を有する温度計測回路に関するものである。
【０００２】
【従来の技術】
従来この種の回路の公知文献としては、例えば“蒲生良治、アナログ回路のトラブル対策、昭和５３年２月第２版、ＣＱ出版株式会社、ｐ．１２〜１４”がある。
図９は上記文献の第１３頁、図１・５（ｂ）に示された従来の定電流回路の一例を示す図である。
図９の回路において、１は入力端子、２は出力端子、Ａ1 は演算増幅器、Ｒ1 ，Ｒ2 ，ＲS ，（Ｒ2 −ＲS ）は抵抗、ＲL は負荷抵抗、ＥS は入力電圧、ｉL は出力電流を示す。
負荷抵抗ＲL に流れる出力電流ｉL は、上記文献に示された下記の（１）式の通りである。
【０００３】
【数１】
（１）式の中に負荷抵抗ＲL の項が無いため、出力電流ｉL は負荷抵抗ＲL の値に関係なく、入力電圧ＥS が一定であれば、出力に一定電流が流れる定電流特性をもっている。
図９の回路の負荷抵抗ＲL に、温度センサ（例えば測温抵抗体）を使用すると、温度センサに加わる温度による抵抗値を電圧値に変換出来るため、温度計測回路として使用できる。
【０００５】
図１０は従来の定電流回路を利用した温度計測回路である。
図１０は図９の回路の負荷抵抗ＲL に、温度センサ（例えばJIS C1604 の測温抵抗体：公称抵抗値１００Ω）を接続した温度計測回路で、入力電圧ＥS は２．５Ｖ、抵抗Ｒ1 は２．５ＫΩ、Ｒ2 は２ＫΩ、Ｒ3 は２．５ＫΩ、Ｒ4 は１ＫΩ、ＲS は１ＫΩとしたもので、温度センサに流れる電流ｉL は、（１）式に上記数値を代入すると、
ｉL ＝（２０００／２５００）×２．５Ｖ／１０００Ω＝２ｍＡとなる。
上記ｉL ＝２ｍＡは定電流であるので、負荷抵抗ＲL の値が変化してもｉL の値は一定であり、この図１０の回路のセンサ抵抗対センサ電流特性を図１１に示す。
【０００６】
上記図１０の回路のセンサ温度（１）に対するセンサ抵抗値（２）、センサ電流（３）、センサ電圧（４）、（４）の各値から０℃における（４）の値の減算値（５）、温度換算値（６）及び温度誤差（７）を求めた各数値が下記の表１に示される。
【０００７】
【表１】
上記表１において、センサ電圧（４）の各値から０℃のときの（４）の値０．２Ｖをそれぞれ減算した値が（５）であり、この（５）の値が１００℃のときに１００．０００となるように（５）の各値に換算係数１００／０．０７８３２≒１２７６．８１を乗算した結果が温度換算値（６）である。またこの温度換算値（６）から計測温度の誤差分のみを取出したのが温度誤差（７）である。
【０００９】
図１２は表１のセンサ温度（１）に対するセンサ電圧（４）の特性を示す図であり、図１３は表１のセンサ温度（１）に対する温度誤差（７）の特性を示す図である。
図１３により、０℃〜１００℃の計測範囲のほぼ中央で約０．３８℃の誤差があることが判る。このような誤差があるにもかかわらず、図１０のような定電流回路は温度計測回路として広く使用されていた。
【００１０】
【発明が解決しようとする課題】
しかしながら、測温抵抗体等の温度センサに定電流を流す従来の温度計測回路では、表１の温度誤差（７）及び図１３に示すように、０℃〜１００℃の計測範囲において、最大で約０．３８℃という温度測定誤差があり、誤差の値が大き過ぎ、計測精度に満足できないという問題点があった。
【００１１】
【課題を解決するための手段】
本発明に係る温度計測回路は、演算増幅器の負側入力端に第１の抵抗Ｒ 1 を介して入力電圧を印加し、前記演算増幅器の負側入力端と出力端との間に第２の抵抗Ｒ 2 を接続し、前記演算増幅器の正側入力端を第３の抵抗Ｒ 3 を介して接地し、基準抵抗Ｒ S と負荷抵抗Ｒ L とを直列に接続してこの基準抵抗Ｒ S の他端を前記演算増幅器の出力端に接続すると共にこの負荷抵抗Ｒ L の他端を接地し、前記基準抵抗Ｒ S と負荷抵抗Ｒ L との接続点と前記演算増幅器の正側入力端との間に第４の抵抗Ｒ 4 を接続し、前記入力電圧に基づく出力電流を前記負荷抵抗Ｒ L に供給する電圧電流変換回路を有する温度計測回路において、
前記第３の抵抗Ｒ 3 の値を第１の抵抗Ｒ 1 の値よりも大きくすることにより、前記負荷抵抗Ｒ L の値の増加にほぼ比例して出力電流の値が増加することを特徴とするものである。
【００１２】
【発明の実施の形態】
実施形態１．
図１は、本発明の実施形態１に係る温度計測回路を示す図である。
図１の回路構成は、図１０の定電流回路と変わらないが、図１０のように抵抗Ｒ1と抵抗Ｒ3の値を等しくせず、抵抗Ｒ1の値よりも抵抗Ｒ3の値を大きくしているため、図１の回路は定電流回路にはならない。
図１において、測温抵抗体ＲLに流れる電流ｉLは、同図の回路解析の結果次の（２）式で示される。
【００１３】
【数２】
図１のＲL に図１０と同一の温度センサ（０℃で１００Ωの測温抵抗体）を接続し、同図に示されるＲ1 ＝２．５ＫΩ、Ｒ2 ＝２ＫΩ、Ｒ3 ＝５．５ＫΩ、Ｒ4 ＝１ＫΩ、ＲS ＝１ＫΩ、ＥS ＝２．５Ｖの値を（２）式に代入して、温度センサに加える温度を０℃〜１００℃に変化させたとき、１０℃毎の各温度における温度センサＲL に流れるセンサ電流ｉL を求めて、下記の表２に示す。
【００１５】
【表２】
なお表２には、表１と同様に、センサ温度（１）に対するセンサ抵抗値（２）、センサ電流（３）、センサ電圧（４）、（４）の各値から０℃における（４）の値の減算値（５）、温度換算値（６）及び温度誤差（７）が記載されている。なお表２の変換係数は１００／０．０８５７２７≒１１６６．４９４となる。 図２は表２のセンサ抵抗値（２）に対するセンサ電流（３）の特性を示す図であり、同図はセンサ抵抗値の増加にほぼ比例して、センサに流れるセンサ電流値が増加していることを示している。
【００１７】
図３は表２のセンサ温度（１）に対するセンサ電圧（４）の特性を示す図であり、図４は表２のセンサ温度（１）に対する温度誤差（７）の特性を示す図である。
表２の温度誤差（７）及び図４で明らかなように、実施形態１においては、抵抗Ｒ1 の値よりも抵抗Ｒ3 の値を大きくして、負荷抵抗値の増加にほぼ比例して出力電流値が増加するようにしたので（図２の特性を参照）、０℃〜１００℃の計測範囲における誤差は、電源変動分や周囲温度の変化による変動分を加えたとしても、最大で０．０３℃以下となり、従来の誤差幅の１／１０以下という高精度での温度計測が可能となる。
【００１８】
実施形態２．
図５は本発明の実施形態２に係る温度計測回路を示す図である。
図５の回路構成は、図１の回路と変わらないが、抵抗Ｒ1と抵抗Ｒ3の値を等しくする代りに、抵抗Ｒ2の値から抵抗ＲSの値を減算した差分値（Ｒ2−ＲS）よりも抵抗Ｒ4の値を小さくするように設定したため、図５の回路は定電流回路にはならない。
この測温抵抗体ＲLに流れる電流ｉLは前記（２）式から求められるので、図５に示されるＲ1＝２．５ＫΩ、Ｒ2＝２ＫΩ、Ｒ3＝２．５ＫΩ、Ｒ4＝５６．２Ω、ＲS＝１ＫΩ、ＥS＝２．５Ｖの値を（２）式に代入し、０℃〜１００℃の範囲で１０℃毎の各温度におけるセンサ電流ｉLを求めて、下記の表３に示す。
【００１９】
【表３】
なお表３には、表２と同様に、センサ温度（１）に対するセンサ抵抗値（２）、センサ電流（３）、センサ電圧（４）、（４）の各値から０℃における（４）の値の減算値（５）、温度換算値（６）及び温度誤差（７）が記載されている。なお表３の変換係数は１００／０．０８５７２７≒１１６６．４９４となる。
図６は表３のセンサ抵抗値（２）に対するセンサ電流（３）の特性を示す図であり、同図はセンサ抵抗値の増加にほぼ比例して、センサに流れるセンサ電流値が増加していることを示している。
【００２１】
図７は表３のセンサ温度（１）に対するセンサ電圧（４）の特性を示す図であり、図８は表３のセンサ温度（１）に対する温度誤差（７）の特性を示す図である。
表３の温度誤差（７）及び図８で明らかなように、実施形態２においては、抵抗Ｒ1 とＲ3 の値を等しくすると共に、抵抗Ｒ2 とＲS との差分値（Ｒ2 −ＲS ）よりも抵抗Ｒ4 の値を小さくして、負荷抵抗値の増加にほぼ比例して出力電流値が増加するようにしたので（図６の特性を参照）、０℃〜１００℃の計測範囲における誤差は、電源変動分や周囲温度の変化による変動分を加えたとしても、最大で０．０３℃以下となり、従来の誤差幅の１／１０以下という高精度での温度計測が可能となる。
【００２２】
【発明の効果】
本発明においては、演算増幅器の負側入力端に第１の抵抗Ｒ 1 を介して入力電圧を印加し、前記演算増幅器の負側入力端と出力端との間に第２の抵抗Ｒ 2 を接続し、前記演算増幅器の正側入力端を第３の抵抗Ｒ 3 を介して接地し、基準抵抗Ｒ S と負荷抵抗Ｒ L とを直列に接続してこの基準抵抗Ｒ S の他端を前記演算増幅器の出力端に接続すると共にこの負荷抵抗Ｒ L の他端を接地し、前記基準抵抗Ｒ S と負荷抵抗Ｒ L との接続点と前記演算増幅器の正側入力端との間に第４の抵抗Ｒ 4 を接続し、前記入力電圧に基づく出力電流を前記負荷抵抗Ｒ L に供給する電圧電流変換回路を有する温度計測回路において、
前記第３の抵抗Ｒ 3 の値を第１の抵抗Ｒ 1 の値よりも大きくすることにより、前記負荷抵抗Ｒ L の値の増加にほぼ比例して出力電流の値が増加するようにしたので、従来よりも計測精度が大幅に改善されるという効果が得られる。
【図面の簡単な説明】
【図１】 本発明の実施形態１に係る温度計測回路を示す図である。
【図２】 図１の回路のセンサ抵抗値対センサ電流特性を示す図である。
【図３】 図１の回路のセンサ温度対センサ電圧特性を示す図である。
【図４】 図１の回路のセンサ温度対温度誤差特性を示す図である。
【図５】 本発明の実施形態２に係る温度計測回路を示す図である。
【図６】 図５の回路のセンサ抵抗値対センサ電流特性を示す図である。
【図７】 図５の回路のセンサ温度対センサ電圧特性を示す図である。
【図８】 図５の回路のセンサ温度対温度誤差特性を示す図である。
【図９】 従来の定電流回路の一例を示す図である。
【図１０】 従来の定電流回路を利用した温度計測回路を示す図である。
【図１１】 図１０の回路のセンサ抵抗値対センサ電流特性を示す図である。
【図１２】 図１０の回路のセンサ温度対センサ電圧特性を示す図である。
【図１３】 図１０の回路のセンサ温度対温度誤差特性を示す図である。
【符号の説明】
１ 入力端子
２ 出力端子
Ａ1 演算増幅器
ＥS 入力電圧
ｉL 出力電流
Ｒ1〜Ｒ4、ＲS 抵抗[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a temperature measurement circuit having a voltage-current conversion circuit using an operational amplifier.
[0002]
[Prior art]
Conventionally known documents of this type of circuit include, for example, “Yoshiharu Gamo, analog circuit trouble countermeasures, February 1978, second edition, CQ Publishing Co., Ltd., p. 12-14”.
FIG. 9 is a diagram showing an example of a conventional constant current circuit shown in page 13 of the above-mentioned document and FIGS. 1 and 5 (b).
In the circuit of FIG. 9, 1 is an input terminal, 2 is an output terminal, A 1 is an operational amplifier, R 1 , R 2 , R S , (R 2 −R S ) are resistors, R L is a load resistor, and E S is The input voltage, i L, indicates the output current.
The output current i L flowing through the load resistor R L is as shown in the following equation (1) shown in the above document.
[0003]
[Expression 1]
Since there is no term of the load resistance R L in the equation (1), the output current i L is a constant current in which a constant current flows to the output if the input voltage E S is constant regardless of the value of the load resistance R L. Has characteristics.
When a temperature sensor (for example, a resistance temperature detector) is used as the load resistance RL of the circuit of FIG. 9, the resistance value due to the temperature applied to the temperature sensor can be converted into a voltage value, and therefore can be used as a temperature measurement circuit.
[0005]
FIG. 10 shows a temperature measurement circuit using a conventional constant current circuit.
Figure 10 is the load resistance R L of the circuit of FIG. 9, (RTD e.g. JIS C1604: nominal resistance 100 [Omega) Temperature sensor temperature measuring circuit connected to the input voltage E S is 2.5V, the resistance R 1 is 2.5 KΩ, R 2 is 2 KΩ, R 3 is 2.5 KΩ, R 4 is 1 KΩ, R S is 1 KΩ, and the current i L flowing through the temperature sensor is substituted into the equation (1) above. Then
i L = (2000/2500) × 2.5 V / 1000Ω = 2 mA.
Since i L = 2 mA is a constant current, the value of i L is constant even if the value of the load resistance R L changes. FIG. 11 shows the sensor resistance vs. sensor current characteristics of the circuit of FIG.
[0006]
The subtracted value of the value of (4) at 0 ° C. from the sensor resistance value (2), sensor current (3), sensor voltage (4), and (4) with respect to the sensor temperature (1) of the circuit of FIG. 5) Each numerical value obtained from the temperature conversion value (6) and the temperature error (7) is shown in Table 1 below.
[0007]
[Table 1]
In Table 1 above, the value obtained by subtracting the value 0.2V of (4) at 0 ° C. from each value of sensor voltage (4) is (5), and when the value of (5) is 100 ° C. The value obtained by multiplying each value of (5) by the
[0009]
12 is a diagram showing the characteristics of the sensor voltage (4) with respect to the sensor temperature (1) in Table 1. FIG. 13 is a diagram showing the characteristics of the temperature error (7) with respect to the sensor temperature (1) in Table 1.
It can be seen from FIG. 13 that there is an error of about 0.38 ° C. at the approximate center of the measurement range from 0 ° C. to 100 ° C. Despite such errors, the constant current circuit as shown in FIG. 10 has been widely used as a temperature measurement circuit.
[0010]
[Problems to be solved by the invention]
However, in a conventional temperature measurement circuit that sends a constant current to a temperature sensor such as a resistance temperature detector, the temperature error (7) in Table 1 and as shown in FIG. There was a temperature measurement error of about 0.38 ° C., and the value of the error was too large, and there was a problem that the measurement accuracy could not be satisfied.
[0011]
[Means for Solving the Problems]
In the temperature measurement circuit according to the present invention, an input voltage is applied to the negative input terminal of the operational amplifier via the first resistor R 1 , and the second voltage is applied between the negative input terminal and the output terminal of the operational amplifier. the resistor R 2 is connected, the operational amplifier to the positive input terminal grounded via a third resistor R 3, the reference resistor R S and the load resistance R L and a are connected in series the reference resistor R S The other end is connected to the output end of the operational amplifier and the other end of the load resistor R L is grounded, and the connection point between the reference resistor R S and the load resistor R L is connected to the positive input end of the operational amplifier. A temperature measurement circuit having a voltage-current conversion circuit that connects a fourth resistor R 4 between them and supplies an output current based on the input voltage to the load resistor R L ;
By making the value of the third resistor R 3 greater than the value of the first resistor R 1 , the value of the output current increases approximately in proportion to the increase of the value of the load resistor R L. To do.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram illustrating a temperature measurement circuit according to the first embodiment of the present invention.
The circuit arrangement of FIG. 1 is not the same as the constant current circuit of FIG. 10, not equal the value of the resistors R 1 and R 3 as shown in FIG. 10, than the value of the resistor R 1 the value of the resistor R 3 The circuit in FIG. 1 does not become a constant current circuit because it is enlarged.
In FIG. 1, the current i L flowing through the resistance temperature detector R L is expressed by the following equation (2) as a result of the circuit analysis of FIG.
[0013]
[Expression 2]
Figure 10 connects the same temperature sensor (RTD 100Ω at 0 ° C.) and the in R L Fig. 1,
[0015]
[Table 2]
In Table 2, as in Table 1 , the sensor resistance value (2), the sensor current (3), the sensor voltage (4), and the sensor voltage (4) with respect to the sensor temperature (1) (4) at 0 ° C. The subtraction value (5), the temperature conversion value (6), and the temperature error (7) are described. Note that the conversion coefficient in Table 2 is 100 / 0.085727≈1166.6494. FIG. 2 is a graph showing the characteristics of the sensor current (3) with respect to the sensor resistance value (2) in Table 2. The figure shows that the sensor current value flowing through the sensor increases in proportion to the increase in the sensor resistance value. It shows that.
[0017]
3 is a graph showing the characteristics of the sensor voltage ( 4 ) with respect to the sensor temperature (1) in Table 2. FIG. 4 is a graph showing the characteristics of the temperature error (7) with respect to the sensor temperature (1) in Table 2.
As apparent from the temperature error (7) in Table 2 and FIG. 4, in the first embodiment, the value of the resistor R 3 is made larger than the value of the resistor R 1 and is approximately proportional to the increase in the load resistance value. Since the output current value is increased (see the characteristics in Fig. 2), the error in the measurement range from 0 ° C to 100 ° C is the maximum even if the fluctuation due to power supply fluctuation or ambient temperature is added. It becomes 0.03 ° C. or less, and temperature measurement with high accuracy of 1/10 or less of the conventional error width becomes possible.
[0018]
FIG. 5 is a diagram showing a temperature measurement circuit according to
The circuit arrangement of FIG. 5 is not different from the circuit of FIG. 1, resistors R 1 and instead of equal the value of the resistor R 3, the value difference value obtained by subtracting a from the value of the resistor R 2 resistor R S (R 2 Since the value of the resistor R 4 is set to be smaller than −R S ), the circuit of FIG. 5 does not become a constant current circuit.
Since the current i L flowing through the resistance temperature detector R L is obtained from the equation (2), R 1 = 2.5 KΩ, R 2 = 2 KΩ, R 3 = 2.5 KΩ, R 4 = shown in FIG. By substituting the values of 56.2Ω, R S = 1KΩ, and E S = 2.5V into the equation (2), the sensor current i L at each temperature of 10 ° C. in the range of 0 ° C. to 100 ° C. is obtained. Table 3 shows.
[0019]
[Table 3]
In Table 3, as in Table 2, the sensor resistance value (2), the sensor current (3), the sensor voltage (4), and the sensor voltage (4) with respect to the sensor temperature (1) (4) at 0 ° C. The subtraction value (5), the temperature conversion value (6), and the temperature error (7) are described. The conversion coefficient of Table 3 is 100 / 0.085727≈1166.694.
FIG. 6 is a graph showing the characteristics of the sensor current (3) with respect to the sensor resistance value (2) in Table 3. The figure shows that the sensor current value flowing through the sensor increases in proportion to the increase in the sensor resistance value. It shows that.
[0021]
FIG. 7 is a diagram showing the characteristics of the sensor voltage ( 4 ) with respect to the sensor temperature (1) in Table 3. FIG. 8 is a diagram showing the characteristics of the temperature error (7) with respect to the sensor temperature (1) in Table 3.
As apparent from the temperature error (7) in Table 3 and FIG. 8, in the second embodiment, the values of the resistors R 1 and R 3 are made equal, and the difference value between the resistors R 2 and R S (R 2 − Since the value of the resistor R 4 is made smaller than R S ) so that the output current value increases almost in proportion to the increase in the load resistance value (see the characteristic of FIG. 6), The error in the measurement range is 0.03 ° C or less at the maximum even if the fluctuation due to power supply fluctuation or ambient temperature change is added, and temperature measurement with high accuracy of 1/10 or less of the conventional error width is possible. It becomes.
[0022]
【The invention's effect】
In the present invention, an input voltage is applied to the negative input terminal of the operational amplifier via the first resistor R 1 , and the second resistor R 2 is connected between the negative input terminal and the output terminal of the operational amplifier. And the positive input end of the operational amplifier is grounded via the third resistor R 3 , the reference resistor R S and the load resistor R L are connected in series, and the other end of the reference resistor R S is connected to the reference resistor R S. Connected to the output terminal of the operational amplifier and the other end of the load resistance RL is grounded, and a fourth point is connected between the connection point of the reference resistance RS and the load resistance RL and the positive input terminal of the operational amplifier. in the resistor R 4 is connected, the temperature measurement circuit having a voltage-current converter circuit for supplying an output current based on the input voltage to the load resistor R L,
Since the value of the third resistor R 3 is made larger than the value of the first resistor R 1 , the value of the output current is increased almost in proportion to the increase of the value of the load resistor R L. Thus, it is possible to obtain an effect that the measurement accuracy is greatly improved as compared with the conventional case.
[Brief description of the drawings]
FIG. 1 is a diagram showing a temperature measurement circuit according to a first embodiment of the present invention.
FIG. 2 is a diagram showing sensor resistance value vs. sensor current characteristics of the circuit of FIG. 1;
3 is a graph showing sensor temperature vs. sensor voltage characteristics of the circuit of FIG.
FIG. 4 is a diagram showing a sensor temperature vs. temperature error characteristic of the circuit of FIG.
FIG. 5 is a diagram showing a temperature measurement circuit according to
6 is a diagram showing a sensor resistance value vs. sensor current characteristic of the circuit of FIG.
7 is a graph showing sensor temperature vs. sensor voltage characteristics of the circuit of FIG.
8 is a graph showing a sensor temperature vs. temperature error characteristic of the circuit of FIG.
FIG. 9 is a diagram illustrating an example of a conventional constant current circuit.
FIG. 10 is a diagram showing a temperature measurement circuit using a conventional constant current circuit.
11 is a graph showing sensor resistance value vs. sensor current characteristics of the circuit of FIG.
12 is a graph showing sensor temperature vs. sensor voltage characteristics of the circuit of FIG.
13 is a graph showing a sensor temperature vs. temperature error characteristic of the circuit of FIG.
[Explanation of symbols]
1
Claims (2)
前記第３の抵抗Ｒ3の値を第１の抵抗Ｒ1の値よりも大きくすることにより、前記負荷抵抗ＲLの値の増加にほぼ比例して出力電流の値が増加することを特徴とする温度計測回路。An input voltage is applied to the negative input terminal of the operational amplifier via the first resistor R 1 , a second resistor R 2 is connected between the negative input terminal and the output terminal of the operational amplifier, and the calculation is performed. The positive input end of the amplifier is grounded via the third resistor R 3 , the reference resistor R S and the load resistor R L are connected in series, and the other end of the reference resistor R S is connected to the output end of the operational amplifier. And the other end of the load resistor R L is grounded, and a fourth resistor R 4 is connected between the connection point of the reference resistor R S and the load resistor R L and the positive input end of the operational amplifier. In a temperature measurement circuit having a voltage-current conversion circuit connected and supplying an output current based on the input voltage to the load resistor R L ,
By making the value of the third resistor R 3 greater than the value of the first resistor R 1 , the value of the output current increases approximately in proportion to the increase of the value of the load resistor R L. Temperature measurement circuit .
前記第１の抵抗Ｒ1と第３の抵抗Ｒ3の値を等しくすると共に、前記第２の抵抗Ｒ2の値から基準抵抗ＲSの値を減算した差分値よりも前記第４の抵抗Ｒ4の値を小さくすることにより、前記負荷抵抗ＲLの値の増加にほぼ比例して出力電流の値が増加することを特徴とする温度計測回路。An input voltage is applied to the negative input terminal of the operational amplifier via the first resistor R 1 , a second resistor R 2 is connected between the negative input terminal and the output terminal of the operational amplifier, and the calculation is performed. The positive input end of the amplifier is grounded via the third resistor R 3 , the reference resistor R S and the load resistor R L are connected in series, and the other end of the reference resistor R S is connected to the output end of the operational amplifier. And the other end of the load resistor R L is grounded, and a fourth resistor R 4 is connected between the connection point of the reference resistor R S and the load resistor R L and the positive input end of the operational amplifier. In a temperature measurement circuit having a voltage-current conversion circuit connected and supplying an output current based on the input voltage to the load resistor R L ,
The values of the first resistor R 1 and the third resistor R 3 are made equal, and the fourth resistor R is smaller than the difference value obtained by subtracting the value of the reference resistor R S from the value of the second resistor R 2. A temperature measurement circuit characterized in that by decreasing the value of 4, the value of the output current increases substantially in proportion to the increase of the value of the load resistance RL .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8032496A JP3811906B2 (en) | 1996-04-02 | 1996-04-02 | Temperature measurement circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8032496A JP3811906B2 (en) | 1996-04-02 | 1996-04-02 | Temperature measurement circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09269340A JPH09269340A (en) | 1997-10-14 |
| JP3811906B2 true JP3811906B2 (en) | 2006-08-23 |
Family
ID=13715089
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8032496A Expired - Fee Related JP3811906B2 (en) | 1996-04-02 | 1996-04-02 | Temperature measurement circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3811906B2 (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56166613A (en) * | 1980-05-26 | 1981-12-21 | Sony Corp | Voltage to current converting circuit |
| JPH056543Y2 (en) * | 1984-10-31 | 1993-02-19 | ||
| JPS61122534A (en) * | 1984-11-20 | 1986-06-10 | Nippon Kokan Kk <Nkk> | Temperature measurement method using a thermistor |
| JPS63103929A (en) * | 1986-10-22 | 1988-05-09 | Terumo Corp | Temperature measuring instrument |
-
1996
- 1996-04-02 JP JP8032496A patent/JP3811906B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09269340A (en) | 1997-10-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0784825B1 (en) | Temperature compensated logarithmic convertor | |
| US7570114B2 (en) | Common mode rejection calibration method for difference amplifiers | |
| GB1577977A (en) | Linearized bridge circuit | |
| US4109196A (en) | Resistance measuring circuit | |
| CN209979092U (en) | Thermal resistor temperature measuring circuit and temperature measuring device | |
| JP3811906B2 (en) | Temperature measurement circuit | |
| JPH09105681A (en) | Temperature measurement circuit | |
| Gift et al. | New configurations for the measurement of small resistance changes | |
| CN113017588B (en) | Blood pressure measuring method, system, device and sphygmomanometer | |
| US6844734B2 (en) | Current detection circuit for A/F sensor | |
| JPS6215415A (en) | Detector for ink level | |
| JPH07198658A (en) | Measurement sensor signal processing circuit device | |
| ATE44827T1 (en) | MONITORING CIRCUIT FOR EVALUATION OF THE UEBERBW. BELOW SPECIFIED LIMIT VALUES. | |
| US6566849B1 (en) | Non-linear temperature compensation circuit | |
| JPH09105680A (en) | Temperature measurement circuit | |
| JP2660889B2 (en) | Power supply current measuring device | |
| JPH039023Y2 (en) | ||
| JP3048377B2 (en) | Grain moisture meter | |
| RU2161860C1 (en) | Integrated converter | |
| JPS5947356B2 (en) | Logarithmic conversion circuit for resistance change sensor | |
| KR930004426Y1 (en) | Circuit for detecting resistance temperature detector | |
| JPS6319802Y2 (en) | ||
| JPS6046452A (en) | Humidity detecting circuit | |
| JPS62266470A (en) | Peak value detection circuit | |
| JPH063463B2 (en) | Electricity detector for signal source |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A977 | Report on retrieval |
Effective date: 20041101 Free format text: JAPANESE INTERMEDIATE CODE: A971007 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20051213 |
|
| A521 | Written amendment |
Effective date: 20060118 Free format text: JAPANESE INTERMEDIATE CODE: A523 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20060509 |
|
| A61 | First payment of annual fees (during grant procedure) |
Effective date: 20060519 Free format text: JAPANESE INTERMEDIATE CODE: A61 |
|
| R150 | Certificate of patent (=grant) or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| LAPS | Cancellation because of no payment of annual fees |