JP2013195085A - Anemometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anemometer using a thermocouple at low costs.SOLUTION: An anemometer 1 is provided with: a thermocouple 5; a heater; an integration circuit 11 for integrating a signal in accordance with an electromotive force from the thermocouple 5; an amplifier circuit 12 for amplifying output of the integration circuit 11; a comparison circuit 13 for outputting a reset signal which returns the integration circuit 11 to a fixed state when output of the amplifier circuit 12 is over a reference value; and a counter circuit 15 for measuring wind velocity on the basis of intervals at which the reset signal is outputted.

Description

  The present invention relates to an anemometer, and more particularly to an anemometer using a thermocouple.

  As a method for measuring the wind direction and the wind speed, for example, a method using a thermocouple as in Patent Document 1 is known. In invention of patent document 1, the temperature difference according to a wind speed is produced on a printed circuit board by heating surrounding air using a heating wire. Since the thermocouple formed on the printed circuit board generates an electromotive force according to the temperature difference between the terminals, the wind direction is measured by detecting the electromotive force. The air volume is measured using a thermistor.

  However, in the invention of Patent Document 1, it is necessary to secure a large area on the printed circuit board in order to form a heating wire (or heater), a thermocouple, and a thermistor.

  Therefore, a method has been proposed in which a thermocouple and a heater are formed inside the IC chip to reduce the area necessary for measuring the wind direction and the wind speed.

  FIG. 4A is a cross-sectional view showing a configuration of a conventional anemometer 101. The anemometer 101 is configured by adhering an IC chip 103 to the back surface of a ceramic disk 102 and sealing the IC chip 103 with a resin 104. When the surface of the ceramic disk 102 is cooled by wind, the temperature distribution on the surface of the ceramic disk 102 changes. By measuring the temperature distribution with the IC chip 103, the wind direction anemometer 101 measures the wind direction and the wind speed.

  More specifically, as shown in FIG. 4B, the IC chip 103 includes a thermocouple 105, a heater 106, and a measurement circuit unit 110. The thermocouple 105 and the heater 106 are formed on each side of the IC chip 103. By heating the surrounding air with the heater 106, a temperature difference corresponding to the wind speed is generated on the back surface of the ceramic disk 102. Thereby, a difference arises in each electromotive force of the thermocouple 105 facing in the lateral direction, and the wind direction anemometer 101 can measure the wind speed by measuring the difference in the electromotive force by the measurement circuit unit 110. Moreover, the wind direction anemometer 101 can also measure a wind direction by measuring the difference of each electromotive force of the thermocouple 105 which faces the vertical direction by the measurement circuit unit 110.

  As shown in FIG. 5, the measurement circuit unit 110 of the IC chip 103 includes a comparator 111 and a latch circuit 112. The comparator 111 detects the difference in electromotive force of the thermocouple 105, and the latch circuit 112 holds the result. The comparator 111 is realized by a preamplifier using an offset removal function. The output of the latch circuit 112 is connected to the heater 106 inside the IC chip 103, and the measurement circuit unit 110 controls the heater 106 so that the temperature difference between the terminals of the thermocouple 105 becomes zero. Since the output of the latch circuit 112 is 0 or 1 serial data, it is leveled by the filter circuit 120 provided outside the IC chip 103 and read as wind speed.

JP 2008-241318 A (released on October 9, 2008)

  Since the conventional anemometer 101 is configured to detect a weak electromotive force difference from the thermocouple 105 with the comparator 111, the measurement sensitivity is low. Therefore, it is necessary to provide the IC chip 103 on a plate having high thermal conductivity such as the ceramic disk 102. Since the ceramic disk 102 is expensive, and it is necessary to pour the resin 104 after bonding the IC chip 103 to the ceramic disk 102, the anemometer 101 is difficult to mass-produce. For this reason, the anemometer 101 has a problem that it costs more than when the IC chip 103 is mounted on a printed circuit board.

  Further, the anemometer 101 requires a filter circuit 120 that equalizes the output of the latch circuit 112. However, since the filter circuit 120 is large in size and easily generates heat, it is usually necessary to provide the filter circuit 120 outside the IC chip 103. For this reason, there is a problem in that the implementation of the filter circuit 120 is costly.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an anemometer using a thermocouple at a low cost.

  In order to solve the above problems, an anemometer according to the present invention is an anemometer including a thermocouple that generates an electromotive force due to a temperature difference between two terminals, and a heater that generates heat, An integration circuit that integrates a signal according to an electromotive force from a thermocouple, and the output of the integration circuit is compared with a reference value, and when the output of the integration circuit exceeds the reference value, the integration circuit is set to a predetermined value. A comparison circuit that outputs a reset signal for returning to a state and a measurement circuit that measures a wind speed based on an interval at which the reset signal is output are provided.

  According to said structure, the temperature difference according to a wind speed arises between the two terminals of a thermocouple with the heat which a heater generate | occur | produces, and a thermocouple generates an electromotive force. Further, the integration circuit integrates a signal corresponding to the electromotive force from the thermocouple, and when the output of the integration circuit exceeds the reference value, the comparison circuit outputs a reset signal. The greater the electromotive force from the thermocouple, the shorter the interval at which the reset signal is output, so the measurement circuit can measure the wind speed based on the interval at which the reset signal is output. Therefore, even if the electromotive force from the thermocouple is small, the wind speed can be measured accurately. Therefore, it is not necessary to mount a thermocouple or heater on a ceramic disk having high thermal conductivity. Therefore, an anemometer using a thermocouple can be provided at low cost.

  The anemometer according to the present invention further includes an amplification circuit that amplifies the output of the integration circuit, and the comparison circuit compares the output of the integration circuit amplified by the amplification circuit with the reference value and performs amplification. The reset signal is preferably output when the output of the integration circuit exceeds the reference value.

  According to the above configuration, since the output of the integration circuit is amplified by the amplification circuit, the interval at which the reset signal is output is shortened. For this reason, when a counter circuit is used as a measurement circuit, the counter circuit is less likely to be saturated and measurement is facilitated.

  In the anemometer according to the present invention, the amplification factor of the amplifier circuit is preferably variable.

  In the anemometer according to the present invention, it is preferable that the integration time of the integration circuit is variable.

  According to the above configuration, instantaneous wind speed measurement and average wind speed measurement can be realized by using the same integration circuit and amplification circuit.

  In the anemometer according to the present invention, it is preferable that the measurement circuit includes an oscillation circuit that generates a clock signal and a counter circuit that counts the clock signal at intervals at which the reset signal is output.

  According to the above configuration, since the interval at which the reset signal is output is obtained from the frequency of the clock signal and the count number of the counter circuit at the interval at which the reset signal is output, the wind speed can be measured.

  Preferably, the anemometer according to the present invention further includes a register circuit, and the counter circuit is returned to a predetermined state when the reset signal is output, and outputs the count number to the register circuit.

  According to the above configuration, the counter circuit is returned to a predetermined state by the reset signal, so that a counter circuit with a small number of bits can be used.

  The anemometer according to the present invention preferably includes frequency adjusting means for adjusting the frequency of the clock signal.

  According to said structure, the measurement precision of an anemometer can be changed by changing the frequency of a clock signal.

  In the anemometer according to the present invention, it is preferable that the frequency adjusting means adjusts the frequency of the clock signal according to a temperature difference between terminals of the thermocouple.

  The smaller the temperature difference between the thermocouple terminals, the longer the output interval of the reset signal. Therefore, the counter circuit can be prevented from being saturated by slowing the frequency of the clock signal by the frequency adjusting means.

  In the anemometer according to the present invention, it is preferable that the integration circuit is a differential integration circuit, and the two terminals of the thermocouple are respectively connected to a differential input terminal of the integration circuit.

  According to said structure, it becomes possible to convert the electromotive force from a thermocouple into an electric current by connecting each terminal of a thermocouple to the differential input terminal of an integration circuit. This eliminates the need to correct the sensitivity of the thermocouple because the sensitivity of the thermocouple does not depend on the ambient temperature.

  The anemometer according to the present invention preferably includes a delay circuit for adjusting the length of the reset signal.

  According to the above configuration, the length of the reset signal can be adjusted according to the integration time of the integration circuit.

  In the anemometer according to the present invention, it is preferable that the comparison circuit outputs a signal indicating which of the two terminals has a higher temperature.

  According to said structure, the anemometer can determine which direction of the direction which connects between the terminals of a thermocouple.

  In the anemometer which concerns on this invention, it is preferable that the said thermocouple is provided with two or more and the direction between the terminals of each thermocouple is mutually different.

  According to said structure, based on the temperature difference between the terminals of each thermocouple, a wind direction can be measured correctly.

  The anemometer according to the present invention preferably includes a replica circuit that is an integration circuit having the same configuration as the integration circuit.

  According to the above configuration, the variation in the absolute value of the integration capacitance of the integration circuit can be corrected by measuring the variation in the absolute value of the integration capacitance by the replica circuit.

  The anemometer according to the present invention preferably further includes a thermometer for measuring the ambient temperature.

  In the anemometer according to the present invention, it is preferable that the sensitivity change of the thermocouple is corrected using the ambient temperature measured by the thermometer.

  According to said structure, when the sensitivity of a thermocouple changes with ambient temperature, the sensitivity of a thermocouple can be correct | amended using the ambient temperature measured with the thermometer.

  In the anemometer according to the present invention, it is preferable that each circuit is built in an IC chip.

  In the anemometer according to the present invention, it is preferable that the thermocouple and the heater are mounted inside the IC chip.

  According to said structure, an anemometer can be reduced in size easily.

  In the anemometer according to the present invention, it is preferable that the thermocouple is provided along an inner edge of the IC chip.

  In the anemometer according to the present invention, the thermocouple is preferably provided on a diagonal line of the IC chip or along the diagonal line.

  According to the above configuration, when a plurality of thermocouples having different directions between the terminals are provided, the wind direction can be accurately measured based on the temperature difference between the terminals of each thermocouple.

  In the anemometer according to the present invention, it is preferable that the thermocouple generates an electromotive force due to a temperature distribution on a surface of the IC chip.

  According to said structure, a wind speed can be measured from the temperature distribution on the surface of IC chip.

  In the anemometer according to the present invention, it is preferable that the IC chip is sealed by a package, and the thermocouple generates an electromotive force by a temperature distribution on a surface of the package.

  According to said structure, a wind speed can be measured from the temperature distribution on the surface of a package.

  In the anemometer according to the present invention, the IC chip is mounted on a substrate, and the thermocouple generates an electromotive force due to a temperature distribution on a back surface of the substrate on which the IC chip is mounted. preferable.

  According to said structure, a wind speed can be measured from the temperature distribution of the back surface of a board | substrate.

  As described above, the anemometer according to the present invention is an anemometer including a thermocouple that generates an electromotive force due to a temperature difference between two terminals, and a heater that generates heat, from the thermocouple. When an integration circuit that integrates a signal according to an electromotive force, an amplification circuit that amplifies the output of the integration circuit, and an output of the amplification circuit is compared with a reference value, and an output of the amplification circuit exceeds the reference value In addition, a comparison circuit that outputs a reset signal that returns the integration circuit to a predetermined state, and a measurement circuit that measures the wind speed based on the interval at which the reset signal is output, are used. The anemometer can be provided at low cost.

(A) is sectional drawing which shows the structure of the anemometer which concerns on embodiment of this invention, (b) is a top view which shows the structure of the IC chip of the said anemometer. It is a circuit diagram which shows the further detailed structure of the anemometer shown in FIG.1 (b). It is a figure which shows operation | movement of the measurement circuit part of the said IC chip. (A) is sectional drawing which shows the structure of the conventional anemometer, (b) is a top view which shows the structure of the IC chip of the anemometer. It is a circuit diagram which shows the further detailed structure of the anemometer shown in FIG.4 (b).

  An embodiment of the present invention will be described below with reference to FIGS.

(Configuration of wind direction anemometer)
Fig.1 (a) is sectional drawing which shows the structure of the anemometer 1 which concerns on this embodiment. The anemometer 1 includes a substrate 2 and an IC chip 3. The IC chip 3 is directly mounted on the surface of the substrate 2 and sealed with a resin package 4. The wind direction anemometer 1 measures the wind direction and wind speed on the surface of the package 4 by measuring the temperature distribution on the surface of the package 4.

  More specifically, as shown in FIG. 1B, the IC chip 3 includes a thermocouple 5, a heater 6, and a measurement circuit unit 10. The thermocouple 5 and the heater 6 are formed on each side of the IC chip 3. By heating the surrounding air with the heater 6, a temperature difference corresponding to the wind speed is generated in the IC chip 3. As a result, a temperature difference is generated between the two terminals of the thermocouple 5 facing in the lateral direction, and the thermocouple 5 generates an electromotive force due to this temperature difference. The anemometer 1 measures the wind speed by measuring the electromotive force by the measurement circuit unit 10. Further, the wind direction anemometer 1 can also measure the wind direction by measuring the electromotive force between the terminals of the thermocouple 5 facing in the vertical direction by the measurement circuit unit 10.

  The IC chip 3 may include a thermometer. By incorporating a thermometer in the IC chip 3, it becomes possible to measure the ambient temperature. When the sensitivity of the thermocouple 5 changes depending on the ambient temperature, the ambient temperature measured with the thermometer is used to Sensitivity can be corrected.

(Circuit configuration of IC chip)
As shown in FIG. 2, the measurement circuit unit 10 of the IC chip 3 includes an integration circuit 11, an amplification circuit 12, a comparison circuit 13, a delay circuit 14, a counter circuit 15, and an oscillation circuit 16.

  The integration circuit 11 is a differential integration circuit including an operational amplifier 11a, two capacitors 11b and 11c, and three switches 11d to 11f, and integrates a current that flows due to an electromotive force between terminals of the thermocouple 5. The operational amplifier 11 a is a fully differential operational amplifier, and two input terminals of the operational amplifier 11 a constitute a differential input of the integrating circuit 11. The capacitor 11b and the switch 11d are connected in parallel between the inverting input terminal and the non-inverting output terminal of the operational amplifier 11a. The capacitor 11c and the switch 11e are connected between the non-inverting input terminal and the inverting output terminal of the operational amplifier 11a. They are connected in parallel. The switch 11f is provided between the two input terminals of the operational amplifier 11a.

  The capacitors 11b and 11c are variable capacitors, and the integration time of the integration circuit 11 can be adjusted by changing the capacitance values of the capacitors 11b and 11c. Further, ON / OFF of the switches 11d to 11f is controlled by a reset signal R described later, and the integration circuit 11 can be returned to a predetermined state by turning on the switches 11d to 11f.

  The amplifier circuit 12 includes an operational amplifier 12a and four resistors 12b to 12e. The resistor 12b is connected between the inverting input terminal and the output terminal of the operational amplifier 12a, and the resistor 12c is connected between the non-inverting input terminal of the operational amplifier 12a and the ground. The resistor 12d is connected between the non-inverting output terminal of the operational amplifier 11a and the inverting input terminal of the operational amplifier 12a, and the resistor 12e is connected between the inverting output terminal of the operational amplifier 11a and the non-inverting input terminal of the operational amplifier 12a. Yes. The resistors 12b and 12c are variable resistors, and the amplification factor of the amplifier circuit 12 can be adjusted by changing the resistance values of the resistors 12b and 12c.

  With the above configuration, the integrating circuit 11 integrates the current flowing by the electromotive force generated in the thermocouple 5 according to the temperature difference between the terminals, and the amplifying circuit 12 amplifies the output of the integrating circuit 11. The signal amplified by the amplifier circuit 12 is compared with a reference value by the comparator circuit 13, and the comparator circuit 13 outputs a reset signal R when the output of the amplifier circuit 12 exceeds the reference value.

  The comparison circuit 13 also outputs a determination signal D indicating which temperature of the terminals of the thermocouple 5 is higher. Thereby, it can be determined which direction the wind direction is between the terminals of the thermocouple 5.

  The reset signal R is input to the integrating circuit 11 and the counter circuit 15 via the delay circuit 14. The integration circuit 11 is returned to a predetermined state by the reset signal R. In addition to the reset signal R, the counter circuit 15 receives the clock signal CL from the oscillation circuit 16.

  The counter circuit 15 and the oscillation circuit 16 constitute a measurement circuit that measures the wind speed based on the interval at which the reset signal is output. The counter circuit 15 continues to count the number of rising edges of the clock signal CL in the interval at which the reset signal R is output. When the reset signal R is input to the counter circuit 15, the count number of the counter circuit 15 is taken into a register circuit (not shown) and then returned to a predetermined value, and the counter circuit 15 newly starts counting.

  Even when the counter circuit 15 is saturated, the count number is returned to a predetermined value, and a signal indicating that the counter circuit 15 is saturated is output from the counter circuit 15.

(Calculation of wind speed)
FIG. 3 is a diagram illustrating an operation of the measurement circuit unit 10 for measuring the wind speed. Assuming that the wind speed is constant, the outputs of the integrating circuit 11 and the amplifying circuit 12 monotonously increase or decrease according to the wind direction. When the output of the amplifier circuit 12 exceeds the reference value, the reset signal R is output from the comparison circuit 13.

  The counter circuit 15 counts the number of rising edges of the clock signal CL during a period from when the reset signal R rises to when the next reset signal R rises, and stores the count number during the period in the register circuit. Thus, the number of clocks stored in the register circuit corresponds to the interval at which the reset signal R is output. For example, the number of clocks can be read as wind speed by referring to a combination table.

  Thus, the measurement circuit unit 10 can measure the wind speed based on the interval at which the reset signal R is output.

(Effect of this embodiment)
As described above, in this embodiment, the wind speed can be measured by the IC chip 3 alone, and an external filter circuit is not required unlike the related art.

  Moreover, in this embodiment, since the measurement circuit unit 10 is realized using the integration circuit 11, the wind speed can be accurately measured even if the electromotive force of the thermocouple 5 is small. Therefore, it is not necessary to mount the IC chip 3 on a ceramic disk having a high thermal conductivity. Moreover, even if the temperature difference between the terminals of the thermocouple 5 is reduced by sealing the IC chip 3 with the package 4, no problem occurs. That is, since the IC chip 3 for measuring the wind direction and wind speed can be sealed in the normal package 4, mass production is easy, and the manufacturing cost of the wind direction anemometer 1 can be reduced.

  The thermocouple 5 may be configured to generate an electromotive force by the temperature distribution on the surface of the IC chip 3 without sealing the IC chip 3 with the package 4. Or you may comprise so that the thermocouple 5 may generate | occur | produce an electromotive force with the temperature distribution of the back surface of the surface in which the IC chip 3 of the board | substrate 2 is mounted. That is, the wind direction anemometer 1 can also measure the wind direction and the wind speed based on the temperature distribution on the surface of the IC chip 3 or the temperature distribution on the back surface of the substrate 2.

(Other features)
In addition, as described above, the integration circuit 11 and the amplification circuit 12 can adjust the integration time and the amplification factor, respectively. Therefore, instantaneous wind speed measurement and average wind speed measurement can be realized using the same integration circuit 11 and amplification circuit 12. Note that the length (output interval) of the reset signal R needs to be changed according to the integration time of the integration circuit 11, and therefore, in the present embodiment, the length of the reset signal R can be adjusted by the delay circuit 14. Yes.

  When the wind speed is weak and the electromotive force from the thermocouple 5 is small, the interval at which the reset signal R is output from the comparison circuit 13 is widened, and the counter circuit 15 is likely to be saturated. Therefore, in this embodiment, the frequency of the clock signal CL from the oscillation circuit 16 is variable. The frequency of the clock signal CL is adjusted by frequency adjusting means such as a frequency dividing circuit. As the temperature difference between the terminals of the thermocouple 5 becomes smaller, the output interval of the reset signal R becomes longer. Therefore, the counter circuit 15 can be prevented from being saturated by slowing the frequency of the clock signal CL. Moreover, the measurement accuracy of the anemometer 1 can be changed by changing the frequency of the clock signal CL according to the application.

  As described above, the electromotive force of the thermocouple 5 can be converted into a current by connecting both ends of the thermocouple 5 to the differential input terminals of the integrating circuit 11. At this time, when the thermocouple 5 is formed of an appropriate material inside the IC chip 3, the Seebeck coefficient of the thermocouple 5 does not depend on the ambient temperature and the temperature between the terminals of the thermocouple 5 from the Mott relational expression. It depends only on the difference.

More specifically, according to Mott's relational expression, between Seebeck coefficient S (V / K) and resistivity ρ (Ω · m),
S = αρ
This relationship holds. That is, the temperature change of the Seebeck coefficient is equal to the temperature change of the resistivity.

The electromotive force V when the temperature difference between the terminals of the thermocouple 5 is ΔT is
V = SΔT
It is represented by Therefore, the current I flowing between the terminals of the thermocouple 5 is
I = V / R = (αρΔT) / (ρL / A) = αAΔT / L
And is proportional only to the temperature difference ΔT. That is, the current I does not depend on the ambient temperature. Therefore, by using the current that flows due to the electromotive force between the terminals of the thermocouple 5, temperature measurement can be performed without considering the ambient temperature. In this case, since it is not necessary to correct the sensitivity of the thermocouple 5 based on the ambient temperature, a thermometer for measuring the ambient temperature becomes unnecessary.

  Further, since the integrating circuit 11 uses the capacitors 11b and 11c to integrate the current flowing due to the electromotive force generated in the thermocouple 5, the variation in the absolute values of the capacitors 11b and 11c is the current value, that is, the wind speed. Equivalent to variation. Therefore, it is preferable that the integrating circuit 11 has a redundant capacity in order to correct variations in absolute values of the capacitors 11b and 11c. The accuracy of the relative value of the capacity is more accurate than the accuracy of the absolute value of the capacity.

  Therefore, it is preferable to provide a replica circuit that is an integration circuit having the same configuration as the integration circuit 11. By measuring the variation in the absolute values of the capacitors 11b and 11c with this replica circuit, the correction value of the capacitor is calculated.

(Modification)
In the embodiment described above, the IC chip 3 is mounted on the substrate 2, but the present invention is not limited to this. The IC chip 3 may be mounted on a film or plastic surface.

  In the above-described embodiment, the thermocouple 5 and the heater 6 are mounted inside the IC chip 3, but may be provided outside the IC chip 3. For example, the thermocouple 5 and the heater 6 may be directly mounted on the substrate, and the wind speed may be measured based on the temperature distribution on the back surface of the substrate.

  In the above-described embodiment, the thermocouple 5 is provided along the inner edge of the IC chip 3. However, the thermocouple 5 may be provided on the diagonal line of the IC chip 3 or along the diagonal line.

  In the above-described embodiment, the output of the integration circuit 11 is amplified by the amplifier circuit 12, and the amplified output is compared with the reference value in the comparison circuit 13. However, the present invention is not limited to this. A configuration in which the output of the integrating circuit 11 is compared with a reference value without providing the amplifier circuit 12 may be employed.

  Further, in the embodiment described above, the anemometer 1 is configured to include a plurality of thermocouples 5 in which the directions between the terminals are different from each other, but may be configured to include only one thermocouple 5. In that case, the wind direction anemometer 1 may measure only the wind speed without measuring the wind direction.

(Additional notes)
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention.

  The present invention can be expressed as follows.

  An anemometer according to the present invention is an anemometer that uses a thermocouple, and integrates a heater that generates heat to create a temperature difference according to the wind speed, and a signal from an electromotive force from the thermocouple. An integrating circuit; an amplifying circuit for amplifying the output of the integrating circuit; a comparing circuit that compares the output of the amplifying circuit with a reference value and outputs a reset signal; and a count circuit that checks an interval at which the reset signal is output And.

  In the anemometer according to the present invention, it is preferable that the thermocouple and the heater are mounted inside the IC.

  In the anemometer according to the present invention, the thermocouple is preferably placed on the inner edge of the IC.

  In the wind direction anemometer according to the present invention, the wind direction is preferably measured by detecting a difference in electromotive force between the thermocouples facing each other.

  In the anemometer according to the present invention, the thermocouple is preferably placed on a diagonal line of the IC.

  In the anemometer according to the present invention, both ends of the thermocouple are connected to the differential input of the integration circuit to convert the electromotive force into a current so that the sensitivity of the thermocouple does not depend on the ambient temperature of the IC. It is preferable to make it.

  In the wind direction anemometer according to the present invention, it is preferable that the IC is directly mounted on the substrate, and the wind direction and the wind speed are measured from the temperature distribution on the IC front surface or the back surface of the substrate.

  In the wind direction anemometer according to the present invention, the IC is preferably sealed in a package, and the wind direction and the wind speed are measured from the temperature distribution on the package surface by the wind.

  In the anemometer according to the present invention, it is preferable that the capacitance value of the integration circuit and the resistance value of the amplification circuit are variable in order to make the integration time of the integration circuit and the amplification factor of the amplification circuit variable.

  In the anemometer according to the present invention, it is preferable that the comparison circuit also outputs a signal for detecting the wind direction.

  The anemometer according to the present invention has a function of adjusting a clock frequency input so that the counter circuit is not saturated when a temperature difference between the thermocouple terminals changes according to the wind speed. Is preferred.

  In the anemometer according to the present invention, it is preferable to change the measurement accuracy by changing the clock frequency input to the counter circuit.

  In the anemometer according to the present invention, the reset signal may be a signal for returning the integration circuit and the counter circuit to a predetermined state and a signal for taking the count number of the counter circuit into a register. preferable.

  The anemometer according to the present invention preferably includes a delay circuit for adjusting the length of the reset signal.

  The anemometer according to the present invention preferably includes a replica circuit having an integration circuit having the same configuration as the integration circuit in order to correct variations in the absolute value of the integration capacity of the integration circuit.

  In the anemometer according to the present invention, it is preferable to measure the ambient temperature by incorporating a thermometer.

  In the anemometer which concerns on this invention, it is preferable to correct | amend the sensitivity change of a thermocouple using the said ambient temperature measured with the said thermometer.

  The present invention can be used for an anemometer using a thermocouple.

1 Anemometer (Anemometer)
2 substrate 3 IC chip 4 package 5 thermocouple 6 heater 10 measurement circuit unit 11 integration circuit 11a operational amplifier 11b capacitance 11c capacitance 11d switch 11e switch 11f switch 12 amplifier circuit 12a operational amplifier 12b resistor 12c resistor 12d resistor 12e resistor 13 comparison circuit 14 delay circuit DESCRIPTION OF SYMBOLS 15 Counter circuit 16 Oscillation circuit 101 Wind direction anemometer 102 Ceramic disk 103 IC chip 104 Resin 105 Thermocouple 106 Heater 110 Measurement circuit part 111 Comparator 112 Latch circuit 120 Filter circuit CL Clock signal D Determination signal R Reset signal

In order to solve the above problems, an anemometer according to the present invention includes an IC chip in which a thermocouple that generates an electromotive force due to a temperature difference between two terminals and a heater that generates heat are incorporated. The thermocouple is formed on each side of the IC chip, and integrates a signal corresponding to an electromotive force from the thermocouple, and outputs the integration circuit as a reference value. The comparison circuit that outputs a reset signal that returns the integration circuit to a predetermined state when the output of the integration circuit exceeds the reference value, and measures the wind speed based on the interval at which the reset signal is output comprising a measuring circuit for, and is characterized that you measure the wind direction based on the output of the integrator circuit.

As described above, an anemometer according to the present invention includes an IC chip in which a thermocouple that generates an electromotive force due to a temperature difference between two terminals and a heater that generates heat are incorporated. The thermocouple is formed on each side of the IC chip, integrates a signal corresponding to the electromotive force from the thermocouple, an amplifier circuit that amplifies the output of the integrator circuit, and A comparison circuit that compares the output of the amplifier circuit with a reference value, and outputs a reset signal that returns the integration circuit to a predetermined state when the output of the amplifier circuit exceeds the reference value, and the reset signal is output. comprising a measuring circuit for measuring the wind velocity, the based on that distance, because the configuration you measure the wind direction based on an output of the integrating circuit, the effect of wind speed meter using a thermocouple can be provided at low cost Play.

Claims (22)

An anemometer comprising a thermocouple that generates an electromotive force due to a temperature difference between two terminals, and a heater that generates heat,
An integrating circuit for integrating a signal corresponding to the electromotive force from the thermocouple;
A comparison circuit that compares the output of the integration circuit with a reference value, and outputs a reset signal that returns the integration circuit to a predetermined state when the output of the integration circuit exceeds the reference value;
A measurement circuit for measuring the wind speed based on the interval at which the reset signal is output;
An anemometer characterized by comprising. An anemometer according to claim 1,
An amplifying circuit for amplifying the output of the integrating circuit;
The comparison circuit compares the output of the integration circuit amplified by the amplification circuit with the reference value, and outputs the reset signal when the amplified output of the integration circuit exceeds the reference value An anemometer characterized by that. An anemometer according to claim 2,
An anemometer characterized in that the amplification factor of the amplification circuit is variable. The anemometer according to any one of claims 1 to 3,
An anemometer characterized in that the integration time of the integration circuit is variable. An anemometer according to any one of claims 1 to 4,
The measuring circuit is
An oscillation circuit for generating a clock signal;
A counter circuit that counts the clock signal in an interval at which the reset signal is output;
An anemometer characterized by comprising. An anemometer according to claim 5,
A register circuit;
When the reset signal is output, the counter circuit returns to a predetermined state and outputs a count number to the register circuit. An anemometer according to claim 5 or 6,
An anemometer comprising frequency adjusting means for adjusting the frequency of the clock signal. An anemometer according to claim 7,
The anemometer, wherein the frequency adjusting means adjusts the frequency of the clock signal according to a temperature difference between terminals of the thermocouple. An anemometer according to any one of claims 1 to 8,
The integrating circuit is a differential integrating circuit;
An anemometer characterized in that the two terminals of the thermocouple are respectively connected to a differential input terminal of the integrating circuit. An anemometer according to any one of claims 1 to 9,
An anemometer comprising a delay circuit for adjusting the length of the reset signal. An anemometer according to any one of claims 1 to 10,
The anemometer, wherein the comparison circuit outputs a signal indicating which of the two terminals has a higher temperature. It is an anemometer of any one of Claims 1-11,
A plurality of the thermocouples;
An anemometer characterized in that directions between terminals of each thermocouple are different from each other. An anemometer according to any one of claims 1 to 12,
An anemometer comprising a replica circuit which is an integration circuit having the same configuration as the integration circuit. An anemometer according to any one of claims 1 to 13,
An anemometer further comprising a thermometer for measuring an ambient temperature. An anemometer according to claim 14,
An anemometer that corrects a change in sensitivity of a thermocouple using the ambient temperature measured by the thermometer. An anemometer according to any one of claims 1 to 15,
An anemometer characterized in that each circuit is built in an IC chip. An anemometer according to claim 16,
The anemometer, wherein the thermocouple and the heater are mounted inside the IC chip. An anemometer according to claim 17,
The anemometer, wherein the thermocouple is provided along an inner edge of the IC chip. An anemometer according to claim 17,
An anemometer characterized in that the thermocouple is provided on or along a diagonal of the IC chip. An anemometer according to any one of claims 17 to 19,
The anemometer, wherein the thermocouple generates an electromotive force based on a temperature distribution on a surface of the IC chip. An anemometer according to any one of claims 17 to 19,
The IC chip is sealed by a package,
The anemometer, wherein the thermocouple generates an electromotive force according to a temperature distribution on a surface of the package. An anemometer according to any one of claims 17 to 19,
The IC chip is mounted on a substrate,
The anemometer is characterized in that the thermocouple generates an electromotive force based on a temperature distribution on a back surface of a surface of the substrate on which the IC chip is mounted.

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