JP5045889B2 - Diode temperature measuring device - Google Patents

Description

The present invention relates to a simple and highly linear apparatus for measuring an absolute temperature in a wide temperature range using a semiconductor pn junction diode or Schottky diode. For example, when a silicon pn junction is used, -200 ° C. to 500 ° C. The present invention relates to an inexpensive temperature measuring apparatus that can accurately and easily measure the temperature with a single silicon pn junction diode in a wide temperature range up to a certain extent.

Conventionally, there has been a temperature measuring device that measures the absolute temperature with high sensitivity using a thermistor. Conventionally, there has been a method of measuring the temperature T by passing a constant current through a pn junction diode called a thermodiode and measuring the change in the forward voltage _Vf due to the change in the temperature T. This is characterized by the good linearity that the change in the forward voltage _Vf is proportional to the absolute temperature. Also, conventionally called IC temperature sensor, utilizing the characteristics of the thermo-diode, combining the different collector currents of the two transistors, and further shorting the base and collector of the transistor so that the transistor can be treated as a diode. In addition, there has been a temperature measuring device that utilizes the fact that the voltage difference of the pn junction diode between the emitter and the base is proportional to the absolute temperature T.

Further, a predetermined constant forward voltage _Vf is applied to the diode invented by the present applicant, and the absolute temperature is measured from a change in the forward current of the diode due to the temperature. The forward voltage _Vf is different with extremely high sensitivity. If set to a value, the temperature measurement range can be changed, and a transistor thermistor (Japanese Patent Laid-Open No. 11-287713 (Japanese Patent No. 3366590)) and a diode thermistor (Japanese Patent Laid-Open No. 3366590), which are temperature sensors that can measure temperature like a thermistor. -264176 (Japanese Patent No. 3583704)).
Patent No. 3366590 Patent No. 3583704

The thermistor is an extremely sensitive absolute temperature sensor, but there is a problem that the temperature range that can be measured by one thermistor is narrow. On the other hand, the transistor thermistor and the diode diode thermistor invented by the present applicant have been developed to widen the temperature range that can be measured by one thermistor. However, although it is extremely high sensitivity like the thermistor, the fluctuation of the applied voltage is reflected in the measured temperature error as much as it is, and there is some problem in linearity because it has an exponential temperature dependence as a thermistor. It is also known that because there are two unknowns, it is necessary to calibrate at least two known temperatures.

In addition, since the conventional thermodiode uses the relationship that the magnitude of the applied DC forward voltage _Vf necessary to maintain a constant DC current Io is proportional to the absolute temperature T, the temperature display uses DC. There was a need to amplify. DC amplification requires offset adjustment, and therefore has a problem of change with time. Also, specifying the forward DC current Io, there reverse saturation current I _s and the DC forward voltage V _f of the diodes of the temperature dependency, there will be two unknowns. Therefore, there was a problem that calibration had to be performed at two different temperatures.

Further, in an IC temperature sensor using transistors, it is necessary to prepare two transistors and set their collector currents to two different values. And it was necessary to install these two transistors so that it might become the same measured temperature, and also there was a problem that they had to be two transistors produced exclusively.

In general, to obtain a constant DC current Io with a constant current circuit means, a DC voltage source that generates a constant voltage using a Zener diode or the like is prepared, and a resistor having a predetermined resistance value is connected to this power source. The current flowing at this time is set to a constant DC current Io, and the circuit configuration is such that this constant DC current Io passes through a load resistance or the like. However, for example, when the breakdown voltage of the Zener diode or the predetermined resistance value of the resistor fluctuates due to temperature or the like, there is a problem that the direct current Io that should be a constant value fluctuates.

The present invention has been made in order to solve the above-described conventional problems, and using any one diode, the output and the absolute temperature T are essentially in a linear relationship through absolute zero, or in an inversely proportional relationship. An object of the present invention is to provide a temperature measuring device that can perform temperature calibration at one temperature, is extremely simple and inexpensive, and has a wide measurement temperature range.

In order to achieve the above object, a diode temperature measuring apparatus according to claim 1 of the present invention includes a semiconductor diode, constant current circuit means for causing a predetermined constant direct current Io to flow through the diode, AC current superimposing circuit means for superimposing an alternating current ΔI having a predetermined alternating current amplitude on the diode, and ΔV measuring circuit means for measuring an AC voltage change ΔV of the diode due to the alternating current ΔI, the direct current Io, the alternating current The temperature is measured using the values of current ΔI and AC voltage change ΔV.

In general, whether the pn junction diode or the Schottky barrier diode has a relationship between the current I and the forward voltage V _f is expressed in terms of energy by multiplying the forward voltage V _f by the elementary charge q. When displayed, when this is larger than kT, which is the absolute temperature T expressed in units of energy, the following equation is obtained.

Here, I _s is the saturation current, n represents an ideal factor, varies due the type of semiconductor. K is a Boltzmann constant.

When Equation 1 is differentiated by V _f and the change in current is ΔI, and the change in voltage V _f is ΔV, the temperature T can be expressed by the following equation as a constant DC current I = Io.

In Equation 2, for example, if constant current circuit means is used to make Io = 100 μA constant, and AC current superimposing circuit means is set to have a constant amplitude of ΔI = 10 μA AC 1 kHz, the ideal coefficient n is a constant. Therefore, it can be seen that the absolute temperature T is proportional to the AC output voltage ΔV (whether it is a silicon semiconductor or a germanium semiconductor, or if the value of the DC current value Io is further determined). Accordingly, α on the right side of Equation 2 is a constant, and represents the slope of the dependence on the AC output voltage ΔV when the temperature T of the diode is obtained in the vicinity of Io = 100 μA. In this case, since the AC output voltage ΔV can be measured using the ΔV measuring circuit means, the unknown is only the ideal coefficient n, and if it is calibrated under a predetermined absolute temperature T, the semiconductor used The ideality factor n of the diode is obtained, and the constant α is determined. In this way, using Equation 2, the arbitrary absolute temperature T is proportional to the AC output voltage ΔV, and can be directly read by measuring the AC output voltage ΔV.

A diode temperature measuring apparatus according to claim 2 of the present invention comprises a semiconductor diode, constant current circuit means for causing a predetermined constant DC current Io to flow through the diode, and an AC voltage having a predetermined AC amplitude. AC voltage superimposing circuit means for superimposing ΔV, and ΔI measuring circuit means for measuring the AC current change ΔI of the diode due to the AC voltage ΔV, the DC current Io, the AC voltage ΔV and the AC current change ΔI The temperature is measured using the value.

The above formula 2 can be modified and expressed as follows.

Here, ΔV is set by the AC voltage superimposing circuit means so as to have a predetermined AC amplitude, for example, a constant amplitude of 4 mV of a 1 kHz sine wave, and the ideal coefficient n is a constant as described above, and the DC current value Since the value of Io is set to a specified constant value, it can be seen that β is a constant. If the AC current change ΔI is measured using ΔI measuring circuit means for measuring the AC current change ΔI, the absolute temperature T can be obtained using Equation 3. As the superposed minute AC voltage ΔV, a forward DC voltage V necessary for flowing a constant DC current Io is applied to the diode, and is superposed on the forward DC voltage V.

According to the present invention, the unknown is only a constant ideal coefficient n, and a constant β is measured by measuring an AC current change ΔI with a predetermined DC current Io and AC voltage ΔV under a single temperature T. Can be determined. From Equation 3, the absolute temperature T is displayed as the reciprocal of the output AC current change ΔI.

In the diode temperature measuring apparatus according to claim 3 of the present invention, the alternating current ΔI superimposed by the alternating current superimposing circuit means is proportional to the direct current Io by the constant current circuit means. When the DC current Io changes due to fluctuations in the ambient temperature or power supply voltage used for the constant current circuit means, or when the AC current ΔI superimposed by the AC current superposition circuit means changes for some reason Therefore, an error occurs in the absolute temperature T to be measured using Equation 2. However, as in the present invention, if the alternating current superposition circuit means is configured in association with the alternating current ΔI that is superimposed in proportion to the direct current Io, even if the direct current Io and the alternating current ΔI vary, Since they cannot be varied independently of each other and are in a proportional relationship, the Io / ΔI term in Equation 2 becomes a constant value. Therefore, for example, if the DC current Io is reduced, the superimposed AC current ΔI is also reduced accordingly, so that the term Io / ΔI in Equation 2 becomes a constant value, and the absolute temperature T measured by the fluctuation of the DC current Io is The error is canceled out and the absolute temperature T can be measured accurately. Of course, even if the direct current Io increases, the accurate absolute temperature T can be measured in the same manner.

It is possible to configure a known shunt circuit by the resistance of the direct current Io by the constant current circuit means so that the superimposed alternating current ΔI is proportional to the direct current Io. If this circuit is mounted in the alternating current superimposing circuit means, it is possible to obtain a superimposing alternating current ΔI proportional to the direct current Io by the constant current circuit means.

The DC current Io from the constant current circuit means is shunted by a resistor, and this is turned on / off by an analog switch or the like, for example, can be used as a superimposed alternating current ΔI in a rectangular waveform of 1 kHz. Of course, an alternating current ΔI that is equivalently superimposed may be generated by changing the direct current Io component itself by connecting a shunt resistor with an analog switch or the like, or by disconnecting it.

Moreover, even if the alternating current ΔI that is superimposed by dividing the resistance by using the DC power supply voltage for creating the direct current Io by the constant current circuit means is superimposed, the superimposed alternating current that is proportional to the direct current Io ΔI can also be easily obtained.

The diode temperature measuring apparatus according to claim 4 of the present invention is a case where the alternating voltage ΔV superimposed by the alternating voltage superimposing circuit means is inversely proportional to the direct current Io by the constant current circuit means. As in the case of the diode temperature measuring device according to claim 3 of the present invention described above, when the predetermined direct current Io varies due to variations in ambient temperature or variations in power supply voltage used for the constant current circuit means, Alternatively, when the AC voltage ΔV superimposed by the AC voltage superimposing circuit means fluctuates for some reason, an error occurs in the absolute temperature T measured using Equation 3. However, as in the present invention, if the AC voltage superimposing circuit means is configured in association with the AC voltage ΔV to be superimposed in inverse proportion to the DC current Io, even if the DC current Io and the AC voltage ΔV fluctuate, Since they cannot be varied independently of each other and are in an inversely proportional relationship, the term of Io · ΔV in Equation 3 becomes a constant value. Therefore, for example, when the DC current Io is reduced, the superimposed AC voltage ΔV is also increased accordingly, so that the term Io · ΔV in Equation 3 becomes a constant value, and the absolute temperature T measured by the fluctuation of the DC current Io is The error is compensated and the absolute temperature T can be measured accurately. Of course, even if the direct current Io increases, the accurate absolute temperature T can be measured in the same manner.

When the DC current Io by the constant current circuit means is passed through a predetermined resistor, for example, the voltage drop is taken out, this voltage is made a desired bias voltage by resistance division or the like, and applied between the emitter and base of the transistor When the collector voltage at the operating point is divided by resistance to create a predetermined superimposed AC voltage ΔV, for example, when a known load straight line is considered, for example, when the DC current Io increases, the emitter-base The bias voltage applied between them increases, and the collector voltage at the operating point decreases. In this way, it is possible to configure a circuit in which the superimposed alternating voltage ΔV is inversely proportional to the direct current Io with respect to a minute fluctuation of the direct current Io by the constant current circuit means. Of course, an AC voltage ΔV that is inversely proportional to the DC current Io can be created using a known circuit that generates an output voltage that is inversely proportional to the DC current Io. By mounting such a circuit that generates an AC voltage ΔV that is inversely proportional to the DC current Io in the AC voltage superimposing circuit means, the term of Io · ΔV in Equation 3 can be made constant. .

The diode temperature measuring apparatus according to claim 5 of the present invention is a case where a pn junction diode or a Schottky barrier diode is used as the diode.

In addition to the silicon (Si) semiconductor, various semiconductors such as germanium (Ge), gallium arsenide (GaAs), silicon carbide (SiC), and diamond can be used as the diode. In particular, a semiconductor having a difficult pn junction is preferably used as a Schottky barrier diode. In addition, when a diode using a semiconductor such as silicon carbide (SiC) or diamond having a large energy gap is used, temperature measurement at a high temperature of 500 ° C. or more can be performed.

If the Schottky barrier diode using a silicon (Si) semiconductor is used as the diode, the higher the barrier of the Schottky barrier diode of the present invention, the higher the measurement possible, so the Schottky barrier created so as to increase the barrier. A diode is better. For this purpose, when the high-concentration n-type Si is used, the Fermi energy Ef approaches the conduction band of the n-type Si or enters into the conduction band when it degenerates. Can be made larger. Furthermore, since the Schottky metal of the Schottky barrier diode has a higher work function, the barrier can be further increased. Therefore, a metal having a high work function such as platinum (Pt) is preferably used.

In a Schottky barrier diode using degenerate high impurity concentration n-type Si, the width of the depletion layer is small, so that a tunnel current flows easily, and the diffusion current flowing over the barrier due to temperature, which is the gist of the present invention, is mainly used. Currents other than the current to be applied contribute, and the above-described Expression 21, Expression 2, and Expression 3 are not satisfied. For this purpose, it is necessary to widen the depletion layer width so that the tunnel current hardly flows. For example, in a Schottky barrier diode by contact with platinum (or platinum silicide, etc.) having a high work function, impurities near the surface of a degenerate high impurity concentration n-type Si semiconductor chip (for example, within a few hundred nanometers from the surface) If the impurity distribution is such that the concentration is reduced and the concentration increases as the depth from the surface increases, the width of the depletion layer increases near the surface, so that the tunnel current component can be reduced to a negligible level.

The diode temperature measuring apparatus according to claim 6 of the present invention is a case where the DC current Io is intermittently passed, and data necessary for temperature measurement is acquired while the DC current Io is flowing. .

According to the present invention, the DC current Io having a predetermined magnitude is repeated by flowing it for 0.1 seconds at a rate of, for example, once per second (flowing in the form of repeated rectangular pulses), and is constant at 10 kHz. If the AC voltage ΔV having the amplitude or the AC current ΔI is superimposed, the power consumption can be reduced. Further, if the superimposed alternating voltage ΔV or alternating current ΔI is generated in a rectangular pulse in synchronism with the applied direct current Io only during that period, the power consumption can be further reduced. It saves some batteries.

The diode temperature measuring apparatus according to claim 7 of the present invention is a case where temperature calibration can be performed using at least one known temperature. When a silicon (Si) semiconductor is used, depending on the impurity concentration, for example, from about −200 ° C. to about 150 ° C., the same ideal coefficient n is applied to each of the pn junction diode or the Schottky barrier diode. A value can be used. Then, from 150 ° C. to about 500 ° C., the ideal coefficient n is obtained within the range, and the value of the direct current Io may be changed as necessary. In such a temperature range, the error can be reduced by switching and measuring so that the ideal coefficient n and the value of the direct current Io suitable for the temperature range are used. Also, when the magnitude of the DC current Io is extremely changed with the same diode (when the linearity is good up to a change of about 5 orders of magnitude near room temperature, but exceeds this range), It is necessary to calibrate and use the value of the ideal coefficient n.

The value of the ideal coefficient n varies depending on the type of semiconductor and the applied voltage range. If the value of n of the diode is known from the beginning, the other coefficient constituting α in Expression 2 or β in Expression 3 Since all are specified values or constants, calibration under one absolute temperature T is not necessary and can be read directly from the output, but there is actually a concern about temperature accuracy. Therefore, as in the present invention, the constant α and the constant β are determined by measuring the alternating current change ΔI under the setting of the predetermined direct current Io and the alternating voltage ΔV under one absolute temperature T. It seems that this is suitable for a diode temperature measuring device whose calibration is accurate under at least one absolute temperature T.

The magnitude of the DC current Io, the superimposed AC voltage ΔV or AC current ΔI may be appropriately set depending on the type of semiconductor forming the diode, the temperature region, and the measurement accuracy.

As described above, according to the present invention, for example, when a commercially available silicon pn junction diode is used with any one diode, for example, about −200 ° C. to about 150 ° C., about 150 ° C. to about 500 ° C. As a result, it is possible to provide a simple diode temperature measuring device with good linearity, in which each region can be calibrated at one temperature in that region.

The value of the ideal coefficient n varies depending on the type of semiconductor. If the value of n is known from the beginning, all others are specified values or constants, so calibration under one absolute temperature T is also necessary. There is an advantage that a diode temperature measuring device that can be directly read from the output can be provided.

Further, according to the present invention, there is an advantage that it is possible to provide a diode temperature measuring apparatus which has no problem of offset, has a simple measuring circuit, and can ignore a change with time because only AC amplification is sufficient instead of DC amplification.

Further, in the IC temperature sensor, it is necessary to prepare two transistors having the same bias voltage and different collector currents, and moreover, it is necessary to expose to the same temperature to be measured. There is an advantage that the temperature can also be measured using a diode, for example, any one commercially available pn junction diode.

Further, according to the present invention, when the power source of the constant current circuit means for generating a constant DC current Io value fluctuates or the constant DC current Io changes due to temperature fluctuations, etc. By making the current ΔI proportional to the DC current Io, or by making the superimposed AC voltage ΔV inversely proportional to the DC current Io, the change in the DC current Io can be compensated, so the correct temperature is displayed. There is an advantage that a diode temperature measuring device can be provided.

The superimposed alternating current ΔI and the superimposed alternating voltage ΔV can be formed into a rectangular waveform as well as a sine waveform. In particular, in the case of a rectangular waveform, a DC current can be formed by turning on and off with an analog switch or the like, or a clock signal can be used, so a signal with a stable amplitude can be easily created. There is an advantage.

In addition, according to the present invention, since the temperature measurement operation can be performed by causing current to flow intermittently, there is an advantage that a low power consumption measuring device can be provided.

Hereinafter, embodiments of the display device of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an absolute temperature T obtained by superimposing a small alternating current ΔI having a constant amplitude according to the present invention on a constant direct current Io flowing through a diode 1 and measuring an alternating voltage change ΔV generated in the diode 1 at this time. 1 is a block diagram of an embodiment for configuring a diode temperature measuring apparatus configured to measure current. In this case, as shown in Equation 2, the absolute temperature T is proportional to the AC voltage change ΔV generated in the diode 1, and the characteristics of the absolute temperature T and the AC voltage change ΔV pass absolute zero. Should be a straight line. According to experiments, when a silicon pn junction diode is used, the liquid nitrogen temperature is approximately 77 K (about −200 ° C.) to 450 K, and even a Schottky diode is a straight line passing through absolute zero from 77 K to 400 K. Has been confirmed.

In FIG. 1, for example, a pn junction diode made of silicon (Si) is used as the diode 1, and a constant DC current Io = 100 μA, for example, is passed through the diode 1 by constant current circuit means. In this embodiment, the DC current Io flows through the DC power supply 2. If necessary, the DC power source 2 may be incorporated in the constant current circuit means. Further, for example, a current of a minute alternating current ΔI = 10 μA having a constant amplitude between peaks is superimposed on the direct current Io by the alternating current superimposing circuit means. At this time, if the AC frequency is set to about 1 kHz to 10 kHz, it is easy to measure when an amplifier such as an OP amplifier is used. Since the minute alternating current ΔI is superimposed, the minute alternating voltage ΔV is generated in the diode 1 correspondingly. This AC voltage ΔV is preferably amplified by an OP amplifier or the like. In practice, it is more practical to have an arithmetic circuit and a temperature display as shown in FIG. 1, and the output AC voltage ΔV, the set DC current Io value, the AC current ΔI value, etc. Using it, it is converted into temperature etc. by the arithmetic circuit and displayed on the temperature display section.

Also, when the DC current Io changes due to changes in ambient temperature or power supply voltage used for the constant current circuit means, or the AC current ΔI superimposed by the AC current superposition circuit means changes for some reason. In this case, if the alternating current superimposing circuit means is configured so that the superimposed alternating current ΔI is proportional to the direct current Io, even if the direct current Io and the alternating current ΔI fluctuate, they can be varied independently. Since there is a proportional relationship, the Io / ΔI term in Equation 2 has a constant value. In FIG. 1, a circuit that configures a known shunt circuit by the resistance of the DC current Io by the constant current circuit means in the AC current superimposing circuit means to easily make the AC current ΔI proportional to the DC current Io. This can be achieved by installing it.

FIG. 2 shows a diode temperature measuring apparatus according to the present invention, in which a small alternating voltage ΔV having a constant amplitude is superimposed on a direct current voltage applied to the diode 1, and an alternating current change ΔI at this time is measured. It is a block diagram of one Example for comprising a temperature measuring apparatus, and is the case where the alternating current voltage (DELTA) V by the alternating voltage superimposing circuit means and the direct current Io by a constant current circuit means are formed independently. The only difference from the case shown in FIG. 1 is that the superposed alternating current signal is a minute alternating current ΔI in FIG. 1, whereas in FIG. . Therefore, the difference is only whether ΔI or ΔV is used as a known (set) minute alternating current signal to be superimposed, and the temperature measurement principle is almost the same. However, when a small AC voltage ΔV having a constant amplitude is superimposed as known, the AC output is proportional to ΔI, but the absolute temperature T is proportional to the inverse of ΔI as shown in Equation 3. Further, in this case, a diode temperature measuring device having a higher temperature sensitivity than the case where a small alternating current ΔI having a constant amplitude is superposed as known is achieved from the relationship between the forward current I of the diode and the voltage V _f. .

FIG. 3 is a block diagram of another embodiment for constructing a diode temperature measuring device for superimposing a small alternating voltage ΔV having a constant amplitude according to the present invention and measuring an alternating current change ΔI at this time. The AC voltage superimposing circuit means is equipped with a circuit that makes the AC voltage ΔV superimposed by the AC voltage superimposing circuit means inversely proportional to the DC current Io in relation to the DC current Io by the constant current circuit means. Is the case. As a result, when the predetermined DC current Io changes due to fluctuations in ambient temperature, fluctuations in the power supply voltage used for the constant current circuit means, or the AC voltage ΔV superimposed by the AC voltage superposition circuit means for some reason. If the AC voltage superimposing circuit means is configured so that the superimposed AC voltage ΔV is inversely proportional to the DC current Io when it fluctuates, even if the DC current Io and the AC voltage ΔV fluctuate, they fluctuate independently. Since it is in an inversely proportional relationship, the fact that the Io · ΔV term in Equation 3 becomes a constant value is used. Therefore, for example, when the DC current Io is reduced, the superimposed AC voltage ΔV is also increased accordingly, so that the term Io · ΔV in Equation 3 becomes a constant value, and the absolute temperature T measured by the fluctuation of the DC current Io is The error is compensated so that an accurate absolute temperature T can be measured.

FIG. 4 shows an embodiment of the diode temperature measuring device according to the present invention in which a direct current Io is intermittently passed and data necessary for temperature measurement is acquired while the direct current Io is flowing. The timing chart of the direct current Io and the timing chart of the alternating current voltage ΔV or alternating current ΔI, which is an alternating current signal with a predetermined constant amplitude, are shown.

As the intermittent DC current Io, for example, a current Io having a constant amplitude (DC component) of 0.1 seconds is repeatedly supplied at a rate of once per second. In this way, an intermittent direct current Io in the form of a rectangular pulse is allowed to flow, and an alternating voltage ΔV or an alternating current ΔI can be generated in synchronism only while the rectangular pulsed current Io is flowing, and these can be superimposed respectively. FIG. 4 shows how this is done. By doing so, the power consumption can be reduced, so that the battery is not wasted and can be used for a long time as a portable temperature measuring device. For the frequency of the superimposed AC voltage ΔV or AC current ΔI, for example, an inexpensive OP amplifier may be used as the amplifier, and it is better to select a stable frequency band of the OP amplifier, for example, about 1-20 kHz is preferable. is there.

As described above, a rectangular pulsed current Io is passed as the intermittent DC current Io. Of course, the oscillator that generates the superimposed AC voltage ΔV and AC current ΔI is always operated, and the rectangular pulsed current Io In synchronization with the current Io, the AC voltage change ΔV and the AC current change ΔI during the period in which the current Io flows may be amplified.

In addition, the above-described embodiment is an embodiment, and it goes without saying that various modifications having the same gist, operation, and effect can be made.

The diode temperature measuring device of the present invention does not require the production of a special diode, can be used with a single commercially available silicon diode, and is achieved by AC amplification unlike a conventional temperature sensor using DC amplification. Since there is no problem of offset, the circuit configuration is very simple and the diode temperature measuring device is inexpensive. In addition, when a specific known diode is used, the ideal coefficient n is known, and thus there is no need for temperature calibration. It is sufficient to calibrate with. In addition, a single diode can measure a wide range of temperatures, and an inexpensive and highly accurate temperature measuring device can be provided.

FIG. 5 is a block diagram of an embodiment in the case where an alternating voltage change ΔV is measured by superimposing a small alternating current ΔI having a constant amplitude in the diode temperature measuring device of the present invention. Example 1 It is a block diagram of one Example at the time of measuring the alternating current change amount ΔI by superimposing a small alternating voltage ΔV having a constant amplitude in the diode temperature measuring device of the present invention. (Example 2) In the diode temperature measuring apparatus of the present invention, a circuit for superimposing a small AC voltage ΔV having a constant amplitude inversely proportional to a constant DC current Io is mounted on the AC voltage superimposing circuit means so as to measure an AC current change ΔI. It is a block diagram of one Example at the time of becoming. (Example 2) The diode temperature measuring device of the present invention is an embodiment in which a direct current Io is intermittently passed and data necessary for temperature measurement is acquired while the direct current Io is flowing. A timing chart of current Io and superimposed AC voltage ΔV or AC current ΔI is shown. (Example 3)

Explanation of symbols

1 Diode 2 DC power supply

Claims (7)

A semiconductor diode; constant current circuit means for causing a predetermined constant DC current Io to flow through the diode; AC current superimposing circuit means for superimposing an AC current ΔI having a predetermined AC amplitude on the diode; and the AC current ΔV measuring circuit means for measuring an AC voltage change ΔV of the diode due to ΔI, and the temperature is measured using the values of the DC current Io, the AC current ΔI, and the AC voltage change ΔV. A diode temperature measuring device. A semiconductor diode; constant current circuit means for causing a predetermined constant DC current Io to flow through the diode; AC voltage superimposing circuit means for superimposing an AC voltage ΔV having a predetermined AC amplitude on the diode; and the AC voltage ΔI measuring circuit means for measuring the change ΔI of the diode AC current due to ΔV, and the temperature is measured using the values of the DC current Io, the AC voltage ΔV, and the AC current change ΔI. A diode temperature measuring device. 2. The diode temperature measuring device according to claim 1, wherein the alternating current ΔI superimposed by the alternating current superimposing circuit means is proportional to the direct current Io by the constant current circuit means. 3. The diode temperature measuring apparatus according to claim 2, wherein the alternating voltage ΔV superimposed by the alternating voltage superimposing circuit means is inversely proportional to the direct current Io by the constant current circuit means. The diode temperature measuring device according to any one of claims 1 to 4, wherein the diode is a pn junction diode or a Schottky barrier diode. 6. The diode temperature measuring apparatus according to claim 1, wherein a DC current Io is intermittently supplied and data necessary for temperature measurement is acquired while the DC current Io is flowing. 7. The diode temperature measuring apparatus according to claim 1, wherein temperature calibration can be performed using at least one known temperature.