WO2018155217A1 - Sensor output amplification circuit - Google Patents

Sensor output amplification circuit Download PDF

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Publication number
WO2018155217A1
WO2018155217A1 PCT/JP2018/004488 JP2018004488W WO2018155217A1 WO 2018155217 A1 WO2018155217 A1 WO 2018155217A1 JP 2018004488 W JP2018004488 W JP 2018004488W WO 2018155217 A1 WO2018155217 A1 WO 2018155217A1
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amplifier circuit
resistance element
negative
characteristic thermistor
sensor
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PCT/JP2018/004488
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French (fr)
Japanese (ja)
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彰宏 北村
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株式会社村田製作所
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Publication of WO2018155217A1 publication Critical patent/WO2018155217A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D3/00—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups
    • G01D3/028—Indicating or recording apparatus with provision for the special purposes referred to in the subgroups mitigating undesired influences, e.g. temperature, pressure
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/30—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/45—Differential amplifiers

Definitions

  • the present invention relates to a sensor output amplifier circuit including a sensor and an amplifier circuit. More specifically, the present invention relates to a sensor output amplifier circuit in which the amplification characteristic has a temperature characteristic and the amplification factor is increased (or decreased) in a desired temperature range. .
  • Patent Document 1 Japanese Patent Laid-Open No. 7-146176 discloses a sensor output amplifier circuit in which the amplification factor is constant regardless of the temperature of the usage environment.
  • FIG. 8 shows a sensor output amplifier circuit (pyroelectric infrared sensor) 1000 disclosed in Patent Document 1.
  • the sensor output amplifier circuit 1000 includes a sensor (pyroelectric element) 101, a feedback resistor 102, and an operational amplifier 103.
  • both ends of the sensor 101 are connected to a pair of input terminals of the operational amplifier 103, respectively.
  • a feedback resistor 102 is connected between the output terminal of the operational amplifier 103 and one input terminal.
  • the sensor output amplifier circuit 1000 is characterized in that a feedback resistor 102 having a negative temperature characteristic is used.
  • the sensor output amplifying circuit 1000 pays attention to the combination of the sensor 101 and the operational amplifier 103 and has a positive temperature characteristic. By giving the feedback resistor 102 a negative temperature characteristic, the two are canceled and used. The amplification factor is kept constant regardless of the environmental temperature.
  • the sensor output amplification circuit 1000 disclosed in Patent Document 1 is intended to make the amplification factor constant regardless of the temperature of the usage environment.
  • the sensor when a sensor designed for indoor use is used indoors, the sensor may malfunction due to cold air or hot air flowing into the room from the outside when the window is opened. May react. In such a case, increase the amplification factor of the sensor output amplifier circuit in the temperature range of room temperature, decrease the amplification factor in the temperature range of cold air or hot air, and appropriately set the threshold voltage at which the subsequent circuit operates. By doing so, malfunction can be prevented.
  • the output voltage of the sensor used may be low in a specific temperature range. In such a case, it is possible to use the sensor without any trouble by increasing the amplification factor of the temperature range of the sensor output amplifier circuit.
  • the output voltage of the sensor used may be extremely high in a specific temperature range, and an overvoltage is applied to the circuit connected to the subsequent stage of the sensor output amplifier circuit, causing the circuit connected to the subsequent stage to fail. May end up.
  • an overvoltage is applied to the circuit connected to the subsequent stage of the sensor output amplifier circuit, causing the circuit connected to the subsequent stage to fail. May end up.
  • by reducing the amplification factor in the temperature range of the sensor output amplifier circuit it is possible to prevent the occurrence of overvoltage and avoid the failure of the circuit connected to the subsequent stage.
  • a sensor output amplifier circuit includes a sensor, a positive input terminal, a negative input terminal, and an output terminal.
  • a first resistance element and a second resistance element, and the operational amplifier, the first resistance element, and the second resistance element constitute a non-inverting amplifier circuit or an inverting amplifier circuit.
  • a first negative characteristic thermistor element is connected in series or in parallel with the resistive element, and a second negative characteristic thermistor element is connected in parallel or in series with the second resistive element. It was made to have characteristics.
  • the sensor output is connected to the positive input terminal, a first resistance element is inserted between the negative input terminal and the ground, and a second resistance element is inserted between the output terminal and the negative input terminal.
  • a non-inverting amplifier circuit is configured, and the first negative characteristic thermistor element is connected in series with the first resistive element, and the second negative characteristic thermistor element is connected in parallel with the second resistive element.
  • the amplification characteristic of the non-inverting amplifier circuit can have a mountain-shaped temperature characteristic.
  • the sensor output is connected to the positive input terminal, the first resistance element is inserted between the negative input terminal and the ground, and the second resistance element is inserted between the output terminal and the negative input terminal.
  • a non-inverting amplifier circuit is configured, the first negative characteristic thermistor element is connected in parallel with the first resistive element, and the second negative characteristic thermistor element is connected in series with the second resistive element. it can.
  • a valley-type temperature characteristic can be given to the amplification characteristic of the non-inverting amplifier circuit.
  • the first capacitor element in series with the first resistance element and the first negative characteristic thermistor element connected in series, or the first resistance element and the first negative characteristic thermistor element connected in parallel.
  • the first resistance element, the first negative characteristic thermistor element, and the first capacitor element constitute a high pass filter, and low frequency noise can be removed from the output of the sensor output amplifier circuit.
  • the second capacitor element is connected in parallel with the second resistor element and the second negative characteristic thermistor element connected in parallel, or the second resistor element and the second negative characteristic thermistor element connected in series. Is also preferable.
  • the second resistance element, the second negative characteristic thermistor element, and the second capacitor element constitute a low-pass filter, and high frequency noise can be removed from the output of the sensor output amplifier circuit.
  • the sensor output is connected to the negative input terminal via the first resistance element, the positive input terminal is connected to the ground, and the second resistance element is inserted between the output terminal and the negative input terminal.
  • an inverting amplifier circuit is configured, and the first negative characteristic thermistor element is connected in series with the first resistive element, and the second negative characteristic thermistor element is connected in parallel with the second resistive element.
  • the amplification characteristic of the inverting amplifier circuit can have a mountain-shaped temperature characteristic.
  • the sensor output is connected to the negative input terminal via the first resistance element, the positive input terminal is connected to the ground, and the second resistance element is inserted between the output terminal and the negative input terminal.
  • an inverting amplifier circuit is configured, and the first negative characteristic thermistor element is connected in parallel with the first resistive element, and the second negative characteristic thermistor element is connected in series with the second resistive element. .
  • the valley-type temperature characteristic can be given to the amplification characteristic of the inverting amplifier circuit.
  • the second resistance element, the second negative characteristic thermistor element, and the capacitor element constitute a low-pass filter, and high frequency noise can be removed from the output of the sensor output amplifier circuit.
  • a pyroelectric sensor element for example, a pyroelectric sensor element, an infrared spectroscopic sensor, a thermoelectric conversion element, or the like can be used.
  • the sensor output amplifying circuit of the present invention has a temperature characteristic of the amplification characteristic, and the amplification factor is large (or small) in a desired temperature range.
  • FIG. 1 is an equivalent circuit diagram of a sensor output amplifier circuit 100 according to a first embodiment.
  • 5 is a graph showing amplification characteristics of a non-inverting amplifier circuit 7 of the sensor output amplifier circuit 100. It is an equivalent circuit diagram of the sensor output amplifier circuit 200 concerning 2nd Embodiment.
  • FIG. 6 is an equivalent circuit diagram of a sensor output amplifier circuit 300 according to a third embodiment. It is an equivalent circuit schematic of the sensor output amplifier circuit 400 concerning 4th Embodiment.
  • FIG. 10 is an equivalent circuit diagram of a sensor output amplifier circuit 500 according to a fifth embodiment.
  • each embodiment shows an embodiment of the present invention by way of example, and the present invention is not limited to the content of the embodiment. Moreover, it is also possible to implement combining the content described in different embodiment, and the implementation content in that case is also included in this invention. Further, the drawings are for helping understanding of the embodiment, and may not be drawn strictly. For example, a drawn component or a dimensional ratio between the components may not match the dimensional ratio described in the specification. In addition, the constituent elements described in the specification may be omitted in the drawings or may be drawn with the number omitted.
  • FIG. 1 shows a sensor output amplifier circuit 100 according to the first embodiment.
  • FIG. 1 is an equivalent circuit diagram of the sensor output amplifier circuit 100.
  • the sensor output amplifier circuit 100 includes a sensor 1, an operational amplifier 2, a first resistance element 3, a second resistance element 4, a first negative characteristic thermistor element 5, and a second negative characteristic thermistor element 6. .
  • a pyroelectric sensor element is used for the sensor 1.
  • the sensor 1 outputs a voltage when a temperature change occurs.
  • the operational amplifier 2 has a positive input terminal, a negative input terminal, and an output terminal.
  • the operational amplifier 2 includes a pair of power supply terminals (not shown).
  • Sensor 1 has one end connected to the ground and the other end connected to the positive input terminal of operational amplifier 2.
  • the negative input terminal of the operational amplifier 2 is connected to the ground via the first resistance element 3 and the first negative characteristic thermistor element 5 connected in series.
  • a second resistance element 4 and a second negative characteristic thermistor element 6 connected in parallel are inserted between the output terminal of the operational amplifier 2 and the negative input terminal of the operational amplifier 2.
  • the second resistance element 4 and the second negative characteristic thermistor element 6 connected in parallel are so-called feedback resistors.
  • the sensor output amplifying circuit 100 includes the operational amplifier 2, the first resistance element 3, the first negative characteristic thermistor element 5, the second resistance element 4, and the second negative characteristic thermistor element 6.
  • An inverting amplifier circuit 7 is configured.
  • Table 1 shows resistance values of the first resistance element 3, the first negative characteristic thermistor element 5, the second resistance element 4, and the second negative characteristic thermistor element 6.
  • the input voltage VIN is amplified at the amplification factor shown in the following (Equation 2), and the output voltage VOUT is output.
  • the sensor output amplifier circuit 100 is assumed to be used within a temperature range of 20 ° C. or more and 35 ° C. or less, for example.
  • the temperature of the use environment is less than 20 ° C. or exceeds 35 ° C., for example, there is a possibility that cold air has entered or hot air has entered. Want to prevent malfunction.
  • the first negative characteristic thermistor element 5 is one whose resistance value increases at a large change rate when it is less than 20 ° C., and the second negative characteristic thermistor element 6 exceeds 35 ° C.
  • a resistor whose resistance value decreases with a large change rate may be used. That, R I is a first resistance element 3 connected in series are combined resistance value of the first negative temperature coefficient thermistor elements 5, and adds "1" in in the shows amplification factor (Equation 2) Therefore, if the first negative characteristic thermistor element 5 has a resistance value that increases at a large change rate when it is less than 20 ° C., the first negative characteristic thermistor element 5 is less than 20 ° C.
  • the amplification factor of the inverting amplifier circuit 7 can be reduced.
  • R II is a combined resistance value of the second resistance element 4 and the second negative characteristic thermistor element 6 connected in parallel, and is added to “1” in (Expression 2) indicating the amplification factor. Therefore, if the second negative temperature coefficient thermistor element 6 has a resistance value that decreases with a large change rate when the temperature exceeds 35 ° C., the non-resistance when the temperature exceeds 35 ° C. is used.
  • the amplification factor of the inverting amplifier circuit 7 can be reduced.
  • FIG. 2 shows the amplification characteristics of the non-inverting amplifier circuit 7.
  • the amplification characteristic of the non-inverting amplifier circuit 7 has a mountain-shaped temperature characteristic.
  • the amplification factor is large when the temperature is 20 ° C. or more and 35 ° C. or less, and when the temperature is less than 20 ° C. When it exceeds, the amplification factor is small.
  • the amplification factor becomes constant regardless of the temperature of the use environment. Become flat.
  • the amplification characteristic of the non-inverting amplifier circuit 7 has a mountain-shaped temperature characteristic.
  • FIG. 3 shows a sensor output amplifier circuit 200 according to the second embodiment.
  • FIG. 3 is an equivalent circuit diagram of the sensor output amplifier circuit 200.
  • the amplification characteristic of the non-inverting amplifier circuit 7 has a mountain-shaped temperature characteristic.
  • the amplification characteristic of the non-inverting amplifier circuit 17 described later has a valley-type temperature characteristic.
  • the sensor output amplifier circuit 200 includes a sensor 1, an operational amplifier 2, a first resistance element 13, a second resistance element 14, a first negative characteristic thermistor element 15, and a second negative characteristic thermistor element 16. .
  • Sensor 1 has one end connected to the ground and the other end connected to the positive input terminal of operational amplifier 2.
  • the negative input terminal of the operational amplifier 2 is connected to the ground via the first resistance element 13 and the first negative characteristic thermistor element 15 connected in parallel.
  • a second resistance element 14 and a second negative characteristic thermistor element 16 connected in series are inserted between the output terminal of the operational amplifier 2 and the negative input terminal of the operational amplifier 2.
  • the second resistance element 14 and the second negative characteristic thermistor element 16 connected in series are so-called feedback resistors.
  • the sensor output amplifier circuit 200 includes the operational amplifier 2, the first resistance element 13, the first negative characteristic thermistor element 15, the second resistance element 14, and the second negative characteristic thermistor element 16 connected as described above. Thus, a non-inverting amplifier circuit 17 is configured.
  • Table 2 shows resistance values of the first resistance element 13, the first negative characteristic thermistor element 15, the second resistance element 14, and the second negative characteristic thermistor element 16.
  • the input voltage VIN is amplified with the amplification factor of (Equation 2) and outputs the output voltage VOUT .
  • the sensor output amplifier circuit 200 reduces the amplification factor of the non-inverting amplifier circuit 17 when the temperature is 20 ° C. or higher and 35 ° C. or lower, and increases the gain when the temperature is lower than 20 ° C. or exceeds 35 ° C. ing. Therefore, the sensor output amplifying circuit 200 uses a first negative characteristic thermistor element 15 having a resistance value that decreases with a large change rate when the temperature exceeds 35 ° C., and a second negative characteristic thermistor element 16 has a 20 When the temperature is lower than 0 ° C., the resistance value increases with a large change rate.
  • R I is a first resistance element 13 connected in parallel are combined resistance value of the first negative temperature coefficient thermistor elements 15, and adds "1" in in the shows amplification factor (Equation 2) Since the first negative characteristic thermistor element 15 has a resistance value that decreases with a large change rate when the temperature exceeds 35 ° C., the first negative characteristic thermistor element 15 has a large change rate. The amplification factor of the non-inverting amplifier circuit 17 is large.
  • R II is a combined resistance value of the second resistance element 14 and the second negative characteristic thermistor element 16 connected in series, and is added to “1” in (Expression 2) indicating the amplification factor.
  • the second negative characteristic thermistor element 16 has a resistance value that increases with a large change rate when the temperature is less than 20 ° C., non-inversion when the temperature is less than 20 ° C.
  • the amplification factor of the amplifier circuit 17 is large.
  • the amplification characteristic of the non-inverting amplifier circuit 17 has a valley-type temperature characteristic.
  • FIG. 4 shows a sensor output amplifier circuit 300 according to the third embodiment.
  • FIG. 4 is an equivalent circuit diagram of the sensor output amplifier circuit 300.
  • the sensor output amplifier circuits 100 and 200 according to the first and second embodiments described above were provided with non-inverting amplifier circuits 7 and 17, respectively.
  • the sensor output amplifier circuit 300 according to the third embodiment includes an inverting amplifier circuit 27 instead of the non-inverting amplifier circuit.
  • the amplification characteristic of the inverting amplification circuit 27 of the sensor output amplification circuit 300 has a mountain-shaped temperature characteristic.
  • the sensor output amplifier circuit 300 includes a sensor 1, an operational amplifier 2, a first resistance element 23, a second resistance element 24, a first negative characteristic thermistor element 25, and a second negative characteristic thermistor element 26. .
  • the sensor 1 has one end connected to the ground and the other end connected to the negative input terminal of the operational amplifier 2 via a first resistance element 23 and a first negative characteristic thermistor element 25 connected in series.
  • the positive input terminal of operational amplifier 2 is connected to ground.
  • a second resistance element 24 and a second negative characteristic thermistor element 26 connected in parallel are inserted between the output terminal of the operational amplifier 2 and the negative input terminal of the operational amplifier 2.
  • the second resistance element 24 and the second negative characteristic thermistor element 26 connected in parallel are so-called feedback resistors.
  • the sensor output amplifier circuit 300 includes the operational amplifier 2, the first resistance element 23, the first negative characteristic thermistor element 25, the second resistance element 24, and the second negative characteristic thermistor element 26 connected as described above.
  • an inverting amplifier circuit 27 is configured.
  • Table 3 shows resistance values of the first resistance element 23, the first negative characteristic thermistor element 25, the second resistance element 24, and the second negative characteristic thermistor element 26.
  • Inverting amplifier circuit 27 includes a first resistive element 23 combined resistance value of the first negative temperature coefficient thermistor elements 25 and R I, a second resistive element 24 and the combined resistance value of the second negative temperature coefficient thermistor elements 26 R II Then, the relationship of the following (Formula 3) is established between the input voltage V IN and the output voltage V OUT .
  • the input voltage VIN is amplified with the following amplification factor (Equation 4), and the output voltage VOUT is output.
  • the sensor output amplifier circuit 300 increases the amplification factor of the inverting amplifier circuit 27 when the temperature is 20 ° C. or higher and 35 ° C. or lower, and decreases the gain when the temperature is lower than 20 ° C. or exceeds 35 ° C. Yes. Therefore, the sensor output amplifier circuit 300 uses the first negative characteristic thermistor element 25 whose resistance value increases at a large change rate when the temperature is less than 20 ° C., and the second negative characteristic thermistor element 26 has a 35 ° C. When the value exceeds the value, the resistance value becomes smaller with a large change rate.
  • R I is the combined resistance value of the first resistance element 23 and the first negative characteristic thermistor element 25 connected in series, and is arranged in the denominator of the fraction constituting (Equation 4) indicating the amplification factor. Therefore, when the first negative characteristic thermistor element 25 has a resistance value that increases with a large change rate when the temperature is less than 20 ° C., the gain of the inverting amplifier circuit 27 when the temperature is less than 20 ° C. is small. It has become.
  • R II includes a second resistor element 24 connected in parallel are combined resistance value between the second negative temperature coefficient thermistor elements 26, and, arranged in the numerator of the fraction constituting shows amplification factor (formula 4) Therefore, when the second negative characteristic thermistor element 26 has a resistance value that decreases with a large change rate when the temperature exceeds 35 ° C., the gain of the inverting amplifier circuit 27 when the temperature exceeds 35 ° C. Is getting smaller.
  • the amplification characteristic of the inverting amplifier circuit 27 has a mountain-shaped temperature characteristic.
  • FIG. 5 shows a sensor output amplifier circuit 400 according to the fourth embodiment.
  • FIG. 5 is an equivalent circuit diagram of the sensor output amplifier circuit 400.
  • the sensor output amplifier circuit 400 according to the fourth embodiment includes an inverting amplifier circuit 37 as in the sensor output amplifier circuit 300 according to the third embodiment described above. However, unlike the sensor output amplifier circuit 300, the amplification characteristic of the inverting amplifier circuit 37 of the sensor output amplifier circuit 400 has a valley-type temperature characteristic.
  • the sensor output amplifier circuit 400 includes the sensor 1, the operational amplifier 2, the first resistance element 33, the second resistance element 34, the first negative characteristic thermistor element 35, and the second negative characteristic thermistor element 36. .
  • the sensor 1 has one end connected to the ground and the other end connected to the positive input terminal of the operational amplifier 2 via a first resistance element 33 and a first negative characteristic thermistor element 35 connected in parallel.
  • the positive input terminal of operational amplifier 2 is connected to ground.
  • a second resistance element 34 and a second negative characteristic thermistor element 36 connected in series are inserted between the output terminal of the operational amplifier 2 and the negative input terminal of the operational amplifier 2.
  • the second resistance element 34 and the second negative characteristic thermistor element 36 connected in series are so-called feedback resistors.
  • the sensor output amplifier circuit 400 includes the operational amplifier 2, the first resistance element 33, the first negative characteristic thermistor element 35, the second resistance element 34, and the second negative characteristic thermistor element 36 connected as described above.
  • an inverting amplifier circuit 37 is configured.
  • Table 4 shows resistance values of the first resistance element 33, the first negative characteristic thermistor element 35, the second resistance element 34, and the second negative characteristic thermistor element 36.
  • the combined resistance value of the first resistance element 33 and the first negative characteristic thermistor element 35 is R I
  • the combined resistance value of the second resistance element 34 and the second negative characteristic thermistor element 36 is R
  • the relationship of (Equation 3) is established between the input voltage V IN and the output voltage V OUT .
  • the input voltage VIN is amplified with the amplification factor of (Equation 4) and outputs the output voltage VOUT .
  • the sensor output amplifier circuit 400 reduces the amplification factor of the inverting amplifier circuit 37 when the temperature is 20 ° C. or higher and 35 ° C. or lower, and increases the gain when the temperature is lower than 20 ° C. or exceeds 35 ° C. Yes. Therefore, the sensor output amplifying circuit 400 uses the first negative characteristic thermistor element 35 having a resistance value that decreases with a large change rate when the temperature exceeds 35 ° C., and the second negative characteristic thermistor element 36 has a 20 When the temperature is lower than 0 ° C., the resistance value increases with a large change rate.
  • R I is a combined resistance value of the first resistance element 33 and the first negative characteristic thermistor element 35 connected in parallel, and is arranged in the denominator of the fraction constituting (Equation 4) indicating the amplification factor. Therefore, when the first negative characteristic thermistor element 35 has a resistance value that decreases with a large change rate when the temperature exceeds 35 ° C., the gain of the inverting amplifier circuit 37 when the temperature exceeds 35 ° C. Is getting bigger.
  • R II is a combined resistance value of the second resistance element 34 and the second negative characteristic thermistor element 36 connected in series, and is arranged in a fractional numerator constituting (Equation 4) indicating the amplification factor.
  • the amplification factor of the inverting amplifier circuit 37 when it is less than 20 ° C. is large. It has become.
  • the inverting amplifier circuit 37 has a valley-type temperature characteristic.
  • FIG. 6 shows a sensor output amplifier circuit 500 according to the fifth embodiment.
  • FIG. 6 is an equivalent circuit diagram of the sensor output amplifier circuit 500.
  • the sensor output amplifier circuit 500 has a configuration added to the sensor output amplifier circuit 100 according to the first embodiment described above. Specifically, a first capacitor 48 was further connected in series with the first resistance element 3 and the first negative characteristic thermistor element 5 connected in series. In addition, a second capacitor 49 was further connected in parallel with the second resistance element 4 and the second negative characteristic thermistor element 6 connected in parallel.
  • the first resistance element 3, the first negative characteristic thermistor element 5 and the first capacitor 48 connected in series form a high-pass filter, and the output from the non-inverting amplifier circuit 7 is low. Frequency noise has been removed.
  • the second resistance element 4 In the sensor output amplifier circuit 500, the second resistance element 4, the second negative characteristic thermistor element 6, and the second capacitor 49 connected in parallel form a low-pass filter, and the output of the non-inverting amplifier circuit 7. High frequency noise has been removed from
  • the sensor output amplifier circuit 200 according to the second embodiment described above can also add a high-pass filter and a low-pass filter by applying the above method.
  • FIG. 7 shows a sensor output amplifier circuit 600 according to the sixth embodiment.
  • FIG. 6 is an equivalent circuit diagram of the sensor output amplifier circuit 600.
  • the sensor output amplifier circuit 600 according to the sixth embodiment has a configuration added to the sensor output amplifier circuit 300 according to the third embodiment described above. Specifically, a capacitor 59 was further connected in parallel with the second resistance element 24 and the second negative characteristic thermistor element 26 connected in parallel.
  • the second resistance element 24, the second negative characteristic thermistor element 26, and the capacitor 59 connected in parallel form a low-pass filter, and high frequency noise is removed from the output of the inverting amplifier circuit 27. Has been.
  • the sensor output amplifier circuit 400 according to the above-described fourth embodiment can also be added with a low-pass filter by applying the above method.
  • the sensor output amplifier circuits 100, 200, 300, 400, 500, 600 according to the first to sixth embodiments have been described above.
  • the present invention is not limited to the contents described above, and various modifications can be made in accordance with the spirit of the invention.
  • pyroelectric sensor elements are used for the sensor 1, but the type of the sensor 1 is arbitrary, for example, an infrared spectroscopic sensor, a thermoelectric conversion element, or the like. It may be.
  • the resistance values of 26 and 36 are also arbitrary, and the resistance values can be selected according to desired temperature characteristics that await the amplification characteristics.

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Abstract

Provided is a sensor output amplification circuit (100) of which the amplification characteristics are provided with a temperature characteristic to increase (or decrease) the amplification factor in a desired temperature range. The sensor output amplification circuit (100) is provided with a sensor (1), an operational amplifier (2) having a plus input terminal, a minus input terminal, and an output terminal, a first resistor element (3), and a second resistor element (4). The output of the sensor (1) is connected to the plus input terminal of the operational amplifier (2). The first resistor element (3) is inserted between the minus input terminal of the operational amplifier (2) and ground. The second resistor element (4) is inserted between the output terminal and the minus input terminal of the operational amplifier (2) to configure a non-inverting amplification circuit. A first negative characteristic thermistor element (5) is connected in series with the first resistor element (3). A second negative characteristic thermistor element (6) is connected in parallel with the second resistor element (4).

Description

センサ出力増幅回路Sensor output amplifier circuit
　本発明は、センサと増幅回路とを備えたセンサ出力増幅回路に関し、さらに詳しくは、増幅特性に温度特性を持たせ、所望の温度範囲における増幅率を大きく（あるいは小さく）したセンサ出力増幅回路に関する。 The present invention relates to a sensor output amplifier circuit including a sensor and an amplifier circuit. More specifically, the present invention relates to a sensor output amplifier circuit in which the amplification characteristic has a temperature characteristic and the amplification factor is increased (or decreased) in a desired temperature range. .
　特許文献１（特開平７-１４６１７６号公報）に、使用環境の温度に関わらず、増幅率を一定にしたセンサ出力増幅回路が開示されている。 Patent Document 1 (Japanese Patent Laid-Open No. 7-146176) discloses a sensor output amplifier circuit in which the amplification factor is constant regardless of the temperature of the usage environment.
　図８に、特許文献１に開示されたセンサ出力増幅回路（焦電型赤外線センサー）１０００を示す。 FIG. 8 shows a sensor output amplifier circuit (pyroelectric infrared sensor) 1000 disclosed in Patent Document 1.
　センサ出力増幅回路１０００は、センサ（焦電素子）１０１と、帰還抵抗１０２と、オペアンプ１０３とで構成されている。 The sensor output amplifier circuit 1000 includes a sensor (pyroelectric element) 101, a feedback resistor 102, and an operational amplifier 103.
　センサ出力増幅回路１０００は、センサ１０１の両端を、それぞれ、オペアンプ１０３の１対の入力端子に接続している。オペアンプ１０３の出力端子と、一方の入力端子との間に、帰還抵抗１０２を接続している。 In the sensor output amplifier circuit 1000, both ends of the sensor 101 are connected to a pair of input terminals of the operational amplifier 103, respectively. A feedback resistor 102 is connected between the output terminal of the operational amplifier 103 and one input terminal.
　センサ出力増幅回路１０００は、帰還抵抗１０２に、負の温度特性を持つものを使用したことを特徴としている。 The sensor output amplifier circuit 1000 is characterized in that a feedback resistor 102 having a negative temperature characteristic is used.
　センサ出力増幅回路１０００は、センサ１０１とオペアンプ１０３とを組合せたものが正の温度特性を持つことに着目し、帰還抵抗１０２に負の温度特性を持たせることによって、両者を打消し合わせ、使用環境の温度に関わらず、増幅率を一定に保つようにしている。 The sensor output amplifying circuit 1000 pays attention to the combination of the sensor 101 and the operational amplifier 103 and has a positive temperature characteristic. By giving the feedback resistor 102 a negative temperature characteristic, the two are canceled and used. The amplification factor is kept constant regardless of the environmental temperature.
特開平７-１４６１７６号公報JP-A-7-146176
　特許文献１に開示されたセンサ出力増幅回路１０００は、使用環境の温度に関わらず、増幅率を一定にすることを目的としている。 The sensor output amplification circuit 1000 disclosed in Patent Document 1 is intended to make the amplification factor constant regardless of the temperature of the usage environment.
　これに対し、所望の温度範囲において、センサ出力増幅回路の増幅率を、大きくしたり、あるいは逆に小さくしたりしたい場合がある。 In contrast, there is a case where it is desired to increase or decrease the amplification factor of the sensor output amplifier circuit in a desired temperature range.
　たとえば、室内で使用することを前提に設計されたセンサを室内で使用している場合に、窓を開け、外から冷風あるいは熱風が室内に流入することで、センサが誤作動して冷風や熱風に反応してしまう場合がある。このような場合には、センサ出力増幅回路の、室温の温度範囲における増幅率を大きくするとともに、冷風や熱風の温度範囲における増幅率を小さくし、かつ後段回路の作動する閾値電圧を適切に設定することによって、誤作動を防ぐことができる。 For example, when a sensor designed for indoor use is used indoors, the sensor may malfunction due to cold air or hot air flowing into the room from the outside when the window is opened. May react. In such a case, increase the amplification factor of the sensor output amplifier circuit in the temperature range of room temperature, decrease the amplification factor in the temperature range of cold air or hot air, and appropriately set the threshold voltage at which the subsequent circuit operates. By doing so, malfunction can be prevented.
　あるいは、使用するセンサの出力電圧が、特定の温度範囲において低い場合がある。そのような場合には、センサ出力増幅回路の、その温度範囲の増幅率を大きくすることによって、支障なくそのセンサを使用することが可能になる。 Or, the output voltage of the sensor used may be low in a specific temperature range. In such a case, it is possible to use the sensor without any trouble by increasing the amplification factor of the temperature range of the sensor output amplifier circuit.
　あるいは逆に、使用するセンサの出力電圧が、特定の温度範囲において極端に高い場合があり、センサ出力増幅回路の後段に接続された回路に過電圧が印加され、後段に接続された回路が故障してしまう場合がある。そのような場合には、センサ出力増幅回路の、その温度範囲の増幅率を小さくすることによって、過電圧の発生を防止し、後段に接続された回路の故障を回避することが可能になる。 Or conversely, the output voltage of the sensor used may be extremely high in a specific temperature range, and an overvoltage is applied to the circuit connected to the subsequent stage of the sensor output amplifier circuit, causing the circuit connected to the subsequent stage to fail. May end up. In such a case, by reducing the amplification factor in the temperature range of the sensor output amplifier circuit, it is possible to prevent the occurrence of overvoltage and avoid the failure of the circuit connected to the subsequent stage.
　このように、センサ出力増幅回路の増幅特性に温度特性を持たせ、所望の温度範囲において、増幅率を大きくしたり、増幅率を小さくしたりしたい場合がある。しかしながら、これまで、センサ出力増幅回路の増幅特性に、簡易かつ安価に温度特性を持たせる方法がなかった。 As described above, there is a case where it is desired to give the amplification characteristic of the sensor output amplifier circuit temperature characteristics and increase the amplification factor or decrease the amplification factor in a desired temperature range. However, until now, there has been no simple and inexpensive method for giving temperature characteristics to the amplification characteristics of the sensor output amplifier circuit.
　本発明は、上述する従来の問題を解決するためになされたものであり、その手段として本発明のセンサ出力増幅回路は、センサと、プラス入力端子とマイナス入力端子と出力端子とを備えたオペアンプと、第１抵抗素子と、第２抵抗素子と、を備え、オペアンプと、第１抵抗素子と、前記第２抵抗素子とで、非反転増幅回路、または、反転増幅回路が構成され、第１抵抗素子と直列または並列に第１負特性サーミスタ素子が接続され、第２抵抗素子と並列または直列に第２負特性サーミスタ素子が接続され、非反転増幅回路または反転増幅回路の増幅特性に、温度特性を持たせるようにした。 The present invention has been made to solve the above-described conventional problems, and as a means therefor, a sensor output amplifier circuit according to the present invention includes a sensor, a positive input terminal, a negative input terminal, and an output terminal. A first resistance element and a second resistance element, and the operational amplifier, the first resistance element, and the second resistance element constitute a non-inverting amplifier circuit or an inverting amplifier circuit. A first negative characteristic thermistor element is connected in series or in parallel with the resistive element, and a second negative characteristic thermistor element is connected in parallel or in series with the second resistive element. It was made to have characteristics.
　たとえば、センサの出力が、プラス入力端子に接続され、マイナス入力端子とグランドとの間に、第１抵抗素子が挿入され、出力端子とマイナス入力端子との間に、第２抵抗素子が挿入されて、非反転増幅回路が構成され、第１抵抗素子と直列に第１負特性サーミスタ素子が接続され、第２抵抗素子と並列に第２負特性サーミスタ素子が接続されたものとすることができる。この場合は、非反転増幅回路の増幅特性に山型の温度特性を持たせることができる。 For example, the sensor output is connected to the positive input terminal, a first resistance element is inserted between the negative input terminal and the ground, and a second resistance element is inserted between the output terminal and the negative input terminal. Thus, a non-inverting amplifier circuit is configured, and the first negative characteristic thermistor element is connected in series with the first resistive element, and the second negative characteristic thermistor element is connected in parallel with the second resistive element. . In this case, the amplification characteristic of the non-inverting amplifier circuit can have a mountain-shaped temperature characteristic.
　あるいは、センサの出力が、プラス入力端子に接続され、マイナス入力端子とグランドとの間に、第１抵抗素子が挿入され、出力端子とマイナス入力端子との間に、第２抵抗素子が挿入されて、非反転増幅回路が構成され、第１抵抗素子と並列に第１負特性サーミスタ素子が接続され、第２抵抗素子と直列に第２負特性サーミスタ素子が接続されたたものとすることができる。この場合は、非反転増幅回路の増幅特性に谷型の温度特性を持たせることができる。 Alternatively, the sensor output is connected to the positive input terminal, the first resistance element is inserted between the negative input terminal and the ground, and the second resistance element is inserted between the output terminal and the negative input terminal. Thus, it is assumed that a non-inverting amplifier circuit is configured, the first negative characteristic thermistor element is connected in parallel with the first resistive element, and the second negative characteristic thermistor element is connected in series with the second resistive element. it can. In this case, a valley-type temperature characteristic can be given to the amplification characteristic of the non-inverting amplifier circuit.
　直列に接続された第１抵抗素子と第１負特性サーミスタ素子、または、並列に接続された第１抵抗素子と第１負特性サーミスタ素子と、直列に、第１キャパシタ素子を接続することも好ましい。この場合には、第１抵抗素子と、第１負特性サーミスタ素子と、第１キャパシタ素子とでハイパスフィルタを構成し、センサ出力増幅回路の出力から低周波ノイズを除去することができる。 It is also preferable to connect the first capacitor element in series with the first resistance element and the first negative characteristic thermistor element connected in series, or the first resistance element and the first negative characteristic thermistor element connected in parallel. . In this case, the first resistance element, the first negative characteristic thermistor element, and the first capacitor element constitute a high pass filter, and low frequency noise can be removed from the output of the sensor output amplifier circuit.
　また、並列に接続された第２抵抗素子と第２負特性サーミスタ素子、または、直列に接続された第２抵抗素子と第２負特性サーミスタ素子と、並列に、第２キャパシタ素子を接続することも好ましい。この場合には、第２抵抗素子と、第２負特性サーミスタ素子と、第２キャパシタ素子とでローパスフィルタを構成し、センサ出力増幅回路の出力から高周波ノイズを除去することができる。 Also, the second capacitor element is connected in parallel with the second resistor element and the second negative characteristic thermistor element connected in parallel, or the second resistor element and the second negative characteristic thermistor element connected in series. Is also preferable. In this case, the second resistance element, the second negative characteristic thermistor element, and the second capacitor element constitute a low-pass filter, and high frequency noise can be removed from the output of the sensor output amplifier circuit.
　また、センサの出力が、第１抵抗素子を介したうえで、マイナス入力端子に接続され、プラス入力端子がグランドに接続され、出力端子とマイナス入力端子との間に、第２抵抗素子が挿入されて、反転増幅回路が構成され、第１抵抗素子と直列に第１負特性サーミスタ素子が接続され、第２抵抗素子と並列に第２負特性サーミスタ素子が接続されたものとすることができる。この場合は、反転増幅回路の増幅特性に山型の温度特性を持たせることができる。 The sensor output is connected to the negative input terminal via the first resistance element, the positive input terminal is connected to the ground, and the second resistance element is inserted between the output terminal and the negative input terminal. Thus, an inverting amplifier circuit is configured, and the first negative characteristic thermistor element is connected in series with the first resistive element, and the second negative characteristic thermistor element is connected in parallel with the second resistive element. . In this case, the amplification characteristic of the inverting amplifier circuit can have a mountain-shaped temperature characteristic.
　あるいは、センサの出力が、第１抵抗素子を介したうえで、マイナス入力端子に接続され、プラス入力端子がグランドに接続され、出力端子とマイナス入力端子との間に、第２抵抗素子が挿入されて、反転増幅回路が構成され、第１抵抗素子と並列に第１負特性サーミスタ素子が接続され、第２抵抗素子と直列に第２負特性サーミスタ素子が接続されたものとすることができる。この場合は、反転増幅回路の増幅特性に谷型の温度特性を持たせることができる。 Alternatively, the sensor output is connected to the negative input terminal via the first resistance element, the positive input terminal is connected to the ground, and the second resistance element is inserted between the output terminal and the negative input terminal. Thus, an inverting amplifier circuit is configured, and the first negative characteristic thermistor element is connected in parallel with the first resistive element, and the second negative characteristic thermistor element is connected in series with the second resistive element. . In this case, the valley-type temperature characteristic can be given to the amplification characteristic of the inverting amplifier circuit.
　並列に接続された第２抵抗素子と第２負特性サーミスタ素子、または、直列に接続された第２抵抗素子と第２負特性サーミスタ素子と、並列に、キャパシタ素子を接続することも好ましい。この場合には、第２抵抗素子と、第２負特性サーミスタ素子と、キャパシタ素子とでローパスフィルタを構成し、センサ出力増幅回路の出力から高周波ノイズを除去することができる。 It is also preferable to connect a capacitor element in parallel with the second resistance element and the second negative characteristic thermistor element connected in parallel, or with the second resistance element and the second negative characteristic thermistor element connected in series. In this case, the second resistance element, the second negative characteristic thermistor element, and the capacitor element constitute a low-pass filter, and high frequency noise can be removed from the output of the sensor output amplifier circuit.
　センサには、たとえば、焦電センサ素子、赤外線分光センサ、熱電変換素子などを使用することができる。 As the sensor, for example, a pyroelectric sensor element, an infrared spectroscopic sensor, a thermoelectric conversion element, or the like can be used.
　本発明のセンサ出力増幅回路は、増幅特性が温度特性を持ち、所望の温度範囲において、増幅率が大きく（あるいは小さく）されている。 The sensor output amplifying circuit of the present invention has a temperature characteristic of the amplification characteristic, and the amplification factor is large (or small) in a desired temperature range.
第１実施形態にかかるセンサ出力増幅回路１００の等価回路図である。1 is an equivalent circuit diagram of a sensor output amplifier circuit 100 according to a first embodiment. センサ出力増幅回路１００の非反転増幅回路７の増幅特性を示すグラフである。5 is a graph showing amplification characteristics of a non-inverting amplifier circuit 7 of the sensor output amplifier circuit 100. 第２実施形態にかかるセンサ出力増幅回路２００の等価回路図である。It is an equivalent circuit diagram of the sensor output amplifier circuit 200 concerning 2nd Embodiment. 第３実施形態にかかるセンサ出力増幅回路３００の等価回路図である。FIG. 6 is an equivalent circuit diagram of a sensor output amplifier circuit 300 according to a third embodiment. 第４実施形態にかかるセンサ出力増幅回路４００の等価回路図である。It is an equivalent circuit schematic of the sensor output amplifier circuit 400 concerning 4th Embodiment. 第５実施形態にかかるセンサ出力増幅回路５００の等価回路図である。FIG. 10 is an equivalent circuit diagram of a sensor output amplifier circuit 500 according to a fifth embodiment. 第６実施形態にかかるセンサ出力増幅回路６００の等価回路図である。FIG. 10 is an equivalent circuit diagram of a sensor output amplifier circuit 600 according to a sixth embodiment. 特許文献１に開示されたセンサ出力増幅回路１０００の等価回路図である。10 is an equivalent circuit diagram of a sensor output amplifier circuit 1000 disclosed in Patent Document 1. FIG.
　以下、図面とともに、本発明を実施するための形態について説明する。 Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
　なお、各実施形態は、本発明の実施の形態を例示的に示したものであり、本発明が実施形態の内容に限定されることはない。また、異なる実施形態に記載された内容を組合せて実施することも可能であり、その場合の実施内容も本発明に含まれる。また、図面は、実施形態の理解を助けるためのものであり、必ずしも厳密に描画されていない場合がある。たとえば、描画された構成要素ないし構成要素間の寸法の比率が、明細書に記載されたそれらの寸法の比率と一致していない場合がある。また、明細書に記載されている構成要素が、図面において省略されている場合や、個数を省略して描画されている場合などがある。 Each embodiment shows an embodiment of the present invention by way of example, and the present invention is not limited to the content of the embodiment. Moreover, it is also possible to implement combining the content described in different embodiment, and the implementation content in that case is also included in this invention. Further, the drawings are for helping understanding of the embodiment, and may not be drawn strictly. For example, a drawn component or a dimensional ratio between the components may not match the dimensional ratio described in the specification. In addition, the constituent elements described in the specification may be omitted in the drawings or may be drawn with the number omitted.
　［第１実施形態］
　図１に、第１実施形態にかかるセンサ出力増幅回路１００を示す。ただし、図１は、センサ出力増幅回路１００の等価回路図である。 [First Embodiment]
FIG. 1 shows a sensor output amplifier circuit 100 according to the first embodiment. However, FIG. 1 is an equivalent circuit diagram of the sensor output amplifier circuit 100.
　センサ出力増幅回路１００は、センサ１と、オペアンプ２と、第１抵抗素子３と、第２抵抗素子４と、第１負特性サーミスタ素子５と、第２負特性サーミスタ素子６とを備えている。 The sensor output amplifier circuit 100 includes a sensor 1, an operational amplifier 2, a first resistance element 3, a second resistance element 4, a first negative characteristic thermistor element 5, and a second negative characteristic thermistor element 6. .
　本実施形態においては、センサ１に、焦電センサ素子を使用した。センサ１は、温度変化が発生した場合に電圧を出力する。 In this embodiment, a pyroelectric sensor element is used for the sensor 1. The sensor 1 outputs a voltage when a temperature change occurs.
　オペアンプ２は、プラス入力端子とマイナス入力端子と出力端子とを備えている。また、オペアンプ２は、図示しないが、1対の電源端子を備えている。 The operational amplifier 2 has a positive input terminal, a negative input terminal, and an output terminal. The operational amplifier 2 includes a pair of power supply terminals (not shown).
　センサ１は、一端がグランドに接続され、他端がオペアンプ２のプラス入力端子に接続されている。 Sensor 1 has one end connected to the ground and the other end connected to the positive input terminal of operational amplifier 2.
　オペアンプ２のマイナス入力端子が、直列に接続された第１抵抗素子３および第１負特性サーミスタ素子５を介して、グランドに接続されている。 The negative input terminal of the operational amplifier 2 is connected to the ground via the first resistance element 3 and the first negative characteristic thermistor element 5 connected in series.
　また、オペアンプ２の出力端子と、オペアンプ２のマイナス入力端子との間に、並列に接続された第２抵抗素子４および第２負特性サーミスタ素子６が挿入されている。並列に接続された第２抵抗素子４および第２負特性サーミスタ素子６は、いわゆる帰還抵抗である。 Also, a second resistance element 4 and a second negative characteristic thermistor element 6 connected in parallel are inserted between the output terminal of the operational amplifier 2 and the negative input terminal of the operational amplifier 2. The second resistance element 4 and the second negative characteristic thermistor element 6 connected in parallel are so-called feedback resistors.
　センサ出力増幅回路１００は、上記の接続により、オペアンプ２と、第１抵抗素子３と、第１負特性サーミスタ素子５と、第２抵抗素子４と、第２負特性サーミスタ素子６とで、非反転増幅回路７が構成されている。 The sensor output amplifying circuit 100 includes the operational amplifier 2, the first resistance element 3, the first negative characteristic thermistor element 5, the second resistance element 4, and the second negative characteristic thermistor element 6. An inverting amplifier circuit 7 is configured.
　第１抵抗素子３、第１負特性サーミスタ素子５、第２抵抗素子４、第２負特性サーミスタ素子６、それぞれの抵抗値を、表１に示す。
Figure JPOXMLDOC01-appb-T000001
 Table 1 shows resistance values of the first resistance element 3, the first negative characteristic thermistor element 5, the second resistance element 4, and the second negative characteristic thermistor element 6.
Figure JPOXMLDOC01-appb-T000001
　第１抵抗素子３と第１負特性サーミスタ素子５との合成抵抗値をＲＩとし、第２抵抗素子４と第２負特性サーミスタ素子６との合成抵抗値をＲＩＩとしたとき、非反転増幅回路７の入力電圧ＶＩＮと出力電圧ＶＯＵＴとは、次の（式１）に示す関係が成立する。
Figure JPOXMLDOC01-appb-M000002
 When the combined resistance value of the first resistance element 3 and the first negative characteristic thermistor element 5 is R I and the combined resistance value of the second resistance element 4 and the second negative characteristic thermistor element 6 is R II , non-inversion The relationship shown in the following (Equation 1) is established between the input voltage V IN and the output voltage V OUT of the amplifier circuit 7.
Figure JPOXMLDOC01-appb-M000002
　すなわち、入力電圧ＶＩＮは、次の（式２）に示す増幅率で増幅され、出力電圧ＶＯＵＴを出力する。
Figure JPOXMLDOC01-appb-M000003
 That is, the input voltage VIN is amplified at the amplification factor shown in the following (Equation 2), and the output voltage VOUT is output.
Figure JPOXMLDOC01-appb-M000003
　センサ出力増幅回路１００は、たとえば、２０℃以上、３５℃以下の温度範囲内での使用を前提としているものであるとする。この場合には、非反転増幅回路７の、２０℃以上、３５℃以下での増幅率を大きくし、２０℃未満の場合や３５℃を超えた場合の増幅率を小さくしたい。すなわち、使用環境の温度が２０℃以上、３５℃以下である場合には、増幅率を大きくし、間違いなく被検出物を検出したい。一方、使用環境の温度が２０℃未満の場合や３５℃を超えた場合は、たとえば、冷風が入り込んだ、あるいは、熱風が入り込んだような場合である可能性があるため、増幅率を小さくして誤作動を防止したい。 Suppose that the sensor output amplifier circuit 100 is assumed to be used within a temperature range of 20 ° C. or more and 35 ° C. or less, for example. In this case, it is desired to increase the amplification factor of the non-inverting amplifier circuit 7 at 20 ° C. or more and 35 ° C. or less, and decrease the amplification factor when the temperature is less than 20 ° C. or exceeds 35 ° C. That is, when the temperature of the usage environment is 20 ° C. or more and 35 ° C. or less, it is desired to increase the amplification factor and to detect the detected object without fail. On the other hand, when the temperature of the use environment is less than 20 ° C. or exceeds 35 ° C., for example, there is a possibility that cold air has entered or hot air has entered. Want to prevent malfunction.
　このような場合には、第１負特性サーミスタ素子５に、２０℃未満の場合に抵抗値が大きな変化率で大きくなるものを使用するとともに、第２負特性サーミスタ素子６に、３５℃を超えた場合に抵抗値が大きな変化率で小さくなるものを使用すれば良い。すなわち、ＲＩは、直列に接続された第１抵抗素子３と第１負特性サーミスタ素子５との合成抵抗値であり、かつ、増幅率を示す（式２）の中において「１」に加算される分数の分母に配置されているため、第１負特性サーミスタ素子５に２０℃未満である場合に抵抗値が大きな変化率で大きくなるものを使用すれば、２０℃未満である場合の非反転増幅回路７の増幅率を小さくすることができる。また、ＲＩＩは、並列に接続された第２抵抗素子４と第２負特性サーミスタ素子６との合成抵抗値であり、かつ、増幅率を示す（式２）の中において「１」に加算される分数の分子に配置されているため、第２負特性サーミスタ素子６に３５℃を超えた場合に抵抗値が大きな変化率で小さくなるものを使用すれば、３５℃を超えた場合の非反転増幅回路７の増幅率を小さくすることができる。 In such a case, the first negative characteristic thermistor element 5 is one whose resistance value increases at a large change rate when it is less than 20 ° C., and the second negative characteristic thermistor element 6 exceeds 35 ° C. In such a case, a resistor whose resistance value decreases with a large change rate may be used. That, R I is a first resistance element 3 connected in series are combined resistance value of the first negative temperature coefficient thermistor elements 5, and adds "1" in in the shows amplification factor (Equation 2) Therefore, if the first negative characteristic thermistor element 5 has a resistance value that increases at a large change rate when it is less than 20 ° C., the first negative characteristic thermistor element 5 is less than 20 ° C. The amplification factor of the inverting amplifier circuit 7 can be reduced. R II is a combined resistance value of the second resistance element 4 and the second negative characteristic thermistor element 6 connected in parallel, and is added to “1” in (Expression 2) indicating the amplification factor. Therefore, if the second negative temperature coefficient thermistor element 6 has a resistance value that decreases with a large change rate when the temperature exceeds 35 ° C., the non-resistance when the temperature exceeds 35 ° C. is used. The amplification factor of the inverting amplifier circuit 7 can be reduced.
　図２に、非反転増幅回路７の増幅特性を示す。図２から分かるように、非反転増幅回路７の増幅特性は山型の温度特性を持ち、２０℃以上、３５℃以下の場合に増幅率が大きく、２０℃未満の場合、および、３５℃を超えた場合に増幅率が小さくなっている。ちなみに、図１に示すセンサ出力増幅回路１００の非反転増幅回路７から、第１負特性サーミスタ素子５および第２負特性サーミスタ素子６を取り除くと、増幅率は使用環境の温度に関わらず一定となりフラットになる。 FIG. 2 shows the amplification characteristics of the non-inverting amplifier circuit 7. As can be seen from FIG. 2, the amplification characteristic of the non-inverting amplifier circuit 7 has a mountain-shaped temperature characteristic. The amplification factor is large when the temperature is 20 ° C. or more and 35 ° C. or less, and when the temperature is less than 20 ° C. When it exceeds, the amplification factor is small. Incidentally, when the first negative characteristic thermistor element 5 and the second negative characteristic thermistor element 6 are removed from the non-inverting amplifier circuit 7 of the sensor output amplifier circuit 100 shown in FIG. 1, the amplification factor becomes constant regardless of the temperature of the use environment. Become flat.
　以上のように、センサ出力増幅回路１００は、非反転増幅回路７の増幅特性が山型の温度特性を持っている。 As described above, in the sensor output amplifier circuit 100, the amplification characteristic of the non-inverting amplifier circuit 7 has a mountain-shaped temperature characteristic.
　［第２実施形態］
　図３に、第２実施形態にかかるセンサ出力増幅回路２００を示す。ただし、図３は、センサ出力増幅回路２００の等価回路図である。 [Second Embodiment]
FIG. 3 shows a sensor output amplifier circuit 200 according to the second embodiment. FIG. 3 is an equivalent circuit diagram of the sensor output amplifier circuit 200.
　上述した第１実施形態にかかるセンサ出力増幅回路１００は、非反転増幅回路７の増幅特性が山型の温度特性を持っていた。これに対し、第２実施形態にかかるセンサ出力増幅回路２００は、後述する非反転増幅回路１７の増幅特性が、谷型の温度特性を持っている。 In the sensor output amplifier circuit 100 according to the first embodiment described above, the amplification characteristic of the non-inverting amplifier circuit 7 has a mountain-shaped temperature characteristic. On the other hand, in the sensor output amplifier circuit 200 according to the second embodiment, the amplification characteristic of the non-inverting amplifier circuit 17 described later has a valley-type temperature characteristic.
　センサ出力増幅回路２００は、センサ１と、オペアンプ２と、第１抵抗素子１３と、第２抵抗素子１４と、第１負特性サーミスタ素子１５と、第２負特性サーミスタ素子１６とを備えている。 The sensor output amplifier circuit 200 includes a sensor 1, an operational amplifier 2, a first resistance element 13, a second resistance element 14, a first negative characteristic thermistor element 15, and a second negative characteristic thermistor element 16. .
　センサ１は、一端がグランドに接続され、他端がオペアンプ２のプラス入力端子に接続されている。 Sensor 1 has one end connected to the ground and the other end connected to the positive input terminal of operational amplifier 2.
　オペアンプ２のマイナス入力端子が、並列に接続された第１抵抗素子１３および第１負特性サーミスタ素子１５を介して、グランドに接続されている。 The negative input terminal of the operational amplifier 2 is connected to the ground via the first resistance element 13 and the first negative characteristic thermistor element 15 connected in parallel.
　また、オペアンプ２の出力端子と、オペアンプ２のマイナス入力端子との間に、直列に接続された第２抵抗素子１４および第２負特性サーミスタ素子１６が挿入されている。直列に接続された第２抵抗素子１４および第２負特性サーミスタ素子１６は、いわゆる帰還抵抗である。 Also, a second resistance element 14 and a second negative characteristic thermistor element 16 connected in series are inserted between the output terminal of the operational amplifier 2 and the negative input terminal of the operational amplifier 2. The second resistance element 14 and the second negative characteristic thermistor element 16 connected in series are so-called feedback resistors.
　センサ出力増幅回路２００は、上記のように接続された、オペアンプ２と、第１抵抗素子１３と、第１負特性サーミスタ素子１５と、第２抵抗素子１４と、第２負特性サーミスタ素子１６とで、非反転増幅回路１７が構成されている。 The sensor output amplifier circuit 200 includes the operational amplifier 2, the first resistance element 13, the first negative characteristic thermistor element 15, the second resistance element 14, and the second negative characteristic thermistor element 16 connected as described above. Thus, a non-inverting amplifier circuit 17 is configured.
　第１抵抗素子１３、第１負特性サーミスタ素子１５、第２抵抗素子１４、第２負特性サーミスタ素子１６、それぞれの抵抗値を、表２に示す。
Figure JPOXMLDOC01-appb-T000004
 Table 2 shows resistance values of the first resistance element 13, the first negative characteristic thermistor element 15, the second resistance element 14, and the second negative characteristic thermistor element 16.
Figure JPOXMLDOC01-appb-T000004
　非反転増幅回路１７においても、第１抵抗素子１３と第１負特性サーミスタ素子１５との合成抵抗値をＲＩとし、第２抵抗素子１４と第２負特性サーミスタ素子１６との合成抵抗値をＲＩＩとしたとき、入力電圧ＶＩＮと出力電圧ＶＯＵＴとは、（式１）の関係が成立する。
Figure JPOXMLDOC01-appb-M000005
 Even in the non-inverting amplifier circuit 17, a first resistive element 13 and the combined resistance value of the first negative temperature coefficient thermistor elements 15 and R I, a second resistive element 14 combined resistance value between the second negative temperature coefficient thermistor elements 16 when the R II, the input voltage V iN and the output voltage V OUT is established relationship (equation 1).
Figure JPOXMLDOC01-appb-M000005
　すなわち、入力電圧ＶＩＮは、（式２）の増幅率で増幅され、出力電圧ＶＯＵＴを出力する。
Figure JPOXMLDOC01-appb-M000006
 That is, the input voltage VIN is amplified with the amplification factor of (Equation 2) and outputs the output voltage VOUT .
Figure JPOXMLDOC01-appb-M000006
　センサ出力増幅回路２００は、たとえば、非反転増幅回路１７の、２０℃以上、３５℃以下の場合の増幅率を小さくし、２０℃未満の場合や３５℃を超えた場合の増幅率を大きくしている。そのために、センサ出力増幅回路２００は、第１負特性サーミスタ素子１５に、３５℃を超えた場合に抵抗値が大きな変化率で小さくなるものを使用し、第２負特性サーミスタ素子１６に、２０℃未満の場合に抵抗値が大きな変化率で大きくなるものを使用している。すなわち、ＲＩは、並列に接続された第１抵抗素子１３と第１負特性サーミスタ素子１５との合成抵抗値であり、かつ、増幅率を示す（式２）の中において「１」に加算される分数の分母に配置されているため、第１負特性サーミスタ素子１５に３５℃を超えた場合に抵抗値が大きな変化率で小さくなるものを使用することにより、３５℃を超えた場合の非反転増幅回路１７の増幅率が大きくなっている。また、ＲＩＩは、直列に接続された第２抵抗素子１４と第２負特性サーミスタ素子１６との合成抵抗値であり、かつ、増幅率を示す（式２）の中において「１」に加算される分数の分子に配置されているため、第２負特性サーミスタ素子１６に２０℃未満の場合に抵抗値が大きな変化率で大きくなるものを使用することにより、２０℃未満の場合の非反転増幅回路１７の増幅率が大きくなっている。 For example, the sensor output amplifier circuit 200 reduces the amplification factor of the non-inverting amplifier circuit 17 when the temperature is 20 ° C. or higher and 35 ° C. or lower, and increases the gain when the temperature is lower than 20 ° C. or exceeds 35 ° C. ing. Therefore, the sensor output amplifying circuit 200 uses a first negative characteristic thermistor element 15 having a resistance value that decreases with a large change rate when the temperature exceeds 35 ° C., and a second negative characteristic thermistor element 16 has a 20 When the temperature is lower than 0 ° C., the resistance value increases with a large change rate. That, R I is a first resistance element 13 connected in parallel are combined resistance value of the first negative temperature coefficient thermistor elements 15, and adds "1" in in the shows amplification factor (Equation 2) Since the first negative characteristic thermistor element 15 has a resistance value that decreases with a large change rate when the temperature exceeds 35 ° C., the first negative characteristic thermistor element 15 has a large change rate. The amplification factor of the non-inverting amplifier circuit 17 is large. R II is a combined resistance value of the second resistance element 14 and the second negative characteristic thermistor element 16 connected in series, and is added to “1” in (Expression 2) indicating the amplification factor. Since the second negative characteristic thermistor element 16 has a resistance value that increases with a large change rate when the temperature is less than 20 ° C., non-inversion when the temperature is less than 20 ° C. The amplification factor of the amplifier circuit 17 is large.
　以上のように、センサ出力増幅回路２００は、非反転増幅回路１７の増幅特性が谷型の温度特性を持っている。 As described above, in the sensor output amplifier circuit 200, the amplification characteristic of the non-inverting amplifier circuit 17 has a valley-type temperature characteristic.
　［第３実施形態］
　図４に、第３実施形態にかかるセンサ出力増幅回路３００を示す。ただし、図４は、センサ出力増幅回路３００の等価回路図である。 [Third Embodiment]
FIG. 4 shows a sensor output amplifier circuit 300 according to the third embodiment. FIG. 4 is an equivalent circuit diagram of the sensor output amplifier circuit 300.
　上述した第１実施形態、第２実施形態にかかるセンサ出力増幅回路１００、２００は、非反転増幅回路７、１７を備えていた。これに対し、第３実施形態にかかるセンサ出力増幅回路３００は、非反転増幅回路に代えて、反転増幅回路２７を備えている。そして、センサ出力増幅回路３００の反転増幅回路２７の増幅特性が、山型の温度特性を持っている。 The sensor output amplifier circuits 100 and 200 according to the first and second embodiments described above were provided with non-inverting amplifier circuits 7 and 17, respectively. In contrast, the sensor output amplifier circuit 300 according to the third embodiment includes an inverting amplifier circuit 27 instead of the non-inverting amplifier circuit. The amplification characteristic of the inverting amplification circuit 27 of the sensor output amplification circuit 300 has a mountain-shaped temperature characteristic.
　センサ出力増幅回路３００は、センサ１と、オペアンプ２と、第１抵抗素子２３と、第２抵抗素子２４と、第１負特性サーミスタ素子２５と、第２負特性サーミスタ素子２６とを備えている。 The sensor output amplifier circuit 300 includes a sensor 1, an operational amplifier 2, a first resistance element 23, a second resistance element 24, a first negative characteristic thermistor element 25, and a second negative characteristic thermistor element 26. .
　センサ１は、一端がグランドに接続され、他端が、直列に接続された第１抵抗素子２３および第１負特性サーミスタ素子２５を介して、オペアンプ２のマイナス入力端子に接続されている。 The sensor 1 has one end connected to the ground and the other end connected to the negative input terminal of the operational amplifier 2 via a first resistance element 23 and a first negative characteristic thermistor element 25 connected in series.
　オペアンプ２のプラス入力端子が、グランドに接続されている。 The positive input terminal of operational amplifier 2 is connected to ground.
　また、オペアンプ２の出力端子と、オペアンプ２のマイナス入力端子との間に、並列に接続された第２抵抗素子２４および第２負特性サーミスタ素子２６が挿入されている。並列に接続された第２抵抗素子２４および第２負特性サーミスタ素子２６は、いわゆる帰還抵抗である。 Also, a second resistance element 24 and a second negative characteristic thermistor element 26 connected in parallel are inserted between the output terminal of the operational amplifier 2 and the negative input terminal of the operational amplifier 2. The second resistance element 24 and the second negative characteristic thermistor element 26 connected in parallel are so-called feedback resistors.
　センサ出力増幅回路３００は、上記のように接続された、オペアンプ２と、第１抵抗素子２３と、第１負特性サーミスタ素子２５と、第２抵抗素子２４と、第２負特性サーミスタ素子２６とで、反転増幅回路２７が構成されている。 The sensor output amplifier circuit 300 includes the operational amplifier 2, the first resistance element 23, the first negative characteristic thermistor element 25, the second resistance element 24, and the second negative characteristic thermistor element 26 connected as described above. Thus, an inverting amplifier circuit 27 is configured.
　第１抵抗素子２３、第１負特性サーミスタ素子２５、第２抵抗素子２４、第２負特性サーミスタ素子２６、それぞれの抵抗値を、表３に示す。
Figure JPOXMLDOC01-appb-T000007
 Table 3 shows resistance values of the first resistance element 23, the first negative characteristic thermistor element 25, the second resistance element 24, and the second negative characteristic thermistor element 26.
Figure JPOXMLDOC01-appb-T000007
　反転増幅回路２７は、第１抵抗素子２３と第１負特性サーミスタ素子２５との合成抵抗値をＲＩとし、第２抵抗素子２４と第２負特性サーミスタ素子２６との合成抵抗値をＲIIとしたとき、入力電圧ＶＩＮと出力電圧ＶＯＵＴとは、次の（式３）の関係が成立する。
Figure JPOXMLDOC01-appb-M000008
 Inverting amplifier circuit 27 includes a first resistive element 23 combined resistance value of the first negative temperature coefficient thermistor elements 25 and R I, a second resistive element 24 and the combined resistance value of the second negative temperature coefficient thermistor elements 26 R II Then, the relationship of the following (Formula 3) is established between the input voltage V IN and the output voltage V OUT .
Figure JPOXMLDOC01-appb-M000008
　すなわち、入力電圧ＶＩＮは、次の（式４）の増幅率で増幅され、出力電圧ＶＯＵＴを出力する。
Figure JPOXMLDOC01-appb-M000009
 That is, the input voltage VIN is amplified with the following amplification factor (Equation 4), and the output voltage VOUT is output.
Figure JPOXMLDOC01-appb-M000009
　センサ出力増幅回路３００は、たとえば、反転増幅回路２７の、２０℃以上、３５℃以下の場合の増幅率を大きくし、２０℃未満の場合や３５℃を超えた場合の増幅率を小さくしている。そのために、センサ出力増幅回路３００は、第１負特性サーミスタ素子２５に、２０℃未満の場合に抵抗値が大きな変化率で大きくなるものを使用し、第２負特性サーミスタ素子２６に、３５℃を超えた場合に抵抗値が大きな変化率で小さくなるものを使用している。すなわち、ＲIは、直列に接続された第１抵抗素子２３と第１負特性サーミスタ素子２５との合成抵抗値であり、かつ、増幅率を示す（式４）を構成する分数の分母に配置されているため、第１負特性サーミスタ素子２５に２０℃未満の場合に抵抗値が大きな変化率で大きくなるものを使用することにより、２０℃未満の場合の反転増幅回路２７の増幅率が小さくなっている。また、ＲIIは、並列に接続された第２抵抗素子２４と第２負特性サーミスタ素子２６との合成抵抗値であり、かつ、増幅率を示す（式４）を構成する分数の分子に配置されているため、第２負特性サーミスタ素子２６に３５℃を超えた場合に抵抗値が大きな変化率で小さくなるものを使用することにより、３５℃を超えた場合の反転増幅回路２７の増幅率が小さくなっている。 For example, the sensor output amplifier circuit 300 increases the amplification factor of the inverting amplifier circuit 27 when the temperature is 20 ° C. or higher and 35 ° C. or lower, and decreases the gain when the temperature is lower than 20 ° C. or exceeds 35 ° C. Yes. Therefore, the sensor output amplifier circuit 300 uses the first negative characteristic thermistor element 25 whose resistance value increases at a large change rate when the temperature is less than 20 ° C., and the second negative characteristic thermistor element 26 has a 35 ° C. When the value exceeds the value, the resistance value becomes smaller with a large change rate. That is, R I is the combined resistance value of the first resistance element 23 and the first negative characteristic thermistor element 25 connected in series, and is arranged in the denominator of the fraction constituting (Equation 4) indicating the amplification factor. Therefore, when the first negative characteristic thermistor element 25 has a resistance value that increases with a large change rate when the temperature is less than 20 ° C., the gain of the inverting amplifier circuit 27 when the temperature is less than 20 ° C. is small. It has become. Also, R II includes a second resistor element 24 connected in parallel are combined resistance value between the second negative temperature coefficient thermistor elements 26, and, arranged in the numerator of the fraction constituting shows amplification factor (formula 4) Therefore, when the second negative characteristic thermistor element 26 has a resistance value that decreases with a large change rate when the temperature exceeds 35 ° C., the gain of the inverting amplifier circuit 27 when the temperature exceeds 35 ° C. Is getting smaller.
　以上のように、センサ出力増幅回路３００は、反転増幅回路２７の増幅特性が山型の温度特性を持っている。 As described above, in the sensor output amplifier circuit 300, the amplification characteristic of the inverting amplifier circuit 27 has a mountain-shaped temperature characteristic.
　［第４実施形態］
　図５に、第４実施形態にかかるセンサ出力増幅回路４００を示す。ただし、図５は、センサ出力増幅回路４００の等価回路図である。 [Fourth Embodiment]
FIG. 5 shows a sensor output amplifier circuit 400 according to the fourth embodiment. FIG. 5 is an equivalent circuit diagram of the sensor output amplifier circuit 400.
　第４実施形態にかかるセンサ出力増幅回路４００は、上述した第３実施形態にかかるセンサ出力増幅回路３００と同様に、反転増幅回路３７を備えている。しかしながら、センサ出力増幅回路４００の反転増幅回路３７の増幅特性は、センサ出力増幅回路３００とは異なり、谷型の温度特性を持っている。 The sensor output amplifier circuit 400 according to the fourth embodiment includes an inverting amplifier circuit 37 as in the sensor output amplifier circuit 300 according to the third embodiment described above. However, unlike the sensor output amplifier circuit 300, the amplification characteristic of the inverting amplifier circuit 37 of the sensor output amplifier circuit 400 has a valley-type temperature characteristic.
　センサ出力増幅回路４００は、センサ１と、オペアンプ２と、第１抵抗素子３３と、第２抵抗素子３４と、第１負特性サーミスタ素子３５と、第２負特性サーミスタ素子３６とを備えている。 The sensor output amplifier circuit 400 includes the sensor 1, the operational amplifier 2, the first resistance element 33, the second resistance element 34, the first negative characteristic thermistor element 35, and the second negative characteristic thermistor element 36. .
　センサ１は、一端がグランドに接続され、他端が、並列に接続された第１抵抗素子３３および第１負特性サーミスタ素子３５を介して、オペアンプ２のプラス入力端子に接続されている。 The sensor 1 has one end connected to the ground and the other end connected to the positive input terminal of the operational amplifier 2 via a first resistance element 33 and a first negative characteristic thermistor element 35 connected in parallel.
　オペアンプ２のプラス入力端子が、グランドに接続されている。 The positive input terminal of operational amplifier 2 is connected to ground.
　また、オペアンプ２の出力端子と、オペアンプ２のマイナス入力端子との間に、直列に接続された第２抵抗素子３４および第２負特性サーミスタ素子３６が挿入されている。直列に接続された第２抵抗素子３４および第２負特性サーミスタ素子３６は、いわゆる帰還抵抗である。 Also, a second resistance element 34 and a second negative characteristic thermistor element 36 connected in series are inserted between the output terminal of the operational amplifier 2 and the negative input terminal of the operational amplifier 2. The second resistance element 34 and the second negative characteristic thermistor element 36 connected in series are so-called feedback resistors.
　センサ出力増幅回路４００は、上記のように接続された、オペアンプ２と、第１抵抗素子３３と、第１負特性サーミスタ素子３５と、第２抵抗素子３４と、第２負特性サーミスタ素子３６とで、反転増幅回路３７が構成されている。 The sensor output amplifier circuit 400 includes the operational amplifier 2, the first resistance element 33, the first negative characteristic thermistor element 35, the second resistance element 34, and the second negative characteristic thermistor element 36 connected as described above. Thus, an inverting amplifier circuit 37 is configured.
　第１抵抗素子３３、第１負特性サーミスタ素子３５、第２抵抗素子３４、第２負特性サーミスタ素子３６、それぞれの抵抗値を、表４に示す。
Figure JPOXMLDOC01-appb-T000010
 Table 4 shows resistance values of the first resistance element 33, the first negative characteristic thermistor element 35, the second resistance element 34, and the second negative characteristic thermistor element 36.
Figure JPOXMLDOC01-appb-T000010
　反転増幅回路３７においても、第１抵抗素子３３と第１負特性サーミスタ素子３５との合成抵抗値をＲIとし、第２抵抗素子３４と第２負特性サーミスタ素子３６との合成抵抗値をＲIIとしたとき、入力電圧ＶＩＮと出力電圧ＶＯＵＴとは、（式３）の関係が成立する。
Figure JPOXMLDOC01-appb-M000011
 Also in the inverting amplifier circuit 37, the combined resistance value of the first resistance element 33 and the first negative characteristic thermistor element 35 is R I , and the combined resistance value of the second resistance element 34 and the second negative characteristic thermistor element 36 is R When II is set, the relationship of (Equation 3) is established between the input voltage V IN and the output voltage V OUT .
Figure JPOXMLDOC01-appb-M000011
　すなわち、入力電圧ＶＩＮは、（式４）の増幅率で増幅され、出力電圧ＶＯＵＴを出力する。
Figure JPOXMLDOC01-appb-M000012
 That is, the input voltage VIN is amplified with the amplification factor of (Equation 4) and outputs the output voltage VOUT .
Figure JPOXMLDOC01-appb-M000012
　センサ出力増幅回路４００は、たとえば、反転増幅回路３７の、２０℃以上、３５℃以下の場合の増幅率を小さくし、２０℃未満の場合や３５℃を超えた場合の増幅率を大きくしている。そのために、センサ出力増幅回路４００は、第１負特性サーミスタ素子３５に、３５℃を超えた場合に抵抗値が大きな変化率で小さくなるものを使用し、第２負特性サーミスタ素子３６に、２０℃未満の場合に抵抗値が大きな変化率で大きくなるものを使用している。すなわち、ＲIは、並列に接続された第１抵抗素子３３と第１負特性サーミスタ素子３５との合成抵抗値であり、かつ、増幅率を示す（式４）を構成する分数の分母に配置されているため、第１負特性サーミスタ素子３５に３５℃を超えた場合に抵抗値が大きな変化率で小さくなるものを使用することにより、３５℃を超えた場合の反転増幅回路３７の増幅率が大きくなっている。また、ＲIIは、直列に接続された第２抵抗素子３４と第２負特性サーミスタ素子３６との合成抵抗値であり、かつ、増幅率を示す（式４）を構成する分数の分子に配置されているため、第２負特性サーミスタ素子３６に２０℃未満の場合に抵抗値が大きな変化率で大きくなるものを使用することにより、２０℃未満の場合の反転増幅回路３７の増幅率が大きくなっている。 For example, the sensor output amplifier circuit 400 reduces the amplification factor of the inverting amplifier circuit 37 when the temperature is 20 ° C. or higher and 35 ° C. or lower, and increases the gain when the temperature is lower than 20 ° C. or exceeds 35 ° C. Yes. Therefore, the sensor output amplifying circuit 400 uses the first negative characteristic thermistor element 35 having a resistance value that decreases with a large change rate when the temperature exceeds 35 ° C., and the second negative characteristic thermistor element 36 has a 20 When the temperature is lower than 0 ° C., the resistance value increases with a large change rate. That is, R I is a combined resistance value of the first resistance element 33 and the first negative characteristic thermistor element 35 connected in parallel, and is arranged in the denominator of the fraction constituting (Equation 4) indicating the amplification factor. Therefore, when the first negative characteristic thermistor element 35 has a resistance value that decreases with a large change rate when the temperature exceeds 35 ° C., the gain of the inverting amplifier circuit 37 when the temperature exceeds 35 ° C. Is getting bigger. R II is a combined resistance value of the second resistance element 34 and the second negative characteristic thermistor element 36 connected in series, and is arranged in a fractional numerator constituting (Equation 4) indicating the amplification factor. Therefore, by using the second negative characteristic thermistor element 36 whose resistance value increases at a large change rate when it is less than 20 ° C., the amplification factor of the inverting amplifier circuit 37 when it is less than 20 ° C. is large. It has become.
　以上のように、センサ出力増幅回路４００は、反転増幅回路３７の増幅特性が谷型の温度特性を持っている。 As described above, in the sensor output amplifier circuit 400, the inverting amplifier circuit 37 has a valley-type temperature characteristic.
　［第５実施形態］
　図６に、第５実施形態にかかるセンサ出力増幅回路５００を示す。ただし、図６は、センサ出力増幅回路５００の等価回路図である。 [Fifth Embodiment]
FIG. 6 shows a sensor output amplifier circuit 500 according to the fifth embodiment. However, FIG. 6 is an equivalent circuit diagram of the sensor output amplifier circuit 500.
　第５実施形態にかかるセンサ出力増幅回路５００は、上述した第１実施形態にかかるセンサ出力増幅回路１００に構成を追加した。具体的には、直列に接続された第１抵抗素子３および第１負特性サーミスタ素子５と直列に、さらに第１キャパシタ４８を接続した。また、並列に接続された第２抵抗素子４および第２負特性サーミスタ素子６と並列に、さらに第２キャパシタ４９を接続した。 The sensor output amplifier circuit 500 according to the fifth embodiment has a configuration added to the sensor output amplifier circuit 100 according to the first embodiment described above. Specifically, a first capacitor 48 was further connected in series with the first resistance element 3 and the first negative characteristic thermistor element 5 connected in series. In addition, a second capacitor 49 was further connected in parallel with the second resistance element 4 and the second negative characteristic thermistor element 6 connected in parallel.
　センサ出力増幅回路５００においては、直列に接続された第１抵抗素子３と、第１負特性サーミスタ素子５と、第１キャパシタ４８とでハイパスフィルタが構成され、非反転増幅回路７の出力から低周波ノイズが除去されている。 In the sensor output amplifier circuit 500, the first resistance element 3, the first negative characteristic thermistor element 5 and the first capacitor 48 connected in series form a high-pass filter, and the output from the non-inverting amplifier circuit 7 is low. Frequency noise has been removed.
　また、センサ出力増幅回路５００においては、並列に接続された第２抵抗素子４と、第２負特性サーミスタ素子６と、第２キャパシタ４９とでローパスフィルタが構成され、非反転増幅回路７の出力から高周波ノイズが除去されている。 In the sensor output amplifier circuit 500, the second resistance element 4, the second negative characteristic thermistor element 6, and the second capacitor 49 connected in parallel form a low-pass filter, and the output of the non-inverting amplifier circuit 7. High frequency noise has been removed from
　なお、上述した第２実施形態にかかるセンサ出力増幅回路２００も、上記の方法を応用することにより、ハイパスフィルタとローパスフィルタとを付加することがきる。 Note that the sensor output amplifier circuit 200 according to the second embodiment described above can also add a high-pass filter and a low-pass filter by applying the above method.
　［第６実施形態］
　図７に、第６実施形態にかかるセンサ出力増幅回路６００を示す。ただし、図６は、センサ出力増幅回路６００の等価回路図である。 [Sixth Embodiment]
FIG. 7 shows a sensor output amplifier circuit 600 according to the sixth embodiment. FIG. 6 is an equivalent circuit diagram of the sensor output amplifier circuit 600.
　第６実施形態にかかるセンサ出力増幅回路６００は、上述した第３実施形態にかかるセンサ出力増幅回路３００に構成を追加した。具体的には、並列に接続された第２抵抗素子２４および第２負特性サーミスタ素子２６と並列に、さらにキャパシタ５９を接続した。 The sensor output amplifier circuit 600 according to the sixth embodiment has a configuration added to the sensor output amplifier circuit 300 according to the third embodiment described above. Specifically, a capacitor 59 was further connected in parallel with the second resistance element 24 and the second negative characteristic thermistor element 26 connected in parallel.
　センサ出力増幅回路６００においては、並列に接続された第２抵抗素子２４と、第２負特性サーミスタ素子２６と、キャパシタ５９とでローパスフィルタが構成され、反転増幅回路２７の出力から高周波ノイズが除去されている。 In the sensor output amplifier circuit 600, the second resistance element 24, the second negative characteristic thermistor element 26, and the capacitor 59 connected in parallel form a low-pass filter, and high frequency noise is removed from the output of the inverting amplifier circuit 27. Has been.
　なお、上述した第４実施形態にかかるセンサ出力増幅回路４００も、上記の方法を応用することにより、ローパスフィルタを付加することがきる。 Note that the sensor output amplifier circuit 400 according to the above-described fourth embodiment can also be added with a low-pass filter by applying the above method.
　以上、第１実施形態～第６実施形態にかかるセンサ出力増幅回路１００、２００、３００、４００、５００、６００について説明した。しかしながら、本発明が上述した内容に限定されることはなく、発明の趣旨に沿って種々の変更をなしことができる。 The sensor output amplifier circuits 100, 200, 300, 400, 500, 600 according to the first to sixth embodiments have been described above. However, the present invention is not limited to the contents described above, and various modifications can be made in accordance with the spirit of the invention.
　たとえば、センサ出力増幅回路１００、２００、３００、４００、５００、６００では、センサ１に焦電センサ素子を使用したが、センサ１の種類は任意であり、たとえば、赤外線分光センサ、熱電変換素子などであっても良い。 For example, in the sensor output amplification circuits 100, 200, 300, 400, 500, and 600, pyroelectric sensor elements are used for the sensor 1, but the type of the sensor 1 is arbitrary, for example, an infrared spectroscopic sensor, a thermoelectric conversion element, or the like. It may be.
　また、第１抵抗素子３、１３、２３、３３、第２抵抗素子４、１４、２４、３４、第１負特性サーミスタ素子５、１５、２５、３５、第２負特性サーミスタ素子６、１６、２６、３６の抵抗値も任意であり、増幅特性に待たせる所望の温度特性によって、抵抗値を選定することができる。 Further, the first resistance elements 3, 13, 23, 33, the second resistance elements 4, 14, 24, 34, the first negative characteristic thermistor elements 5, 15, 25, 35, the second negative characteristic thermistor elements 6, 16, The resistance values of 26 and 36 are also arbitrary, and the resistance values can be selected according to desired temperature characteristics that await the amplification characteristics.
１・・・センサ
２・・・オペアンプ
３、１３、２３、３３・・・第１抵抗素子
４、１４、２４、３４・・・第２抵抗素子
５、１５、２５、３５・・・第１負特性サーミスタ素子
６、１６、２６、３６・・・第２負特性サーミスタ素子
７、１７・・・非反転増幅回路
２７、３７・・・反転増幅回路
４８・・・第１キャパシタ素子
４９・・・第２キャパシタ素子
５９・・・キャパシタ素子
１００、２００、３００、４００、５００、６００・・・センサ出力増幅回路 DESCRIPTION OF SYMBOLS 1 ... Sensor 2 ... Operational amplifier 3, 13, 23, 33 ... 1st resistance element 4, 14, 24, 34 ... 2nd resistance element 5, 15, 25, 35 ... 1st Negative characteristic thermistor elements 6, 16, 26, 36 ... second negative characteristic thermistor elements 7, 17 ... non-inverting amplifier circuit 27, 37 ... inverting amplifier circuit 48 ... first capacitor element 49 ... Second capacitor element 59: Capacitor element 100, 200, 300, 400, 500, 600 ... Sensor output amplifier circuit

Claims (9)

  1. 　センサと、
    　プラス入力端子とマイナス入力端子と出力端子とを備えたオペアンプと、
    　第１抵抗素子と、
    　第２抵抗素子と、を備え、
    　前記オペアンプと、前記第１抵抗素子と、前記第２抵抗素子とで、非反転増幅回路、または、反転増幅回路が構成され、
    　前記第１抵抗素子と直列または並列に第１負特性サーミスタ素子が接続され、
    　前記第２抵抗素子と並列または直列に第２負特性サーミスタ素子が接続され、
    　前記非反転増幅回路または前記反転増幅回路の増幅特性に、温度特性を持たせたセンサ出力増幅回路。     A sensor,
    An operational amplifier having a positive input terminal, a negative input terminal, and an output terminal;
    A first resistance element;
    A second resistance element,
    The operational amplifier, the first resistance element, and the second resistance element constitute a non-inverting amplifier circuit or an inverting amplifier circuit.
    A first negative characteristic thermistor element is connected in series or in parallel with the first resistance element,
    A second negative temperature coefficient thermistor element is connected in parallel or in series with the second resistance element;
    A sensor output amplifier circuit in which the non-inverting amplifier circuit or the inverting amplifier circuit has a temperature characteristic as an amplification characteristic.
  2. 　前記センサの出力が、前記プラス入力端子に接続され、
    　前記マイナス入力端子とグランドとの間に、前記第１抵抗素子が挿入され、
    　前記出力端子と前記マイナス入力端子との間に、前記第２抵抗素子が挿入されて、非反転増幅回路が構成され、
    　前記第１抵抗素子と直列に第１負特性サーミスタ素子が接続され、
    　前記第２抵抗素子と並列に第２負特性サーミスタ素子が接続された、請求項１に記載されたセンサ出力増幅回路。     The output of the sensor is connected to the positive input terminal,
    The first resistance element is inserted between the negative input terminal and the ground,
    The second resistance element is inserted between the output terminal and the negative input terminal to constitute a non-inverting amplifier circuit,
    A first negative characteristic thermistor element is connected in series with the first resistance element,
    The sensor output amplification circuit according to claim 1, wherein a second negative characteristic thermistor element is connected in parallel with the second resistance element.
  3. 　前記センサの出力が、前記プラス入力端子に接続され、
    　前記マイナス入力端子とグランドとの間に、前記第１抵抗素子が挿入され、
    　前記出力端子と前記マイナス入力端子との間に、前記第２抵抗素子が挿入されて、非反転増幅回路が構成され、
    　前記第１抵抗素子と並列に第１負特性サーミスタ素子が接続され、
    　前記第２抵抗素子と直列に第２負特性サーミスタ素子が接続された、請求項１に記載されたセンサ出力増幅回路。     The output of the sensor is connected to the positive input terminal,
    The first resistance element is inserted between the negative input terminal and the ground,
    The second resistance element is inserted between the output terminal and the negative input terminal to constitute a non-inverting amplifier circuit,
    A first negative characteristic thermistor element is connected in parallel with the first resistance element,
    The sensor output amplifier circuit according to claim 1, wherein a second negative characteristic thermistor element is connected in series with the second resistance element.
  4. 　直列に接続された前記第１抵抗素子と前記第１負特性サーミスタ素子、または、並列に接続された前記第１抵抗素子と前記第１負特性サーミスタ素子と、直列に、第１キャパシタ素子が接続された、請求項２または３に記載されたセンサ出力増幅回路。 The first capacitor element is connected in series with the first resistor element and the first negative characteristic thermistor element connected in series, or the first resistor element and the first negative characteristic thermistor element connected in parallel. The sensor output amplifier circuit according to claim 2 or 3.
  5. 　並列に接続された前記第２抵抗素子と前記第２負特性サーミスタ素子、または、直列に接続された前記第２抵抗素子と前記第２負特性サーミスタ素子と、並列に、第２キャパシタ素子が接続された、請求項２ないし４のいずれか１項に記載されたセンサ出力増幅回路。 A second capacitor element is connected in parallel with the second resistance element and the second negative characteristic thermistor element connected in parallel, or the second resistance element and the second negative characteristic thermistor element connected in series. The sensor output amplifier circuit according to any one of claims 2 to 4.
  6. 　前記センサの出力が、前記第１抵抗素子を介したうえで、前記マイナス入力端子に接続され、
    　前記プラス入力端子がグランドに接続され、
    　前記出力端子と前記マイナス入力端子との間に、前記第２抵抗素子が挿入されて、反転増幅回路が構成され、
    　前記第１抵抗素子と直列に第１負特性サーミスタ素子が接続され、
    　前記第２抵抗素子と並列に第２負特性サーミスタ素子が接続された、請求項１に記載されたセンサ出力増幅回路。     The output of the sensor is connected to the negative input terminal via the first resistance element,
    The positive input terminal is connected to ground,
    The second resistance element is inserted between the output terminal and the negative input terminal to constitute an inverting amplifier circuit,
    A first negative characteristic thermistor element is connected in series with the first resistance element,
    The sensor output amplification circuit according to claim 1, wherein a second negative characteristic thermistor element is connected in parallel with the second resistance element.
  7. 　前記センサの出力が、前記第１抵抗素子を介したうえで、前記マイナス入力端子に接続され、
    　前記プラス入力端子がグランドに接続され、
    　前記出力端子と前記マイナス入力端子との間に、前記第２抵抗素子が挿入されて、反転増幅回路が構成され、
    　前記第１抵抗素子と並列に第１負特性サーミスタ素子が接続され、
    　前記第２抵抗素子と直列に第２負特性サーミスタ素子が接続された、請求項１に記載されたセンサ出力増幅回路。     The output of the sensor is connected to the negative input terminal via the first resistance element,
    The positive input terminal is connected to ground,
    The second resistance element is inserted between the output terminal and the negative input terminal to constitute an inverting amplifier circuit,
    A first negative characteristic thermistor element is connected in parallel with the first resistance element,
    The sensor output amplifier circuit according to claim 1, wherein a second negative characteristic thermistor element is connected in series with the second resistance element.
  8. 　並列に接続された前記第２抵抗素子と前記第２負特性サーミスタ素子、または、直列に接続された前記第２抵抗素子と前記第２負特性サーミスタ素子と、並列に、キャパシタ素子が接続された、請求項６または７のいずれか１項に記載されたセンサ出力増幅回路。 A capacitor element is connected in parallel with the second resistance element and the second negative characteristic thermistor element connected in parallel, or the second resistance element and the second negative characteristic thermistor element connected in series. 8. A sensor output amplifying circuit according to claim 6 or 7.
  9. 　前記センサが、焦電センサ素子、赤外線分光センサ、熱電変換素子のいずれかである、請求項１ないし８のいずれか１項に記載されたセンサ出力増幅回路。 The sensor output amplifier circuit according to any one of claims 1 to 8, wherein the sensor is any one of a pyroelectric sensor element, an infrared spectroscopic sensor, and a thermoelectric conversion element.
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